June 24, 2010

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One who characterizes deductive knowledge in terms of justification that is independent of experience is faced with the task of articulating the relevant sense of experience, and proponents of the deductive ly cites intuition or intuitive apprehension as the source of deductive justification. Furthermore, they maintain that these terms refer to a distinctive type of experience that is both common and familiar to most individuals. Hence, there is a broad sense of experience in which deductive justification is dependent of experience. An initially attractive strategy is to suggest that theoretical justification must be independent of sense experience. But this account is too narrow since memory, for example, is not a form of sense experience, but justification based on memory is presumably not deductive. There appear to remain only two options: Provide a general characterization of the relevant sense of experience or enumerates those sources that are experiential. General characterizations of experience often maintain that experience provides information specific to the actual world while non-experiential sources provide information about all possible worlds. This approach, however, reduces the concept of non-experiential justification to the concept of being justified in believing a necessary truth. Accounts by enumeration have two problems (1) there is some controversy about which sources to include in the list, and (2) there is no guarantee that the list is complete. It is generally agreed that perception and memory should be included. Introspection, however, is problematic, and beliefs about ones conscious states and about the manner in which one is appeared to are plausible regarded as experientially justified. Yet, some, such as Pap (1958), maintain that experiments in imagination are the source of deductive justification. Even if this contention is rejected and deductive justification is characterized as justification independent of the evidence of perception, memory and introspection, it remains possible that there are other sources of justification. If it should be the case that clairvoyance, for example, is a source of justified beliefs, such beliefs would be justified deductively on the enumerative account.


The most common approach to offering a positive characterization of deductive justification is to maintain that in the case of basic deductive propositions, understanding the proposition is sufficient to justify one in believing that it is true. This approach faces two pressing issues. What is it to understand a proposition in the manner that suffices for justification? Proponents of the approach typically distinguish understanding the words used to express a proposition from apprehending the proposition itself and maintain that it is the latter which are relevant to deductive justification. But this move simply shifts the problem to that of specifying what it is to apprehend a proposition. Without a solution to this problem, it is difficult, if possible, to evaluate the account since one cannot be sure that the account since on cannot be sure that the requisite sense of apprehension does not justify paradigmatic inductive propositions as well. Even less is said about the manner in which apprehending a proposition justifies one in believing that it is true. Proponents are often content with the bald assertions that one who understands a basic deductive proposition can thereby see that it is true. But what requires explanation is how understanding a proposition enable one to see that it is true.

Difficulties in characterizing deductive justification in a term either of independence from experience or of its source have led, out-of-the-ordinary to present the concept of necessity into their accounts, although this appeal takes various forms. Some have employed it as a necessary condition for deductive justification, others have employed it as a sufficient condition, while still others have employed it as both. In claiming that necessity is a criterion of the deductive. Kant held that necessity is a sufficient condition for deductive justification. This claim, however, needs further clarification. There are three theses regarding the relationship between the theoretically and the necessary that can be distinguished: (I) if p is a necessary proposition and 'S' is justified in believing that 'p' is necessary, then 'S's' justification is deductive: (ii) If 'p' is a necessary proposition and 'S' is justified in believing that 'p' is necessarily true, then 'S's' justification is deductive: And (iii) If 'p' is a necessary proposition and 'S' is justified in believing that 'p', then 'S's' justification is deductive. For example, many proponents of deductive contend that all knowledge of a necessary proposition is deductive. (2) and (3) have the shortcoming of setting by stipulation the issue of whether inductive knowledge of necessary propositions is possible. (I) does not have this shortcoming since the recent examples offered in support of this claim by Kriple (1980) and others have been cases where it is alleged that knowledge of the truth value of necessary propositions is knowable inductive. (I) has the shortcoming, however, of either ruling out the possibility of being justified in believing that a proposition is necessary on the basis of testimony or else sanctioning such justification as deductive. (ii) and (iii), of course, suffer from an analogous problem. These problems are symptomatic of a general shortcoming of the approach: It attempts to provide a sufficient condition for deductive justification solely in terms of the modal status of the proposition believed without making reference to the manner in which it is justified. This shortcoming, however, can be avoided by incorporating necessity as a necessary but not sufficient condition for a prior justification as, for example, in Chisholm (1989). Here there are two theses that must be distinguished: (1) If 'S' is justified deductively in believing that 'p', then p is necessarily true. (2) If 'p' is justified deductively in believing that 'p'. Then 'p' is a necessary proposition. (1) and (2), however, allows this possibility. A further problem with both (1) and (2) is that it is not clear whether they permit deductively justified beliefs about the modal status of a proposition. For they require that in order for 'S' to be justified deductively in believing that 'p' is a necessary preposition it must be necessary that p is a necessary proposition. But the status of iterated modal propositions is controversial. Finally, (1) and (2) both preclude by stipulation the position advanced by Kripke (1980) and Kitcher (1980) that there is deductive knowledge of contingent propositions.

The concept of rational unrevisability has also been invoked to characterize deductive justification. The precise sense of rational unrevisability has been presented in different ways. Putnam (1983) takes rational unrevisability to be both a necessary and sufficient condition for deductive justification while Kitcher (1980) takes it to be only a necessary condition. There are also two different senses of rational unrevisability that have been associated with the deductive (I) a proposition is weakly unreviable just in case it is rationally unrevisable in light of any future experiential evidence, and (II) a proposition is strongly unrevisable just in case it is rationally unrevisable in light of any future evidence. Let us consider the plausibility of requiring either form of rational unrevisability as a necessary condition for deductive justification. The view that a proposition is justified deductive only if it is strongly unrevisable entails that if a non-experiential source of justified beliefs is fallible but self-correcting, it is not a deductive source of justification. Casullo (1988) has argued that it vis implausible to maintain that a proposition that is justified non-experientially is not justified deductively merely because it is revisable in light of further non-experiential evidence. The view that a proposition is justified deductively only if it is, weakly unrevisable is not open to this objection since it excludes only recession in light of experiential evidence. It does, however, face a different problem. To maintain that 'S's' justified belief that 'p' is justified deductively is to make a claim about the type of evidence that justifies 'S' in believing that 'p'. On the other hand, to maintain that 'S's' justified belief that p is rationally revisable in light of experiential evidence is to make a claim about the type of evidence that can defeat 'S's' justification for believing that p that a claim about the type of evidence that justifies 'S' in believing that 'p'. Hence, it has been argued by Edidin (1984) and Casullo (1988) that to hold that a belief is justified deductively only if it is weakly unrevisable is either to confuse supporting evidence with defeating evidence or to endorse some implausible this about the relationship between the two such as that if evidence of the sort as the kind 'A' can defeat the justification conferred on 'S's belief that 'p' by evidence of kind 'B' then 'S's' justification for believing that 'p' is based on evidence of kind 'A'.

The most influential idea in the theory of meaning in the past hundred years is the thesis that the meaning of an indicative sentence is given by its truth-conditions. On this conception, to understand a sentence is to know its truth-conditions. The conception was first clearly formulated by Fridge, was developed in a distinctive way by the early Wittgenstein, and is a leading idea of Donald Herbert Davidson (1917-), who is also known for rejection of the idea of as conceptual scheme, thought of as something peculiar to one language or one way of looking at the world, arguing that where the possibility of translation stops so dopes the coherence of the idea that there is anything to translate. His [papers are collected in the Essays on Actions and Events (1980) and Inquiries into Truth and Interpretation (1983). However, the conception has remained so central that those who offer opposing theories characteristically define their position by reference to it.

Wittgensteins main achievement is a uniform theory of language that yields an explanation of logical truth. A factual sentence achieves sense by dividing the possibilities exhaustively into two groups, those that would make it true and those that would make it false. A truth of logic does not divide the possibilities but comes out true in all of them. It, therefore, lacks sense and says nothing, but it is not nonsense. It is a self-cancellation of sense, necessarily true because it is a tautology, the limiting case of factual discourse, like the figure '0' in mathematics. Language takes many forms and even factual discourse does not consist entirely of sentences like The fork is placed to the left of the knife. However, the first thing that he gave up was the idea that this sentence itself needed further analysis into basic sentences mentioning simple objects with no internal structure. He was to concede, that a descriptive word will often get its meaning partly from its place in a system, and he applied this idea to colour-words, arguing that the essential relations between different colours do not indicate that each colour has an internal structure that needs to be taken apart. On the contrary, analysis of our colour-words would only reveal the same pattern-ranges of incompatible properties-recurring at every level, because that is how we carve up the world.

Indeed, it may even be the case that of our ordinary language is created by moves that we ourselves make. If so, the philosophy of language will lead into the connexion between the meaning of a word and the applications of it that its users intend to make. There is also an obvious need for people to understand each others meanings of their words. There are many links between the philosophy of language and the philosophy of mind and it is not surprising that the impersonal examination of language in the Tractatus: was replaced by a very different, anthropocentric treatment in Philosophical Investigations?

If the logic of our language is created by moves that we ourselves make, various kinds of realizes are threatened. First, the way in which our descriptive language carves up the world will not be forces on us by the natures of things, and the rules for the application of our words, which feel the external constraints, will really come from within us. That is a concession to nominalism that is, perhaps, readily made. The idea that logical and mathematical necessity is also generated by what we ourselves accomplish what is more paradoxical. Yet, that is the conclusion of Wittgenstein (1956) and (1976), and here his anthropocentricism has carried less conviction. However, a paradox is not sure of error and it is possible that what is needed here is a more sophisticated concept of objectivity than Platonism provides.

In his later work Wittgenstein brings the great problem of philosophy down to earth and traces them to very ordinary origins. His examination of the concept of following a rule takes him back to a fundamental question about counting things and sorting them into types: What qualifies as doing the same again? Of a courser, this question as an inconsequential fundamental and would suggest that we forget it and get on with the subject. But Wittgensteins question is not so easily dismissed. It has the naive profundity of questions that children ask when they are first taught a new subject. Such questions remain unanswered without detriment to their learning, but they point the only way to complete understanding of what is learned.

It is, nevertheless, the meaning of a complex expression in a function of the meaning of its constituents, that is, indeed, that it is just a statement of what it is for an expression to be semantically complex. It is one of the initial attractions of the conception of meaning as truth-conditions that it permits a smooth and satisfying account of the way in which the meaning of a complex expression is a dynamic function of the meaning of its constituents. On the truth-conditional conception, to give the meaning of an expression is to state the contribution it makes to the truth-conditions of sentences in which it occurs. for singular terms-proper names, indexicals, and certain pronouns -this is done by stating the reference of the term in question.

The truth condition of a statement is the condition the world must meet if the statement is to be true. To know this condition is equivalent to knowing the meaning of the statement. Although, this sounds as if it gives a solid anchorage for meaning, some of the security disappears when it turns out that the truth condition can only be defined by repeating the very same statement, the truth condition of snow is white is that snow is white, the truth condition of Britain would have capitulated had Hitler invaded is that Britain would halve capitulated had Hitler invaded. It is disputed whether this element of running-on-the-spot disqualifies truth conditions from playing the central role in a substantive theory of meaning. Truth-conditional theories of meaning are sometimes opposed by the view that to know the meaning of a statement is to be able to users it in a network of inferences.

Whatever it is that makes what would otherwise be mere sounds and inscriptions into instruments of communication and understanding. The philosophical problem is to demystifying this power, and to re-taste it to what we know of ourselves and the world. Contributions to this study include the theory of speech acts and the investigation of communication and the relationship between words and ideas and words and the world. Together with a general bias towards the sensory, in that what lies in the mind may be thought of as something like images, and a belief hat thinking is well explained as the manipulation of images, this was developed through an understanding need to be thought of more in terms of rules and organizing principle than of any kind of copy of what is given in experience.

It has become more common to think of ideas, or concepts, as dependant upon social and especially linguistic structures, than the self-standing creations of an individual mind but the tension between the objective and the subjective aspect of the matter lingers on, for instance in debates about the possibility of objective knowledge of 'indeterminancy' in translation, and of identity between the thoughts people entertain at one time and those that they entertain at another.

Apparent facts to be explained about the distinction between knowing things and knowing about thing are these. Knowledge about things is essentially propositional knowledge, where the mental states involved refer to specific things, this propositional knowledge can be more or less complete, can be justified inferentially and on the basis of experience, and can be communicated. knowing things, on the one hand, involves experience of things. This experiential knowledge provides an epistemic basis for knowledge about things, and in some sense is difficult or impossible to communicate, perhaps because it is more or less vague, least of mention, as knowing by vicarious living through, a sort of knowledge by acquaintance that amounts to knowing what an experience is like.

What makes a belief justified and what makes a true belief knowledge? It is natural to think that whether a belief deserves one of these appraisals depends on what caused the subject to have the belief. Some causal theories of knowledge have it that a true belief that p is knowledge just in case that the right sort of causal connections to the fact that p. Such a criterion can be applied only to cases where the fact that p is a sort that can enter into causal relations, this seems to exclude mathematical and other necessary fact and perhaps any fact expressed by a universal generalization, and proponents of this sort of criterion have usually supposed that it is limited to perceptual knowledge of particular facts about the subject's environment.

A contrast relating the more general (colour) to the more specific (red). It was originally introduced by W.E. Johnson, and, one kind of usage, the contrast differs from that of genres to species, in that the specific differences identifying a determinate is itself a medication of the determinable. Thus, what différentiâtes red from blue is just colour, Whereas many different properties may differentiate a member of one species, for instance of animals, from those of another.

What is more, belonging to the doctrine of determinism that every event has a cause. The usual explanation of this is that for every event, there is some antecedent state, related in such a way hat it would break a law of nature for this antecedent state to exist, yet the event not to happen. This is a purely metaphysical claim, and carries no implications for whether we can in principle predict the event. The main interests in determinism has been in assessing its implications for free-will, however, quantum physics is essentially indeterminate yet, the view that our actions are subject to quantum indéterminists hardly encourages a sense of our own responsibility for them. It is often supposed that if an action is the end of a causal chain, i.e., determined, and the cause stretch back in time to the event for which an agent is not conceivable responsibility, then the agent is not responsible for the action. The dilemma adds that if an action is not the end of such a chain, then either it or one of its causes occurs at random, in that no antecedent event brought it about, and in that case nobody is responsible for its occurrence either, so whether or not determinism is true, responsibility is shown to be illusory.

The theorist of truth conditions should insist that not every true statement about the reference of an expression be fit to be an axiom in a meaning-giving theory of truth for a languages. The axiom:

London refers to the city in which there was a huge fire in 1666

is a true statement about the reference of London?. It is a consequence of a theory that substitutes this axiom for A! In our simple truth theory that London is beautiful is true if and only if the city in which there was a huge fire in 1666 is beautiful. Since a subject can understand the name London without knowing that last-mentioned truth conditions, this replacement axiom is not fit to be an axiom in a meaning-specifying truth theory. It is, of course, incumbent on a theorist of meaning as truth conditions to state the constraints on the acceptability of axioms in a way that does not presuppose a deductive, non-truth conditional conception of meaning.

Among the many challenges facing the theorist of truth conditions, two are particularly salient and fundamental. First, the theorist has to answer the charge of triviality or vacuity. Second, the theorist must offer an account of what it is for a persons languages to be truly descriptive by a semantic theory containing a given semantic axiom.

We can take the charge of triviality first. In more detail, it would run thus: Since the content of a claim that the sentence Paris is beautiful in which is true of the divisional region, which is no more than the claim that Paris is beautiful, we can trivially describe understanding a sentence, if we wish, as knowing its truth-conditions, but this gives us no substantive account of understanding whatsoever. Something other than a grasp to truth conditions must provide the substantive account. The charge rests upon what has been called the redundancy theory of truth, the theory that, is somewhat more discriminative. Horwich calls the minimal theory of truth, or deflationary view of truth, as fathered by Fridge and Ramsey. The essential claim is that the predicate . . . is true does not have a sense, i.e., expresses no substantive or profound or explanatory concepts that ought be the topic of philosophical enquiry. The approach admits of different versions, but centers on the points (1) that it is true that p says no more nor less than p (hence redundancy) (2) that in less direct context, such as everything he said was true, or all logical consequences of true propositions are true, the predicate functions as a device enabling us; to generalize than as an adjective or predicate describing the thing he said, or the kinds of propositions that follow from true propositions. For example, the second may translate as (∀ p, q) (p & p ➝ q ➝ q) where there is no use of a notion of truth.

There are technical problems in interpreting all uses of the notion of truth in such ways, but they are not generally felt to be insurmountable. The approach needs to explain away apparently substantive uses of the notion, such of a science aims at the truth, or truth is a norm governing discourse. Indeed, postmodernist writing frequently advocates that we must abandon such norms, along with a discredited objective conception of truth. But perhaps, we can have the norms even when objectivity is problematic, since they can be framed without mention of truth: Science wants it to be so that whenever science holds that 'p'. Then 'p'. Discourse is to be regulated by the principle that it is wrong to assert 'p' when 'not-p'.

The disquotational theory of truth finds that the simplest formulation is the claim that expressions of the formed 'S' is true mean the same as expressions of the form 'S'. Some philosophers dislike the idea of sameness of meaning, and if this is disallowed, then the claim is that the two forms are equivalent in any sense of equivalence that matters. That is, it makes no difference whether people say Dogs bark is true, or whether they say that dogs bark. In the former representation of what they say the sentence Dogs bark is mentioned, but in the latter it appears to be used, so the claim that the two are equivalent needs careful formulation and defence. On the face of it someone might know that Dogs bark is true without knowing what it means, for instance, if one were to find it in a list of acknowledged truths, although he does not understand English, and this is different from knowing that dogs bark. Disquotational theories are usually presented as versions of the redundancy theory of truth.

The minimal theory states that the concept of truth is exhausted by the fact that it conforms to the equivalence principle, the principle that for any proposition 'p', it is true that 'p' if and only if 'p'. Many different philosophical theories of truth will, with suitable qualifications, accept that equivalence principle. The distinguishing feature of the minimal theory is its claim that the equivalence principle exhausts the notion of truths. It is how widely accepted, that both by opponents and supporters of truth conditional theories of meaning, that it is inconsistent to accept both minimal theory of truth and a truth conditional account of meaning (Davidson, 1990, Dummett, 1959 and Horwich, 1990). If the claim that the sentence Paris is beautiful is true is exhausted by its equivalence to the claim that Paris is beautiful, it is circular to try to explain the sentences meaning in terms of its truth conditions. The minimal theory of truth has been endorsed by Ramsey, Ayer, the later Wittgenstein, Quine, Strawson, Horwich and-confusingly and inconsistently if be it correct-Fridge himself. But is the minimal theory correct?

The minimal or redundancy theory treats instances of the equivalence principle as definitional of truth for a given sentence. But in fact, it seems that each instance of the equivalence principle can itself be explained. The truths from which such an instance as: London is beautiful is true if and only if London is beautiful, preserve a right to be interpreted specifically of this would be a pseudo-explanation if the fact that London refers to London is beautiful has the truth-condition it does. But that is very implausible: It is, after all, possible to understand the name London without understanding the predicate is beautiful. The idea that facts about the reference of particular words can be explanatory of facts about the truth conditions of sentences containing them in no way requires any naturalistic or any other kind of reduction of the notion of reference. Nor is the idea incompatible with the plausible point that singular reference can be attributed at all only to something that is capable of combining with other expressions to form complete sentences. That still leaves room for facts about an expressions having the particular reference it does to be partially explanatory of the particular truth condition possessed by a given sentence containing it. The minimal; theory thus treats as definitional or stimulative something that is in fact open to explanation. What makes this explanation possible is that there is a general notion of truth that has, among the many links that hold it in place, systematic connections with the semantic values of sub-sentential expressions.

A second problem with the minimal theory is that it seems impossible to formulate it without at some point relying implicitly on features and principles involving truths that go beyond anything countenanced by the minimal theory. If the minimal theory treats truth as a predicate of anything linguistic, be it utterances, type-in-a-languages, or whatever, then the equivalence schema will not cover all cases, but only those in the theorists own languages. Some account has to be given of truth for sentences of other languages. Speaking of the truth of language-independence propositions or thoughts will only postpone, not avoid, this issue, since at some point principles have to be stated associating these languages-independent entities with sentences of particular languages. The defender of the minimalist theory is likely to say that if a sentence 'S' of a foreign language is best translated by our sentence 'p', then the foreign sentence 'S' is true if and only if 'p'. Now the best translation of a sentence must preserve the concepts expressed in the sentence. Constraints involving a general notion of truth are persuasive in a plausible philosophical theory of concepts. It is, for example, a condition of adequacy on an individualized account of any concept that there exists what is called Determination Theory for that account-that is, a specification of how the account contributes to fixing the semantic value of that concept, the notion of a concepts semantic value is the notion of something that makes a certain contribution to the truth conditions of thoughts in which the concept occurs. but this is to presuppose, than to elucidate, a general notion of truth.

It is also plausible that there are general constraints on the form of such Determination Theories, constraints that involve truth and which are not derivable from the minimalists conception. Suppose that concepts are individuated by their possession conditions. A concept is something that is capable of being a constituent of such contentual representational in a way of thinking of something-a particular object, or property, or relation, or another entity. A possession condition may in various says makes a thankers possession of a particular concept dependent upon his relations to his environment. Many possession conditions will mention the links between a concept and the thinkers perceptual experience. Perceptual experience represents the world for being a certain way. It is arguable that the only satisfactory explanation of what it is for perceptual experience to represent the world in a particular way must refer to the complex relations of the experience to the subjects environment. If this is so, then mention of such experiences in a possession condition will make possession of that condition will make possession of that concept dependent in part upon the environment relations of the thinker. Burge (1979) has also argued from intuitions about particular examples that, even though the thinkers non-environmental properties and relations remain constant, the conceptual content of his mental state can vary if the thinkers social environment is varied. A possession condition which property individuates such a concept must take into account the thinkers social relations, in particular his linguistic relations.

One such plausible general constraint is then the requirement that when a thinker forms beliefs involving a concept in accordance with its possession condition, a semantic value is assigned to the concept in such a way that the belief is true. Some general principles involving truth can indeed, as Horwich has emphasized, be derived from the equivalence schema using minimal logical apparatus. Consider, for instance, the principle that Paris is beautiful and London is beautiful is true if and only if Paris is beautiful is true if and only if Paris is beautiful is true and London is beautiful is true. This follows logically from the three instances of the equivalence principle: Paris is beautiful and London is beautiful is rue if and only if Paris is beautiful, and London is beautiful is true if and only if London is beautiful. But no logical manipulations of the equivalence schemas will allow the deprivation of that general constraint governing possession conditions, truth and the assignment of semantic values. That constraint can have courses be regarded as a further elaboration of the idea that truth is one of the aims of judgement.

We now turn to the other question, What is it for a persons languages to be correctly describable by a semantic theory containing a particular axiom, such as the axiom A6 above for conjunction? This question may be addressed at two depths of generality. At the shallower level, the question may take for granted the persons possession of the concept of conjunction, and be concerned with what has to be true for the axiom correctly to describe his languages. At a deeper level, an answer should not duck the issue of what it is to possess the concept. The answers to both questions are of great interest: We will take the lesser level of generality first.

When a person means conjunction by sand, he is not necessarily capable of formulating the explicitly of the axiom. Even if he can formulate it, his ability to formulate it is not the causal basis of his capacity to hear sentences containing the word and as meaning something involving conjunction. Nor is it the causal basis of his capacity to mean something involving conjunction by sentences he utters containing the word and. Is it then right to regard a truth theory as part of an unconscious psychological computation, and to regard understanding a sentence as involving a particular way of depriving a theorem from a truth theory at some level of conscious proceedings? One problem with this is that it is quite implausible that everyone who speaks the same languages has to use the same algorithms for computing the meaning of a sentence. In the past thirteen years, thanks particularly to the work of Davies and Evans, a conception has evolved according to which an axiom is true of a persons languages only if there is a common component in the explanation of his understanding of each sentence containing the word and, a common component that explains why each such sentence is understood as meaning something involving conjunction (Davies, 1987). This conception can also be elaborated in computational terms: Suggesting that for an axiom to be true of a persons languages is for the unconscious mechanisms which produce understanding to draw on the information that a sentence of the form 'A' and 'B' are true if and only if 'A' is true and 'B' is true (Peacocke, 1986). Many different algorithms may equally draw n this information. The psychological reality of a semantic theory thus involves, in Marrs' (1982) famous classification, something intermediate between his level one, the function computed, and his level two, the algorithm by which it is computed. This conception of the psychological reality of a semantic theory can also be applied to syntactic and phonol logical theories. Theories in semantics, syntax and phonology are not themselves required to specify the particular algorithms that the languages user employs. The identification of the particular computational methods employed is a task for psychology. But semantics, syntactic and phonology theories are answerable to psychological data, and are potentially refutable by them-for these linguistic theories do make commitments to the information drawn upon by mechanisms in the languages user.

This answer to the question of what it is for an axiom to be true of a persons languages clearly takes for granted the persons possession of the concept expressed by the word treated by the axiom. In the example of the axiom A6, the information drawn upon is that sentences of the form 'A' and 'B' are true if and only if 'A' is true and 'B' is true. This informational content employs, as it has to if it is to be adequate, the concept of conjunction used in stating the meaning of sentences containing and. So the computational answer we have returned needs further elaboration if we are to address the deeper question, which does not want to take for granted possession of the concepts expressed in the languages. It is at this point that the theory of linguistic understanding has to draws upon a theory of concepts. It is plausible that the concepts of conjunction are individuated by the following condition for a thinker to possess it.

Finally, this response to the deeper question allows us to answer two challenges to the conception of meaning as truth-conditions. First, there was the question left hanging earlier, of how the theorist of truth-conditions is to say what makes one axiom of a semantic theory is correctly in that of another, when the two axioms assign the same semantic values, but do so by means of different concepts. Since the different concepts will have different possession conditions, the dovetailing accounts, at the deeper level of what it is for each axiom to be correct for a persons languages will be different accounts. Second, there is a challenge repeatedly made by the minimalist theorists of truth, to the effect that the theorist of meaning as truth-conditions should give some non-circular account of what it is to understand a sentence, or to be capable of understanding all sentences containing a given constituent. For each expression in a sentence, the corresponding dovetailing account, together with the possession condition, supplies a non-circular account of what it is to understand any sentence containing that expression. The combined accounts for each of he expressions that comprise a given sentence together constitute a non-circular account of what it is to understand the compete sentences. Taken together, they allow the theorists of meaning as truth-conditions fully to meet the challenge.

A curious view common to that which is expressed by an utterance or sentence: The proposition or claim made about the world. By extension, the content of a predicate or other sub-sentential component is what it contributes to the content of sentences that contain it. The nature of content is the central concern of the philosophy of languages, in that mental states have contents: A belief may have the content that the prime minister will resign. A concept is something that is capable of bringing a constituent of such contents.

Several different concepts may each be ways of thinking of the same object. A person may think of himself in the first-person way, or think of himself as the spouse of Mary Smith, or as the person located in a certain room now. More generally, a concept c is distinct from a concept d if it is possible for a person rationally to believe d is such-and-such. As words can be combined to form structured sentences, concepts have also been conceived as combinable into structured complex contents. When these complex contents are expressed in English by that . . . clauses, as in our opening examples, they will be capable of being true or false, depending on the way the world is.

The general system of concepts with which we organize our thoughts and perceptions are to encourage a conceptual scheme of which the outstanding elements of our every day conceptual formalities include spatial and temporal relations between events and enduring objects, causal relations, other persons, meaning-bearing utterances of others, . . . and so on. To see the world as containing such things is to share this much of our conceptual scheme. A controversial argument of Davidson's urges that we would be unable to interpret speech from a different conceptual scheme as even meaningful, Davidson daringly goes on to argue that since translation proceeds according ti a principle of clarity, and since it must be possible of an omniscient translator to make sense of, us we can be assured that most of the beliefs formed within the commonsense conceptual framework are true.

Concepts are to be distinguished from a stereotype and from conceptions. The stereotypical spy may be a middle-level official down on his luck and in need of money. None the less, we can come to learn that Anthony Blunt, art historian and Surveyor of the Queens Pictures, are a spy; we can come to believe that something falls under a concept while positively disbelieving that the same thing falls under the stereotype associated wit the concept. Similarly, a persons conception of a just arrangement for resolving disputes may involve something like contemporary Western legal systems. But whether or not it would be correct, it is quite intelligible for someone to rejects this conception by arguing that it dies not adequately provide for the elements of fairness and respect that are required by the concepts of justice.

Basically, a concept is that which is understood by a term, particularly a predicate. To posses a concept is to be able to deploy a term expressing it in making judgements, in which the ability connexion is such things as recognizing when the term applies, and being able to understand the consequences of its application. The term idea was formally used in the came way, but is avoided because of its associations with subjective matters inferred upon mental imagery in which may be irrelevant to the possession of a concept. In the semantics of Fridge, a concept is the reference of a predicate, and cannot be referred to by a subjective term, although its recognition of as a concept, in that some such notion is needed to the explanatory justification of which that sentence of unity finds of itself from being thought of as namely categorized lists of itemized priorities.

A theory of a particular concept must be distinguished from a theory of the object or objects it selectively picks the outlying of the theory of the concept under which is partially contingent of the theory of thought and/or epistemology. A theory of the object or objects is part of metaphysics and ontology. Some figures in the history of philosophy-and are open to the accusation of not having fully respected the distinction between the kinds of theory. Descartes appears to have moved from facts about the indubitability of the thought I think, containing the first-person was of thinking, to conclusions about the nonmaterial nature of the object he himself was. But though the goals of a theory of concepts and a theory of objects are distinct, each theory is required to have an adequate account of its relation to the other theory. A theory if concept is unacceptable if it gives no account of how the concept is capable of picking out the object it evidently does pick out. A theory of objects is unacceptable if it makes it impossible to understand how we could have concepts of those objects.

A fundamental question for philosophy is: What individuates a given concept-that is, what makes it the one it is, rather than any other concept? One answer, which has been developed in great detail, is that it is impossible to give a non-trivial answer to this question (Schiffer, 1987). An alternative approach, addressees the question by starting from the idea that a concept id individuated by the condition that must be satisfied if a thinker is to posses that concept and to be capable of having beliefs and other attitudes whose content contains it as a constituent. So, to take a simple case, one could propose that the logical concept and is individuated by this condition, it be the unique concept 'C' to posses that a thinker has to find these forms of inference compelling, without basing them on any further inference or information: From any two premisses 'A' and 'B', 'ACB' can be inferred, and from any premiss 'ACB', each of 'A' and 'B' can be inferred. Again, a relatively observational concept such as round can be individuated in part by stating that the thinker finds specified contents containing it compelling when he has certain kinds of perception, and in part by relating those judgements containing the concept and which are not based on perception to those judgements that are. A statement that individuates a concept by saying what is required for a thinker to posses it can be described as giving the possession condition for the concept.

A possession condition for a particular concept may actually make use of that concept. The possession condition for and does so. We can also expect to use relatively observational concepts in specifying the kind of experience that have to be mentioned in the possession conditions for relatively observational concepts. What we must avoid is mention of the concept in question as such within the content of the attitudes attributed to the thinker in the possession condition. Otherwise we would be presupposing possession of the concept in an account that was meant to elucidate its possession. In talking of what the thinker finds compelling, the possession conditions can also respect an insight of the later Wittgenstein: That to find her finds it natural to go on in new cases in applying the concept.

Sometimes a family of concepts has this property: It is not possible to master any one of the members of the family without mastering the others. Two of the families that plausibly have this status are these: The family consisting of some simple concepts 0, 1, 2, . . . of the natural numbers and the corresponding concepts of numerical quantifiers there are 0 so-and-so, there is 1 so-and-so, . . . and the family consisting of the concepts; belief and desire. Such families have come to be known as local holism. A local holism does not prevent the individuation of a concept by its possession condition. Rather, it demands that all the concepts in the family be individuated simultaneously. So one would say something of this form: Belief and desire form the unique pair of concepts C1 and C2 such that for as thinker to posses them are to meet such-and-such condition involving the thinker, C1 and C2. For these and other possession conditions to individuate properly, it is necessary that there be some ranking of the concepts treated. The possession conditions for concepts higher in the ranking must presuppose only possession of concepts at the same or lower levels in the ranking.

A possession conditions may in various ways make a thinkers possession of a particular concept dependent upon his relations to his environment. Many possession conditions will mention the links between a concept and the thinkers perceptual experience. Perceptual experience represents the world as a certain way. It is arguable that the only satisfactory explanation of what it is for perceptual experience to represent the world in a particular way must refer to the complex relations of the experience to the subjects environment. If this is so, then mention of such experiences in a possession condition will make possession of that concept dependent in part upon the environmental relations of the thinker. Burge (1979) has also argued from intuitions about particular examples that, even though the thinkers non-environmental properties and relations remain constant, the conceptual content of his mental state can vary if the thinkers social environment is varied. A possession condition that properly individuates such a concept must take into account the thinkers social relations, in particular his linguistic relations.

Concepts have a normative dimension, a fact strongly emphasized by Kripke. For any judgement whose content involves a given concept, there is a correctness condition for that judgement, a condition that is dependent in part upon the identity of the concept. The normative character of concepts also extends into making the territory of a thinkers reasons for making judgements. A thinkers visual perception can give him good reason for judging That man is bald: It does not by itself give him good reason for judging Rostropovich is bald, even if the man he sees is Rostropovich. All these normative connections must be explained by a theory of concepts one approach to these matters is to look to the possession condition for the concept, and consider how the referent of a concept is fixed from it, together with the world. One proposal is that the referent of the concept is that object or, property, or function, . . . which makes the practices of judgement and inference mentioned in the possession condition always lead to true judgements and truth-preserving inferences. This proposal would explain why certain reasons are necessity good reasons for judging given contents. Provided the possession condition permits us to say what it is about a thinkers previous judgements that masker it, the case that he is employing one concept rather than another, this proposal would also have another virtue. It would allow us to say how the correctness condition is determined for a judgement in which the concept is applied to newly encountered objects. The judgement is correct if the new object has the property that in fact makes the judgmental practices mentioned in the possession condition yield true judgements, or truth-preserving inferences.

These manifesting dissimilations have occasioned the affiliated differences accorded within the distinction as associated with Leibniz, who declares that there are only two kinds of truths-truths of reason and truths of fact. The forms are all either explicit identities, i.e., of the form 'A' is 'A', 'AB' is 'B', etc., or they are reducible to this form by successively substituting equivalent terms. Leibniz dubs them truths of reason because the explicit identities are self-evident deducible truths, whereas the rest can be converted to such by purely rational operations. Because their denial involves a demonstrable contradiction, Leibniz also says that truths of reason rest on the principle of contradiction, or identity and that they are necessary [propositions, which are true of all possible words. Some examples are All equilateral rectangles are rectangles and All bachelors are unmarried: The first is already of the form 'AB' is 'B' and the latter can be reduced to this form by substituting unmarried man fort Bachelors. Other examples, or so Leibniz believes, are God exists and the truths of logic, arithmetic and geometry.

Truths of fact, on the other hand, cannot be reduced to an identity and our only way of knowing them is empirically by reference to the facts of the empirical world. Likewise, since their denial does not involve a contradiction, their truth is merely contingent: They could have been otherwise and hold of the actual world, but not of every possible one. Some examples are Caesar crossed the Rubicon and Leibniz was born in Leipzig, as well as propositions expressing correct scientific generalizations. In Leibniz's view, truths of fact rest on the principle of sufficient reason, which states that nothing can be so unless there is a reason that it is so. This reason is that the actual world (by which he means the total collection of things past, present and future) is better than any other possible worlds and was therefore created by God.

In defending the principle of sufficient reason, Leibniz runs into serious problems. He believes that in every true proposition, the concept of the predicate is contained in that of the subject. (This holds even for propositions like Caesar crossed the Rubicon: Leibniz thinks anyone who did not cross the Rubicon, would not have been Caesar). And this containment relationship! Which is eternal and unalterable even by God ~? Guarantees that every truth has a sufficient reason. If truths consists in concept containment, however, then it seems that all truths are analytic and hence necessary, and if they are all necessary, surely they are all truths of reason. Leibniz responds that not every truth can be reduced to an identity in a finite number of steps, in some instances revealing the connexion between subject and predicate concepts would requite an infinite analysis. But while this may entail that we cannot prove such propositions as deductively manifested, it does not appear to show that the proposition could have been false. Intuitively, it seems a better ground for supposing that it is necessary truth of a special sort. A related question arises from the idea that truths of fact depend on Gods decision to creates the best of all possible worlds: If it is part of the concept of this world that it is best, now could its existence be other than necessary? Leibniz answers that its existence is only hypothetically necessary, i.e., it follows from Gods decision to create this world, but God had the power to decide otherwise. Yet God is necessarily good and non-deceiving, so how could he have decided to do anything else? Leibniz says much more about these masters, but it is not clear whether he offers any satisfactory solutions.

Leibniz and others have thought of truths as a property of propositions, where the latter are conceived as things that may be expressed by, but are distinct from, linguistic items like statements. On another approach, truth is a property of linguistic entities, and the basis of necessary truth in convention. Thus A.J. Ayer, for example,. Argued that the only necessary truths are analytic statements and that the latter rest entirely on our commitment to use words in certain ways.

The slogan the meaning of a statement is its method of verification expresses the empirical verifications theory of meaning. It is more than the general criterion of meaningfulness if and only if it is empirically verifiable. If says in addition what the meaning of a sentence is: It is all those observations that would confirm or disconfirmed the sentence. Sentences that would be verified or falsified by all the same observations are empirically equivalent or have the same meaning. A sentence is said to be cognitively meaningful if and only if it can be verified or falsified in experience. This is not meant to require that the sentence be conclusively verified or falsified, since universal scientific laws or hypotheses (which are supposed to pass the test) are not logically deducible from any amount of actually observed evidence.

When one predicates necessary truth of a preposition one speaks of modality dedicto. For one ascribes the modal property, necessary truth, to a dictum, namely, whatever proposition is taken as necessary. A venerable tradition, however, distinguishes this from necessary de re, wherein one predicates necessary or essential possession of some property to an on object. For example, the statement '4' is necessarily greater than '2' might be used to predicate of the object, '4', the property, being necessarily greater than '2'. That objects have some of their properties necessarily, or essentially, and others only contingently, or accidentally, are a main part of the doctrine called; essentialism. Thus, an essentials might say that Socrates had the property of being bald accidentally, but that of being self-identical, or perhaps of being human, essentially. Although essentialism has been vigorously attacked in recent years, most particularly by Quine, it also has able contemporary proponents, such as Plantinga.

Modal necessity as seen by many philosophers whom have traditionally held that every proposition has a modal status as well as a truth value. Every proposition is either necessary or contingent as well as either true or false. The issue of knowledge of the modal status of propositions has received much attention because of its intimate relationship to the issue of deductive reasoning. For example, no propositions of the theoretic content that all knowledge of necessary propositions is deductively knowledgeable. Others reject this claim by citing Kripkes (1980) alleged cases of necessary theoretical propositions. Such contentions are often inconclusive, for they fail to take into account the following tripartite distinction: 'S' knows the general modal status of 'p' just in case 'S' knows that 'p' is a necessary proposition or 'S' knows the truth that 'p' is a contingent proposition. 'S' knows the truth value of 'p' just in case 'S' knows that 'p' is true or 'S' knows that 'p' is false. 'S' knows the specific modal status of 'p' just in case 'S' knows that 'p' is necessarily true or 'S' knows that 'p' is necessarily false or 'S' knows that 'p' is contingently true or 'S' knows that 'p' is contingently false. It does not follow from the fact that knowledge of the general modal status of a proposition is a deductively reasoned distinctive modal status is also given to theoretical principles. Nor des it follow from the fact that knowledge of a specific modal status of a proposition is theoretically given as to the knowledge of its general modal status that also is deductive.

The certainties involving reason and a truth of fact are much in distinction by associative measures given through Leibniz, who declares that there are only two kinds of truths-truths of reason and truths of fact. The former are all either explicit identities, i.e., of the form 'A' is 'A', 'AB' is 'B', etc., or they are reducible to this form by successively substituting equivalent terms. Leibniz dubs them truths of reason because the explicit identities are self-evident theoretical truth, whereas the rest can be converted to such by purely rational operations. Because their denial involves a demonstrable contradiction, Leibniz also says that truths of reason rest on the principle of contraction, or identity and that they are necessary propositions, which are true of all possible worlds. Some examples are that All bachelors are unmarried: The first is already of the form 'AB' is 'B' and the latter can be reduced to this form by substituting unmarried man for Bachelors. Other examples, or so Leibniz believes, are God exists and the truth of logic, arithmetic and geometry.

Truths of fact, on the other hand, cannot be reduced to an identity and our only way of knowing hem os a theoretical manifestations, or by reference to the fact of the empirical world. Likewise, since their denial does not involve as contradiction, their truth is merely contingent: They could have been otherwise and hold of the actual world, but not of every possible one. Some examples are Caesar crossed the Rubicon and Leibniz was born in Leipzig, as well as propositions expressing correct scientific generalizations. In Leibniz's view, truths of fact rest on the principle of sufficient reason, which states that nothing can be so unless thee is a reason that it is so. This reason is that the actual world (by which he means the total collection of things past, present and future) is better than any other possible world and was therefore created by God.

In defending the principle of sufficient reason, Leibniz runs into serious problems. He believes that in every true proposition, the concept of the predicate is contained in that of the subject. (This holds even for propositions like Caesar crossed the Rubicon: Leibniz thinks anyone who did not cross the Rubicon would not have been Caesar) And this containment relationship-that is eternal and unalterable even by God-guarantees that every truth has a sufficient reason. If truth consists in concept containment, however, then it seems that all truths are analytic and hence necessary, and if they are all necessary, surely they are all truths of reason. Leibniz responds that not evert truth can be reduced to an identity in a finite number of steps: In some instances revealing the connexion between subject and predicate concepts would require an infinite analysis. But while this may entail that we cannot prove such propositions as deductively probable, it does not appear to show that the proposition could have been false. Intuitively, it seems a better ground for supposing that it is a necessary truth of a special sort. A related question arises from the idea that truths of fact depend on Gods decision to create the best world, if it is part of the concept of this world that it is best, how could its existence be other than necessary? Leibniz answers that its existence is only hypothetically necessary, i.e., it follows from Gods decision to create this world, but God is necessarily good, so how could he have decided to do anything else? Leibniz says much more about the matters, but it is not clear whether he offers any satisfactory solutions.

The modality of a proposition is the way in which it is true or false. The most important division is between propositions true of necessity, and those true as a things are: Necessary as opposed to contingent propositions. Other qualifiers sometimes called modal include the tense indicators It will be the case that 'p' or It was the case that 'p', and there are affinities between the deontic indicators, as it ought to be the case that 'p' or it is permissible that 'p', and the logical modalities as a logic that study the notions of necessity and possibility. Modal logic was of a great importance historically, particularly in the light of various doctrines concerning the necessary properties of the deity, but was not a central topic of modern logic in its golden period at the beginning of the 20th century. It was, however, revived by C. I. Lewis, by adding to a propositional or predicate calculus two operators, □ and ◊ (sometimes written N and M), meaning necessarily and possibly, respectively. These like p ➞ ◊ p and □ p ➞ p will be to include □ p ➞ □□ p , if a proposition is necessary, and ◊ p ➞ □ ◊ p, if a proposition is possible. The classical modal theory for modal logic, due to Kripke and the Swedish logician Stig Kanger, involves valuing propositions not as true or false simplicitiers, but as true or false art possible worlds, with necessity then corresponding to truth in all worlds, and possibly to truths in some world.

The doctrine advocated by David Lewis, which different possible worlds are to be thought of as existing exactly as this one does. Thinking in terms of possibilities is thinking of real worlds where things are different, this view has been charged with misrepresenting it as some insurmountably unseeing to why it is good to save the child from drowning, since there is still a possible world in which she (or her counterpart) drowned, and from the standpoint of the universe it should make no difference that world is actual. Critics asio charge either that the notion fails to fit with a coherent theory of how we know about possible worlds, or with a coherent theory about possible worlds, or with a coherent theory of why we are interested in them, but Lewis denies that any other way of interpreting modal statements is tenable.

Knowledge and belief, according to most epistemologists, knowledge entails belief, so that I cannot know that such and such is the case unless I believer that such and such is the case. Others think this entailment thesis can be rendered more accurately if we substitute for belief some closely related attitude. For instance, several philosophers would prefer to say that knowledge entail psychological certainties (Prichard, 1950 and Ayer, 1956) or conviction (Lehrer, 1974) or acceptance (Lehrer, 1989). None the less, there are arguments against all versions of the thesis that knowledge requires having a belief-like attitude toward the known. These arguments are given by philosophers who think that knowledge and belief (or a facsimile) are mutually incompatible (the incomparability thesis), or by ones who say that knowledge does not entail belief, or vice versa, so that each may exist without the other, but the two may also coexist (the separability thesis).

The incompatibility thesis is sometimes traced to Plato, 429-347 Bc in view of his claim that knowledge is infallible while belief or opinion is fallible (Republic 476-9). But this claim would not support the thesis. Belief might be a component of an infallible form of knowledge in spite of the fallibility of belief. Perhaps, knowledge involves some factor that compensates for the fallibility of belief.

A. Duncan-Jones (1939: Also Vendler, 1978) cite linguistic evidence to back up the incompatibility thesis. He notes that people often say I do not believer she is guilty. I know she is and the like, which suggest that belief rule out knowledge. However, as Lehrer (1974) indicates, the above exclamation is only a more emphatic way of saying I do not just believer she is guilty, I know she is where just makes it especially clear that the speaker is signalling that she has something more salient than mere belief, not that she has something inconsistent with belief, namely knowledge. Compare: You do not hurt him, you killed him.

A. Prichard (1966) offers a defence of the incompatibility thesis that hinges on the equation of knowledge with certainty (both infallibility and psychological certitude) and the assumption that when we believer in the truth of a claim we are not certain about its truth. Given that belief always involves uncertainty while knowledge never dies, believing something rules out the possibility of knowing it. Unfortunately, however, Prichard gives us no goods reason to grant that states of belief are never ones involving confidence. Conscious beliefs clearly involve some level of confidence, to suggest that we cease to believer things about which we are completely confident is bizarre.

A.D. Woozley (1953) defends a version of the separability thesis. Woozley's version, which deals with psychological certainty rather than belief per se, is that knowledge can exist in the absence of confidence about the item known, although might also be accompanied by confidence as well. Woozley remarks that the test of whether I know something is what I can do, where what I can do may include answering questions. On the basis of this remark he suggests that even when people are unsure of the truth of a claim, they might know that the claim is true. We unhesitatingly attribute knowledge to people who give correct responses on examinations even if those people show no confidence in their answers. Woozley acknowledges, however, that it would be odd for those who lack confidence to claim knowledge. It would be peculiar to say, I am unsure whether my answer is true: Still, I know it is correct. But this tension Woozley explains using a distinction between conditions under which we are justified in making a claim (such as a claim to know something), and conditions under which the claim we make is true. While I know such and such might be true even if I am unsure whether such and such holds, nonetheless it would be inappropriate for me to claim that I know that such and such unless I were sure of the truth of my claim.

Colin Radford (1966) extends Woozley's defence of the separability thesis. In Radford's view, not only is knowledge compatible with the lack of certainty, it is also compatible with a complete lack of belief. He argues by example. In one example, Jean has forgotten that he learned some English history years priori and yet he is able to give several correct responses to questions such as When did the Battle of Hastings occur? Since he forgot that he took history, he considers the correct response to be no more than guesses. Thus, when he says that the Battle of Hastings took place in 1066 he would deny having the belief that the Battle of Hastings took place in 1066. A disposition he would deny being responsible (or having the right to be convincing) that 1066 was the correct date. Radford would none the less insist that Jean know when the Battle occurred, since clearly be remembering the correct date. Radford admits that it would be inappropriate for Jean to say that he knew when the Battle of Hastings occurred, but, like Woozley he attributes the impropriety to a fact about when it is and is not appropriate to claim knowledge. When we claim knowledge, we ought, at least to believer that we have the knowledge we claim, or else our behavior is intentionally misleading.

Those that agree with Radford's defence of the separability thesis will probably think of belief as an inner state that can be detected through introspection. That Jean lacks beliefs about English history is plausible on this Cartesian picture since Jean does not find himself with any beliefs about English history when ne seek them out. One might criticize Radford, however, by rejecting that Cartesian view of belief. One could argue that some beliefs are thoroughly unconscious, for example. Or one could adopt a behaviourist conception of belief, such as Alexander Bains (1859), according to which having beliefs is a matter of the way people are disposed to behave (and has not Radford already adopted a behaviourist conception of knowledge?) Since Jean gives the correct response when queried, a form of verbal behavior, a behaviourist would be tempted to credit him with the belief that the Battle of Hastings occurred in 1066.

D.M. Armstrong (1873) takes a different tack against Radford. Jean does know that the Battle of Hastings took place in 1066. Armstrong will grant Radfod that point, in fact, Armstrong suggests that Jean believer that 1066 is not the date the Battle of Hastings occurred, for Armstrong equates the belief that such and such is just possible but no more than just possible with the belief that such and such is not the case. However, Armstrong insists, Jean also believes that the Battle did occur in 1066. After all, had Jean been mistaught that the Battle occurred in 1066, and subsequently guessed that it took place in 1066, we would surely describe the situation as one in which Jeans false belief about the Battle became unconscious over time but persisted of a memory trace that was causally responsible for his guess. Out of consistency, we must describe Radford's original case as one that Jeans true belief became unconscious but persisted long enough to cause his guess. Thus, while Jean consciously believes that the Battle did not occur in 1066, unconsciously he does believer it occurred in 1066. So after all, Radford does not have a counterexample to the claim that knowledge entails belief.

Armstrong's response to Radford was to reject Radford's claim that the examinee lacked the relevant belief about English history. Another response is to argue that the examinee lacks the knowledge Radford attributes to him (cf. Sorenson, 1982). If Armstrong is correct in suggesting that Jean believes both that 1066 is and that it is not the date of the Battle of Hastings, one might deny Jean knowledge on the grounds that people who believer the denial of what they believer cannot be said to' know the truth of their belief. Another strategy might be to compare the examine case with examples of ignorance given in recent attacks on externalist accounts of knowledge (needless to say. Externalists themselves would tend not to favour this strategy). Consider the following case developed by BonJour (1985): For no apparent reason, Samantha believes that she is clairvoyant. Again, for no apparent reason, she one day comes to believer that the President is in New York City, even though she has every reason to believer that the President is in Washington, D.C. In fact, Samantha is a completely reliable clairvoyant, and she has arrived at her belief about the whereabouts of the President thorough the power of her clairvoyance. Yet surely Samanthas belief is completely irrational. She is not justified in thinking what she does. If so, then she does not know where the President is. But Radford's examinee is unconventional. Even if Jean lacks the belief that Radford denies him, Radford does not have an example of knowledge that is unattended with belief. Suppose that Jeans memory had been sufficiently powerful to produce the relevant belief. As Radford says, in having every reason to suppose that his response is mere guesswork, and he has every reason to consider his belief false. His belief would be an irrational one, and hence one about whose truth Jean would be ignorant.

Least has been of mention to an approaching view from which perception basis upon itself as a fundamental philosophical topic both for its central place in a theory of knowledge, and its central place un any theory of consciousness. Philosophy in this area is constrained by a number of properties that we believer to hold of perception, (1) It gives us knowledge of the world around us. (2) We are conscious of that world by being aware of sensible qualities: Colour, sounds, tastes, smells, felt warmth, and the shapes and positions of objects in the environment. (3) Such consciousness is effected through highly complex information channels, such as the output of the three different types of colour-sensitive cells in the eye, or the channels in the ear for interpreting pulses of air pressure as frequencies of sound. (4) There ensues even more complex neurophysiological coding of that information, and eventually higher-order brain functions bring it about that we interpreted the information so received. (Much of this complexity has been revealed by the difficulties of writing programs enabling computers to recognize quite simple aspects of the visual scene.) The problem is to avoid thinking of here being a central, ghostly, conscious self, fed information in the same way that a screen if fed information by a remote television camera. Once such a model is in place, experience will seem like a veil getting between us and the world, and the direct objects of perception will seem to be private items in an inner theater or sensorium. The difficulty of avoiding this model is epically cute when we considered the secondary qualities of colour, sound, tactile feelings and taste, which can easily seem to have a purely private existence inside the perceiver, like sensation of pain. Calling such supposed items names like sense-data or percepts exacerbates the tendency, but once the model is in place, the first property, that perception gives us knowledge of the world and its surrounding surfaces, is quickly threatened, for there will now seem little connexion between these items in immediate experience and any independent reality. Reactions to this problem include scepticism and idealism.

A more hopeful approach is to claim that the complexities of (3) and (4) explain how we can have direct acquaintance of the world, than suggesting that the acquaintance we do have been at best indirect. It is pointed out that perceptions are not like sensation, precisely because they have a content, or outer-directed nature. To have a perception is to be aware of the world for being such-and-such a way, than to enjoy a mere modification of sensation. But such direct realism has to be sustained in the face of the evident personal (neurophysiological and other) factors determining haw we perceive. One approach is to ask why it is useful to be conscious of what we perceive, when other aspects of our functioning work with information determining responses without any conscious awareness or intervention. A solution to this problem would offer the hope of making consciousness part of the natural world, than a strange optional extra.

Furthering, perceptual knowledge is knowledge acquired by or through the senses and includes most of what we know. We cross intersections when we see the light turn green, head for the kitchen when we smell the roast burning, squeeze the fruit to determine its ripeness, and climb out of bed when we hear the alarm ring. In each case we come to know something-that the light has turned green, that the roast is burning, that the melon is overripe, and that it is time to get up-by some sensory means. Seeing that the light has turned green is learning something-that, the light has turned green-by use of the eyes. Feeling that the melon is overripe is coming to know a fact-that the melon is overripe-by ones sense to touch. In each case the resulting knowledge is somehow based on, derived from or grounded in the sort of experience that characterizes the sense modality in question.

Much of our perceptual knowledge is indirect, dependent or derived. By this I mean that the facts we describe ourselves as learning, as coming to know, by perceptual means are pieces of knowledge that depend on our coming to know something else, some other fact, in a more direct way. We see, by the gauge, that we need gas, see, by the newspapers, that our team has lost again, see, by her expression, that she is nervous. This derived or dependent sort of knowledge is particularly prevalent in the cases of vision, but it occurs, to a lesser degree, in every sense modality. We install bells and other noise-makers so that we calm for example, hear (by the bell) that someone is at the door and (by the alarm) that its time to get up. When we obtain knowledge in this way, it is clear that unless one can see, hence, comes to know something about the gauge (that it says) and, hence, know that one is described as coming to know by perceptual means. If one cannot hear that the bell is ringing, one cannot-in at least in this way-hear that ones visitors have arrived. In such cases one sees (hears, smells, etc.) that 'a' is 'F', coming to know thereby that 'a' is 'F', by seeing (hearing, etc.) that some other condition, 'b's' being 'G', obtains when this occurs, the knowledge (that a is F) is derived from, or dependent on, the more basic perceptual knowledge that 'b' is 'G'.

Perhaps as a better strategy is to tie an account save that part that evidence could justify explanation for it is its truth alone. Since, at least the time of Aristotle philosophers of explanatory knowledge have emphasizes of its importance that, in its simplest Termes, we want to know not only what are the composite peculiarities and particulars points of issue but also why it is. This consideration suggests that we define an explanation as an answer to a why-question. Such a definition would, however, be too broad, because some why-questions are requests for consolation (Why did my son have to die?) Or moral justification (Why should women not be paid the same as men for the same work?) It would also be too narrow because some explanations are responses to how-questions (How does radar work?) Or how-possibility-questions (How is it possible for cats always to land their feet?)

In its overall sense, to explain means to make clear, to make plain, or to provide understanding. Definition of this sort are philosophically unhelpful, for the terms used in the deficient are no less problematic than the term to be defined. Moreover, since a wide variety of things require explanation, and since many different types of explanation exist, as more complex explanation is required. To facilitate the requirement leaves, least of mention, for us to consider by introduction a bit of technical terminology. The term explanation is used to refer to that which is to be explained: The term explanans refers to that which does the explaining, the explanans and the explanation taken together constitute the explanation.

One common type of explanation occurs when deliberate human actions are explained in terms of conscious purposes. Why did you go to the pharmacy yesterday? Because I had a headache and needed to get some aspirin. It is tacitly assumed that aspirin is an appropriate medication for headaches and that going t the pharmacy would bean efficient way of getting some. Such explanations are, of course, teleological, referring, ss they do, to goals. The explanans is not the realization of a future goal - if the pharmacy happened to be closed for stocktaking the aspirin would have ben obtained there, bu t that would not invalidate the explanation. Some philosophers would say that the antecedent desire to achieve the end is what doers the explaining: Others might say that the explaining is done by the nature of the goal and the fact that the action promoted the chances of realizing it. (Taylor, 1964). In that it should not be automatically be assumed that such explanations are causal. Philosophers differ considerably on whether these explanations are to be framed in terms of cause or reason, but the distinction cannot be used to show that the relation between reasons and the actions they justify is in no way causal, and there are many differing analyses of such concepts as intention and agency. Expanding the domain beyond consciousness, Freud maintained, in addition, that much human behavior can be explained in terms of unconscious and conscious wishes. Those Freudian explanations should probably be construed as basically causal.

Problems arise when teleological explanations are offered in other context. The behavior of non-human animals is often explained in terms of purpose, e.g., the mouse ran to escape from the cat. In such cases the existence of conscious purpose seems dubious. The situation is still more problematic when a supra-empirical purpose in invoked -, e.g., the explanations of living species in terms of Gods purpose, or the vitalistic explanations of biological phenomena in terms of a entelechy or vital principle. In recent years an anthropic principle has received attention in cosmology (Barrow and Tipler, 1986). All such explanations have been concerned by many philosophers an anthropomorphic.

Nevertheless, philosophers and scientists often maintain that functional explanations play an important an legitimate role in various sciences such as, evolutionary biology, anthropology and sociology. For example, of the peppered moth in Liverpool, the change in colour from the light phase to the dark phase and back again to the light phase provided adaption to a changing environment and fulfilled the function of reducing predation on the spaces. In the study of primitive soviets anthropologists have maintained that various rituals the (rain dance) which may be inefficacious in braining about their manifest Gaels (producing rain), actually cohesion at a period of stress (often a drought). Philosophers who admit teleological and/or functional explanations in common sense and science oftentimes take pans to argue that such explanations can be annualized entirely in terms of efficient causes, thereby escaping the charge of anthropomorphism (Wright, 1976): Again, however, not all philosophers agree.

Mainly to avoid the incursion of unwanted theology, metaphysics, or anthropomorphism into science, many philosophers and scientists, especially during the first half of the twentieth century - held that science provides only descriptions and predictions of natural phenomena, but not explanations for a series of influential philosophers of science - including Karl Popper (1935) Carl Hempel and Paul Oppenheim (1948) and Hempel (1965) - maintained that empirical science can explain natural phenomena without appealing to metaphysics or theology. It appears that this view is now accepted by the vast majority of philosophers of science, though there is sharp disagreement on the nature of scientific explanation.

Nevertheless, one important variety of reliability theory is a conclusive reason account, which includes a requirement that one’s reasons for believing that ‘h’ be such that in one’s circumstances, if h* were not to occur then, e.g., one would not have the reasons one does for believing that ‘h’, or, e.g., one would not believe that ‘h’. Roughly, the latter are demanded by theories that treat a Knower as ‘tracking the truth’, theories that include the further demand that is roughly, if it were the case, that ‘h’, then one would believe that ‘h’. A version of the tracking theory has been defended by Robert Nozick (1981), who adds that if what he calls a ‘method’ has been used to arrive at the belief that ‘h’, then the antecedent clauses of the two conditionals that characterize tracking will need to include the hypothesis that one would employ the very same method.

But unless more conditions are added to Nozick’s analysis, it will be too weak to explain why one lack’s knowledge in a version of the last variant of the tricky Mr Notgot case described above, where we add the following details: (a) Mr Notgot’s compulsion is not easily changed, (b) while in the office, Mr Notgot has no other easy trick of the relevant type to play on one) one arrives at one’s belief that ‘h’, not by reasoning through a false belief ut by basing belief that ‘h’, upon a true existential generalization of one’s evidence.

Nozick’s analysis is in addition too strong to permit anyone ever to know that ‘h’: ‘Some of my beliefs about beliefs might be otherwise, e.g., I might have rejected on of them’. If I know that ‘h5' then satisfaction of the antecedent of one of Nozick’s conditionals would involve its being false that ‘h5', thereby thwarting satisfaction of the consequent’s requirement that I not then believe that ‘h5'. For the belief that ‘h5' is itself one of my beliefs about beliefs (Shope, 1984).

Some philosophers think that the category of knowing for which true. Justified believing (accepting) is a requirement constituting only a species of Propositional knowledge, construed as an even broader category. They have proposed various examples of ‘PK’ that do not satisfy the belief and/or justification conditions of the tripartite analysis. Such cases are often recognized by analyses of Propositional knowledge in terms of powers, capacities, or abilities. For instance, Alan R. White (1982) treats ‘PK’ as merely the ability to provide a correct answer to a possible questions, however, White may be equating ‘producing’ knowledge in the sense of producing ‘the correct answer to a possible question’ with ‘displaying’ knowledge in the sense of manifesting knowledge. (White, 1982). The latter can be done even by very young children and some non-human animals independently of their being asked questions, understanding questions, or recognizing answers to questions. Indeed, an example that has been proposed as an instance of knowing that ‘h’ without believing or accepting that ‘h’ can be modified so as to illustrate this point. Two examples concerns an imaginary person who has no special training or information about horses or racing, but who in an experiment persistently and correctly picks the winners of upcoming horseraces. If the example is modified so that the hypothetical ‘seer’ never picks winners but only muses over whether those horses wight win, or only reports those horses winning, this behaviour should be as much of a candidate for the person’s manifesting knowledge that the horse in question will win as would be the behaviour of picking it as a winner.

These considerations expose limitations in Edward Craig’s analysis (1990) of the concept of knowing of a person’s being a satisfactory informant in relation to an inquirer who wants to find out whether or not ‘h’. Craig realizes that counterexamples to his analysis appear to be constituted by Knower who are too recalcitrant to inform the inquirer, or too incapacitate to inform, or too discredited to be worth considering (as with the boy who cried ‘Wolf’). Craig admits that this might make preferable some alternative view of knowledge as a different state that helps to explain the presence of the state of being a suitable informant when the latter does obtain. Such the alternate, which offers a recursive definition that concerns one’s having the power to proceed in a way representing the state of affairs, causally involved in one’s proceeding in this way. When combined with a suitable analysis of representing, this theory of propositional knowledge can be unified with a structurally similar analysis of knowing how to do something.

Knowledge and belief, according to most epistemologists, knowledge entails belief, so that I cannot know that such and such is the case unless I believe that such and such is the case. Others think this entailment thesis can be rendered more accurately if we substitute for belief some closely related attitude. For instance, several philosophers would prefer to say that knowledge entail psychological certainties (Prichard, 1950 and Ayer, 1956) or conviction (Lehrer, 1974) or acceptance (Lehrer, 1989). None the less, there are arguments against all versions of the thesis that knowledge requires having a belief-like attitude toward the known. These arguments are given by philosophers who think that knowledge and belief (or a facsimile) are mutually incompatible (the incomparability thesis), or by ones who say that knowledge does not entail belief, or vice versa, so that each may exist without the other, but the two may also coexist (the separability thesis).

The incompatibility thesis is sometimes traced to Plato ©. 429-347 BC) in view of his claim that knowledge is infallible while belief or opinion is fallible (‘Republic’ 476-9). But this claim would not support the thesis. Belief might be a component of an infallible form of knowledge in spite of the fallibility of belief. Perhaps, knowledge involves some factor that compensates for the fallibility of belief.

A. Duncan-Jones (1939: Also Vendler, 1978) cite linguistic evidence to back up the incompatibility thesis. He notes that people often say ‘I do not believe she is guilty. I know she is’ and the like, which suggest that belief rule out knowledge. However, as Lehrer (1974) indicates, the above exclamation is only a more emphatic way of saying ‘I do not just believe she is guilty, I know she is’ where ‘just’ makes it especially clear that the speaker is signalling that she has something more salient than mere belief, not that she has something inconsistent with belief, namely knowledge. Compare: ‘You do not hurt him, you killed him’.

H.A. Prichard (1966) offers a defence of the incompatibility thesis that hinges on the equation of knowledge with certainty (both infallibility and psychological certitude) and the assumption that when we believe in the truth of a claim we are not certain about its truth. Given that belief always involves uncertainty while knowledge never dies, believing something rules out the possibility of knowing it. Unfortunately, however, Prichard gives ‘us’ no goods reason to grant that states of belief are never ones involving confidence. Conscious beliefs clearly involve some level of confidence, to suggest that we cease to believe things about which we are completely confident is bizarre.

A.D. Woozley (1953) defends a version of the separability thesis. Woozley’s version, which deals with psychological certainty rather than belief per se, is that knowledge can exist in the absence of confidence about the item known, although might also be accompanied by confidence as well. Woozley remarks that the test of whether I know something is ‘what I can do, where what I can do may include answering questions’. On the basis of this remark he suggests that even when people are unsure of the truth of a claim, they might know that the claim is true. We unhesitatingly attribute knowledge to people who give correct responses on examinations even if those people show no confidence in their answers. Woozley acknowledges, however, that it would be odd for those who lack confidence to claim knowledge. It would be peculiar to say, ‘I am unsure whether my answer is true: Still, I know it is correct’. But this tension Woozley explains using a distinction between conditions under which we are justified in making a claim (such as a claim to know something), and conditions under which the claim we make is true. While ‘I know such and such’ might be true even if I am unsure whether such and such holds, nonetheless it would be inappropriate for me to claim that I know that such and such unless I were sure of the truth of my claim.

Colin Radford (1966) extends Woozley’s defence of the separability thesis. In Radford’s view, not only is knowledge compatible with the lack of certainty, it is also compatible with a complete lack of belief. He argues by example. In one example, Jean has forgotten that he learned some English history year’s priori and yet he is able to give several correct responses to questions such as ‘When did the Battle of Hastings occur’? Since he forgot that he took history, he considers the correct response to be no more than guesses. Thus, when he says that the Battle of Hastings took place in 1066 he would deny having the belief that the Battle of Hastings took place in 1066. A disposition he would deny being responsible (or having the right to be convincing) that 1066 was the correct date. Radford would none the less insist that Jean know when the Battle occurred, since clearly be remembering the correct date. Radford admits that it would be inappropriate for Jean to say that he knew when the Battle of Hastings occurred, but, like Woozley he attributes the impropriety to a fact about when it is and is not appropriate to claim knowledge. When we claim knowledge, we ought, at least to believe that we have the knowledge we claim, or else our behaviour is ‘intentionally misleading’.

Those that agree with Radford’s defence of the separability thesis will probably think of belief as an inner state that can be detected through introspection. That Jean lack’s beliefs about English history is plausible on this Cartesian picture since Jean does not find himself with any beliefs about English history when ne seek them out. One might criticize Radford, however, by rejecting that Cartesian view of belief. One could argue that some beliefs are thoroughly unconscious, for example. Or one could adopt a behaviourist conception of belief, such as Alexander Bain’s (1859), according to which having beliefs is a matter of the way people are disposed to behave (and has not Radford already adopted a behaviourist conception of knowledge?) Since Jean gives the correct response when queried, a form of verbal behaviour, a behaviourist would be tempted to credit him with the belief that the Battle of Hastings occurred in 1066.

D.M. Armstrong (1873) takes a different tack against Radford. Jean does know that the Battle of Hastings took place in 1066. Armstrong will grant Radfod that point, in fact, Armstrong suggests that Jean believe that 1066 is not the date the Battle of Hastings occurred, for Armstrong equates the belief that such and such is just possible but no more than just possible with the belief that such and such is not the case. However, Armstrong insists, Jean also believes that the Battle did occur in 1066. After all, had Jean been mistaught that the Battle occurred in 1066, and subsequently ‘guessed’ that it took place in 1066, we would surely describe the situation as one in which Jean’s false belief about the Battle became unconscious over time but persisted of a memory trace that was causally responsible for his guess. Out of consistency, we must describe Radford’s original case as one that Jean’s true belief became unconscious but persisted long enough to cause his guess. Thus, while Jean consciously believes that the Battle did not occur in 1066, unconsciously he does believe it occurred in 1066. So after all, Radford does not have a counterexample to the claim that knowledge entails belief.

Armstrong’s response to Radford was to reject Radford’s claim that the examinee lacked the relevant belief about English history. Another response is to argue that the examinee lacks the knowledge Radford attributes to him (cf. Sorenson, 1982). If Armstrong is correct in suggesting that Jean believes both that 1066 is and that it is not the date of the Battle of Hastings, one might deny Jean knowledge on the grounds that people who believe the denial of what they believe cannot be said t know the truth of their belief. Another strategy might be to compare the examine case with examples of ignorance given in recent attacks on externalist accounts of knowledge (needless to say. Externalists themselves would tend not to favour this strategy). Consider the following case developed by BonJour (1985): For no apparent reason, Samantha believes that she is clairvoyant. Again, for no apparent reason, she one day comes to believe that the President is in New York City, even though she has every reason to believe that the President is in Washington, D.C. In fact, Samantha is a completely reliable clairvoyant, and she has arrived at her belief about the whereabouts of the President thorough the power of her clairvoyance. Yet surely Samantha’s belief is completely irrational. She is not justified in thinking what she does. If so, then she does not know where the President is. But Radford’s examinee is unconventional. Even if Jean lacks the belief that Radford denies him, Radford does not have an example of knowledge that is unattended with belief. Suppose that Jean’s memory had been sufficiently powerful to produce the relevant belief. As Radford says, in having every reason to suppose that his response is mere guesswork, and he has every reason to consider his belief false. His belief would be an irrational one, and hence one about whose truth Jean would be ignorant.

Least has been of mention to an approaching view from which ‘perception’ basis upon itself as a fundamental philosophical topic both for its central place in ant theory of knowledge, and its central place un any theory of consciousness. Philosophy in this area is constrained by a number of properties that we believe to hold of perception, (1) It gives ‘us’ knowledge of the world around ‘us’. (2) We are conscious of that world by being aware of ‘sensible qualities’: Colour, sounds, tastes, smells, felt warmth, and the shapes and positions of objects in the environment. (3) Such consciousness is effected through highly complex information channels, such as the output of the three different types of colour-sensitive cells in the eye, or the channels in the ear for interpreting pulses of air pressure as frequencies of sound. (4) There ensues even more complex neurophysiological coding of that information, and eventually higher-order brain functions bring it about that we interpreted the information so received. (Much of this complexity has been revealed by the difficulties of writing programs enabling computers to recognize quite simple aspects of the visual scene.) The problem is to avoid thinking of here being a central, ghostly, conscious self, fed information in the same way that a screen if fed information by a remote television camera. Once such a model is in place, experience will seem like a veil getting between ‘us’ and the world, and the direct objects of perception will seem to be private items in an inner theatre or sensorium. The difficulty of avoiding this model is epically cute when we considered the secondary qualities of colour, sound, tactile feelings and taste, which can easily seem to have a purely private existence inside the perceiver, like sensation of pain. Calling such supposed items names like ‘sense-data’ or ‘percepts’ exacerbates the tendency, but once the model is in place, the first property, that perception gives ‘us’ knowledge of the world and its surrounding surfaces, is quickly threatened, for there will now seem little connection between these items in immediate experience and any independent reality. Reactions to this problem include ‘scepticism’ and ‘idealism’.

A more hopeful approach is to claim that the complexities of (3) and (4) explain how we can have direct acquaintance of the world, than suggesting that the acquaintance we do have been at best indirect. It is pointed out that perceptions are not like sensation, precisely because they have a content, or outer-directed nature. To have a perception is to be aware of the world for being such-and-such a way, than to enjoy a mere modification of sensation. But such direct realism has to be sustained in the face of the evident personal (neurophysiological and other) factors determining haw we perceive. One approach is to ask why it is useful to be conscious of what we perceive, when other aspects of our functioning work with information determining responses without any conscious awareness or intervention. A solution to this problem would offer the hope of making consciousness part of the natural world, than a strange optional extra.

Furthering, perceptual knowledge is knowledge acquired by or through the senses and includes most of what we know. We cross intersections when we see the light turn green, head for the kitchen when we smell the roast burning, squeeze the fruit to determine its ripeness, and climb out of bed when we hear the alarm ring. In each case we come to know something-that the light has turned green, that the roast is burning, that the melon is overripe, and that it is time to get up-by some sensory means. Seeing that the light has turned green is learning something-that, the light has turned green-by use of the eyes. Feeling that the melon is overripe is coming to know a fact-that the melon is overripe-by one’s sense to touch. In each case the resulting knowledge is somehow based on, derived from or grounded in the sort of experience that characterizes the sense modality in question.

Much of our perceptual knowledge is indirect, dependent or derived. By this I mean that the facts we describe ourselves as learning, as coming to know, by perceptual means are pieces of knowledge that depend on our coming to know something else, some other fact, in a more direct way. We see, by the gauge, that we need gas, see, by the newspapers, that our team has lost again, see, by her expression, that she is nervous. This derived or dependent sort of knowledge is particularly prevalent in the cases of vision, but it occurs, to a lesser degree, in every sense modality. We install bells and other noise-makers so that we calm for example, hear (by the bell) that someone is at the door and (by the alarm) that its time to get up. When we obtain knowledge in this way, it is clear that unless one sees-hence, comes to know something about the gauge (that it says) and (hence, know) that one is described as coming to know by perceptual means. If one cannot hear that the bell is ringing, one cannot-in at least in this way-hear that one’s visitors have arrived. In such cases one sees (hears, smells, etc.) that ‘a’ is ‘F’, coming to know thereby that ‘a’ is ‘F’, by seeing (hearing, etc.) that some other condition, ‘b’s’ being ‘G’, obtains when this occurs, the knowledge (that ‘a’ is ‘F’) is derived from, or dependent on, the more basic perceptual knowledge that ‘b’ is ‘G’.

Perhaps as a better strategy is to tie an account save that part that evidence could justify explanation for it is its truth alone. Since, at least the time of Aristotle philosophers of explanatory knowledge have emphasizes of its importance that, in its simplest therms, we want to know not only what are the composite peculiarities and particulars points of issue but also why it is. This consideration suggests that we define an explanation as an answer to a why-question. Such a definition would, however, be too broad, because some why-questions are requests for consolation (Why did my son have to die?) Or moral justification (Why should women not be paid the same as men for the same work?) It would also be too narrow because some explanations are responses to how-questions (How does radar work?) Or how-possibility-questions (How is it possible for cats always to land their feet?)

In its overall sense, ‘to explain’ means to make clear, to make plain, or to provide understanding. Definition of this sort are philosophically unhelpful, for the terms used in the deficient are no less problematic than the term to be defined. Moreover, since a wide variety of things require explanation, and since many different types of explanation exist, as more complex explanation is required. To facilitate the requirement leaves, least of mention, for us to consider by introduction a bit of technical terminology. The term ‘explanation’ is used to refer to that which is to be explained: The term ‘explanans’ refers to that which does the explaining, the explanans and the explanation taken together constitute the explanation.

One common type of explanation occurs when deliberate human actions are explained in terms of conscious purposes. ‘Why did you go to the pharmacy yesterday?’ ‘Because I had a headache and needed to get some aspirin.’ It is tacitly assumed that aspirin is an appropriate medication for headaches and that going t the pharmacy would bean efficient way of getting some. Such explanations are, of course, teleological, referring, ss they do, to goals. The explanans is not the realisation of a future goal - if the pharmacy happened to be closed for stocktaking the aspirin would have ben obtained there, bu t that would not invalidate the explanation. Some philosophers would say that the antecedent desire to achieve the end is what doers the explaining: Others might say that the explaining is done by the nature of the goal and the fact that the action promoted the chances of realizing it. (Taylor, 1964). In that it should not be automatically be assumed that such explanations are causal. Philosophers differ considerably on whether these explanations are to be framed in terms of cause or reason, but the distinction cannot be used to show that the relation between reasons and the actions they justify is in no way causal, and there are many differing analyses of such concepts as intention and agency. Expanding the domain beyond consciousness, Freud maintained, in addition, that much human behaviour can be explained in terms of unconscious and conscious wishes. Those Freudian explanations should probably be construed as basically causal.

Problems arise when teleological explanations are offered in other context. The behaviour of non-human animals is often explained in terms of purpose, e.g., the mouse ran to escape from the cat. In such cases the existence of conscious purpose seems dubious. The situation is still more problematic when a supr-empirical purpose in invoked -, e.g., the explanations of living species in terms of God’s purpose, or the vitalistic explanations of biological phenomena in terms of a entelechy or vital principle. In recent years an ‘anthropic principle’ has received attention in cosmology (Barrow and Tipler, 1986). All such explanations have been condemned by many philosophers an anthropomorphic.

Nevertheless, philosophers and scientists often maintain that functional explanations play an important an legitimate role in various sciences such as, evolutionary biology, anthropology and sociology. For example, of the peppered moth in Liverpool, the change in colour from the light phase to the dark phase and back again to the light phase provided adaption to a changing environment and fulfilled the function of reducing predation on the spacies. In the study of primitive soviets anthropologists have maintained that various rituals the (rain dance) which may be inefficacious in braining about their manifest goals (producing rain), actually cohesion at a period of stress (often a drought). Philosophers who admit teleological and/or functional explanations in common sense and science oftentimes take pans to argue that such explanations can be annualized entirely in terms of efficient causes, thereby escaping the charge of anthropomorphism (Wright, 1976): Again, however, not all philosophers agree.

Mainly to avoid the incursion of unwanted theology, metaphysics, or anthropomorphism into science, many philosophers and scientists, especially during the first half of the twentieth century - held that science provides only descriptions and predictions of natural phenomena, but not explanations for a series of influential philosophers of science - including Karl Popper (1935) Carl Hempel and Paul Oppenheim (1948) and Hempel (1965) - maintained that empirical science can explain natural phenomena without appealing to metaphysics or theology. It appears that this view is now accepted by the vast majority of philosophers of science, though there is sharp disagreement on the nature of scientific explanation.

The foregoing approach, developed by Hempel, Popper and others, became virtually a ‘received view’ in the 1960s and 1970s. According to this view, to give a scientific explanation of any natural phenomenon is to show how this phenomena can be subsumed under a law of nature. A particular repture in a water pipe can be explained by citing the universal law that water expands when it freezes and the fact that the temperature of water in a pipe dropped below the freezing point. General law, as well as particular facts, can be explained by subsumption, the law of conservation of linear momentum can be explained by derivation from Newton’s second and third laws of motion. Each of these explanations is a deductive argument: The explanans contains one or more statements of universal laws and, in many cases, statements deceiving initial conditions. This pattern of explanation is known as the deductive-nomological (D-N) model. Any such argument shows that the explanandun had to occur given the explanans.

Many, though not all, adherents of the received view allow for explanation by subsumption under statistical laws. Hempel (1965) offers as an example the case of a man who recovered quickly from a streptococcus infection as a result of treatment with penicillin. Although not all strep infections’ clear up quickly under this treatment, the probability of recovery in such cases is high, and this is sufficient for legitimate explanation According to Hempel. This example conforms to the inductive-statistical (I-S) model. Such explanations are viewed as arguments, but they are inductive than deductive. In these instances the explanation confers high inductive probability on the explanandum. An explanation of a particular fact satisfying either the D-N or I-S model is an argument to the effect that the fact in question was to b e expected by virtue of the explanans.

The received view been subjected to strenuous criticism by adherents of the causal/mechanical approach to scientific explanation (Salmon 1990). Many objections to the received view we engendered by he absence of caudal constraints (due largely to worries about Hume’s critique) on the N-D and I-S models. Beginning in the late 1950s, Michael Scriven advanced serious counter-examples to Hempel’s models: He was followed in the 1960s by Wesley Salmon and in the 1970s by Peter Railton. As accorded to the view, one explains phenomena identifying causes (a death is explained reacting from a massive cerebral haemorrhage) or by exposing underlying mechanisms (the behaviour of a gas is explained in terms of the motion of constituent molecules).

A unification approach to explanation carries with the basic idea that we understand our world more adequately to the extent that we can reduce the number of independent assumptions we must introduce to account for what goes on in it. Accordingly, we understand phenomena to the degree that we can fit them into an overall world picture or Weltanschauung. In order to serve in scientific explanation, the world picture must be scientifically well founded.

During the pas half-century much philosophical attention has ben focussed on explanation in science and in history. Considerable controversy has surrounded the question of whether historical explanation must be scientific, or whether history requires explanations of different types. Many diverse views have been articulated: The forgoing brief survey does not exhaust the variety (Salmon, 19990).

In everyday life we encounter many types of explanation, which appear not to raise philosophical difficulties, in addition to those already made of mention. Prior to take-off a flight attendant explains how to use the safety equipment on the aero-plane. In a museum the guide explain the significance of a famous painting. A mathematics teacher explains a geometrical proof to a bewildered student. A newspaper story explains how a prisoner escaped. Additional examples come easily to mind, the main point is to remember the great variety of contexts in which explanations are sought and given into.

Another item of importance to epistemology is the wider held notion that non-demonstrative inferences can be characterized as inference to the best explanation. Given the variety of views on the nature of explanation, this popular slogan can hardly provide a useful philosophical analysis

Early versions of defeasibility theories had difficulty allowing for the existence of evidence that was ‘merely misleading,’ as in the case where one does know that h3: ‘Tom Grabit stole a book from the library,’ thanks to having seen him steal it, yet where, unbeknown to oneself, Tom’s mother out of dementia gas testified that Tom was far away from the library at the time of the theft. One’s justifiably believing that she gave the testimony would destroy one’s justification for believing that h3' if added by itself to one’s present evidence.

At least some defeasibility theories cannot deal with the knowledge one has while dying that h4: ‘In this life there is no timer at which I believe that ‘d’, where the proposition that 'd' expresses the details regarding some philosophical matter, e.g., the maximum number of blades of grass ever simultaneously growing on the earth. When it just so happens that it is true that ‘d’, defeasibility analyses typically consider the addition to one’s dying thoughts of a belief that ‘d’ in such a way as to improperly rule out actual knowledge that ‘h4'.

A quite different approach to knowledge, and one able to deal with some Gettier-type cases, involves developing some type of causal theory of Propositional knowledge. The interesting thesis that counts as a causal theory of justification (in the meaning of ‘causal theory’: Intended here) is the that of a belief is justified just in case it was produced by a type of process that is ‘globally’ reliable, that is, its propensity to produce true beliefs-that can be defined (to a god enough approximation) as the proportion of the bailiffs it produces (or would produce where it used as much as opportunity allows) that are true-is sufficiently meaningful-variations of this view have been advanced for both knowledge and justified belief. The first formulation of reliability account of knowing appeared in a note by F.P. Ramsey (1931), who said that a belief was knowledge if it is true, certain can obtain by a reliable process. P. Unger (1968) suggested that 'S’ knows that ‘p’ just in case it is not at all accidental that ‘S’ is right about its being the case that ‘p’. D.M. Armstrong (1973) said that a non-inferential belief qualified as knowledge if the belief has properties that are nominally sufficient for its truth, i.e., guarantee its truth through and by the laws of nature.

Such theories require that one or another specified relation hold that can be characterized by mention of some aspect of cassation concerning one’s belief that ‘h’ (or one’s acceptance of the proposition that ‘h’) and its relation to state of affairs ‘h*’, e.g., 'h' causes the belief: 'h' is causally sufficient for the belief 'h' and the belief have a common cause. Such simple versions of a causal theory are able to deal with the original Notgot case, since it involves no such causal relationship, but cannot explain why there is ignorance in the variants where Notgot and Berent Enç (1984) have pointed out that sometimes one knows of ‘χ’ that is ø thanks to recognizing a feature merely correlated with the presence of øness without endorsing a causal theory themselves, there suggest that it would need to be elaborated so as to allow that one’s belief that ‘χ’ has ø has been caused by a factor whose correlation with the presence of øness has caused in oneself, e.g., by evolutionary adaption in one’s ancestors, the disposition that one manifests in acquiring the belief in response to the correlated factor. Not only does this strain the unity of as causal theory by complicating it, but no causal theory without other shortcomings has been able to cover instances of deductively reasoned knowledge.

Causal theories of Propositional knowledge differ over whether they deviate from the tripartite analysis by dropping the requirements that one’s believing (accepting) that ‘h’ be justified. The same variation occurs regarding reliability theories, which present the Knower as reliable concerning the issue of whether or not ‘h’, in the sense that some of one’s cognitive or epistemic states, θ, are such that, given further characteristics of oneself-possibly including relations to factors external to one and which one may not be aware-it is nomologically necessary (or at least probable) that ‘h’. In some versions, the reliability is required to be ‘global’ in as far as it must concern a nomologically (probabilistic) relationship) relationship of states of type θ to the acquisition of true beliefs about a wider range of issues than merely whether or not ‘h’. There is also controversy about how to delineate the limits of what constitutes a type of relevant personal state or characteristic. (For example, in a case where Mr Notgot has not been shamming and one does know thereby that someone in the office owns a Ford, such as a way of forming beliefs about the properties of persons spatially close to one, or instead something narrower, such as a way of forming beliefs about Ford owners in offices partly upon the basis of their relevant testimony?)

One important variety of reliability theory is a conclusive reason account, which includes a requirement that one’s reasons for believing that ‘h’ be such that in one’s circumstances, if h* were not to occur then, e.g., one would not have the reasons one does for believing that ‘h’, or, e.g., one would not believe that ‘h’. Roughly, the latter is demanded by theories that treat a Knower as ‘tracking the truth’, theories that include the further demand that is roughly, if it were the case, that ‘h’, then one would believe that ‘h’. A version of the tracking theory has been defended by Robert Nozick (1981), who adds that if what he calls a ‘method’ has been used to arrive at the belief that ‘h’, then the antecedent clauses of the two conditionals that characterize tracking will need to include the hypothesis that one would employ the very same method.

But unless more conditions are added to Nozick’s analysis, it will be too weak to explain why one lack’s knowledge in a version of the last variant of the tricky Mr Notgot case described above, where we add the following details: (a) Mr Notgot’s compulsion is not easily changed, (b) while in the office, Mr Notgot has no other easy trick of the relevant type to play on one, and finally for one’s belief that ‘h’, not by reasoning through a false belief ut by basing belief that ‘h’, upon a true existential generalization of one’s evidence.

Nozick’s analysis is in addition too strong to permit anyone ever to know that ‘h’: ‘Some of my beliefs about beliefs might be otherwise, e.g., I might have rejected on of them’. If I know that ‘h5' then satisfaction of the antecedent of one of Nozick’s conditionals would involve its being false that ‘h5', thereby thwarting satisfaction of the consequent’s requirement that I not then believe that ‘h5'. For the belief that ‘h5' is itself one of my beliefs about beliefs (Shope, 1984).

Some philosophers think that the category of knowing for which is true. Justified believing (accepting) is a requirement constituting only a species of Propositional knowledge, construed as an even broader category. They have proposed various examples of ‘PK’ that do not satisfy the belief and/or justification conditions of the tripartite analysis. Such cases are often recognized by analyses of Propositional knowledge in terms of powers, capacities, or abilities. For instance, Alan R. White (1982) treats ‘PK’ as merely the ability to provide a correct answer to a possible questions, however, White may be equating ‘producing’ knowledge in the sense of producing ‘the correct answer to a possible question’ with ‘displaying’ knowledge in the sense of manifesting knowledge. (White, 1982). The latter can be done even by very young children and some non-human animals independently of their being asked questions, understanding questions, or recognizing answers to questions. Indeed, an example that has been proposed as an instance of knowing that ‘h’ without believing or accepting that ‘h’ can be modified so as to illustrate this point. Two examples concerns an imaginary person who has no special training or information about horses or racing, but who in an experiment persistently and correctly picks the winners of upcoming horseraces. If the example is modified so that the hypothetical ‘seer’ never picks winners but only muses over whether those horses wight win, or only reports those horses winning, this behaviour should be as much of a candidate for the person’s manifesting knowledge that the horse in question will win as would be the behaviour of picking it as a winner.

These considerations expose limitations in Edward Craig’s analysis (1990) of the concept of knowing of a person’s being a satisfactory informant in relation to an inquirer who wants to find out whether or not ‘h’. Craig realizes that counterexamples to his analysis appear to be constituted by Knower who are too recalcitrant to inform the inquirer, or too incapacitate to inform, or too discredited to be worth considering (as with the boy who cried ‘Wolf’). Craig admits that this might make preferable some alternative view of knowledge as a different state that helps to explain the presence of the state of being a suitable informant when the latter does obtain. Such the alternate, which offers a recursive definition that concerns one’s having the power to proceed in a way representing the state of affairs, causally involved in one’s proceeding in this way. When combined with a suitable analysis of representing, this theory of propositional knowledge can be unified with a structurally similar analysis of knowing how to do something.

Knowledge and belief, according to most epistemologists, knowledge entails belief, so that I cannot know that such and such is the case unless I believe that such and such is the case. Others think this entailment thesis can be rendered more accurately if we substitute for belief some closely related attitude. For instance, several philosophers would prefer to say that knowledge entail psychological certainties (Prichard, 1950 and Ayer, 1956) or conviction (Lehrer, 1974) or acceptance (Lehrer, 1989). None the less, there are arguments against all versions of the thesis that knowledge requires having a belief-like attitude toward the known. These arguments are given by philosophers who think that knowledge and belief (or a facsimile) are mutually incompatible (the incomparability thesis), or by ones who say that knowledge does not entail belief, or vice versa, so that each may exist without the other, but the two may also coexist (the separability thesis).

The incompatibility thesis is sometimes traced to Plato (429-347 Bc) in view of his claim that knowledge is infallible while belief or opinion is fallible (‘Republic’ 476-9). But this claim would not support the thesis. Belief might be a component of an infallible form of knowledge in spite of the fallibility of belief. Perhaps, knowledge involves some factor that compensates for the fallibility of belief.

A. Duncan-Jones (1939: Also Vendler, 1978) cite linguistic evidence to back up the incompatibility thesis. He notes that people often say ‘I do not believe she is guilty. I know she is’ and the like, which suggest that belief rule out knowledge. However, as Lehrer (1974) indicates, the above exclamation is only a more emphatic way of saying ‘I do not just believe she is guilty, I know she is’ where ‘just’ makes it especially clear that the speaker is signalling that she has something more salient than mere belief, not that she has something inconsistent with belief, namely knowledge. Compare: ‘You do not hurt him, you killed him.'

H.A. Prichard (1966) offers a defence of the incompatibility thesis that hinges on the equation of knowledge with certainty (both infallibility and psychological certitude) and the assumption that when we believe in the truth of a claim we are not certain about its truth. Given that belief always involves uncertainty while knowledge never dies, believing something rules out the possibility of knowing it. Unfortunately, however, Prichard gives ‘us’ no goods reason to grant that states of belief are never ones involving confidence. Conscious beliefs clearly involve some level of confidence, to suggest that we cease to believe things about which we are completely confident is bizarre.

A.D. Woozley (1953) defends a version of the separability thesis. Woozley’s version, which deals with psychological certainty rather than belief per se, is that knowledge can exist in the absence of confidence about the item known, although might also be accompanied by confidence as well. Woozley remarks that the test of whether I know something is ‘what I can do, where what I can do may include answering questions.’ On the basis of this remark he suggests that even when people are unsure of the truth of a claim, they might know that the claim is true. We unhesitatingly attribute knowledge to people who give correct responses on examinations even if those people show no confidence in their answers. Woozley acknowledges, however, that it would be odd for those who lack confidence to claim knowledge. It would be peculiar to say, I am unsure whether my answer is true: Still, I know it is correct But this tension Woozley explains using a distinction between conditions under which we are justified in making a claim (such as a claim to know something), and conditions under which the claim we make is true. While ‘I know such and such’ might be true even if I am unsure whether such and such holds, nonetheless it would be inappropriate for me to claim that I know that such and such unless I were sure of the truth of my claim.

Colin Radford (1966) extends Woozley’s defence of the separability thesis. In Radford’s view, not only is knowledge compatible with the lack of certainty, it is also compatible with a complete lack of belief. He argues by example. In one example, Jean has forgotten that he learned some English history year’s priori and yet he is able to give several correct responses to questions such as ‘When did the Battle of Hastings occur?’ Since he forgot that he took history, he considers the correct response to be no more than guesses. Thus, when he says that the Battle of Hastings took place in 1066 he would deny having the belief that the Battle of Hastings took place in 1066. A disposition he would deny being responsible (or having the right to be convincing) that 1066 was the correct date. Radford would none the less insist that Jean know when the Battle occurred, since clearly be remembering the correct date. Radford admits that it would be inappropriate for Jean to say that he knew when the Battle of Hastings occurred, but, like Woozley he attributes the impropriety to a fact about when it is and is not appropriate to claim knowledge. When we claim knowledge, we ought, at least to believe that we have the knowledge we claim, or else our behaviour is ‘intentionally misleading’.

Those that agree with Radford’s defence of the separability thesis will probably think of belief as an inner state that can be detected through introspection. That Jean lack’s beliefs about English history is plausible on this Cartesian picture since Jean does not find himself with any beliefs about English history when ne seek them out. One might criticize Radford, however, by rejecting that Cartesian view of belief. One could argue that some beliefs are thoroughly unconscious, for example. Or one could adopt a behaviourist conception of belief, such as Alexander Bain’s (1859), according to which having beliefs is a matter of the way people are disposed to behave (and has not Radford already adopted a behaviourist conception of knowledge?) Since Jean gives the correct response when queried, a form of verbal behaviour, a behaviourist would be tempted to credit him with the belief that the Battle of Hastings occurred in 1066.

D.M. Armstrong (1873) takes a different tack against Radford. Jean does know that the Battle of Hastings took place in 1066. Armstrong will grant Radfod that point, in fact, Armstrong suggests that Jean believe that 1066 is not the date the Battle of Hastings occurred, for Armstrong equates the belief that such and such is just possible but no more than just possible with the belief that such and such is not the case. However, Armstrong insists, Jean also believes that the Battle did occur in 1066. After all, had Jean been mistaught that the Battle occurred in 1066, and subsequently ‘guessed’ that it took place in 1066, we would surely describe the situation as one in which Jean’s false belief about the Battle became unconscious over time but persisted of a memory trace that was causally responsible for his guess. Out of consistency, we must describe Radford’s original case as one that Jean’s true belief became unconscious but persisted long enough to cause his guess. Thus, while Jean consciously believes that the Battle did not occur in 1066, unconsciously he does believe it occurred in 1066. So after all, Radford does not have a counterexample to the claim that knowledge entails belief.

Armstrong’s response to Radford was to reject Radford’s claim that the examinee lacked the relevant belief about English history. Another response is to argue that the examinee lacks the knowledge Radford attributes to him (cf. Sorenson, 1982). If Armstrong is correct in suggesting that Jean believes both that 1066 is and that it is not the date of the Battle of Hastings, one might deny Jean knowledge on the grounds that people who believe the denial of what they believe cannot be said t know the truth of their belief. Another strategy might be to compare the examine case with examples of ignorance given in recent attacks on externalist accounts of knowledge (needless to say. Externalists themselves would tend not to favour this strategy). Consider the following case developed by BonJour (1985): For no apparent reason, Samantha believes that she is clairvoyant. Again, for no apparent reason, she one day comes to believe that the President is in New York City, even though she has every reason to believe that the President is in Washington, DC. In fact, Samantha is a completely reliable clairvoyant, and she has arrived at her belief about the whereabouts of the President thorough the power of her clairvoyance. Yet surely Samantha’s belief is completely irrational. She is not justified in thinking what she does. If so, then she does not know where the President is. But Radford’s examinee is unconventional. Even if Jean lacks the belief that Radford denies him, Radford does not have an example of knowledge that is unattended with belief. Suppose that Jean’s memory had been sufficiently powerful to produce the relevant belief. As Radford says, in having every reason to suppose that his response is mere guesswork, and he has every reason to consider his belief false. His belief would be an irrational one, and hence one about whose truth Jean would be ignorant.

Least has been of mention to an approaching view from which ‘perception’ basis upon itself as a fundamental philosophical topic both for its central place in ant theory of knowledge, and its central place un any theory of consciousness. Philosophy in this area is constrained by a number of properties that we believe to hold of perception, (1) It gives ‘us’ knowledge of the world around ‘us,’ (2) We are conscious of that world by being aware of ‘sensible qualities’: Colour, sounds, tastes, smells, felt warmth, and the shapes and positions of objects in the environment. (3) Such consciousness is effected through highly complex information channels, such as the output of the three different types of colour-sensitive cells in the eye, or the channels in the ear for interpreting pulses of air pressure as frequencies of sound. (4) There ensues even more complex neurophysiological coding of that information, and eventually higher-order brain functions bring it about that we interpreted the information so received. (Much of this complexity has been revealed by the difficulties of writing programs enabling computers to recognize quite simple aspects of the visual scene.) The problem is to avoid thinking of here being a central, ghostly, conscious self, fed information in the same way that a screen if fed information by a remote television camera. Once such a model is in place, experience will seem like a veil getting between ‘us’ and the world, and the direct objects of perception will seem to be private items in an inner theatre or sensorium. The difficulty of avoiding this model is epically cute when we considered the secondary qualities of colour, sound, tactile feelings and taste, which can easily seem to have a purely private existence inside the perceiver, like sensation of pain. Calling such supposed items names like ‘sense-data’ or ‘percepts’ exacerbates the tendency, but once the model is in place, the first property, that perception gives ‘us’ knowledge of the world and its surrounding surfaces, is quickly threatened, for there will now seem little connection between these items in immediate experience and any independent reality. Reactions to this problem include ‘scepticism’ and ‘idealism.’

A more hopeful approach is to claim that the complexities of (3) and (4) explain how we can have direct acquaintance of the world, than suggesting that the acquaintance we do have been at best indirect. It is pointed out that perceptions are not like sensation, precisely because they have a content, or outer-directed nature. To have a perception is to be aware of the world for being such-and-such a way, than to enjoy a mere modification of sensation. But such direct realism has to be sustained in the face of the evident personal (neurophysiological and other) factors determining haw we perceive. One approach is to ask why it is useful to be conscious of what we perceive, when other aspects of our functioning work with information determining responses without any conscious awareness or intervention. A solution to this problem would offer the hope of making consciousness part of the natural world, than a strange optional extra.

Furthering, perceptual knowledge is knowledge acquired by or through the senses and includes most of what we know. We cross intersections when we see the light turn green, head for the kitchen when we smell the roast burning, squeeze the fruit to determine its ripeness, and climb out of bed when we hear the alarm ring. In each case we come to know something-that the light has turned green, that the roast is burning, that the melon is overripe, and that it is time to get up-by some sensory means. Seeing that the light has turned green is learning something-that the light has turned green-by use of the eyes. Feeling that the melon is overripe is coming to know a fact-that the melon is overripe-by one’s sense to touch. In each case the resulting knowledge is somehow based on, derived from or grounded in the sort of experience that characterizes the sense modality in question.

Much of our perceptual knowledge is indirect, dependent or derived. By this I mean that the facts we describe ourselves as learning, as coming to know, by perceptual means are pieces of knowledge that depend on our coming to know something else, some other fact, in a more direct way. We see, by the gauge, that we need gas, see, by the newspapers, that our team has lost again, see, by her expression, that she is nervous. This derived or dependent sort of knowledge is particularly prevalent in the cases of vision, but it occurs, to a lesser degree, in every sense modality. We install bells and other noise-makers so that we calm for example, hear (by the bell) that someone is at the door and (by the alarm) that its time to get up. When we obtain knowledge in this way, it is clear that unless one sees-hence, comes to know something about the gauge (that it says) and (hence, know) that one is described as coming to know by perceptual means. If one cannot hear that the bell is ringing, one cannot-in at least in this way-hear that one’s visitors have arrived. In such cases one sees (hears, smells, etc.) that ‘a’ is ‘F’, coming to know thereby that ‘a’ is ‘F’, by seeing (hearing, etc.) that some other condition, ‘b’s’ being ‘G’, obtains when this occurs, the knowledge (that ‘a’ is ‘F’) is derived from, or dependent on, the more basic perceptual knowledge that ‘b’ is ‘G’.

And finally, the representational Theory of mind (RTM) (which goes back at least to Aristotle) takes as its starting point commonsense mental states, such as thoughts, beliefs, desires, perceptions and images. Such states are said to have ‘intentionality’ - they are about or refer to things, and may be evaluated with respect to properties like consistency, truth, appropriateness and accuracy. (For example, the thought that cousins are not related is inconsistent, the belief that Elvis is dead is true, the desire to eat the moon is inappropriate, a visual experience of a ripe strawberry as red is accurate, an image of George W. Bush with deadlocks is inaccurate.)

The Representational Theory of Mind, defines such intentional mental states as relations to mental representations, and explains the intentionality of the former in terms of the semantic properties of the latter. For example, to believe that Elvis is dead is to be appropriately related to a mental representation whose propositional content is that Elvis is dead. (The desire that Elvis be dead, the fear that he is dead, the regret that he is dead, etc., involve different relations to the same mental representation.) To perceive a strawberry is to have a sensory experience of some kind which is appropriately related to (e.g., caused by) the strawberry Representational theory of mind also understands mental processes such as thinking, reasoning and imagining as sequences of intentional mental states. For example, to imagine the moon rising over a mountain is to entertain a series of mental images of the moon (and a mountain). To infer a proposition q from the propositions p and if 'p' then 'q' is (among other things) to have a sequence of thoughts of the form 'p', 'if p' then 'q', 'q'.

Contemporary philosophers of mind have typically supposed (or at least hoped) that the mind can be naturalized - i.e., that all mental facts have explanations in the terms of natural science. This assumption is shared within cognitive science, which attempts to provide accounts of mental states and processes in terms (ultimately) of features of the brain and central nervous system. In the course of doing so, the various sub-disciplines of cognitive science (including cognitive and computational psychology and cognitive and computational neuroscience) postulate a number of different kinds of structures and processes, many of which are not directly implicated by mental states and processes as commonsensical conceived. There remains, however, a shared commitment to the idea that mental states and processes are to be explained in terms of mental representations.

In philosophy, recent debates about mental representation have centred around the existence of propositional attitudes (beliefs, desires, etc.) and the determination of their contents (how they come to be about what they are about), and the existence of phenomenal properties and their relation to the content of thought and perceptual experience. Within cognitive science itself, the philosophically relevant debates have been focussed on the computational architecture of the brain and central nervous system, and the compatibility of scientific and commonsense accounts of mentality.

Intentional Realists such as Dretske (e.g., 1988) and Fodor (e.g., 1987) note that the generalizations we apply in everyday life in predicting and explaining each other's behaviour (often collectively referred to as ‘folk psychology’) are both remarkably successful and indispensable. What a person believes, doubts, desires, fears, etc. is a highly reliable indicator of what that person will do; and we have no other way of making sense of each other's behaviour than by ascribing such states and applying the relevant generalizations. We are thus committed to the basic truth of commonsense psychology and, hence, to the existence of the states its generalizations refer to. (Some realists, such as Fodor, also hold that commonsense psychology will be vindicated by cognitive science, given that propositional attitudes can be construed as computational relations to mental representations.)

Intentional Eliminativists, such as Churchland, (perhaps) Dennett and (at one time) Stich argue that no such things as propositional attitudes (and their constituent representational states) are implicated by the successful explanation and prediction of our mental lives and behaviour. Churchland denies that the generalizations of commonsense propositional-attitude psychology are true. He (1981) argues that folk psychology is a theory of the mind with a long history of failure and decline, and that it resists incorporation into the framework of modern scientific theories (including cognitive psychology). As such, it is comparable to alchemy and phlogiston theory, and ought to suffer a comparable fate. Commonsense psychology is false, and the states (and representations) it postulates simply don't exist. (It should be noted that Churchland is not an eliminativist about mental representation tout court.

Dennett (1987) grants that the generalizations of commonsense psychology are true and indispensable, but denies that this is sufficient reason to believe in the entities they appear to refer to. He argues that to give an intentional explanation of a system's behaviour is merely to adopt the ‘intentional stance’ toward it. If the strategy of assigning contentful states to a system and predicting and explaining its behaviour (on the assumption that it is rational - i.e., that it behaves as it should, given the propositional attitudes it should have in its environment) is successful, then the system is intentional, and the propositional-attitude generalizations we apply to it are true. But there is nothing more to having a propositional attitude than this.

Though he has been taken to be thus claiming that intentional explanations should be construed instrumentally, Dennett (1991) insists that he is a ‘moderate’ realist about propositional attitudes, since he believes that the patterns in the behaviour and behavioural dispositions of a system on the basis of which we (truly) attribute intentional states to it are objectively real. In the event that there are two or more explanatorily adequate but substantially different systems of intentional ascriptions to an individual, however, Dennett claims there is no fact of the matter about what the system believes (1987, 1991). This does suggest an irrealism at least with respect to the sorts of things Fodor and Dretske take beliefs to be; though it is not the view that there is simply nothing in the world that makes intentional explanations true.

(Davidson 1973, 1974 and Lewis 1974 also defend the view that what it is to have a propositional attitude is just to be interpretable in a particular way. It is, however, not entirely clear whether they intend their views to imply irrealism about propositional attitudes.). Stich (1983) argues that cognitive psychology does not (or, in any case, should not) taxonomize mental states by their semantic properties at all, since attribution of psychological states by content is sensitive to factors that render it problematic in the context of a scientific psychology. Cognitive psychology seeks causal explanations of behaviour and cognition, and the causal powers of a mental state are determined by its intrinsic ‘structural’ or ‘syntactic’ properties. The semantic properties of a mental state, however, are determined by its extrinsic properties - e.g., its history, environmental or intra-mental relations. Hence, such properties cannot figure in causal-scientific explanations of behaviour. (Fodor 1994 and Dretske 1988 are realist attempts to come to grips with some of these problems.) Stich proposes a syntactic theory of the mind, on which the semantic properties of mental states play no explanatory role.

It is a traditional assumption among realists about mental representations that representational states come in two basic varieties (Boghossian 1995). There are those, such as thoughts, which are composed of concepts and have no phenomenal (‘what-it's-like’) features (‘qualia’), and those, such as sensory experiences, which have phenomenal features but no conceptual constituents. (Non-conceptual content is usually defined as a kind of content that states of a creature lacking concepts might nonetheless enjoy. On this taxonomy, mental states can represent either in a way analogous to expressions of natural languages or in a way analogous to drawings, paintings, maps or photographs. (Perceptual states such as seeing that something is blue, are sometimes thought of as hybrid states, consisting of, for example, a Non-conceptual sensory experience and a thought, or some more integrated compound of sensory and conceptual components.)

Some historical discussions of the representational properties of mind (e.g., Aristotle 1984, Locke 1689/1975, Hume 1739/1978) seem to assume that Non-conceptual representations - percepts (‘impressions’), images (‘ideas’) and the like - are the only kinds of mental representations, and that the mind represents the world in virtue of being in states that resemble things in it. On such a view, all representational states have their content in virtue of their phenomenal features. Powerful arguments, however, focussing on the lack of generality (Berkeley 1975), ambiguity (Wittgenstein 1953) and non-compositionality (Fodor 1981) of sensory and imagistic representations, as well as their unsuitability to function as logical (Frége 1918/1997, Geach 1957) or mathematical (Frége 1884/1953) concepts, and the symmetry of resemblance (Goodman 1976), convinced philosophers that no theory of mind can get by with only Non-conceptual representations construed in this way.

Contemporary disagreement over Non-conceptual representation concerns the existence and nature of phenomenal properties and the role they play in determining the content of sensory experience. Dennett (1988), for example, denies that there are such things as qualia at all; while Brandom (2002), McDowell (1994), Rey (1991) and Sellars (1956) deny that they are needed to explain the content of sensory experience. Among those who accept that experiences have phenomenal content, some (Dretske, Lycan, Tye) argue that it is reducible to a kind of intentional content, while others (Block, Loar, Peacocke) argue that it is irreducible.

There has also been dissent from the traditional claim that conceptual representations (thoughts, beliefs) lack phenomenology. Chalmers (1996), Flanagan (1992), Goldman (1993), Horgan and Tiensen (2003), Jackendoff (1987), Levine (1993, 1995, 2001), McGinn (1991), Pitt (2004), Searle (1992), Siewert (1998) and Strawson (1994), claim that purely symbolic (conscious) representational states themselves have a (perhaps proprietary) phenomenology. If this claim is correct, the question of what role phenomenology plays in the determination of content reprises for conceptual representation; and the eliminativist ambitions of Sellars, Brandom, Rey, would meet a new obstacle. (It would also raise prima face problems for reductivist representationalism

The representationalist thesis is often formulated as the claim that phenomenal properties are representational or intentional. However, this formulation is ambiguous between a reductive and a non-deductive claim (though the term ‘representationalism’ is most often used for the reductive claim). On one hand, it could mean that the phenomenal content of an experience is a kind of intentional content (the properties it represents). On the other, it could mean that the (irreducible) phenomenal properties of an experience determine an intentional content. Representationalists such as Dretske, Lycan and Tye would assent to the former claim, whereas phenomenalists such as Block, Chalmers, Loar and Peacocke would assent to the latter. (Among phenomenalists, there is further disagreement about whether qualia are intrinsically representational (Loar) or not (Block, Peacocke).

Most (reductive) representationalists are motivated by the conviction that one or another naturalistic explanation of intentionality is, in broad outline, correct, and by the desire to complete the naturalization of the mental by applying such theories to the problem of phenomenality. (Needless to say, most phenomenalists (Chalmers is the major exception) are just as eager to naturalize the phenomenal - though not in the same way.)

The main argument for representationalism appeals to the transparency of experience (cf. Tye 2000: 45-51). The properties that characterize what it's like to have a perceptual experience are presented in experience as properties of objects perceived: in attending to an experience, one seems to ‘see through it’ to the objects and properties it is experiences of. They are not presented as properties of the experience itself. If nonetheless they were properties of the experience, perception would be massively deceptive. But perception is not massively deceptive. According to the representationalist, the phenomenal character of an experience is due to its representing objective, non-experiential properties. (In veridical perception, these properties are locally instantiated; in illusion and hallucination, they are not.) On this view, introspection is indirect perception: one comes to know what phenomenal features one's experience has by coming to know what objective features it represents.

In order to account for the intuitive differences between conceptual and sensory representations, representationalists appeal to their structural or functional differences. Dretske (1995), for example, distinguishes experiences and thoughts on the basis of the origin and nature of their functions: an experience of a property 'P' is a state of a system whose evolved function is to indicate the presence of 'P' in the environment; a thought representing the property 'P', on the other hand, is a state of a system whose assigned (learned) function is to calibrate the output of the experiential system. Rey (1991) takes both thoughts and experiences to be relations to sentences in the language of thought, and distinguishes them on the basis of (the functional roles of) such sentences' constituent predicates. Lycan (1987, 1996) distinguishes them in terms of their functional-computational profiles. Tye (2000) distinguishes them in terms of their functional roles and the intrinsic structure of their vehicles: thoughts are representations in a language-like medium, whereas experiences are image-like representations consisting of ‘symbol-filled arrays.’ (the account of mental images in Tye 1991.)

Phenomenalists tend to make use of the same sorts of features (function, intrinsic structure) in explaining some of the intuitive differences between thoughts and experiences; but they do not suppose that such features exhaust the differences between phenomenal and non-phenomenal representations. For the phenomenalism, it is the phenomenal properties of experiences - qualia themselves - that constitute the fundamental difference between experience and thought. Peacocke (1992), for example, develops the notion of a perceptual ‘scenario’ (an assignment of phenomenal properties to coordinates of a three-dimensional egocentric space), whose content is ‘correct’ (a semantic property) if in the corresponding ‘scene’ (the portion of the external world represented by the scenario) properties are distributed as their phenomenal analogues are in the scenario.

Another sort of representation championed by phenomenalists (e.g., Block, Chalmers (2003) and Loar (1996)) is the ‘phenomenal concept’ - a conceptual/phenomenal hybrid consisting of a phenomenological ‘sample’ (an image or an occurrent sensation) integrated with (or functioning as) a conceptual component. Phenomenal concepts are postulated to account for the apparent fact (among others) that, as McGinn (1991) puts it, ‘you cannot form [introspective] concepts of conscious properties unless you yourself instantiate those properties.’ One cannot have a phenomenal concept of a phenomenal property 'P', and, hence, phenomenal beliefs about P, without having experience of 'P', because 'P' itself is (in some way) constitutive of the concept of 'P'. (Jackson 1982, 1986 and Nagel 1974.)

Though imagery has played an important role in the history of philosophy of mind, the important contemporary literature on it is primarily psychological. In a series of psychological experiments done in the 1970s (summarized in Kosslyn 1980 and Shepard and Cooper 1982), subjects' response time in tasks involving mental manipulation and examination of presented figures was found to vary in proportion to the spatial properties (size, orientation, etc.) of the figures presented. The question of how these experimental results are to be explained has kindled a lively debate on the nature of imagery and imagination.

Kosslyn (1980) claims that the results suggest that the tasks were accomplished via the examination and manipulation of mental representations that themselves have spatial properties - i.e., pictorial representations, or images. Others, principally Pylyshyn (1979, 1981, 2003), argue that the empirical facts can be explained in terms exclusively of discursive, or propositional representations and cognitive processes defined over them. (Pylyshyn takes such representations to be sentences in a language of thought.)

The idea that pictorial representations are literally pictures in the head is not taken seriously by proponents of the pictorial view of imagery The claim is, rather, that mental images represent in a way that is relevantly like the way pictures represent. (Attention has been focussed on visual imagery - hence the designation ‘pictorial’; though of course there may imagery in other modalities - auditory, olfactory, etc. - as well.)

The distinction between pictorial and discursive representation can be characterized in terms of the distinction between analog and digital representation (Goodman 1976). This distinction has itself been variously understood (Fodor & Pylyshyn 1981, Goodman 1976, Haugeland 1981, Lewis 1971, McGinn 1989), though a widely accepted construal is that analog representation is continuous (i.e., in virtue of continuously variable properties of the representation), while digital representation is discrete (i.e., in virtue of properties a representation either has or doesn't have) (Dretske 1981). (An analog/digital distinction may also be made with respect to cognitive processes. (Block 1983.)) On this understanding of the analog/digital distinction, imagistic representations, which represent in virtue of properties that may vary continuously (such as being more or less bright, loud, vivid, etc.), would be analog, while conceptual representations, whose properties do not vary continuously (a thought cannot be more or less about Elvis: either it is or it is not) would be digital.

It might be supposed that the pictorial/discursive distinction is best made in terms of the phenomenal/nonphenomenal distinction, but it is not obvious that this is the case. For one thing, there may be nonphenomenal properties of representations that vary continuously. Moreover, there are ways of understanding pictorial representation that presuppose neither phenomenality nor analogicity. According to Kosslyn (1980, 1982, 1983), a mental representation is ‘quasi-pictorial’ when every part of the representation corresponds to a part of the object represented, and relative distances between parts of the object represented are preserved among the parts of the representation. But distances between parts of a representation can be defined functionally rather than spatially - for example, in terms of the number of discrete computational steps required to combine stored information about them. (Rey 1981.)

Tye (1991) proposes a view of images on which they are hybrid representations, consisting both of pictorial and discursive elements. On Tye's account, images are ‘(labelled) interpreted symbol-filled arrays.’ The symbols represent discursively, while their arrangement in arrays has representational significance (the location of each ‘cell’ in the array represents a specific viewer-centred 2-D location on the surface of the imagined object)

The contents of mental representations are typically taken to be abstract objects (properties, relations, propositions, sets, etc.). A pressing question, especially for the naturalist, is how mental representations come to have their contents. Here the issue is not how to naturalize content (abstract objects can't be naturalized), but, rather, how to provide a naturalistic account of the content-determining relations between mental representations and the abstract objects they express. There are two basic types of contemporary naturalistic theories of content-determination, causal-informational and functional.

Causal-informational theories (Dretske 1981, 1988, 1995) hold that the content of a mental representation is grounded in the information it carries about what does (Devitt 1996) or would (Fodor 1987, 1990) cause it to occur. There is, however, widespread agreement that causal-informational relations are not sufficient to determine the content of mental representations. Such relations are common, but representation is not. Tree trunks, smoke, thermostats and ringing telephones carry information about what they are causally related to, but they do not represent (in the relevant sense) what they carry information about. Further, a representation can be caused by something it does not represent, and can represent something that has not caused it.

The main attempts to specify what makes a causal-informational state a mental representation are Asymmetric Dependency Theories (e.g., Fodor 1987, 1990, 1994) and Teleological Theories (Fodor 1990, Millikan 1984, Papineau 1987, Dretske 1988, 1995). The Asymmetric Dependency Theory distinguishes merely informational relations from representational relations on the basis of their higher-order relations to each other: informational relations depend upon representational relations, but not vice-versa. For example, if tokens of a mental state type are reliably caused by horses, cows-on-dark-nights, zebras-in-the-mist and Great Danes, then they carry information about horses, etc. If, however, such tokens are caused by cows-on-dark-nights, etc. because they were caused by horses, but not vice versa, then they represent horses.

According to Teleological Theories, representational relations are those a representation-producing mechanism has the selected (by evolution or learning) function of establishing. For example, zebra-caused horse-representations do not mean zebra, because the mechanism by which such tokens are produced has the selected function of indicating horses, not zebras. The horse-representation-producing mechanism that responds to zebras is malfunctioning.

Functional theories (Block 1986, Harman 1973), hold that the content of a mental representation is grounded in its (causal computational, inferential) relations to other mental representations. They differ on whether relata should include all other mental representations or only some of them, and on whether to include external states of affairs. The view that the content of a mental representation is determined by its inferential/computational relations with all other representations is holism; the view it is determined by relations to only some other mental states is localism (or molecularism). (The view that the content of a mental state depends on none of its relations to other mental states is atomism.) Functional theories that recognize no content-determining external relata have been called solipsistic (Harman 1987). Some theorists posit distinct roles for internal and external connections, the former determining semantic properties analogous to sense, the latter determining semantic properties analogous to reference (McGinn 1982, Sterelny 1989)

(Reductive) representationalists (Dretske, Lycan, Tye) usually take one or another of these theories to provide an explanation of the (Non-conceptual) content of experiential states. They thus tend to be Externalists about phenomenological as well as conceptual content. Phenomenalists and non-deductive representationalists (Block, Chalmers, Loar, Peacocke, Siewert), on the other hand, take it that the representational content of such states is (at least in part) determined by their intrinsic phenomenal properties. Further, those who advocate a phenomenology-based approach to conceptual content (Horgan and Tiensen, Loar, Pitt, Searle, Siewert) also seem to be committed to internalist individuation of the content (if not the reference) of such states.

Generally, those who, like informational theorists, think relations to one's (natural or social) environment are (at least partially) determinative of the content of mental representations are Externalists (e.g., Burge 1979, 1986, McGinn 1977, Putnam 1975), whereas those who, like some proponents of functional theories, think representational content is determined by an individual's intrinsic properties alone, are internalists (or individualists; cf. Putnam 1975, Fodor 1981)

This issue is widely taken to be of central importance, since psychological explanation, whether commonsense or scientific, is supposed to be both causal and content-based. (Beliefs and desires cause the behaviours they do because they have the contents they do. For example, the desire that one have a beer and the beliefs that there is beer in the refrigerator and that the refrigerator is in the kitchen may explain one's getting up and going to the kitchen.) If, however, a mental representation's having a particular content is due to factors extrinsic to it, it is unclear how its having that content could determine its causal powers, which, arguably, must be intrinsic. Some who accept the standard arguments for externalism have argued that internal factors determine a component of the content of a mental representation. They say that mental representations have both ‘narrow’ content (determined by intrinsic factors) and ‘wide’ or ‘broad’ content (determined by narrow content plus extrinsic factors). (This distinction may be applied to the sub-personal representations of cognitive science as well as to those of commonsense psychology.

Narrow content has been variously construed. Putnam (1975), Fodor (1982)), and Block (1986), for example, seem to understand it as something like de dicto content (i.e., Frégean sense, or perhaps character, à la Kaplan 1989). On this construal, narrow content is context-independent and directly expressible. Fodor (1987) and Block (1986), however, have also characterized narrow content as radically inexpressible. On this construal, narrow content is a kind of proto-content, or content-determinant, and can be specified only indirectly, via specifications of context/wide-content pairings. On both construal, narrow contents are characterized as functions from context to (wide) content. The narrow content of a representation is determined by properties intrinsic to it or its possessor such as its syntactic structure or its intra-mental computational or inferential role (or its phenomenology.

Burge (1986) has argued that causation-based worries about externalist individuation of psychological content, and the introduction of the narrow notion, are misguided. Fodor (1994, 1998) has more recently urged that a scientific psychology might not need narrow content in order to supply naturalistic (causal) explanations of human cognition and action, since the sorts of cases they were introduced to handle, viz., Twin-Earth cases and Frége cases, are either nomologically impossible or dismissible as exceptions to non-strict psychological laws.

The leading contemporary version of the Representational Theory of Mind, the Computational Theory of Mind (CTM), claims that the brain is a kind of computer and that mental processes are computations. According to the computational theory of mind, cognitive states are constituted by computational relations to mental representations of various kinds, and cognitive processes are sequences of such states. The computational theory of mind and the representational theory of mind, may by attempting to explain all psychological states and processes in terms of mental representation. In the course of constructing detailed empirical theories of human and animal cognition and developing models of cognitive processes implementable in artificial information processing systems, cognitive scientists have proposed a variety of types of mental representations. While some of these may be suited to be mental relata of commonsense psychological states, some - so-called ‘subpersonal’ or ‘sub-doxastic’ representations - are not. Though many philosophers believe that computational theory of mind can provide the best scientific explanations of cognition and behaviour, there is disagreement over whether such explanations will vindicate the commonsense psychological explanations of prescientific representational theory of mind.

According to Stich's (1983) Syntactic Theory of Mind, for example, computational theories of psychological states should concern themselves only with the formal properties of the objects those states are relations to. Commitment to the explanatory relevance of content, however, is for most cognitive scientists fundamental (Fodor 1981, Pylyshyn 1984, Von Eckardt 1993). That mental processes are computations, which computations are rule-governed sequences of semantically evaluable objects, and that the rules apply to the symbols in virtue of their content, are central tenets of mainstream cognitive science.

Explanations in cognitive science appeal to a many different kinds of mental representation, including, for example, the ‘mental models’ of Johnson-Laird 1983, the ‘retinal arrays,’ ‘primal sketches’ and ‘2½ -D sketches’ of Marr 1982, the ‘frames’ of Minsky 1974, the ‘sub-symbolic’ structures of Smolensky 1989, the ‘quasi-pictures’ of Kosslyn 1980, and the ‘interpreted symbol-filled arrays’ of Tye 1991 - in addition to representations that may be appropriate to the explanation of commonsense psychological states. Computational explanations have been offered of, among other mental phenomena, belief (Fodor 1975, Field 1978), visual perception (Marr 1982, Osherson, et al. 1990), rationality (Newell and Simon 1972, Fodor 1975, Johnson-Laird and Wason 1977), language learning and (Chomsky 1965, Pinker 1989), and musical comprehension (Lerdahl and Jackendoff 1983).

A fundamental disagreement among proponents of computational theory of mind concerns the realization of personal-level representations (e.g., thoughts) and processes (e.g., inferences) in the brain. The central debate here is between proponents of Classical Architectures and proponents of Conceptionist Architectures.

The classicists (e.g., Turing 1950, Fodor 1975, Fodor and Pylyshyn 1988, Marr 1982, Newell and Simon 1976) hold that mental representations are symbolic structures, which typically have semantically evaluable constituents, and that mental processes are rule-governed manipulations of them that are sensitive to their constituent structure. The connectionists (e.g., McCulloch & Pitts 1943, Rumelhart 1989, Rumelhart and McClelland 1986, Smolensky 1988) hold that mental representations are realized by patterns of activation in a network of simple processors (‘nodes’) and that mental processes consist of the spreading activation of such patterns. The nodes themselves are, typically, not taken to be semantically evaluable; nor do the patterns have semantically evaluable constituents. (Though there are versions of Connectionism - ‘localist’ versions - on which individual nodes are taken to have semantic properties (e.g., Ballard 1986, Ballard & Hayes 1984).) It is arguable, however, that localist theories are neither definitive nor representative of the Conceptionist program (Smolensky 1988, 1991, Chalmers 1993).

Classicists are motivated (in part) by properties thought seems to share with language. Fodor's Language of Thought Hypothesis (LOTH) (Fodor 1975, 1987), according to which the system of mental symbols constituting the neural basis of thought is structured like a language, provides a well-worked-out version of the classical approach as applied to commonsense psychology. According to the language of thought hypothesis, the potential infinity of complex representational mental states is generated from a finite stock of primitive representational states, in accordance with recursive formation rules. This combinatorial structure accounts for the properties of productivity and systematicity of the system of mental representations. As in the case of symbolic languages, including natural languages (though Fodor does not suppose either that the language of thought hypothesis explains only linguistic capacities or that only verbal creatures have this sort of cognitive architecture), these properties of thought are explained by appeal to the content of the representational units and their combinability into contentful complexes. That is, the semantics of both language and thought is compositional: the content of a complex representation is determined by the contents of its constituents and their structural configuration.

Connectionists are motivated mainly by a consideration of the architecture of the brain, which apparently consists of layered networks of interconnected neurons. They argue that this sort of architecture is unsuited to carrying out classical serial computations. For one thing, processing in the brain is typically massively parallel. In addition, the elements whose manipulation drives computation in Conceptionist networks (principally, the connections between nodes) are neither semantically compositional nor semantically evaluable, as they are on the classical approach. This contrast with classical computationalism is often characterized by saying that representation is, with respect to computation, distributed as opposed to local: representation is local if it is computationally basic; and distributed if it is not. (Another way of putting this is to say that for classicists mental representations are computationally atomic, whereas for connectionists they are not.)

Moreover, connectionists argue that information processing as it occurs in Conceptionist networks more closely resembles some features of actual human cognitive functioning. For example, whereas on the classical view learning involves something like hypothesis formation and testing (Fodor 1981), on the Conceptionist model it is a matter of evolving distribution of ‘weight’ (strength) on the connections between nodes, and typically does not involve the formulation of hypotheses regarding the identity conditions for the objects of knowledge. The Conceptionist network is ‘trained up’ by repeated exposure to the objects it is to learn to distinguish; and, though networks typically require many more exposures to the objects than do humans, this seems to model at least one feature of this type of human learning quite well.

Further, degradation in the performance of such networks in response to damage is gradual, not sudden as in the case of a classical information processor, and hence more accurately models the loss of human cognitive function as it typically occurs in response to brain damage. It is also sometimes claimed that Conceptionist systems show the kind of flexibility in response to novel situations typical of human cognition - situations in which classical systems are relatively ‘brittle’ or ‘fragile.’

Some philosophers have maintained that Connectionism entails that there are no propositional attitudes. Ramsey, Stich and Garon (1990) have argued that if Conceptionist models of cognition are basically correct, then there are no discrete representational states as conceived in ordinary commonsense psychology and classical cognitive science. Others, however (e.g., Smolensky 1989), hold that certain types of higher-level patterns of activity in a neural network may be roughly identified with the representational states of commonsense psychology. Still others (e.g., Fodor & Pylyshyn 1988, Heil 1991, Horgan and Tienson 1996) argue that language-of-thought style representation is both necessary in general and realizable within Conceptionist architectures. (MacDonald & MacDonald 1995 collects the central contemporary papers in the classicist/Conceptionist debate, and provides useful introductory material as well.

Whereas Stich (1983) accepts that mental processes are computational, but denies that computations are sequences of mental representations, others accept the notion of mental representation, but deny that computational theory of mind provides the correct account of mental states and processes.

Van Gelder (1995) denies that psychological processes are computational. He argues that cognitive systems are dynamic, and that cognitive states are not relations to mental symbols, but quantifiable states of a complex system consisting of (in the case of human beings) a nervous system, a body and the environment in which they are embedded. Cognitive processes are not rule-governed sequences of discrete symbolic states, but continuous, evolving total states of dynamic systems determined by continuous, simultaneous and mutually determining states of the systems' components. Representation in a dynamic system is essentially information-theoretic, though the bearers of information are not symbols, but state variables or parameters.

Horst (1996), on the other hand, argues that though computational models may be useful in scientific psychology, they are of no help in achieving a philosophical understanding of the intentionality of commonsense mental states. computational theory of mind attempts to reduce the intentionality of such states to the intentionality of the mental symbols they are relations to. But, Horst claims, the relevant notion of symbolic content is essentially bound up with the notions of convention and intention. So the computational theory of mind involves itself in a vicious circularity: the very properties that are supposed to be reduced are (tacitly) appealed to in the reduction.

To say that a mental object has semantic properties is, paradigmatically, to say that it may be about, or be true or false of, an object or objects, or that it may be true or false simpliciter. Suppose I think that ocelots take snuff. I am thinking about ocelots, and if what I think of them (that they take snuff) is true of them, then my thought is true. According to representational theory of mind such states are to be explained as relations between agents and mental representations. To think that ocelots take snuff is to token in some way a mental representation whose content is that ocelots take snuff. On this view, the semantic properties of mental states are the semantic properties of the representations they are relations to.

Linguistic acts seem to share such properties with mental states. Suppose I say that ocelots take snuff. I am talking about ocelots, and if what I say of them (that they take snuff) is true of them, then my utterance is true. Now, to say that ocelots take snuff is (in part) to utter a sentence that means that ocelots take snuff. Many philosophers have thought that the semantic properties of linguistic expressions are inherited from the intentional mental states they are conventionally used to express (Grice 1957, Fodor 1978, Schiffer1972/1988, Searle 1983). On this view, the semantic properties of linguistic expressions are the semantic properties of the representations that are the mental relata of the states they are conventionally used to express.

It is also widely held that in addition to having such properties as reference, truth-conditions and truth - so-called extensional properties - expressions of natural languages also have intensional properties, in virtue of expressing properties or propositions - i.e., in virtue of having meanings or senses, where two expressions may have the same reference, truth-conditions or truth value, yet express different properties or propositions (Frége 1892/1997). If the semantic properties of natural-language expressions are inherited from the thoughts and concepts they express (or vice versa, or both), then an analogous distinction may be appropriate for mental representations.

Søren Aabye Kierkegaard (1813-1855), a Danish religious philosopher, whose concern with individual existence, choice, and commitment profoundly influenced modern theology and philosophy, especially existentialism.

Søren Kierkegaard wrote of the paradoxes of Christianity and the faith required to reconcile them. In his book Fear and Trembling, Kierkegaard discusses Genesis 22, in which God commands Abraham to kill his only son, Isaac. Although God made an unreasonable and immoral demand, Abraham obeyed without trying to understand or justify it. Kierkegaard regards this ‘leap of faith’ as the essence of Christianity.

Kierkegaard was born in Copenhagen on May 15, 1813. His father was a wealthy merchant and strict Lutheran, whose gloomy, guilt-ridden piety and vivid imagination strongly influenced Kierkegaard. Kierkegaard studied theology and philosophy at the University of Copenhagen, where he encountered Hegelian philosophy and reacted strongly against it. While at the university, he ceased to practice Lutheranism and for a time led an extravagant social life, becoming a familiar figure in the theatrical and café society of Copenhagen. After his father's death in 1838, however, he decided to resume his theological studies. In 1840 he became engaged to the 17-year-old Regine Olson, but almost immediately he began to suspect that marriage was incompatible with his own brooding, complicated nature and his growing sense of a philosophical vocation. He abruptly broke off the engagement in 1841, but the episode took on great significance for him, and he repeatedly alluded to it in his books. At the same time, he realized that he did not want to become a Lutheran pastor. An inheritance from his father allowed him to devote himself entirely to writing, and in the remaining 14 years of his life he produced more than 20 books.

Kierkegaard's work is deliberately unsystematic and consists of essays, aphorisms, parables, fictional letters and diaries, and other literary forms. Many of his works were originally published under pseudonyms. He applied the term existential to his philosophy because he regarded philosophy as the expression of an intensely examined individual life, not as the construction of a monolithic system in the manner of the 19th-century German philosopher Georg Wilhelm Friedrich Hegel, whose work he attacked in Concluding Unscientific Postscript (1846; trans. 1941). Hegel claimed to have achieved a complete rational understanding of human life and history; Kierkegaard, on the other hand, stressed the ambiguity and paradoxical nature of the human situation. The fundamental problems of life, he contended, defy rational, objective explanation; the highest truth is subjective.

Kierkegaard maintained that systematic philosophy not only imposes a false perspective on human existence but that it also, by explaining life in terms of logical necessity, becomes a means of avoiding choice and responsibility. Individuals, he believed, create their own natures through their choices, which must be made in the absence of universal, objective standards. The validity of a choice can only be determined subjectively.

In his first major work, Either/Or (2 volumes, 1843; trans. 1944), Kierkegaard described two spheres, or stages of existence, that the individual may choose: the aesthetic and the ethical. The aesthetic way of life is a refined hedonism, consisting of a search for pleasure and a cultivation of mood. The aesthetic individual constantly seeks variety and novelty in an effort to stave off boredom but eventually must confront boredom and despair. The ethical way of life involves an intense, passionate commitment to duty, to unconditional social and religious obligations. In his later works, such as Stages on Life's Way (1845; trans. 1940), Kierkegaard discerned in this submission to duty a loss of individual responsibility, and he proposed a third stage, the religious, in which one submits to the will of God but in doing so finds authentic freedom. In Fear and Trembling (1846; trans. 1941) Kierkegaard focused on God's command that Abraham sacrifice his son Isaac (Genesis 22: 1-19), an act that violates Abraham's ethical convictions. Abraham proves his faith by resolutely setting out to obey God's command, even though he cannot understand it. This ‘suspension of the ethical,’ as Kierkegaard called it, allows Abraham to achieve an authentic commitment to God. To avoid ultimate despair, the individual must make a similar ‘leap of faith’ into a religious life, which is inherently paradoxical, mysterious, and full of risk. One is called to it by the feeling of dread (The Concept of Dread,1844; trans. 1944), which is ultimately a fear of nothingness.

Toward the end of his life Kierkegaard was involved in bitter controversies, especially with the established Danish Lutheran church, which he regarded as worldly and corrupt. His later works, such as The Sickness Unto Death (1849; trans. 1941), reflect an increasingly somber view of Christianity, emphasizing suffering as the essence of authentic faith. He also intensified his attack on modern European society, which he denounced in The Present Age (1846; trans. 1940) for its lack of passion and for its quantitative values. The stress of his prolific writing and of the controversies in which he engaged gradually undermined his health; in October 1855 he fainted in the street, and he died in Copenhagen on November 11, 1855.

Kierkegaard's influence was at first confined to Scandinavia and to German-speaking Europe, where his work had a strong impact on Protestant theology and on such writers as the 20th-century Austrian novelist Franz Kafka. As existentialism emerged as a general European movement after World War I, Kierkegaard's work was widely translated, and he was recognized as one of the seminal figures of modern culture.

Since scientists, during the nineteenth century were engrossed with uncovering the workings of external reality and seemingly knew of themselves that these virtually overflowing burdens of nothing, in that were about the physical substrates of human consciousness, the business of examining the distributive contribution in dynamic functionality and structural foundation of mind became the province of social scientists and humanists. Adolphe Quételet proposed a ‘social physics’ that could serve as the basis for a new discipline called sociology, and his contemporary Auguste Comte concluded that a true scientific understanding of the social reality was quite inevitable. Mind, in the view of these figures, was a separate and distinct mechanism subject to the lawful workings of a mechanical social reality.

More formal European philosophers, such as Immanuel Kant, sought to reconcile representations of external reality in mind with the motions of matter-based on the dictates of pure reason. This impulse was also apparent in the utilitarian ethics of Jerry Bentham and John Stuart Mill, in the historical materialism of Karl Marx and Friedrich Engels, and in the pragmatism of Charles Smith, William James and John Dewey. These thinkers were painfully aware, however, of the inability of reason to posit a self-consistent basis for bridging the gap between mind and matter, and each remains obliged to conclude that the realm of the mental exists only in the subjective reality of the individual.

The fatal flaw of pure reason is, of course, the absence of emotion, and purely explanations of the division between subjective reality and external reality, of which had limited appeal outside the community of intellectuals. The figure most responsible for infusing our understanding of the Cartesian dualism with contextual representation of our understanding with emotional content was the death of God theologian Friedrich Nietzsche 1844-1900. After declaring that God and ‘divine will’, did not exist, Nietzsche reified the ‘existence’ of consciousness in the domain of subjectivity as the ground for individual ‘will’ and summarily reducing all previous philosophical attempts to articulate the ‘will to truth’. The dilemma, forth in, had seemed to mean, by the validation, . . . as accredited for doing of science, in that the claim that Nietzsche’s earlier versions to the ‘will to truth’, disguises the fact that all alleged truths were arbitrarily created in the subjective reality of the individual and are expressed or manifesting the individualism of ‘will’.

In Nietzsche’s view, the separation between mind and matter is more absolute and total than previously been imagined. Based on the assumption that there is no really necessary correspondence between linguistic constructions of reality in human subjectivity and external reality, he deuced that we are all locked in ‘a prison house of language’. The prison as he concluded it, was also a ‘space’ where the philosopher can examine the ‘innermost desires of his nature’ and articulate a new message of individual existence founded on ‘will’.

Those who fail to enact their existence in this space, Nietzsche says, are enticed into sacrificing their individuality on the nonexistent altars of religious beliefs and democratic or socialists’ ideals and become, therefore, members of the anonymous and docile crowd. Nietzsche also invalidated the knowledge claims of science in the examination of human subjectivity. Science, he said. Is not exclusive to natural phenomenons and favors reductionistic examination of phenomena at the expense of mind? It also seeks to reduce the separateness and uniqueness of mind with mechanistic descriptions that disallow and basis for the free exercise of individual will.

Nietzsche’s emotionally charged defense of intellectual freedom and radial empowerment of mind as the maker and transformer of the collective fictions that shape human reality in a soulless mechanistic universe proved terribly influential on twentieth-century thought. Furthermore, Nietzsche sought to reinforce his view of the subjective character of scientific knowledge by appealing to an epistemological crisis over the foundations of logic and arithmetic that arose during the last three decades of the nineteenth century. Through a curious course of events, attempted by Edmund Husserl 1859-1938, a German mathematician and a principal founder of phenomenology, wherefor to resolve this crisis resulted in a view of the character of consciousness that closely resembled that of Nietzsche.

The best-known disciple of Husserl was Martin Heidegger, and the work of both figures greatly influenced that of the French atheistic existentialist Jean-Paul Sartre. The work of Husserl, Heidegger, and Sartre became foundational to that of the principal architects of philosophical postmodernism, and deconstructionist Jacques Lacan, Roland Barthes, Michel Foucault and Jacques Derrida. It obvious attribution of a direct linkage between the nineteenth-century crisis about the epistemological foundations of mathematical physics and the origin of philosophical postmodernism served to perpetuate the Cartesian two-world dilemma in an even more oppressive form. It also allows us better to understand the origins of cultural ambience and the ways in which they could resolve that conflict.

The mechanistic paradigms of the late in the nineteenth century where the one Einstein came to know when he studied physics. Most physicists believed that it represented an eternal truth, but Einstein was open to fresh ideas. Inspired by Mach’s critical mind, he demolished the Newtonian ideas of space and time and replaced them with new, ‘relativistic’ notions.

Jean-Paul Sartre (1905-1980), was a French philosopher, dramatist, novelist, and political journalist, who was a leading exponent of existentialism. Jean-Paul Sartre helped to develop existential philosophy through his writings, novels, and plays. Much of Sartre’s work focuses on the dilemma of choice faced by free individuals and on the challenge of creating meaning by acting responsibly in an indifferent world. In stating that ‘man is condemned to be free,’ Sartre reminds us of the responsibility that accompanies human decisions.

Sartre was born in Paris, June 21, 1905, and educated at the Écôle Normale Supérieure in Paris, the University of Fribourg in Switzerland, and the French Institute in Berlin. He taught philosophy at various lycées from 1929 until the outbreak of World War II, when he was called into military service. In 1940-41 he was imprisoned by the Germans; after his release, he taught in Neuilly, France, and later in Paris, and was active in the French Resistance. The German authorities, unaware of his underground activities, permitted the production of his antiauthoritarian play The Flies (1943; trans. 1946) and the publication of his major philosophic work Being and Nothingness (1943; trans. 1953). Sartre gave up teaching in 1945 and founded the political and literary magazine Les Temps Modernes, of which he became editor in chief. Sartre was active after 1947 as an independent Socialist, critical of both the USSR and the United States in the so-called cold war years. Later, he supported Soviet positions but still frequently criticized Soviet policies. Most of his writing of the 1950s deals with literary and political problems. Sartre rejected the 1964 Nobel Prize in literature, explaining that to accept such an award would compromise his integrity as a writer.

Sartre's philosophic works combine the phenomenology of the German philosopher Edmund Husserl, the metaphysics of the German philosophers Georg Wilhelm Friedrich Hegel and Martin Heidegger, and the social theory of Karl Marx into a single view called existentialism. This view, which relates philosophical theory to life, literature, psychology, and political action, stimulated so much popular interest that existentialism became a worldwide movement.

In his early philosophic work, Being and Nothingness, Sartre conceived humans as beings who create their own world by rebelling against authority and by accepting personal responsibility for their actions, unaided by society, traditional morality, or religious faith. Distinguishing between human existence and the nonhuman world, he maintained that human existence is characterized by nothingness, that is, by the capacity to negate and rebel. His theory of existential psychoanalysis asserted the inescapable responsibility of all individuals for their own decisions and made the recognition of one's absolute freedom of choice the necessary condition for authentic human existence. His plays and novels express the belief that freedom and acceptance of personal responsibility are the main values in life and that individuals must rely on their creative powers rather than on social or religious authority.

In his later philosophic work Critique of Dialectical Reason (1960; trans. 1976), Sartre's emphasis shifted from existentialist freedom and subjectivity to Marxist social determinism. Sartre argued that the influence of modern society over the individual is so great as to produce serialization, by which he meant loss of self. Individual power and freedom can only be regained through group revolutionary action. Despite this exhortation to revolutionary political activity, Sartre himself did not join the Communist Party, thus retaining the freedom to criticize the Soviet invasions of Hungary in 1956 and Czechoslovakia in 1968. He died in Paris, April 15, 1980.

The part of the theory of design or semiotics, that concerns the relationship between speakers and their signs. the study of the principles governing appropriate conversational moves is called general pragmatized, applied pragmatics treats of special kinds of linguistic interaction such as inter-views and speech asking, nevertheless, the philosophical movement that has had a major impact on American culture from the late 19th century to the present. Pragmatism calls for ideas and theories to be tested in practice, by assessing whether acting upon the idea or theory produces desirable or undesirable results. According to pragmatists, all claims about truth, knowledge, morality, and politics must be tested in this way. Pragmatism has been critical of traditional Western philosophy, especially the notion that there are absolute truths and absolute values. Although pragmatism was popular for a time in France, England, and Italy, most observers believe that it encapsulates an American faith in know-how and practicality and an equally American distrust of abstract theories and ideologies.

Pragmatists regard all theories and institutions as tentative hypotheses and solutions. For this reason they believed that efforts to improve society, through such means as education or politics, must be geared toward problem solving and must be ongoing. Through their emphasis on connecting theory to practice, pragmatist thinkers attempted to transform all areas of philosophy, from metaphysics to ethics and political philosophy.

Pragmatism sought a middle ground between traditional ideas about the nature of reality and radical theories of nihilism and irrationalism, which had become popular in Europe in the late 19th century. Traditional metaphysics assumed that the world has a fixed, intelligible structure and that human beings can know absolute or objective truths about the world and about what constitutes moral behavior. Nihilism and irrationalism, on the other hand, denied those very assumptions and their certitude. Pragmatists today still try to steer a middle course between contemporary offshoots of these two extremes.

The ideas of the pragmatists were considered revolutionary when they first appeared. To some critics, pragmatism’s refusal to affirm any absolutes carried negative implications for society. For example, pragmatists do not believe that a single absolute idea of goodness or justice exists, but rather that these concepts are changeable and depend on the context in which they are being discussed. The absence of these absolutes, critics feared, could result in a decline in moral standards. The pragmatists’ denial of absolutes, moreover, challenged the foundations of religion, government, and schools of thought. As a result, pragmatism influenced developments in psychology, sociology, education, semiotics (the study of signs and symbols), and scientific method, as well as philosophy, cultural criticism, and social reform movements. Various political groups have also drawn on the assumptions of pragmatism, from the progressive movements of the early 20th century to later experiments in social reform.

Pragmatism is best understood in its historical and cultural context. It arose during the late 19th century, a period of rapid scientific advancement typified by the theories of British biologist Charles Darwin, whose theories suggested to many thinkers that humanity and society are in a perpetual state of progress. During this same period a decline in traditional religious beliefs and values accompanied the industrialization and material progress of the time. In consequence it became necessary to rethink fundamental ideas about values, religion, science, community, and individuality.

The three most important pragmatists are American philosophers Charles Sanders Peirce, William James, and John Dewey. Peirce was primarily interested in scientific method and mathematics; his objective was to infuse scientific thinking into philosophy and society, and he believed that human comprehension of reality was becoming ever greater and that human communities were becoming increasingly progressive. Peirce developed pragmatism as a theory of meaning - in particular, the meaning of concepts used in science. The meaning of the concept ‘brittle,’ for example, is given by the observed consequences or properties that objects called ‘brittle’ exhibit. For Peirce, the only rational way to increase knowledge was to form mental habits that would test ideas through observation, experimentation, or what he called inquiry. Many philosophers known as logical positivists, a group of philosophers who have been influenced by Peirce, believed that our evolving species was fated to get ever closer to Truth. Logical positivists emphasize the importance of scientific verification, rejecting the assertion of positivism that personal experience is the basis of true knowledge.

James moved pragmatism in directions that Peirce strongly disliked. He generalized Peirce’s doctrines to encompass all concepts, beliefs, and actions; he also applied pragmatist ideas to truth as well as to meaning. James was primarily interested in showing how systems of morality, religion, and faith could be defended in a scientific civilization. He argued that sentiment, as well as logic, is crucial to rationality and that the great issues of life - morality and religious belief, for example - are leaps of faith. As such, they depend upon what he called ‘the will to believe’ and not merely on scientific evidence, which can never tell us what to do or what is worthwhile. Critics charged James with relativism (the belief that values depend on specific situations) and with crass expediency for proposing that if an idea or action works the way one intends, it must be right. But James can more accurately be described as a pluralist - someone who believes the world to be far too complex for any one philosophy to explain everything.

Dewey’s philosophy can be described as a version of philosophical naturalism, which regards human experience, intelligence, and communities as ever-evolving mechanisms. Using their experience and intelligence, Dewey believed, human beings can solve problems, including social problems, through inquiry. For Dewey, naturalism led to the idea of a democratic society that allows all members to acquire social intelligence and progress both as individuals and as communities. Dewey held that traditional ideas about knowledge, truth, and values, in which absolutes are assumed, are incompatible with a broadly Darwinian world-view in which individuals and society are progressing. In consequence, he felt that these traditional ideas must be discarded or revised. Indeed, for pragmatists, everything people know and do depends on a historical context and is thus tentative rather than absolute.

Many followers and critics of Dewey believe he advocated elitism and social engineering in his philosophical stance. Others think of him as a kind of romantic humanist. Both tendencies are evident in Dewey’s writings, although he aspired to synthesize the two realms.

The pragmatist tradition was revitalized in the 1980s by American philosopher Richard Rorty, who has faced similar charges of elitism for his belief in the relativism of values and his emphasis on the role of the individual in attaining knowledge. Interest has renewed in the classic pragmatists - Pierce, James, and Dewey - as an alternative to Rorty’s interpretation of the tradition.

In an ever-changing world, pragmatism has many benefits. It defends social experimentation as a means of improving society, accepts pluralism, and rejects dead dogmas. But a philosophy that offers no final answers or absolutes and that appears vague as a result of trying to harmonize opposites may also be unsatisfactory to some.

One of the five branches into which semiotics is usually divided the study of meaning of words, and their relation of designed to the object studied, a semantic is provided for a formal language when an interpretation or model is specified. Nonetheless, the Semantics, the Greek semantikos, ‘significant,’ the study of the meaning of linguistic signs - that is, words, expressions, and sentences. Scholars of semantics try to one answer such questions as ‘What is the meaning of (the word) X?’ They do this by studying what signs are, as well as how signs possess significance - that is, how they are intended by speakers, how they designate (make reference to things and ideas), and how they are interpreted by hearers. The goal of semantics is to match the meanings of signs - what they stand for - with the process of assigning those meanings.

Semantics is studied from philosophical (pure) and linguistic (descriptive and theoretical) approaches, plus an approach known as general semantics. Philosophers look at the behavior that goes with the process of meaning. Linguists study the elements or features of meaning as they are related in a linguistic system. General semanticists concentrate on meaning as influencing what people think and do.

These semantic approaches also have broader application. Anthropologists, through descriptive semantics, study what people categorize as culturally important. Psychologists draw on theoretical semantic studies that attempt to describe the mental process of understanding and to identify how people acquire meaning (as well as sound and structure) in language. Animal behaviorists research how and what other species communicate. Exponents of general semantics examine the different values (or connotations) of signs that supposedly mean the same thing (such as ‘the victor at Jena’ and ‘the loser at Waterloo,’ both referring to Napoleon). Also in a general-semantics vein, literary critics have been influenced by studies differentiating literary language from ordinary language and describing how literary metaphors evoke feelings and attitudes.

In the late 19th century Michel Jules Alfred Breal, a French philologist, proposed a ‘science of significations’ that would investigate how sense is attached to expressions and other signs. In 1910 the British philosophers Alfred North Whitehead and Bertrand Russell published Principia Mathematica, which strongly influenced the Vienna Circle, a group of philosophers who developed the rigorous philosophical approach known as logical positivism.

One of the leading figures of the Vienna Circle, the German philosopher Rudolf Carnap, made a major contribution to philosophical semantics by developing symbolic logic, a system for analyzing signs and what they designate. In logical positivism, meaning is a relationship between words and things, and its study is empirically based: Because language, ideally, is a direct reflection of reality, signs match things and facts. In symbolic logic, however, mathematical notation is used to state what signs designate and to do so more clearly and precisely than is possible in ordinary language. Symbolic logic is thus itself a language, specifically, a metalanguage (formal technical language) used to talk about an object language (the language that is the object of a given semantic study).

An object language has a speaker (for example, a French woman) using expressions (such as la plume rouge) to designate a meaning (in this case, to indicate a definite pen - plume - of the color red - rouge). The full description of an object language in symbols is called the semiotic of that language. A language's semiotic has the following aspects: (1) a semantic aspect, in which signs (words, expressions, sentences) are given specific designations; (2) a pragmatic aspect, in which the contextual relations between speakers and signs are indicated; and (3) a syntactic aspect, in which formal relations among the elements within signs (for example, among the sounds in a sentence) are indicated.

An interpreted language in symbolic logic is an object language together with rules of meaning that link signs and designations. Each interpreted sign has a truth condition - a condition that must be met in order for the sign to be true. A sign's meaning is what the sign designates when its truth condition is satisfied. For example, the expression or sign ‘the moon is a sphere’ is understood by someone who knows English; however, although it is understood, it may or may not be true. The expression is true if the thing it is extended to - the moon - is in fact spherical. To determine the sign's truth value, one must look at the moon for oneself.

The symbolic logic of logical positivist philosophy thus represents an attempt to get at meaning by way of the empirical verifiability of signs - by whether the truth of the sign can be confirmed by observing something in the real world. This attempt at understanding meaning has been only moderately successful. The Austrian-British philosopher Ludwig Wittgenstein rejected it in favor of his ‘ordinary language’ philosophy, in which he asserted that thought is based on everyday language. Not all signs designate things in the world, he pointed out, nor can all signs be associated with truth values. In his approach to philosophical semantics, the rules of meaning are disclosed in how speech is used.

From ordinary-language philosophy has evolved the current theory of speech-act semantics. The British philosopher J. L. Austin claimed that, by speaking, a person performs an act, or does something (such as state, predict, or warn), and that meaning is found in what an expression does, in the act it performs. The American philosopher John R. Searle extended Austin's ideas, emphasizing the need to relate the functions of signs or expressions to their social context. Searle asserted that speech encompasses at least three kinds of acts: (1) elocutionary acts, in which things are said with a certain sense or reference (as in ‘the moon is a sphere’); (2) illocutionary acts, in which such acts as promising or commanding are performed by means of speaking; and (3) perlocutionary acts, in which the speaker, by speaking, does something to someone else (for example, angers, consoles, or persuades someone). The speaker's intentions are conveyed by the illocutionary force that is given to the signs - that is, by the actions implicit in what is said. To be successfully meant, however, the signs must also be appropriate, sincere, consistent with the speaker's general beliefs and conduct, and recognizable as meaningful by the hearer.

What has developed in philosophical semantics, then, is a distinction between truth-based semantics and speech-act semantics. Some critics of speech-act theory believe that it deals primarily with meaning in communication (as opposed to meaning in language) and thus is part of the pragmatic aspect of a language's semiotic - that it relates to signs and to the knowledge of the world shared by speakers and hearers, rather than relating to signs and their designations (semantic aspect) or to formal relations among signs (syntactic aspect). These scholars hold that semantics should be restricted to assigning interpretations to signs alone - independent of a speaker and hearer.

Researchers in descriptive semantics examine what signs mean in particular languages. They aim, for instance, to identify what constitutes nouns or noun phrases and verbs or verb phrases. For some languages, such as English, this is done with subject-predicate analysis. For languages without clear-cut distinctions between nouns, verbs, and prepositions, it is possible to say what the signs mean by analyzing the structure of what are called propositions. In such an analysis, a sign is seen as an operator that combines with one or more arguments (also signs), often nominal arguments (noun phrases) or, relates nominal arguments to other elements in the expression (such as prepositional phrases or adverbial phrases). For example, in the expression ‘Bill gives Mary the book,’‘gives’ is an operator that relates the arguments ‘Bill,’‘Mary,’ and ‘the book.’

Whether using subject-predicate analysis or propositional analysis, descriptive semanticists establish expression classes (classes of items that can substitute for one another within a sign) and classes of items within the conventional parts of speech (such as nouns and verbs). The resulting classes are thus defined in terms of syntax, and they also have semantic roles; that is, the items in these classes perform specific grammatical functions, and in so doing they establish meaning by predicating, referring, making distinctions among entities, relations, or actions. For example, ‘kiss’ belongs to an expression class with other items such as ‘hit’ and ‘see,’ as well as to the conventional part of speech ‘verb,’ in which it is part of a subclass of operators requiring two arguments (an actor and a receiver). In ‘Mary kissed John,’ the syntactic role of ‘kiss’ is to relate two nominal arguments (‘Mary’ and ‘John’), whereas its semantic role is to identify a type of action. Unfortunately for descriptive semantics, however, it is not always possible to find a one-to-one correlation of syntactic classes with semantic roles. For instance, ‘John’ has the same semantic role - to identify a person - in the following two sentences: ‘John is easy to please’ and ‘John is eager to please.’ The syntactic role of ‘John’ in the two sentences, however, is different: In the first, ‘John’ is the receiver of an action; in the second, ‘John’ is the actor.

Linguistic semantics is also used by anthropologists called ethnoscientists to conduct formal semantic analysis (componential analysis) to determine how expressed signs - usually single words as vocabulary items called lexemes - in a language are related to the perceptions and thoughts of the people who speak the language. Componential analysis tests the idea that linguistic categories influence or determine how people view the world; this idea is called the Whorf hypothesis after the American anthropological linguist Benjamin Lee Whorf, who proposed it. In componential analysis, lexemes that have a common range of meaning constitute a semantic domain. Such a domain is characterized by the distinctive semantic features (components) that differentiate individual lexemes in the domain from one another, and also by features shared by all the lexemes in the domain. Such componential analysis points out, for example, that in the domain ‘seat’ in English, the lexemes ‘chair,’‘sofa,’‘loveseat,’ and ‘bench’ can be distinguished from one another according to how many people are accommodated and whether a back support is included. At the same time all these lexemes share the common component, or feature, of meaning ‘something on which to sit.’

Linguists pursuing such componential analysis hope to identify a universal set of such semantic features, from which are drawn the different sets of features that characterize different languages. This idea of universal semantic features has been applied to the analysis of systems of myth and kinship in various cultures by the French anthropologist Claude Lévi-Strauss. He showed that people organize their societies and interpret their place in these societies in ways that, despite apparent differences, have remarkable underlying similarities.

Linguists concerned with theoretical semantics are looking for a general theory of meaning in language. To such linguists, known as transformational-generative grammarians, meaning is part of the linguistic knowledge or competence that all humans possess. A generative grammar as a model of linguistic competence has a phonological (sound-system), a syntactic, and a semantic component. The semantic component, as part of a generative theory of meaning, is envisioned as a system of rules that govern how interpretable signs are interpreted and determine that other signs (such as ‘Colorless green ideas sleep furiously’), although grammatical expressions, are meaningless - semantically blocked. The rules must also account for how a sentence such as ‘They passed the port at midnight’ can have at least two interpretations.

Generative semantics grew out of proposals to explain a speaker's ability to produce and understand new expressions where grammar or syntax fails. Its goal is to explain why and how, for example, a person understands at first hearing that the sentence ‘Colorless green ideas sleep furiously’ has no meaning, even though it follows the rules of English grammar; or how, in hearing a sentence with two possible interpretations (such as ‘They passed the port at midnight’), one decides which meaning applies.

In generative semantics, the idea developed that all information needed to semantically interpret a sign (usually a sentence) is contained in the sentence's underlying grammatical or syntactic deep structure. The deep structure of a sentence involves lexemes (understood as words or vocabulary items composed of bundles of semantic features selected from the proposed universal set of semantic features). On the sentence's surface (that is, when it is spoken) these lexemes will appear as nouns, verbs, adjectives, and other parts of speech - that is, as vocabulary items. When the sentence is formulated by the speaker, semantic roles (such as subject, object, predicate) are assigned to the lexemes; the listener hears the spoken sentence and interprets the semantic features that are meant.

Whether deep structure and semantic interpretation are distinct from one another is a matter of controversy. Most generative linguists agree, however, that a grammar should generate the set of semantically well-formed expressions that are possible in a given language, and that the grammar should associate a semantic interpretation with each expression.

Another subject of debate is whether semantic interpretation should be understood as syntactically based (that is, coming from a sentence's deep structure); or whether it should be seen as semantically based. According to Noam Chomsky, an American scholar who is particularly influential in this field, it is possible - in a syntactically based theory - for surface structure and deep structure jointly to determine the semantic interpretation of an expression.

The focus of general semantics is how people evaluate words and how that evaluation influences their behavior. Begun by the Polish American linguist Alfred Korzybski and long associated with the American semanticist and politician S. I. Hayakawa, general semantics has been used in efforts to make people aware of dangers inherent in treating words as more than symbols. It has been extremely popular with writers who use language to influence people's ideas. In their work, these writers use general-semantics guidelines for avoiding loose generalizations, rigid attitudes, inappropriate finality, and imprecision. Some philosophers and linguists, however, have criticized general semantics as lacking scientific rigor, and the approach has declined in popularity.

Positivism, system of philosophy based on experience and empirical knowledge of natural phenomena, in which metaphysics and theology are regarded as inadequate and imperfect systems of knowledge. The doctrine was first called positivism by the 19th-century French mathematician and philosopher Auguste Comte (1798-1857), but some of the positivist concepts may be traced to the British philosopher David Hume, the French philosopher Duc de Saint-Simon, and the German philosopher Immanuel Kant.

Comte chose the word positivism on the ground that it indicated the ‘reality’ and ‘constructive tendency’ that he claimed for the theoretical aspect of the doctrine. He was, in the main, interested in a reorganization of social life for the good of humanity through scientific knowledge, and thus control of natural forces. The two primary components of positivism, the philosophy and the polity (or program of individual and social conduct), were later welded by Comte into a whole under the conception of a religion, in which humanity was the object of worship. A number of Comte's disciples refused, however, to accept this religious development of his philosophy, because it seemed to contradict the original positivist philosophy. Many of Comte's doctrines were later adapted and developed by the British social philosophers John Stuart Mill and Herbert Spencer and by the Austrian philosopher and physicist Ernst Mach.

The principle named But rejected by the English economist and philosopher John Maynard Keyes (1883-1946) whereby if there is no known reason for asserting one than another out of several alternatives, then relative to our knowledge they have an equal probability. Without restriction the principle leads to contradiction, for example, if we know nothing about the nationality of a person, we might argue that the probability is equal that she comes from England or France, and equal that she comes from Scotland or France. But from the first two assertions the probability that she belongs to Britain must be at least double the probability that be belongs to France.

A paradox arises when a set class of apparent incontrovertible premises gives unacceptable or contradictory conclusions. To solve a paradox will involve either showing that there is a hidden flaw in the premises, or that the reasoning is erroneous, or that the apparently unacceptable conclusion can, in fact, be tolerated. Paradoxes are therefore important in philosophy, for until one is solved it shows that there is something about our reasoning and our concepts that we do not understand.

By comparison, the moral philosopher and epistemologist Bernard Bolzano (1781-1848) argues, though, that there is something else, an infinity that doe not have this whatever you need it to be elasticity. In fact a truly infinite quantity (for example, the length of a straight ligne unbounded in either direction, meaning: The magnitude of the spatial entity containing all the points determined solely by their abstractly conceivable relation to two fixed points) does not by any means need to be variable, and in adduced example it is in fact not variable. Conversely, it is quite possible for a quantity merely capable of being taken greater than we have already taken it, and of becoming larger than any pre-assigned (finite) quantity, nevertheless it is to mean, in that of all times is merely finite, which holds in particular of every numerical quantity 1, 2, 3, 4, 5.

In other words, for Bolzano there could be a true infinity that was not a variable something that was only bigger than anything you might specify. Such a true infinity was the result of joining two pints together and extending that ligne in both directions without stopping. And what is more, he could separate off the demands of calculus, using a finite quality without ever bothering with the slippery potential infinity. Here was both a deeper understanding of the nature of infinity and the basis on which are built in his safe infinity free calculus.

This use of the inexhaustible follows on directly from most Bolzanos’ criticism of the way that ∞ we used as a variable something that would be bigger than anything you could specify, but never quite reached the true, absolute infinity. In Paradoxes of the Infinity Bolzano points out that is possible for a quantity merely capable of becoming larger than any one pre-assigned (finite) quantity, nevertheless to remain at all times merely finite.

Bolzano intended this as a criticism of the way infinity was treated, but Professor Jacquette sees it instead of a way of masking use of practical applications like calculus without the need for weasel words about infinity.

By replacing ∞ with ¤ we do away with one of the most common requirements for infinity, but is there anything left that map out to the real world? Can we confine infinity to that pure mathematical other world, where anything, however unreal, can be constructed, and forget about it elsewhere? Surprisingly, this seems to have been the view, at least at one point in time, even of the German mathematician and founder of set-theory Georg Cantor (1845-1918), himself, whose comments in 1883, that only the finite numbers are real.

Keeping within the lines of reason, both the Cambridge mathematician and philosopher Frank Plumpton Ramsey (1903-30) and the Italian mathematician G. Peano (1858-1932) have been to distinguish logical paradoxes and that depend upon the notion of reference or truth (semantic notions), such are the postulates justifying mathematical induction. It ensures that a numerical series is closed, in the sense that nothing but zero and its successors can be numbers. In that any series satisfying a set of axioms can be conceived as the sequence of natural numbers. Candidates from set theory include the Zermelo numbers, where the empty set is zero, and the successor of each number is its unit set, and the von Neuman numbers, where each number is the set of all smaller numbers. A similar and equally fundamental complementarity exists in the relation between zero and infinity. Although the fullness of infinity is logically antithetical to the emptiness of zero, infinity can be obtained from zero with a simple mathematical operation. The division of many numbers by zero is infinity, while the multiplication of any number by zero is zero.

With the set theory developed by the German mathematician and logician Georg Cantor. From 1878 to 1807, Cantor created a theory of abstract sets of entities that eventually became a mathematical discipline. A set, as he defined it, is a collection of definite and distinguished objects in thought or perception conceived as a whole.

Cantor attempted to prove that the process of counting and the definition of integers could be placed on a solid mathematical foundation. His method was to repeatedly place the elements in one set into one-to-one correspondence with those in another. In the case of integers, Cantor showed that each integer (1, 2, 3, . . . n) could be paired with an even integers (2, 4, 6, . . . n), and, therefore, that the set of all integers was equal to the set of all even numbers.

Amazingly, Cantor discovered that some infinite sets were large than others and that infinite sets formed a hierarchy of greater infinities. After this failed attempt to save the classical view of logical foundations and internal consistency of mathematical systems, it soon became obvious that a major crack had appeared in the seemingly sold foundations of number and mathematics. Meanwhile, an impressive number of mathematicians began to see that everything from functional analysis to the theory of real numbers depended on the problematic character of number itself.

While, in the theory of probability Ramsey was the first to show how a personalized theory could be developed, based on precise behavioural notions of preference and expectation. In the philosophy of language, Ramsey was one of the first thinkers to accept a redundancy theory of truth, which hr combined with radical views of the function of man y kinds of propositions. Neither generalizations nor causal propositions, nor those treating probability or ethics, describe facts, but each has a different specific function in our intellectual economy.

Ramsey advocates that of a sentence generated by taking all the sentence affirmed in a scientific theory that use some term, e.g., quark. Replacing the term by a variable, and existentially quantifying into the result. Instead of saying quarks have such-and-such properties, Ramsey postdated that the sentence as saying that there is something that has those properties. If the process is repeated, the sentence gives the topic-neutral structure of the theory, but removes any implications that we know what the term so treated denote. It leaves open the possibility of identifying the theoretical item with whatever it is that best fits the description provided. Nonetheless, it was pointed out by the Cambridge mathematician Newman that if the process is carried out for all except the logical bones of the theory, then by the Löwenheim-Skolem theorem, the result will be interpretable in any domain of sufficient cardinality, and the content of the theory may reasonably be felt to have been lost.

It seems, that the most taken of paradoxes in the foundations of set theory as discovered by Russell in 1901. Some classes have themselves as members: The class of all abstract objects, for example, is an abstract object, whereby, others do not: The class of donkeys is not itself a donkey. Now consider the class of all classes that are not members of themselves, is this class a member of itself, that, if it is, then it is not, and if it is not, then it is.

The paradox is structurally similar to easier examples, such as the paradox of the barber. Such one like a village having a barber in it, who shaves all and only the people who do not have in themselves. Who shaves the barber? If he shaves himself, then he does not, but if he does not shave himself, then he does not. The paradox is actually just a proof that there is no such barber or in other words, that the condition is inconsistent. All the same, it is no to easy to say why there is no such class as the one Russell defines. It seems that there must be some restriction on the kind of definition that are allowed to define classes and the difficulty that of finding a well-motivated principle behind any such restriction.

The French mathematician and philosopher Henri Jules Poincaré (1854-1912) believed that paradoxes like those of Russell and the barber were due to such as the impredicative definitions, and therefore proposed banning them. But, it tuns out that classical mathematics required such definitions at too many points for the ban to be easily absolved. Having, in turn, as forwarded by Poincaré and Russell, was that in order to solve the logical and semantic paradoxes it would have to ban any collection (set) containing members that can only be defined by means of the collection taken as a whole. It is, effectively by all occurring principles into which have an adopting vicious regress, as to mark the definition for which involves no such failure. There is frequently room for dispute about whether regresses are benign or vicious, since the issue will hinge on whether it is necessary to reapply the procedure. The cosmological argument is an attempt to find a stopping point for what is otherwise seen as being an infinite regress, and, to ban of the predicative definitions.

The investigation of questions that arise from reflection upon sciences and scientific inquiry, are such as called of a philosophy of science. Such questions include, what distinctions in the methods of science? s there a clear demarcation between scenes and other disciplines, and how do we place such enquires as history, economics or sociology? And scientific theories probable or more in the nature of provisional conjecture? Can the be verified or falsified? What distinguished good from bad explanations? Might there be one unified since, embracing all the special science? For much of the 20th century there questions were pursued in a highly abstract and logical framework it being supposed that as general logic of scientific discovery that a general logic of scientific discovery a justification might be found. However, many now take interests in a more historical, contextual and sometimes sociological approach, in which the methods and successes of a science at a particular time are regarded less in terms of universal logical principles and procedure, and more in terms of their availability to methods and paradigms as well as the social context.

In addition, to general questions of methodology, there are specific problems within particular sciences, giving subjects as biology, mathematics and physics.

The intuitive certainty that sparks aflame the dialectic awarenesses for its immediate concerns are either of the truth or by some other in an object of apprehensions, such as a concept. Awareness as such, has to its amounting quality value the place where philosophical understanding of the source of our knowledge are, however, in covering the sensible apprehension of things and pure intuition it is that which stricture sensation into the experience of things accent of its direction that orchestrates the celestial overture into measures in space and time.

The notion that determines how something is seen or evaluated of the status of law and morality especially associated with St Thomas Aquinas and the subsequent scholastic tradition. More widely, any attempt to cement the moral and legal order together with the nature of the cosmos or how the nature of human beings, for which sense it is also found in some Protestant writers, and arguably derivative from a Platonic view of ethics, and is implicit in ancient Stoicism. Law stands above and apart from the activities of human lawmaker, it constitutes an objective set of principles that can be seen true by natural light or reason, and (in religion versions of the theory) that express Gods will for creation. Non-religious versions of the theory substitute objective conditions for human flourishing as the source of constraints upon permissible actions and social arrangements. Within the natural law tradition, different views have been held about the relationship between the rule of law about God s will, for instance the Dutch philosopher Hugo Grothius (1583-1645), similarly takes upon the view that the content of natural law is independent of any will, including that of God, while the German theorist and historian Samuel von Pufendorf (1632-94) takes the opposite view, thereby facing the problem of one horn of the Euthyphro dilemma, that simply states, that its dilemma arises from whatever the source of authority is supposed to be, for in which do we care about the general good because it is good, or do we just call good things that we care about. Wherefore, by facing the problem that may be to assume of a strong form, in which it is claimed that various facts entail values, or a weaker form, from which it confines itself to holding that reason by itself is capable of discerning moral requirements that are supped of binding to all human bings regardless of their desires

Although the morality of people send the ethical amount from which the same thing, is that there is a usage that restricts morality to systems such as that of the German philosopher and founder of ethical philosophy Immanuel Kant (1724-1804), based on notions such as duty, obligation, and principles of conduct, reserving ethics for more than the Aristotelian approach to practical reasoning based on the notion of a virtue, and generally avoiding the separation of moral considerations from other practical considerations. The scholarly issues are complex, with some writers seeing Kant as more Aristotelian and Aristotle as, ore involved in a separate sphere of responsibility and duty, than the simple contrast suggests. Some theorists see the subject in terms of a number of laws (as in the Ten Commandments). The status of these laws may be test they are the edicts of a divine lawmaker, or that they are truths of reason, knowable deductively. Other approaches to ethics (e.g., eudaimonism, situation ethics, virtue ethics) eschew general principles as much as possible, frequently disguising the great complexity of practical reasoning. For Kantian notion of the moral law is a binding requirement of the categorical imperative, and to understand whether they are equivalent at some deep level. Kants own applications of the notion are not always convincing, as for one cause of confusion in relating Kants ethics to theories such additional expressivism is that it is easy, but mistaken, to suppose that the categorical nature of the imperative means that it cannot be the expression of sentiment, but must derive from something unconditional or necessary such as the voice of reason.

For which ever reason, the mortal being makes of its presence to the future of weighing of that which one must do, or that which can be required of one. The term carries implications of that which is owed (due) to other people, or perhaps in onself. Universal duties would be owed to persons (or sentient beings) as such, whereas special duty in virtue of specific relations, such as being the child of someone, or having made someone a promise. Duty or obligation is the primary concept of deontological approaches to ethics, but is constructed in other systems out of other notions. In the system of Kant, a perfect duty is one that must be performed whatever the circumstances: Imperfect duties may have to give way to the more stringent ones. In another way, perfect duties are those that are correlative with the right to others, imperfect duties are not. Problems with the concept include the ways in which due needs to be specified (a frequent criticism of Kant is that his notion of duty is too abstract). The concept may also suggest of a regimented view of ethical life in which we are all forced conscripts in a kind of moral army, and may encourage an individualistic and antagonistic view of social relations.

The most generally accepted account of externalism and/or internalism, that this distinction is that a theory of justification is internalist if only if it requiem that all of the factors needed for a belief to be epistemologically justified for a given person be cognitively accessible to that person, internal to cognitive perceptivity, and externalist, if it allows that at least some of the justifying factors need not be thus accessible, so that thy can be external to the believers cognitive perceptive, beyond any such given relations. However, epistemologists often use the distinction between internalist and externalist theories of epistemic justification without offering any very explicit explication.

The externalist/internalist distinction has been mainly applied to theories of epistemic justification: It has also been applied in a closely related way to accounts of knowledge and in a rather different way to accounts of belief and thought contents.

The internalist requirement of cognitive accessibility can be interpreted in at least two ways: A strong version of internalism would require that the believe actually be aware of the justifying factor in order to be justified: While a weaker version would require only that he be capable of becoming aware of them by focussing his attentions appropriately, but without the need for any change of position, new information, etc. Though the phrase cognitively accessible suggests the weak interpretation, the main intuitive motivation for internalism, viz the idea that epistemic justification requires that the believe actually have in his cognitive possession a reason for thinking that the belief is true, and would require the strong interpretation.

Perhaps, the clearest example of an internalist position would be a Foundationalist view according to which foundational beliefs pertain to immediately experienced states of mind and other beliefs are justified by standing in cognitively accessible logical or inferential relations to such foundational beliefs. Such a view could count as either a strong or a weak version of internalism, depending on whether actual awareness of the justifying elements or only the capacity to become aware of them is required. Similarly, a coherent view could also be internalist, if both the beliefs or other states with which a justification belief is required to cohere and the coherence relations themselves are reflectively accessible.

It should be carefully noticed that when internalism is construed in this way, it is neither necessary nor sufficient by itself for internalism that the justifying factors literally be internal mental states of the person in question. Not necessary, necessary, because on at least some views, e.g., a direct realist view of perception, something other than a mental state of the believe can be cognitively accessible: Not sufficient, because there are views according to which at least some mental states need not be actual (strong version) or even possible (weak version) objects of cognitive awareness. Also, on this way of drawing the distinction, a hybrid view, according to which some of the factors required for justification must be cognitively accessible while others need not and in general will not be, would count as an externalist view. Obviously too, a view that was externalist in relation to a strong version of internalism (by not requiring that the believe actually be aware of all justifiable factors) could still be internalist in relation to a weak version (by requiring that he at least be capable of becoming aware of them).

The most prominent recent externalist views have been versions of reliabilism, whose requirements for justification is roughly that the belief be produced in a way or via a process that makes of objectively likely that the belief is true. What makes such a view externalist is the absence of any requirement that the person for whom the belief is justified have any sort of cognitive access to the relations of reliability in question. Lacking such access, such a person will in general have no reason for thinking that the belief is true or likely to be true , but will, on such an account, nonetheless be epistemically justified in according it. Thus such a view arguably marks a major break from the modern epistemological tradition, stemming from Descartes, which identifies epistemic justification with having a reason, perhaps even a conclusive reason for thinking that the belief is true. An epistemologist working within this tradition is likely to feel that the externalist, than offering a competing account of the same concept of epistemic justification with which the traditional epistemologist is concerned, has simply changed the subject.

The main objection to externalism rests on the intuitive certainty that the basic requirement for epistemic justification is that the acceptance of the belief in question be rational or responsible in relation to the cognitive goal of truth, which seems to require in turn that the believe actually be dialectally aware of a reason for thinking that the belief is true (or, at the very least, that such a reason be available to him). Since the satisfaction of an externalist condition is neither necessary nor sufficient for the existence of such a cognitively accessible reason, it is argued, externalism is mistaken as an account of epistemic justification. This general point has been elaborated by appeal to two sorts of putative intuitive counter-examples to externalism. The first of these challenges the necessity of belief which seem intuitively to be justified, but for which the externalist conditions are not satisfied. The standard examples in this sort are cases where beliefs are produced in some very nonstandard way, e.g., by a Cartesian demon, but nonetheless, in such a way that the subjective experience of the believe is indistinguishable from that of someone whose beliefs are produced more normally. The intuitive claim is that the believe in such a case is nonetheless epistemically justified, as much so as one whose belief is produced in a more normal way, and hence that externalist account of justification must be mistaken.

Perhaps the most striking reply to this sort of counter-example, on behalf of a cognitive process is to be assessed in normal possible worlds, i.e., in possible worlds that are actually the way our world is common-seismically believed to be, than in the world which contains the belief being judged. Since the cognitive processes employed in the Cartesian demon cases are, for which we may assume, reliable when assessed in this way, the reliability can agree that such beliefs are justified. The obvious, to a considerable degree of bringing out the issue of whether it is or not an adequate rationale for this construal of Reliabilism, so that the reply is not merely a notional presupposition guised as having representation.

The correlative way of elaborating on the general objection to justificatory externalism challenges the sufficiency of the various externalist conditions by citing cases where those conditions are satisfied, but where the believers in question seem intuitively not to be justified. In this context, the most widely discussed examples have to do with possible occult cognitive capacities, like clairvoyance. Considering the point in application once, again, to Reliabilism, the claim is that to think that he has such a cognitive power, and, perhaps, even good reasons to the contrary, is not rational or responsible and therefore not epistemically justified in accepting the belief that result from his clairvoyance, despite the fact that the Reliabilist condition is satisfied.

One sort of response to this latter sorts of objection is to bite the bullet and insist that such believers are in fact justified, dismissing the seeming intuitions to the contrary as latent internalist prejudice. A more widely adopted response attempts to impose additional conditions, usually of a roughly internalized sort, which will rule out the offending example, while stopping far of a full internalism. But, while there is little doubt that such modified versions of externalism can handle particular cases, as well enough to avoid clear intuitive implausibility, the usually problematic cases that they cannot handle, and also whether there is and clear motivation for the additional requirements other than the general internalist view of justification that externalist are committed to reject.

A view in this same general vein, one that might be described as a hybrid of internalism and externalism holds that epistemic justification requires that there is a justificatory factor that is cognitively accessible to the believe in question (though it need not be actually grasped), thus ruling out, e.g., a pure Reliabilism. At the same time, however, though it must be objectively true that beliefs for which such a factor is available are likely to be true, in addition, the fact need not be in any way grasped or cognitively accessible to the believe. In effect, of the premises needed to argue that a particular belief is likely to be true, one must be accessible in a way that would satisfy at least weakly internalized. The internalist will respond that this hybrid view is of no help at all in meeting the objection and has no belief nor is it held in the rational, responsible way that justification intuitively seems to require, for the believe in question, lacking one crucial premise, still has no reason at all for thinking that his belief is likely to be true.

An alternative to giving an externalist account of epistemic justification, one which may be more defensible while still accommodating many of the same motivating concerns, is to give an externalist account of knowledge directly, without relying on an intermediate account of justification. Such a view will obviously have to reject the justified true belief account of knowledge, holding instead that knowledge is true belief which satisfies the chosen externalist condition, e.g., a result of a reliable process (and perhaps, further conditions as well). This makes it possible for such a view to retain internalist account of epistemic justification, though the centrality of that concept to epistemology would obviously be seriously diminished.

Such an externalist account of knowledge can accommodate the commonsense conviction that animals, young children, and unsophisticated adults posses knowledge, though not the weaker conviction (if such a conviction does exists) that such individuals are epistemically justified in their beliefs. It is also at least less vulnerable to internalist counter-examples of the sort discussed, since the intuitions involved there pertain more clearly to justification than to knowledge. What is uncertain is what ultimate philosophical significance the resulting conception of knowledge is supposed to have. In particular, does it have any serious bearing on traditional epistemological problems and on the deepest and most troubling versions of scepticism, which seems in fact to be primarily concerned with justification, the an knowledge?`

A rather different use of the terms internalism and externalism has to do with the issue of how the content of beliefs and thoughts is determined: According to an internalist view of content, the content of such intention states depends only on the non-relational, internal properties of the individuals mind or grain, and not at all on his physical and social environment: While according to an externalist view, content is significantly affected by such external factors and suggests a view that appears of both internal and external elements are standardly classified as an external view.

As with justification and knowledge, the traditional view of content has been strongly internalized in character. The main argument for externalism derives from the philosophy of language, more specifically from the various phenomena pertaining to natural kind terms, indexicals, etc. that motivate the views that have come to be known as direct reference theories. Such phenomena seem at least to show that the belief or thought content that can be properly attributed to a person is dependant on facts about his environment, e.g., whether he is on Earth or Twin Earth, what is fact pointing at, the classificatory criteria employed by expects in his social group, etc. - not just on what is going on internally in his mind or brain.

An objection to externalist account of content is that they seem unable to do justice to our ability to know the content of our beliefs or thought from the inside, simply by reflection. If content is depend on external factors pertaining to the environment, then knowledge of content should depend on knowledge of these factors - which will not in general be available to the person whose belief or thought is in question.

The adoption of an externalized account of mental content would seem to support an externalist account of justification, by way that if part or all of the content of a belief inaccessible to the believe, then both the justifying status of other beliefs in relation to that content and the status of that content justifying the beliefs will be similarly inaccessible, thus contravening the internalist requirement for justification. An internalist must insist that there are no justifiable relations of these sorts, that our internally associable content can either be justified or justly anything else: But such a response appears lame unless it is coupled with an attempt to show that the externalist account of content is mistaken.

A great deal of philosophical effort has been lavished on the attempt to naturalize content, i.e. to explain in non-semantic,. Non-intentional terms what it is for something to be represental (have content) and what it is for something to have some particular content rather than some other. There appear to be only four types of theory that have been proposed: Theories that ground representation in (1) similarity, (2) conversance, (3) functional role, (4) teleology.

Similarly, theories hold that 'r' represents 'x' in virtue of being similar to 'x'. This has seemed hopeless to most as a theory of mental representation because it appears to require that things in the brain must share properties with the things they represent: To represent a cat as furry appears to require something furry in the brain. Perhaps, a notion of similarity that is naturalistic and does not involve property sharing can be worked out, but it is not obvious how.

Covariance theories hold that 'r's' represent 'x' is grounded in the fact that 'r's' occurrence canaries with that of 'x'. This is most compelling he n one thinks about detection systems, the firing a neural structures in the visual system is said to represent vertical orientations, if its firing varies with the occurrence of vertical lines in the visual field of perceptivity.

Functional role theories hold that 'r's' represent 'x' is grounded in the functional role 'r' has in the representing system, i.e., on the relations imposed by specific cognitive processes imposed by specific cognitive processes between 'r' and other representations in the system's repertoire. Functional role theories take their cue from such common-sense ideas as that people cannot believer that cats are furry if they did not know that cats are animals or that fur is like hair.

Teleological theories hold that 'r' represent 'x' if it is 'r's' function to indicate, i.e., covary with 'x'. Teleological theories differ depending on the theory of functions they import. Perhaps the most important distinction is that between historical theories of functions. Historical theories individuated functional states (hence contents) in a way that is sensitive to the historical development of the state, i.e., to factors such as the way the state was 'learned', or the way it evolved. An historical theory might hold that the function of 'r' is to indicate 'x' only if the capacity to token 'r' was developed (selected, learned) because it indicates 'x'. Thus, a state physically indistinguishable from 'r's' historical origins would not represent 'x' according to historical theories.

Theories of representational content may be classified according to whether they are atomistic or holistic and according to whether they are externalistic or internalistic, whereby, emphasizing the priority of a whole over its parts. Furthermore, in the philosophy of language, this becomes the claim that the meaning of an individual word or sentence can only be understood in terms of its relation to an indefinitely larger body of language, such as a whole theory, or even a whole language or form of life. In the philosophy of mind a mental state similarly may be identified only in terms of its relations with others. Moderate holism may allow the other things besides these relationships also count; extreme holism would hold that a network of relationships is all that we have. A holistic view of science holds that experience only confirms or disconfirms large bodies of doctrine, impinging at the edges, and leaving some leeway over the adjustment that it requires.

Once, again, in the philosophy of mind and language, the view that what is thought, or said, or experienced, is essentially dependent on aspects of the world external to the mind of the subject. The view goes beyond holding that such mental states are typically caused by external factors, to insist that they could not have existed as they now do without the subject being embedded in an external world of a certain kind. It is these external relations that make up the essence or identify of the mental state. Externalism is thus opposed to the Cartesian separation of the mental from the physical, since that holds that the mental could in principle exist as it does even if there were no external world at all. Various external factors have been advanced as ones on which mental content depends, including the usage of experts, the linguistic, norms of the community. And the general causal relationships of the subject. In the theory of knowledge, externalism is the view that a person might know something by being suitably situated with respect to it, without that relationship being in any sense within his purview. The person might, for example, be very reliable in some respect without believing that he is. The view allows that you can know without being justified in believing that you know.

However, atomistic theories take a representation's content to be something that can be specified independent entity of that representation' s relations to other representations. What the American philosopher of mind, Jerry Alan Fodor (1935-) calls the crude causal theory, for example, takes a representation to be a
cow
- a menial representation with the same content as the word 'cow' - if its tokens are caused by instantiations of the property of being-a-cow, and this is a condition that places no explicit constraints on how
cow
's must or might relate to other representations. Holistic theories contrasted with atomistic theories in taking the relations a representation bears to others to be essential to its content. According to functional role theories, a representation is a
cow
if it behaves like a
cow
should behave in inference.

Internalist theories take the content of a representation to be a matter determined by factors internal to the system that uses it. Thus, what Block (1986) calls 'short-armed' functional role theories are internalist. Externalist theories take the content of a representation to be determined, in part at least, by factors external to the system that uses it. Covariance theories, as well as telelogical theories that invoke an historical theory of functions, take content to be determined by 'external' factors. Crossing the atomist-holistic distinction with the internalist-externalist distinction.

Externalist theories (sometimes called non-individualistic theories) have the consequence that molecule for molecule are coincide with the identical cognitive systems might yet harbour representations with different contents. This has given rise to a controversy concerning 'narrow' content. If we assume some form of externalist theory is correct, then content is, in the first instance 'wide' content, i.e., determined in part by factors external to the representing system. On the other hand, it seems clear that, on plausible assumptions about how to individuate psychological capacities, internally equivalent systems must have the same psychological capacities. Hence, it would appear that wide content cannot be relevant to characterizing psychological equivalence. Since cognitive science generally assumes that content is relevant to characterizing psychological equivalence, philosophers attracted to externalist theories of content have sometimes attempted to introduce 'narrow' content, i.e., an aspect or kind of content that is equivalent internally equivalent systems. The simplest such theory is Fodor's idea (1987) that narrow content is a function from contents (i.e., from whatever the external factors are) to wide contents.

All the same, what a person expresses by a sentence is often a function of the environment in which he or she is placed. For example, the disease I refer to by the term like 'arthritis', or the kind of tree I refer to as a 'Maple' will be defined by criteria of which I know next to nothing. This raises the possibility of imagining two persons in rather different environments, but in which everything appears the same to each of them. The wide content of their thoughts and sayings will be different if the situation surrounding them is appropriately different: 'situation' may include the actual objects they perceive or the chemical or physical kinds of object in the world they inhabit, or the history of their words, or the decisions of authorities on what counts as an example, of one of the terms they use. The narrow content is that part of their thought which remains identical, through their identity of the way things appear, regardless of these differences of surroundings. Partisans of wide content may doubt whether any content in this sense narrow, partisans of narrow content believer that it is the fundamental notion, with wide content being explicable in terms of narrow content plus context.

Even so, the distinction between facts and values has outgrown its name: it applies not only to matters of fact vs, matters of value, but also to statements that something is, vs. statements that something ought to be. Roughly, factual statements - 'is statements' in the relevant sense - represent some state of affairs as obtaining, whereas normative statements - evaluative, and deontic ones - attribute goodness to something, or ascribe, to an agent, an obligation to act. Neither distinction is merely linguistic. Specifying a book's monetary value is making a factual statement, though it attributes a kind of value. 'That is a good book' expresses a value judgement though the term 'value' is absent (nor would 'valuable' be synonymous with 'good'). Similarly, 'we are morally obligated to fight' superficially expresses a statement, and 'By all indications it ough to rain' makes a kind of ought-claim; but the former is an ought-statement, the latter an (epistemic) is-statement.

Theoretical difficulties also beset the distinction. Some have absorbed values into facts holding that all value is instrumental, roughly, to have value is to contribute - in a factual analyzable way - to something further which is (say) deemed desirable. Others have suffused facts with values, arguing that facts (and observations) are 'theory-impregnated' and contending that values are inescapable to theoretical choice. But while some philosophers doubt that fact/value distinctions can be sustained, there persists a sense of a deep difference between evaluating, or attributing an obligation and, on the other hand, saying how the world is.

Fact/value distinctions, may be defended by appeal to the notion of intrinsic value, value a thing has in itself and thus independently of its consequences. Roughly, a value statement (proper) is an ascription of intrinsic value, one to the effect that a thing is to some degree good in itself. This leaves open whether ought-statements are implicitly value statements, but even if they imply that something has intrinsic value - e.g., moral value - they can be independently characterized, say by appeal to rules that provide (justifying) reasons for action. One might also ground the fact value distinction in the attributional (or even motivational) component apparently implied by the making of valuational or deontic judgements: Thus, 'it is a good book, but that is no reason for a positive attribute towards it' and 'you ought to do it, but there is no reason to' seem inadmissible, whereas, substituting, 'an expensive book' and 'you will do it' yields permissible judgements. One might also argue that factual judgements are the kind which are in principle appraisable scientifically, and thereby anchor the distinction on the factual side. This ligne is plausible, but there is controversy over whether scientific procedures are 'value-free' in the required way.

Philosophers differ regarding the sense, if any, in which epistemology is normative (roughly, valuational). But what precisely is at stake in this controversy is no clearly than the problematic fact/value distinction itself. Must epistemologists as such make judgements of value or epistemic responsibility? If epistemology is naturalizable, then even epistemic principles simply articulate under what conditions - say, appropriate perceptual stimulations - a belief is justified, or constitutes knowledge. Its standards of justification, then would be like standards of, e.g., resilience for bridges. It is not obvious, however, that there appropriate standards can be established without independent judgements that, say, a certain kind of evidence is good enough for justified belief (or knowledge). The most plausible view may be that justification is like intrinsic goodness, though it supervenes on natural properties, it cannot be analysed wholly in factual statements.

Thus far, belief has been depicted as being all-or-nothing, however, as a resulting causality for which we have grounds for thinking it true, and, all the same, its acceptance is governed by epistemic norms, and, least of mention, it is partially subject to voluntary control and has functional affinities to belief. Still, the notion of acceptance, like that of degrees of belief, merely extends the standard picture, and does not replace it.

Traditionally, belief has been of epistemological interest in its propositional guise: 'S' believes that 'p', where 'p' is a reposition towards which an agent, 'S' exhibits an attitude of acceptance. Not all belief is of this sort. If I trust you to say, I believer you. And someone may believer in Mr. Radek, or in a free-market economy, or in God. It is sometimes supposed that all belief is 'reducible' to propositional belief, belief-that. Thus, my believing you might be thought a matter of my believing, is, perhaps, that what you say is true, and your belief in free markets or God, is a matter of your believing that free-market economies are desirable or that God exists.

Some philosophers have followed St, Thomas Aquinas (1225-74), in supposing that to believer in God is simply to believer that certain truths hold while others argue that belief-in is a distinctive attitude, on that includes essentially an element of trust. More commonly, belief-in has been taken to involve a combination of propositional belief together with some further attitude.

The moral philosopher Richard Price (1723-91) defends the claim that there are different sorts of belief-in, some, but not all reducible to beliefs-that. If you believer in God, you believer that God exists, that God is good, you believer that God is good, etc. But according to Price, your belief involves, in addition, a certain complex pro-attitude toward its object. Even so, belief-in outruns the evidence for the corresponding belief-that. Does this diminish its rationality? If belief-in presupposes believes-that, it might be thought that the evidential standards for the former must be, at least, as high as standards for the latter. And any additional pro-attitude might be thought to require a further layer of justification not required for cases of belief-that.

Belief-in may be, in general, less susceptible to alternations in the face of unfavourable evidence than belief-that. A believe who encounters evidence against God's existence may remain unshaken in his belief, in part because the evidence does not bear on his pro-attitude. So long as this is united with his belief that God exists, the reasonably so in a way that an ordinary propositional belief that would not.

Some philosophers think that the category of knowing for which true. Justified believing (accepting) is a requirement constituting only a species of Propositional knowledge, construed as an even broader category. They have proposed various examples of 'PK' that do not satisfy the belief and/ort justification conditions of the tripartite analysis. Such cases are often recognized by analyses of Propositional knowledge in terms of powers, capacities, or abilities. For instance, Alan R. White (1982) treats 'PK' as merely the ability to provide a correct answer to a possible questions, however, White may be equating 'producing' knowledge in the sense of producing 'the correct answer to a possible question' with 'displaying' knowledge in the sense of manifesting knowledge. (White, 1982). The latter can be done even by very young children and some non-human animals independently of their being asked questions, understanding questions, or recognizing answers to questions. Indeed, an example that has been proposed as an instance of knowing that 'h' without believing or accepting that 'h' can be modified so as to illustrate this point. Two examples concerns an imaginary person who has no special training or information about horses or racing, but who in an experiment persistently and correctly picks the winners of upcoming horseraces. If the example is modified so that the hypothetical 'seer' never picks winners but only muses over whether those horses wight win, or only reports those horses winning, this behaviour should be as much of a candidate for the person's manifesting knowledge that the horse in question will win as would be the behaviour of picking it as a winner.

These considerations expose limitations in Edward Craig's analysis (1990) of the concept of knowing of a person's being a satisfactory informant in relation to an inquirer who wants to find out whether or not 'h'. Craig realizes that counterexamples to his analysis appear to be constituted by Knower who are too recalcitrant to inform the inquirer, or too incapacitate to inform, or too discredited to be worth considering (as with the boy who cried 'Wolf'). Craig admits that this might make preferable some alternative view of knowledge as a different state that helps to explain the presence of the state of being a suitable informant when the latter does obtain. Such the alternate, which offers a recursive definition that concerns one's having the power to proceed in a way representing the state of affairs, causally involved in one's proceeding in this way. When combined with a suitable analysis of representing, this theory of propositional knowledge can be unified with a structurally similar analysis of knowing how to do something.

Knowledge and belief, according to most epistemologists, knowledge entails belief, so that I cannot know that such and such is the case unless I believe that such and such is the case. Others think this entailment thesis can be rendered more accurately if we substitute for belief some closely related attitude. For instance, several philosophers would prefer to say that knowledge entail psychological certainties (Prichard, 1950 and Ayer, 1956) or conviction (Lehrer, 1974) or acceptance (Lehrer, 1989). None the less, there are arguments against all versions of the thesis that knowledge requires having a belief-like attitude toward the known. These arguments are given by philosophers who think that knowledge and belief (or a facsimile) are mutually incompatible (the incomparability thesis), or by ones who say that knowledge does not entail belief, or vice versa, so that each may exist without the other, but the two may also coexist (the separability thesis).

The incompatibility thesis is sometimes traced to Plato ©. 429-347 BC) in view of his claim that knowledge is infallible while belief or opinion is fallible ('Republic' 476-9). But this claim would not support the thesis. Belief might be a component of an infallible form of knowledge in spite of the fallibility of belief. Perhaps, knowledge involves some factor that compensates for the fallibility of belief.

A. Duncan-Jones (1939: Also Vendler, 1978) cite linguistic evidence to back up the incompatibility thesis. He notes that people often say 'I do not believe she is guilty. I know she is' and the like, which suggest that belief rule out knowledge. However, as Lehrer (1974) indicates, the above exclamation is only a more emphatic way of saying 'I do not just believe she is guilty, I know she is' where 'just' makes it especially clear that the speaker is signalling that she has something more salient than mere belief, not that she has something inconsistent with belief, namely knowledge. Compare: 'You do not hurt him, you killed him'.

H.A. Prichard (1966) offers a defence of the incompatibility thesis that hinges on the equation of knowledge with certainty (both infallibility and psychological certitude) and the assumption that when we believe in the truth of a claim we are not certain about its truth. Given that belief always involves uncertainty while knowledge never dies, believing something rules out the possibility of knowing it. Unfortunately, however, Prichard gives 'us' no goods reason to grant that states of belief are never ones involving confidence. Conscious beliefs clearly involve some level of confidence, to suggest that we cease to believe things about which we are completely confident is bizarre.

A.D. Woozley (1953) defends a version of the separability thesis. Woozley's version, which deals with psychological certainty rather than belief per se, is that knowledge can exist in the absence of confidence about the item known, although might also be accompanied by confidence as well. Woozley remarks that the test of whether I know something is 'what I can do, where what I can do may include answering questions'. On the basis of this remark he suggests that even when people are unsure of the truth of a claim, they might know that the claim is true. We unhesitatingly attribute knowledge to people who give correct responses on examinations even if those people show no confidence in their answers. Woozley acknowledges, however, that it would be odd for those who lack confidence to claim knowledge. It would be peculiar to say, 'I am unsure whether my answer is true: Still, I know it is correct'. But this tension Woozley explains using a distinction between conditions under which we are justified in making a claim (such as a claim to know something), and conditions under which the claim we make is true. While 'I know such and such' might be true even if I am unsure whether such and such holds, nonetheless it would be inappropriate for me to claim that I know that such and such unless I were sure of the truth of my claim.

Colin Radford (1966) extends Woozley's defence of the separability thesis. In Radford's view, not only is knowledge compatible with the lack of certainty, it is also compatible with a complete lack of belief. He argues by example. In one example, Jean has forgotten that he learned some English history year's priori and yet he is able to give several correct responses to questions such as 'When did the Battle of Hastings occur'? Since he forgot that he took history, he considers the correct response to be no more than guesses. Thus, when he says that the Battle of Hastings took place in 1066 he would deny having the belief that the Battle of Hastings took place in 1066. A disposition he would deny being responsible (or having the right to be convincing) that 1066 was the correct date. Radford would none the less insist that Jean know when the Battle occurred, since clearly be remembering the correct date. Radford admits that it would be inappropriate for Jean to say that he knew when the Battle of Hastings occurred, but, like Woozley he attributes the impropriety to a fact about when it is and is not appropriate to claim knowledge. When we claim knowledge, we ought, at least to believe that we have the knowledge we claim, or else our behaviour is 'intentionally misleading'.

Those that agree with Radford's defence of the separability thesis will probably think of belief as an inner state that can be detected through introspection. That Jean lack's beliefs about English history is plausible on this Cartesian picture since Jean does not find himself with any beliefs about English history when ne seek them out. One might criticize Radford, however, by rejecting that Cartesian view of belief. One could argue that some beliefs are thoroughly unconscious, for example. Or one could adopt a behaviourist conception of belief, such as Alexander Bain's (1859), according to which having beliefs is a matter of the way people are disposed to behave (and has not Radford already adopted a behaviourist conception of knowledge?) Since Jean gives the correct response when queried, a form of verbal behaviour, a behaviourist would be tempted to credit him with the belief that the Battle of Hastings occurred in 1066.

D.M. Armstrong (1873) takes a different tack against Radford. Jean does know that the Battle of Hastings took place in 1066. Armstrong will grant Radfod that point, in fact, Armstrong suggests that Jean believe that 1066 is not the date the Battle of Hastings occurred, for Armstrong equates the belief that such and such is just possible but no more than just possible with the belief that such and such is not the case. However, Armstrong insists, Jean also believes that the Battle did occur in 1066. After all, had Jean been mistaught that the Battle occurred in 1066, and subsequently 'guessed' that it took place in 1066, we would surely describe the situation as one in which Jean's false belief about the Battle became unconscious over time but persisted of a memory trace that was causally responsible for his guess. Out of consistency, we must describe Radford's original case as one that Jean's true belief became unconscious but persisted long enough to cause his guess. Thus, while Jean consciously believes that the Battle did not occur in 1066, unconsciously he does believe it occurred in 1066. So after all, Radford does not have a counterexample to the claim that knowledge entails belief.

Armstrong's response to Radford was to reject Radford's claim that the examinee lacked the relevant belief about English history. Another response is to argue that the examinee lacks the knowledge Radford attributes to him (cf. Sorenson, 1982). If Armstrong is correct in suggesting that Jean believes both that 1066 is and that it is not the date of the Battle of Hastings, one might deny Jean knowledge on the grounds that people who believe the denial of what they believe cannot be said t know the truth of their belief. Another strategy might be to compare the examine case with examples of ignorance given in recent attacks on externalist accounts of knowledge (needless to say. Externalists themselves would tend not to favour this strategy). Consider the following case developed by BonJour (1985): For no apparent reason, Samantha believes that she is clairvoyant. Again, for no apparent reason, she one day comes to believe that the President is in New York City, even though she has every reason to believe that the President is in Washington, D.C. In fact, Samantha is a completely reliable clairvoyant, and she has arrived at her belief about the whereabouts of the President thorough the power of her clairvoyance. Yet surely Samantha's belief is completely irrational. She is not justified in thinking what she does. If so, then she does not know where the President is. But Radford's examinee is unconventional. Even if Jean lacks the belief that Radford denies him, Radford does not have an example of knowledge that is unattended with belief. Suppose that Jean's memory had been sufficiently powerful to produce the relevant belief. As Radford says, in having every reason to suppose that his response is mere guesswork, and he has every reason to consider his belief false. His belief would be an irrational one, and hence one about whose truth Jean would be ignorant.

Least has been of mention to an approaching view from which 'perception' basis upon itself as a fundamental philosophical topic both for its central place in ant theory of knowledge, and its central place un any theory of consciousness. Philosophy in this area is constrained by a number of properties that we believe to hold of perception, (1) It gives 'us' knowledge of the world around 'us'. (2) We are conscious of that world by being aware of 'sensible qualities': Colour, sounds, tastes, smells, felt warmth, and the shapes and positions of objects in the environment. (3) Such consciousness is effected through highly complex information channels, such as the output of the three different types of colour-sensitive cells in the eye, or the channels in the ear for interpreting pulses of air pressure as frequencies of sound. (4) There ensues even more complex neurophysiological coding of that information, and eventually higher-order brain functions bring it about that we interpreted the information so received. (Much of this complexity has been revealed by the difficulties of writing programs enabling computers to recognize quite simple aspects of the visual scene.) The problem is to avoid thinking of here being a central, ghostly, conscious self, fed information in the same way that a screen if fed information by a remote television camera. Once such a model is in place, experience will seem like a veil getting between 'us' and the world, and the direct objects of perception will seem to be private items in an inner theatre or sensorium. The difficulty of avoiding this model is epically cute when we considered the secondary qualities of colour, sound, tactile feelings and taste, which can easily seem to have a purely private existence inside the perceiver, like sensation of pain. Calling such supposed items names like 'sense-data' or 'percepts' exacerbates the tendency, but once the model is in place, the first property, that perception gives 'us' knowledge of the world and its surrounding surfaces, is quickly threatened, for there will now seem little connection between these items in immediate experience and any independent reality. Reactions to this problem include 'scepticism' and 'idealism'.

A more hopeful approach is to claim that the complexities of (3) and (4) explain how we can have direct acquaintance of the world, than suggesting that the acquaintance we do have been at best indirect. It is pointed out that perceptions are not like sensation, precisely because they have a content, or outer-directed nature. To have a perception is to be aware of the world for being such-and-such a way, than to enjoy a mere modification of sensation. But such direct realism has to be sustained in the face of the evident personal (neurophysiological and other) factors determining haw we perceive. One approach is to ask why it is useful to be conscious of what we perceive, when other aspects of our functioning work with information determining responses without any conscious awareness or intervention. A solution to this problem would offer the hope of making consciousness part of the natural world, than a strange optional extra.

Furthering, perceptual knowledge is knowledge acquired by or through the senses and includes most of what we know. We cross intersections when we see the light turn green, head for the kitchen when we smell the roast burning, squeeze the fruit to determine its ripeness, and climb out of bed when we hear the alarm ring. In each case we come to know something-that the light has turned green, that the roast is burning, that the melon is overripe, and that it is time to get up-by some sensory means. Seeing that the light has turned green is learning something-that, the light has turned green-by use of the eyes. Feeling that the melon is overripe is coming to know a fact-that the melon is overripe-by one's sense to touch. In each case the resulting knowledge is somehow based on, derived from or grounded in the sort of experience that characterizes the sense modality in question.

Much of our perceptual knowledge is indirect, dependent or derived. By this I mean that the facts we describe ourselves as learning, as coming to know, by perceptual means are pieces of knowledge that depend on our coming to know something else, some other fact, in a more direct way. We see, by the gauge, that we need gas, see, by the newspapers, that our team has lost again, see, by her expression, that she is nervous. This derived or dependent sort of knowledge is particularly prevalent in the cases of vision, but it occurs, to a lesser degree, in every sense modality. We install bells and other noise-makers so that we calm for example, hear (by the bell) that someone is at the door and (by the alarm) that its time to get up. When we obtain knowledge in this way, it is clear that unless one sees-hence, comes to know something about the gauge (that it says) and (hence, know) that one is described as coming to know by perceptual means. If one cannot hear that the bell is ringing, one cannot-in at least in this way-hear that one's visitors have arrived. In such cases one sees (hears, smells, etc.) that 'a' is 'F', coming to know thereby that 'a' is 'F', by seeing (hearing, etc.) that some other condition, 'b's' being 'G', obtains when this occurs, the knowledge (that 'a' is 'F') is derived from, or dependent on, the more basic perceptual knowledge that 'b' is 'G'.

Perhaps as a better strategy is to tie an account save that part that evidence could justify explanation for it is its truth alone. Since, at least the time of Aristotle philosophers of explanatory knowledge have emphasizes of its importance that, in its simplest therms, we want to know not only what are the composite peculiarities and particulars points of issue but also why it is. This consideration suggests that we define an explanation as an answer to a why-question. Such a definition would, however, be too broad, because some why-questions are requests for consolation (Why did my son have to die?) Or moral justification (Why should women not be paid the same as men for the same work?) It would also be too narrow because some explanations are responses to how-questions (How does radar work?) Or how-possibility-questions (How is it possible for cats always to land their feet?)

In its overall sense, 'to explain' means to make clear, to make plain, or to provide understanding. Definition of this sort are philosophically unhelpful, for the terms used in the deficient are no less problematic than the term to be defined. Moreover, since a wide variety of things require explanation, and since many different types of explanation exist, as more complex explanation is required. To facilitate the requirement leaves, least of mention, for us to consider by introduction a bit of technical terminology. The term 'explanation' is used to refer to that which is to be explained: The term 'explanans' refers to that which does the explaining, the explanans and the explanation taken together constitute the explanation.

One common type of explanation occurs when deliberate human actions are explained in terms of conscious purposes. 'Why did you go to the pharmacy yesterday?' 'Because I had a headache and needed to get some aspirin.' It is tacitly assumed that aspirin is an appropriate medication for headaches and that going t the pharmacy would bean efficient way of getting some. Such explanations are, of course, teleological, referring, ss they do, to goals. The explanans is not the realisation of a future goal - if the pharmacy happened to be closed for stocktaking the aspirin would have ben obtained there, bu t that would not invalidate the explanation. Some philosophers would say that the antecedent desire to achieve the end is what doers the explaining: Others might say that the explaining is done by the nature of the goal and the fact that the action promoted the chances of realizing it. (Taylor, 1964). In that it should not be automatically be assumed that such explanations are causal. Philosophers differ considerably on whether these explanations are to be framed in terms of cause or reason, but the distinction cannot be used to show that the relation between reasons and the actions they justify is in no way causal, and there are many differing analyses of such concepts as intention and agency. Expanding the domain beyond consciousness, Freud maintained, in addition, that much human behaviour can be explained in terms of unconscious and conscious wishes. Those Freudian explanations should probably be construed as basically causal.

Problems arise when teleological explanations are offered in other context. The behaviour of non-human animals is often explained in terms of purpose, e.g., the mouse ran to escape from the cat. In such cases the existence of conscious purpose seems dubious. The situation is still more problematic when a supr-empirical purpose in invoked, e.g., the explanations of living species in terms of God's purpose, or the vitalistic explanations of biological phenomena in terms of a entelechy or vital principle. In recent years an 'anthropic principle' has received attention in cosmology (Barrow and Tipler, 1986). All such explanations have been condemned by many philosophers an anthropomorphic.

Nevertheless, philosophers and scientists often maintain that functional explanations play an important an legitimate role in various sciences such as, evolutionary biology, anthropology and sociology. For example, of the peppered moth in Liverpool, the change in colour from the light phase to the dark phase and back again to the light phase provided adaption to a changing environment and fulfilled the function of reducing predation on the spacies. In the study of primitive soviets anthropologists have maintained that various rituals the (rain dance) which may be inefficacious in braining about their manifest gaols (producing rain), actually cohesion at a period of stress (often a drought). Philosophers who admit teleological and/or functional explanations in common sense and science oftentimes take pans to argue that such explanations can be annualized entirely in terms of efficient causes, thereby escaping the charge of anthropomorphism (Wright, 1976): Again, however, not all philosophers agree.

Causal theories of Propositional knowledge differ over whether they deviate from the tripartite analysis by dropping the requirements that one's believing (accepting) that 'h' be justified. The same variation occurs regarding reliability theories, which present the Knower as reliable concerning the issue of whether or not 'h', in the sense that some of one's cognitive or epistemic states, θ, are such that, given further characteristics of oneself-possibly including relations to factors external to one and which one may not be aware-it is nomologically necessary (or at least probable) that 'h'. In some versions, the reliability is required to be 'global' in as far as it must concern a nomologically (probabilistic-relationship) relationship that states of type θ to the acquisition of true beliefs about a wider range of issues than merely whether or not 'h'. There is also controversy about how to delineate the limits of what constitutes a type of relevant personal state or characteristic. (For example, in a case where Mr Notgot has not been shamming and one does know thereby that someone in the office owns a Ford, such as a way of forming beliefs about the properties of persons spatially close to one, or instead something narrower, such as a way of forming beliefs about Ford owners in offices partly upon the basis of their relevant testimony?)

One important variety of reliability theory is a conclusive reason account, which includes a requirement that one's reasons for believing that 'h' be such that in one's circumstances, if h* were not to occur then, e.g., one would not have the reasons one does for believing that 'h', or, e.g., one would not believe that 'h'. Roughly, the latter is demanded by theories that treat a Knower as 'tracking the truth', theories that include the further demand that is roughly, if it were the case, that 'h', then one would believe that 'h'. A version of the tracking theory has been defended by Robert Nozick (1981), who adds that if what he calls a 'method' has been used to arrive at the belief that 'h', then the antecedent clauses of the two conditionals that characterize tracking will need to include the hypothesis that one would employ the very same method.

But unless more conditions are added to Nozick's analysis, it will be too weak to explain why one lack's knowledge in a version of the last variant of the tricky Mr Notgot case described above, where we add the following details: (a) Mr Notgot's compulsion is not easily changed, (b) while in the office, Mr Notgot has no other easy trick of the relevant type to play on one, and finally for one's belief that 'h', not by reasoning through a false belief ut by basing belief that 'h', upon a true existential generalization of one's evidence.

Nozick's analysis is in addition too strong to permit anyone ever to know that 'h': 'Some of my beliefs about beliefs might be otherwise, e.g., I might have rejected on of them'. If I know that 'h5' then satisfaction of the antecedent of one of Nozick's conditionals would involve its being false that 'h5', thereby thwarting satisfaction of the consequent's requirement that I not then believe that 'h5'. For the belief that 'h5' is itself one of my beliefs about beliefs (Shope, 1984).

Some philosophers think that the category of knowing for which is true. Justified believing (accepting) is a requirement constituting only a species of Propositional knowledge, construed as an even broader category. They have proposed various examples of 'PK' that do not satisfy the belief and/ort justification conditions of the tripartite analysis. Such cases are often recognized by analyses of Propositional knowledge in terms of powers, capacities, or abilities. For instance, Alan R. White (1982) treats 'PK' as merely the ability to provide a correct answer to a possible questions, however, White may be equating 'producing' knowledge in the sense of producing 'the correct answer to a possible question' with 'displaying' knowledge in the sense of manifesting knowledge. (White, 1982). The latter can be done even by very young children and some non-human animals independently of their being asked questions, understanding questions, or recognizing answers to questions. Indeed, an example that has been proposed as an instance of knowing that 'h' without believing or accepting that 'h' can be modified so as to illustrate this point. Two examples concerns an imaginary person who has no special training or information about horses or racing, but who in an experiment persistently and correctly picks the winners of upcoming horseraces. If the example is modified so that the hypothetical 'seer' never picks winners but only muses over whether those horses wight win, or only reports those horses winning, this behaviour should be as much of a candidate for the person's manifesting knowledge that the horse in question will win as would be the behaviour of picking it as a winner.

These considerations expose limitations in Edward Craig's analysis (1990) of the concept of knowing of a person's being a satisfactory informant in relation to an inquirer who wants to find out whether or not 'h'. Craig realizes that counterexamples to his analysis appear to be constituted by Knower who are too recalcitrant to inform the inquirer, or too incapacitate to inform, or too discredited to be worth considering (as with the boy who cried 'Wolf'). Craig admits that this might make preferable some alternative view of knowledge as a different state that helps to explain the presence of the state of being a suitable informant when the latter does obtain. Such the alternate, which offers a recursive definition that concerns one's having the power to proceed in a way representing the state of affairs, causally involved in one's proceeding in this way. When combined with a suitable analysis of representing, this theory of propositional knowledge can be unified with a structurally similar analysis of knowing how to do something.

Knowledge and belief, according to most epistemologists, knowledge entails belief, so that I cannot know that such and such is the case unless I believe that such and such is the case. Others think this entailment thesis can be rendered more accurately if we substitute for belief some closely related attitude. For instance, several philosophers would prefer to say that knowledge entail psychological certainties (Prichard, 1950 and Ayer, 1956) or conviction (Lehrer, 1974) or acceptance (Lehrer, 1989). None the less, there are arguments against all versions of the thesis that knowledge requires having a belief-like attitude toward the known. These arguments are given by philosophers who think that knowledge and belief (or a facsimile) are mutually incompatible (the incomparability thesis), or by ones who say that knowledge does not entail belief, or vice versa, so that each may exist without the other, but the two may also coexist (the separability thesis).

The incompatibility thesis is sometimes traced to Plato (429-347 Bc) in view of his claim that knowledge is infallible while belief or opinion is fallible ('Republic' 476-9). But this claim would not support the thesis. Belief might be a component of an infallible form of knowledge in spite of the fallibility of belief. Perhaps, knowledge involves some factor that compensates for the fallibility of belief.

A. Duncan-Jones (1939: Also Vendler, 1978) cite linguistic evidence to back up the incompatibility thesis. He notes that people often say 'I do not believe she is guilty. I know she is' and the like, which suggest that belief rule out knowledge. However, as Lehrer (1974) indicates, the above exclamation is only a more emphatic way of saying 'I do not just believe she is guilty, I know she is' where 'just' makes it especially clear that the speaker is signalling that she has something more salient than mere belief, not that she has something inconsistent with belief, namely knowledge. Compare: 'You do not hurt him, you killed him.'

H.A. Prichard (1966) offers a defence of the incompatibility thesis that hinges on the equation of knowledge with certainty (both infallibility and psychological certitude) and the assumption that when we believe in the truth of a claim we are not certain about its truth. Given that belief always involves uncertainty while knowledge never dies, believing something rules out the possibility of knowing it. Unfortunately, however, Prichard gives 'us' no goods reason to grant that states of belief are never ones involving confidence. Conscious beliefs clearly involve some level of confidence, to suggest that we cease to believe things about which we are completely confident is bizarre.

A.D. Woozley (1953) defends a version of the separability thesis. Woozley's version, which deals with psychological certainty rather than belief per se, is that knowledge can exist in the absence of confidence about the item known, although might also be accompanied by confidence as well. Woozley remarks that the test of whether I know something is 'what I can do, where what I can do may include answering questions.' On the basis of this remark he suggests that even when people are unsure of the truth of a claim, they might know that the claim is true. We unhesitatingly attribute knowledge to people who give correct responses on examinations even if those people show no confidence in their answers. Woozley acknowledges, however, that it would be odd for those who lack confidence to claim knowledge. It would be peculiar to say, I am unsure whether my answer is true: Still, I know it is correct But this tension Woozley explains using a distinction between conditions under which we are justified in making a claim (such as a claim to know something), and conditions under which the claim we make is true. While 'I know such and such' might be true even if I am unsure whether such and such holds, nonetheless it would be inappropriate for me to claim that I know that such and such unless I were sure of the truth of my claim.

Colin Radford (1966) extends Woozley's defence of the separability thesis. In Radford's view, not only is knowledge compatible with the lack of certainty, it is also compatible with a complete lack of belief. He argues by example. In one example, Jean has forgotten that he learned some English history year's priori and yet he is able to give several correct responses to questions such as 'When did the Battle of Hastings occur?' Since he forgot that he took history, he considers the correct response to be no more than guesses. Thus, when he says that the Battle of Hastings took place in 1066 he would deny having the belief that the Battle of Hastings took place in 1066. A disposition he would deny being responsible (or having the right to be convincing) that 1066 was the correct date. Radford would none the less insist that Jean know when the Battle occurred, since clearly be remembering the correct date. Radford admits that it would be inappropriate for Jean to say that he knew when the Battle of Hastings occurred, but, like Woozley he attributes the impropriety to a fact about when it is and is not appropriate to claim knowledge. When we claim knowledge, we ought, at least to believe that we have the knowledge we claim, or else our behaviour is 'intentionally misleading'.

Those that agree with Radford's defence of the separability thesis will probably think of belief as an inner state that can be detected through introspection. That Jean lack's beliefs about English history is plausible on this Cartesian picture since Jean does not find himself with any beliefs about English history when ne seek them out. One might criticize Radford, however, by rejecting that Cartesian view of belief. One could argue that some beliefs are thoroughly unconscious, for example. Or one could adopt a behaviourist conception of belief, such as Alexander Bain's (1859), according to which having beliefs is a matter of the way people are disposed to behave (and has not Radford already adopted a behaviourist conception of knowledge?) Since Jean gives the correct response when queried, a form of verbal behaviour, a behaviourist would be tempted to credit him with the belief that the Battle of Hastings occurred in 1066.

D.M. Armstrong (1873) takes a different tack against Radford. Jean does know that the Battle of Hastings took place in 1066. Armstrong will grant Radfod that point, in fact, Armstrong suggests that Jean believe that 1066 is not the date the Battle of Hastings occurred, for Armstrong equates the belief that such and such is just possible but no more than just possible with the belief that such and such is not the case. However, Armstrong insists, Jean also believes that the Battle did occur in 1066. After all, had Jean been mistaught that the Battle occurred in 1066, and subsequently 'guessed' that it took place in 1066, we would surely describe the situation as one in which Jean's false belief about the Battle became unconscious over time but persisted of a memory trace that was causally responsible for his guess. Out of consistency, we must describe Radford's original case as one that Jean's true belief became unconscious but persisted long enough to cause his guess. Thus, while Jean consciously believes that the Battle did not occur in 1066, unconsciously he does believe it occurred in 1066. So after all, Radford does not have a counterexample to the claim that knowledge entails belief.

Armstrong's response to Radford was to reject Radford's claim that the examinee lacked the relevant belief about English history. Another response is to argue that the examinee lacks the knowledge Radford attributes to him (cf. Sorenson, 1982). If Armstrong is correct in suggesting that Jean believes both that 1066 is and that it is not the date of the Battle of Hastings, one might deny Jean knowledge on the grounds that people who believe the denial of what they believe cannot be said t know the truth of their belief. Another strategy might be to compare the examine case with examples of ignorance given in recent attacks on externalist accounts of knowledge (needless to say. Externalists themselves would tend not to favour this strategy). Consider the following case developed by BonJour (1985): For no apparent reason, Samantha believes that she is clairvoyant. Again, for no apparent reason, she one day comes to believe that the President is in New York City, even though she has every reason to believe that the President is in Washington, DC. In fact, Samantha is a completely reliable clairvoyant, and she has arrived at her belief about the whereabouts of the President thorough the power of her clairvoyance. Yet surely Samanthas belief is completely irrational. She is not justified in thinking what she does. If so, then she does not know where the President is. But Radford's examinee is unconventional. Even if Jean lacks the belief that Radford denies him, Radford does not have an example of knowledge that is unattended with belief. Suppose that Jean's memory had been sufficiently powerful to produce the relevant belief. As Radford says, in having every reason to suppose that his response is mere guesswork, and he has every reason to consider his belief false. His belief would be an irrational one, and hence one about whose truth Jean would be ignorant.

Least has been of mention to an approaching view from which 'perception' basis upon itself as a fundamental philosophical topic both for its central place in ant theory of knowledge, and its central place un any theory of consciousness. Philosophy in this area is constrained by a number of properties that we believe to hold of perception, (1) It gives 'us' knowledge of the world around 'us,' (2) We are conscious of that world by being aware of 'sensible qualities': Colour, sounds, tastes, smells, felt warmth, and the shapes and positions of objects in the environment. (3) Such consciousness is effected through highly complex information channels, such as the output of the three different types of colour-sensitive cells in the eye, or the channels in the ear for interpreting pulses of air pressure as frequencies of sound. (4) There ensues even more complex neurophysiological coding of that information, and eventually higher-order brain functions bring it about that we interpreted the information so received. (Much of this complexity has been revealed by the difficulties of writing programs enabling computers to recognize quite simple aspects of the visual scene.) The problem is to avoid thinking of here being a central, ghostly, conscious self, fed information in the same way that a screen if fed information by a remote television camera. Once such a model is in place, experience will seem like a veil getting between 'us' and the world, and the direct objects of perception will seem to be private items in an inner theatre or sensorium. The difficulty of avoiding this model is epically cute when we considered the secondary qualities of colour, sound, tactile feelings and taste, which can easily seem to have a purely private existence inside the perceiver, like sensation of pain. Calling such supposed items names like 'sense-data' or 'percepts' exacerbates the tendency, but once the model is in place, the first property, that perception gives 'us' knowledge of the world and its surrounding surfaces, is quickly threatened, for there will now seem little connection between these items in immediate experience and any independent reality. Reactions to this problem include 'scepticism' and 'idealism.'

A more hopeful approach is to claim that the complexities of (3) and (4) explain how we can have direct acquaintance of the world, than suggesting that the acquaintance we do have been at best indirect. It is pointed out that perceptions are not like sensation, precisely because they have a content, or outer-directed nature. To have a perception is to be aware of the world for being such-and-such a way, than to enjoy a mere modification of sensation. But such direct realism has to be sustained in the face of the evident personal (neurophysiological and other) factors determining haw we perceive. One approach is to ask why it is useful to be conscious of what we perceive, when other aspects of our functioning work with information determining responses without any conscious awareness or intervention. A solution to this problem would offer the hope of making consciousness part of the natural world, than a strange optional extra.

Furthering, perceptual knowledge is knowledge acquired by or through the senses and includes most of what we know. We cross intersections when we see the light turn green, head for the kitchen when we smell the roast burning, squeeze the fruit to determine its ripeness, and climb out of bed when we hear the alarm ring. In each case we come to know something-that the light has turned green, that the roast is burning, that the melon is overripe, and that it is time to get up-by some sensory means. Seeing that the light has turned green is learning something-that the light has turned green-by use of the eyes. Feeling that the melon is overripe is coming to know a fact-that the melon is overripe-by one's sense to touch. In each case the resulting knowledge is somehow based on, derived from or grounded in the sort of experience that characterizes the sense modality in question.

Much as much of our perceptual knowledge is indirect, dependent or derived. By this I mean that the facts we describe ourselves as learning, as coming to know, by perceptual means are pieces of knowledge that depend on our coming to know something else, some other fact, in a more direct way. We see, by the gauge, that we need gas, see, by the newspapers, that our team has lost again, see, by her expression, that she is nervous. This derived or dependent sort of knowledge is particularly prevalent in the cases of vision, but it occurs, to a lesser degree, in every sense modality. We install bells and other noise-makers so that we calm for example, hear (by the bell) that someone is at the door and (by the alarm) that its time to get up. When we obtain knowledge in this way, it is clear that unless one sees-hence, comes to know something about the gauge (that it says) and (hence, know) that one is described as coming to know by perceptual means. If one cannot hear that the bell is ringing, one cannot-in at least in this way-hear that one's visitors have arrived. In such cases one sees (hears, smells, etc.) that 'a' is 'F', coming to know thereby that 'a' is 'F', by seeing (hearing, etc.) that some other condition, 'b's' being 'G', obtains when this occurs, the knowledge (that 'a' is 'F') is derived from, or dependent on, the more basic perceptual knowledge that 'b' is 'G'.

And finally, the representational Theory of mind (RTM) (which goes back at least to Aristotle) takes as its starting point commonsense mental states, such as thoughts, beliefs, desires, perceptions and images. Such states are said to have 'intentionality' - they are about or refer to things, and may be evaluated with respect to properties like consistency, truth, appropriateness and accuracy. (For example, the thought that cousins are not related is inconsistent, the belief that Elvis is dead is true, the desire to eat the moon is inappropriate, a visual experience of a ripe strawberry as red is accurate, an image of George W. Bush with dreadlocks is inaccurate.)

The Representational Theory of Mind, defines such intentional mental states as relations to mental representations, and explains the intentionality of the former in terms of the semantic properties of the latter. For example, to believe that Elvis is dead is to be appropriately related to a mental representation whose propositional content is that Elvis is dead. (The desire that Elvis be dead, the fear that he is dead, the regret that he is dead, etc., involve different relations to the same mental representation.) To perceive a strawberry is to have a sensory experience of some kind which is appropriately related to (e.g., caused by) the strawberry Representational theory of mind also understands mental processes such as thinking, reasoning and imagining as sequences of intentional mental states. For example, to imagine the moon rising over a mountain is to entertain a series of mental images of the moon (and a mountain). To infer a proposition q from the propositions p and if 'p' then 'q' is (among other things) to have a sequence of thoughts of the form 'p', 'if p' then 'q', 'q'.

Contemporary philosophers of mind have typically supposed (or at least hoped) that the mind can be naturalized - i.e., that all mental facts have explanations in the terms of natural science. This assumption is shared within cognitive science, which attempts to provide accounts of mental states and processes in terms (ultimately) of features of the brain and central nervous system. In the course of doing so, the various sub-disciplines of cognitive science (including cognitive and computational psychology and cognitive and computational neuroscience) postulate a number of different kinds of structures and processes, many of which are not directly implicated by mental states and processes as commonsensical conceived. There remains, however, a shared commitment to the idea that mental states and processes are to be explained in terms of mental representations.

In philosophy, recent debates about mental representation have centred around the existence of propositional attitudes (beliefs, desires, etc.) and the determination of their contents (how they come to be about what they are about), and the existence of phenomenal properties and their relation to the content of thought and perceptual experience. Within cognitive science itself, the philosophically relevant debates have been focussed on the computational architecture of the brain and central nervous system, and the compatibility of scientific and commonsense accounts of mentality.

Intentional Realists such as Dretske (e.g., 1988) and Fodor (e.g., 1987) note that the generalizations we apply in everyday life in predicting and explaining each other's behaviour (often collectively referred to as 'folk psychology') are both remarkably successful and indispensable. What a person believes, doubts, desires, fears, etc. is a highly reliable indicator of what that person will do; and we have no other way of making sense of each other's behaviour than by ascribing such states and applying the relevant generalizations. We are thus committed to the basic truth of commonsense psychology and, hence, to the existence of the states its generalizations refer to. (Some realists, such as Fodor, also hold that commonsense psychology will be vindicated by cognitive science, given that propositional attitudes can be construed as computational relations to mental representations.)

Intentional Eliminativists, such as Churchland, (perhaps) Dennett and (at one time) Stich argue that no such things as propositional attitudes (and their constituent representational states) are implicated by the successful explanation and prediction of our mental lives and behaviour. Churchland denies that the generalizations of commonsense propositional-attitude psychology are true. He (1981) argues that folk psychology is a theory of the mind with a long history of failure and decline, and that it resists incorporation into the framework of modern scientific theories (including cognitive psychology). As such, it is comparable to alchemy and phlogiston theory, and ought to suffer a comparable fate. Commonsense psychology is false, and the states (and representations) it postulates simply don't exist. (It should be noted that Churchland is not an eliminativist about mental representation tout court.

Dennett (1987) grants that the generalizations of commonsense psychology are true and indispensable, but denies that this is sufficient reason to believe in the entities they appear to refer to. He argues that to give an intentional explanation of a system's behaviour is merely to adopt the 'intentional stance' toward it. If the strategy of assigning contentful states to a system and predicting and explaining its behaviour (on the assumption that it is rational - i.e., that it behaves as it should, given the propositional attitudes it should have in its environment) is successful, then the system is intentional, and the propositional-attitude generalizations we apply to it are true. But there is nothing more to having a propositional attitude than this.

Though he has been taken to be thus claiming that intentional explanations should be construed instrumentally, Dennett (1991) insists that he is a 'moderate' realist about propositional attitudes, since he believes that the patterns in the behaviour and behavioural dispositions of a system on the basis of which we (truly) attribute intentional states to it are objectively real. In the event that there are two or more explanatorily adequate but substantially different systems of intentional ascriptions to an individual, however, Dennett claims there is no fact of the matter about what the system believes (1987, 1991). This does suggest an irrealism at least with respect to the sorts of things Fodor and Dretske take beliefs to be; though it is not the view that there is simply nothing in the world that makes intentional explanations true.

(Davidson 1973, 1974 and Lewis 1974 also defend the view that what it is to have a propositional attitude is just to be interpretable in a particular way. It is, however, not entirely clear whether they intend their views to imply irrealism about propositional attitudes.). Stich (1983) argues that cognitive psychology does not (or, in any case, should not) taxonomize mental states by their semantic properties at all, since attribution of psychological states by content is sensitive to factors that render it problematic in the context of a scientific psychology. Cognitive psychology seeks causal explanations of behaviour and cognition, and the causal powers of a mental state are determined by its intrinsic 'structural' or 'syntactic' properties. The semantic properties of a mental state, however, are determined by its extrinsic properties - e.g., its history, environmental or intra-mental relations. Hence, such properties cannot figure in causal-scientific explanations of behaviour. (Fodor 1994 and Dretske 1988 are realist attempts to come to grips with some of these problems.) Stich proposes a syntactic theory of the mind, on which the semantic properties of mental states play no explanatory role.

It is a traditional assumption among realists about mental representations that representational states come in two basic varieties (Boghossian 1995). There are those, such as thoughts, which are composed of concepts and have no phenomenal ('what-it's-like') features ('qualia'), and those, such as sensory experiences, which have phenomenal features but no conceptual constituents. (Non-conceptual content is usually defined as a kind of content that states of a creature lacking concepts might nonetheless enjoy. On this taxonomy, mental states can represent either in a way analogous to expressions of natural languages or in a way analogous to drawings, paintings, maps or photographs. (Perceptual states such as seeing that something is blue, are sometimes thought of as hybrid states, consisting of, for example, a Non-conceptual sensory experience and a thought, or some more integrated compound of sensory and conceptual components.)

Some historical discussions of the representational properties of mind (e.g., Aristotle 1984, Locke 1689/1975, Hume 1739/1978) seem to assume that Non-conceptual representations - percepts ('impressions'), images ('ideas') and the like - are the only kinds of mental representations, and that the mind represents the world in virtue of being in states that resemble things in it. On such a view, all representational states have their content in virtue of their phenomenal features. Powerful arguments, however, focussing on the lack of generality (Berkeley 1975), ambiguity (Wittgenstein 1953) and non-compositionality (Fodor 1981) of sensory and imagistic representations, as well as their unsuitability to function as logical (Frége 1918/1997, Geach 1957) or mathematical (Frége 1884/1953) concepts, and the symmetry of resemblance (Goodman 1976), convinced philosophers that no theory of mind can get by with only Non-conceptual representations construed in this way.

Contemporary disagreement over Non-conceptual representation concerns the existence and nature of phenomenal properties and the role they play in determining the content of sensory experience. Dennett (1988), for example, denies that there are such things as qualia at all; while Brandom (2002), McDowell (1994), Rey (1991) and Sellars (1956) deny that they are needed to explain the content of sensory experience. Among those who accept that experiences have phenomenal content, some (Dretske, Lycan, Tye) argue that it is reducible to a kind of intentional content, while others (Block, Loar, Peacocke) argue that it is irreducible.

The representationalist thesis is often formulated as the claim that phenomenal properties are representational or intentional. However, this formulation is ambiguous between a reductive and a non-deductive claim (though the term 'representationalism' is most often used for the reductive claim). On one hand, it could mean that the phenomenal content of an experience is a kind of intentional content (the properties it represents). On the other, it could mean that the (irreducible) phenomenal properties of an experience determine an intentional content. Representationalists such as Dretske, Lycan and Tye would assent to the former claim, whereas phenomenalists such as Block, Chalmers, Loar and Peacocke would assent to the latter. (Among phenomenalists, there is further disagreement about whether qualia are intrinsically representational (Loar) or not (Block, Peacocke).

Most (reductive) representationalists are motivated by the conviction that one or another naturalistic explanation of intentionality is, in broad outline, correct, and by the desire to complete the naturalization of the mental by applying such theories to the problem of phenomenality. (Needless to say, most phenomenalists (Chalmers is the major exception) are just as eager to naturalize the phenomenal - though not in the same way.)

The main argument for representationalism appeals to the transparency of experience (cf. Tye 2000: 45-51). The properties that characterize what it's like to have a perceptual experience are presented in experience as properties of objects perceived: in attending to an experience, one seems to 'see through it' to the objects and properties it is experiences of. They are not presented as properties of the experience itself. If nonetheless they were properties of the experience, perception would be massively deceptive. But perception is not massively deceptive. According to the representationalist, the phenomenal character of an experience is due to its representing objective, non-experiential properties. (In veridical perception, these properties are locally instantiated; in illusion and hallucination, they are not.) On this view, introspection is indirect perception: one comes to know what phenomenal features one's experience has by coming to know what objective features it represents.

In order to account for the intuitive differences between conceptual and sensory representations, representationalists appeal to their structural or functional differences. Dretske (1995), for example, distinguishes experiences and thoughts on the basis of the origin and nature of their functions: an experience of a property 'P' is a state of a system whose evolved function is to indicate the presence of 'P' in the environment; a thought representing the property 'P', on the other hand, is a state of a system whose assigned (learned) function is to calibrate the output of the experiential system. Rey (1991) takes both thoughts and experiences to be relations to sentences in the language of thought, and distinguishes them on the basis of (the functional roles of) such sentences' constituent predicates. Lycan (1987, 1996) distinguishes them in terms of their functional-computational profiles. Tye (2000) distinguishes them in terms of their functional roles and the intrinsic structure of their vehicles: thoughts are representations in a language-like medium, whereas experiences are image-like representations consisting of 'symbol-filled arrays.' (the account of mental images in Tye 1991.)

Phenomenalists tend to make use of the same sorts of features (function, intrinsic structure) in explaining some of the intuitive differences between thoughts and experiences; but they do not suppose that such features exhaust the differences between phenomenal and non-phenomenal representations. For the phenomenalists, it is the phenomenal properties of experiences - qualia themselves - that constitute the fundamental difference between experience and thought. Peacocke (1992), for example, develops the notion of a perceptual 'scenario' (an assignment of phenomenal properties to coordinates of a three-dimensional egocentric space), whose content is 'correct' (a semantic property) if in the corresponding 'scene' (the portion of the external world represented by the scenario) properties are distributed as their phenomenal analogues are in the scenario.

Another sort of representation championed by phenomenalists (e.g., Block, Chalmers (2003) and Loar (1996)) is the 'phenomenal concept' -, a conceptual/phenomenal hybrid consisting of a phenomenological 'sample' (an image or an occurrent sensation) integrated with (or functioning as) a conceptual component. Phenomenal concepts are postulated to account for the apparent fact (among others) that, as McGinn (1991) puts it, 'you cannot form [introspective] concepts of conscious properties unless you yourself instantiate those properties.' One cannot have a phenomenal concept of a phenomenal property 'P', and, hence, phenomenal beliefs about P, without having experience of 'P', because 'P' itself is (in some way) constitutive of the concept of 'P'. (Jackson 1982, 1986 and Nagel 1974.)

Though imagery has played an important role in the history of philosophy of mind, the important contemporary literature on it is primarily psychological. In a series of psychological experiments done in the 1970s (summarized in Kosslyn 1980 and Shepard and Cooper 1982), subjects' response time in tasks involving mental manipulation and examination of presented figures was found to vary in proportion to the spatial properties (size, orientation, etc.) of the figures presented. The question of how these experimental results are to be explained has kindled a lively debate on the nature of imagery and imagination.

Kosslyn (1980) claims that the results suggest that the tasks were accomplished via the examination and manipulation of mental representations that themselves have spatial properties, i.e., pictorial representations, or images. Others, principally Pylyshyn (1979, 1981, 2003), argue that the empirical facts can be explained in terms exclusively of discursive, or propositional representations and cognitive processes defined over them. (Pylyshyn takes such representations to be sentences in a language of thought.)

The idea that pictorial representations are literally pictures in the head is not taken seriously by proponents of the pictorial view of imagery The claim is, rather, that mental images represent in a way that is relevantly like the way pictures represent. (Attention has been focussed on visual imagery - hence the designation 'pictorial'; though of course there may imagery in other modalities - auditory, olfactory, etc. - as well.)

The distinction between pictorial and discursive representation can be characterized in terms of the distinction between analog and digital representation (Goodman 1976). This distinction has itself been variously understood (Fodor & Pylyshyn 1981, Goodman 1976, Haugeland 1981, Lewis 1971, McGinn 1989), though a widely accepted construal is that analog representation is continuous (i.e., in virtue of continuously variable properties of the representation), while digital representation is discrete (i.e., in virtue of properties a representation either has or doesn't have) (Dretske 1981). (An analog/digital distinction may also be made with respect to cognitive processes. (Block 1983.)) On this understanding of the analog/digital distinction, imagistic representations, which represent in virtue of properties that may vary continuously (such as being more or less bright, loud, vivid, etc.), would be analog, while conceptual representations, whose properties do not vary continuously (a thought cannot be more or less about Elvis: either it is or it is not) would be digital.

It might be supposed that the pictorial/discursive distinction is best made in terms of the phenomenal/nonphenomenal distinction, but it is not obvious that this is the case. For one thing, there may be nonphenomenal properties of representations that vary continuously. Moreover, there are ways of understanding pictorial representation that presuppose neither phenomenality nor analogicity. According to Kosslyn (1980, 1982, 1983), a mental representation is 'quasi-pictorial' when every part of the representation corresponds to a part of the object represented, and relative distances between parts of the object represented are preserved among the parts of the representation. But distances between parts of a representation can be defined functionally rather than spatially - for example, in terms of the number of discrete computational steps required to combine stored information about them. (Rey 1981.)

Tye (1991) proposes a view of images on which they are hybrid representations, consisting both of pictorial and discursive elements. On Tye's account, images are '(labelled) interpreted symbol-filled arrays.' The symbols represent discursively, while their arrangement in arrays has representational significance (the location of each 'cell' in the array represents a specific viewer-centred 2-D location on the surface of the imagined object)

The contents of mental representations are typically taken to be abstract objects (properties, relations, propositions, sets, etc.). A pressing question, especially for the naturalist, is how mental representations come to have their contents. Here the issue is not how to naturalize content (abstract objects can't be naturalized), but, rather, how to provide a naturalistic account of the content-determining relations between mental representations and the abstract objects they express. There are two basic types of contemporary naturalistic theories of content-determination, causal-informational and functional.

Causal-informational theories (Dretske 1981, 1988, 1995) hold that the content of a mental representation is grounded in the information it carries about what does (Devitt 1996) or would (Fodor 1987, 1990) cause it to occur. There is, however, widespread agreement that causal-informational relations are not sufficient to determine the content of mental representations. Such relations are common, but representation is not. Tree trunks, smoke, thermostats and ringing telephones carry information about what they are causally related to, but they do not represent (in the relevant sense) what they carry information about. Further, a representation can be caused by something it does not represent, and can represent something that has not caused it.

The main attempts to specify what makes a causal-informational state a mental representation are Asymmetric Dependency Theories (e.g., Fodor 1987, 1990, 1994) and Teleological Theories (Fodor 1990, Millikan 1984, Papineau 1987, Dretske 1988, 1995). The Asymmetric Dependency Theory distinguishes merely informational relations from representational relations on the basis of their higher-order relations to each other: informational relations depend upon representational relations, but not vice-versa. For example, if tokens of a mental state type are reliably caused by horses, cows-on-dark-nights, zebras-in-the-mist and Great Danes, then they carry information about horses, etc. If, however, such tokens are caused by cows-on-dark-nights, etc. because they were caused by horses, but not vice versa, then they represent horses.

According to Teleological Theories, representational relations are those a representation-producing mechanism has the selected (by evolution or learning) function of establishing. For example, zebra-caused horse-representations do not mean zebra, because the mechanism by which such tokens are produced has the selected function of indicating horses, not zebras. The horse-representation-producing mechanism that responds to zebras is malfunctioning.

Functional theories (Block 1986, Harman 1973), hold that the content of a mental representation is grounded in its (causal computational, inferential) relations to other mental representations. They differ on whether relata should include all other mental representations or only some of them, and on whether to include external states of affairs. The view that the content of a mental representation is determined by its inferential/computational relations with all other representations is holism; the view it is determined by relations to only some other mental states is localism (or molecularism). (The view that the content of a mental state depends on none of its relations to other mental states is atomism.) Functional theories that recognize no content-determining external relata have been called solipsistic (Harman 1987). Some theorists posit distinct roles for internal and external connections, the former determining semantic properties analogous to sense, the latter determining semantic properties analogous to reference (McGinn 1982, Sterelny 1989)

(Reductive) representationalists (Dretske, Lycan, Tye) usually take one or another of these theories to provide an explanation of the (Non-conceptual) content of experiential states. They thus tend to be Externalists (see the next section) about phenomenological as well as conceptual content. Phenomenalists and non-deductive representationalists (Block, Chalmers, Loar, Peacocke, Siewert), on the other hand, take it that the representational content of such states is (at least in part) determined by their intrinsic phenomenal properties. Further, those who advocate a phenomenology-based approach to conceptual content (Horgan and Tiensen, Loar, Pitt, Searle, Siewert) also seem to be committed to internalist individuation of the content (if not the reference) of such states.

Generally, those who, like informational theorists, think relations to one's (natural or social) environment are (at least partially) determinative of the content of mental representations are Externalists (e.g., Burge 1979, 1986, McGinn 1977, Putnam 1975), whereas those who, like some proponents of functional theories, think representational content is determined by an individual's intrinsic properties alone, are internalists (or individualists; cf. Putnam 1975, Fodor 1981)

This issue is widely taken to be of central importance, since psychological explanation, whether commonsense or scientific, is supposed to be both causal and content-based. (Beliefs and desires cause the behaviours they do because they have the contents they do. For example, the desire that one have a beer and the beliefs that there is beer in the refrigerator and that the refrigerator is in the kitchen may explain one's getting up and going to the kitchen.) If, however, a mental representation's having a particular content is due to factors extrinsic to it, it is unclear how its having that content could determine its causal powers, which, arguably, must be intrinsic. Some who accept the standard arguments for externalism have argued that internal factors determine a component of the content of a mental representation. They say that mental representations have both 'narrow' content (determined by intrinsic factors) and 'wide' or 'broad' content (determined by narrow content plus extrinsic factors). (This distinction may be applied to the sub-personal representations of cognitive science as well as to those of commonsense psychology.

Narrow content has been variously construed. Putnam (1975), Fodor (1982)), and Block (1986), for example, seem to understand it as something like directorial content (i.e., Frégean sense, or perhaps character, à la Kaplan 1989). On this construal, narrow content is context-independent and directly expressible. Fodor (1987) and Block (1986), however, have also characterized narrow content as radically inexpressible. On this construal, narrow content is a kind of proto-content, or content-determinant, and can be specified only indirectly, via specifications of context/wide-content pairings. On both construal, narrow contents are characterized as functions from context to (wide) content. The narrow content of a representation is determined by properties intrinsic to it or its possessor such as its syntactic structure or its intra-mental computational or inferential role (or its phenomenology.

Burge (1986) has argued that causation-based worries about externalist individuation of psychological content, and the introduction of the narrow notion, are misguided. Fodor (1994, 1998) has more recently urged that a scientific psychology might not need narrow content in order to supply naturalistic (causal) explanations of human cognition and action, since the sorts of cases they were introduced to handle, viz., Twin-Earth cases and Frége cases, are either nomologically impossible or dismissible as exceptions to non-strict psychological laws.

The leading contemporary version of the Representational Theory of Mind, the Computational Theory of Mind (CTM), claims that the brain is a kind of computer and that mental processes are computations. According to the computational theory of mind, cognitive states are constituted by computational relations to mental representations of various kinds, and cognitive processes are sequences of such states. The computational theory of mind and the representational theory of mind, may by attempting to explain all psychological states and processes in terms of mental representation. In the course of constructing detailed empirical theories of human and animal cognition and developing models of cognitive processes implementable in artificial information processing systems, cognitive scientists have proposed a variety of types of mental representations. While some of these may be suited to be mental relata of commonsense psychological states, some - so-called 'subpersonal' or 'sub-doxastic' representations - are not. Though many philosophers believe that computational theory of mind can provide the best scientific explanations of cognition and behaviour, there is disagreement over whether such explanations will vindicate the commonsense psychological explanations of prescientific representational theory of mind.

According to Stich's (1983) Syntactic Theory of Mind, for example, computational theories of psychological states should concern themselves only with the formal properties of the objects those states are relations to. Commitment to the explanatory relevance of content, however, is for most cognitive scientists fundamental (Fodor 1981, Pylyshyn 1984, Von Eckardt 1993). That mental processes are computations, which computations are rule-governed sequences of semantically evaluable objects, and that the rules apply to the symbols in virtue of their content, are central tenets of mainstream cognitive science.

Explanations in cognitive science appeal to a many different kinds of mental representation, including, for example, the 'mental models' of Johnson-Laird 1983, the 'retinal arrays,' 'primal sketches' and '2½ -D sketches' of Marr 1982, the 'frames' of Minsky 1974, the 'sub-symbolic' structures of Smolensky 1989, the 'quasi-pictures' of Kosslyn 1980, and the 'interpreted symbol-filled arrays' of Tye 1991 - in addition to representations that may be appropriate to the explanation of commonsense psychological states. Computational explanations have been offered of, among other mental phenomena, belief (Fodor 1975, Field 1978), visual perception (Marr 1982, Osherson, et al. 1990), rationality (Newell and Simon 1972, Fodor 1975, Johnson-Laird and Wason 1977), language learning and (Chomsky 1965, Pinker 1989), and musical comprehension (Lerdahl and Jackendoff 1983).

The classicists (e.g., Turing 1950, Fodor 1975, Fodor and Pylyshyn 1988, Marr 1982, Newell and Simon 1976) hold that mental representations are symbolic structures, which typically have semantically evaluable constituents, and that mental processes are rule-governed manipulations of them that are sensitive to their constituent structure. The connectionists (e.g., McCulloch & Pitts 1943, Rumelhart 1989, Rumelhart and McClelland 1986, Smolensky 1988) hold that mental representations are realized by patterns of activation in a network of simple processors ('nodes') and that mental processes consist of the spreading activation of such patterns. The nodes themselves are, typically, not taken to be semantically evaluable; nor do the patterns have semantically evaluable constituents. (Though there are versions of Connectionism -, 'localist' versions - on which individual nodes are taken to have semantic properties (e.g., Ballard 1986, Ballard & Hayes 1984).) It is arguable, however, that localist theories are neither definitive nor representative of the Conceptionist program (Smolensky 1988, 1991, Chalmers 1993).

Classicists are motivated (in part) by properties thought seems to share with language. Fodor's Language of Thought Hypothesis (LOTH) (Fodor 1975, 1987), according to which the system of mental symbols constituting the neural basis of thought is structured like a language, provides a well-worked-out version of the classical approach as applied to commonsense psychology. According to the language of thought hypothesis, the potential infinity of complex representational mental states is generated from a finite stock of primitive representational states, in accordance with recursive formation rules. This combinatorial structure accounts for the properties of productivity and systematicity of the system of mental representations. As in the case of symbolic languages, including natural languages (though Fodor does not suppose either that the language of thought hypothesis explains only linguistic capacities or that only verbal creatures have this sort of cognitive architecture), these properties of thought are explained by appeal to the content of the representational units and their combinability into contentful complexes. That is, the semantics of both language and thought is compositional: the content of a complex representation is determined by the contents of its constituents and their structural configuration.

Connectionists are motivated mainly by a consideration of the architecture of the brain, which apparently consists of layered networks of interconnected neurons. They argue that this sort of architecture is unsuited to carrying out classical serial computations. For one thing, processing in the brain is typically massively parallel. In addition, the elements whose manipulation drives computation in Conceptionist networks (principally, the connections between nodes) are neither semantically compositional nor semantically evaluable, as they are on the classical approach. This contrast with classical computationalism is often characterized by saying that representation is, with respect to computation, distributed as opposed to local: representation is local if it is computationally basic; and distributed if it is not. (Another way of putting this is to say that for classicists mental representations are computationally atomic, whereas for connectionists they are not.)

Moreover, connectionists argue that information processing as it occurs in Conceptionist networks more closely resembles some features of actual human cognitive functioning. For example, whereas on the classical view learning involves something like hypothesis formation and testing (Fodor 1981), on the Conceptionist model it is a matter of evolving distribution of 'weight' (strength) on the connections between nodes, and typically does not involve the formulation of hypotheses regarding the identity conditions for the objects of knowledge. The Conceptionist network is 'trained up' by repeated exposure to the objects it is to learn to distinguish; and, though networks typically require many more exposures to the objects than do humans, this seems to model at least one feature of this type of human learning quite well.

Further, degradation in the performance of such networks in response to damage is gradual, not sudden as in the case of a classical information processor, and hence more accurately models the loss of human cognitive function as it typically occurs in response to brain damage. It is also sometimes claimed that Conceptionist systems show the kind of flexibility in response to novel situations typical of human cognition - situations in which classical systems are relatively 'brittle' or 'fragile.'

Some philosophers have maintained that Connectionism entails that there are no propositional attitudes. Ramsey, Stich and Garon (1990) have argued that if Conceptionist models of cognition are basically correct, then there are no discrete representational states as conceived in ordinary commonsense psychology and classical cognitive science. Others, however (e.g., Smolensky 1989), hold that certain types of higher-level patterns of activity in a neural network may be roughly identified with the representational states of commonsense psychology. Still others (e.g., Fodor & Pylyshyn 1988, Heil 1991, Horgan and Tienson 1996) argue that language-of-thought style representation is both necessary in general and realizable within Conceptionist architectures. (MacDonald & MacDonald 1995 collects the central contemporary papers in the classicist/Conceptionist debate, and provides useful introductory material as well.

Whereas Stich (1983) accepts that mental processes are computational, but denies that computations are sequences of mental representations, others accept the notion of mental representation, but deny that computational theory of mind provides the correct account of mental states and processes.

Van Gelder (1995) denies that psychological processes are computational. He argues that cognitive systems are dynamic, and that cognitive states are not relations to mental symbols, but quantifiable states of a complex system consisting of (in the case of human beings) a nervous system, a body and the environment in which they are embedded. Cognitive processes are not rule-governed sequences of discrete symbolic states, but continuous, evolving total states of dynamic systems determined by continuous, simultaneous and mutually determining states of the systems components. Representation in a dynamic system is essentially information-theoretic, though the bearers of information are not symbols, but state variables or parameters.

Horst (1996), on the other hand, argues that though computational models may be useful in scientific psychology, they are of no help in achieving a philosophical understanding of the intentionality of commonsense mental states. computational theory of mind attempts to reduce the intentionality of such states to the intentionality of the mental symbols they are relations to. But, Horst claims, the relevant notion of symbolic content is essentially bound up with the notions of convention and intention. So the computational theory of mind involves itself in a vicious circularity: the very properties that are supposed to be reduced are (tacitly) appealed to in the reduction.

To say that a mental object has semantic properties is, paradigmatically, to say that it may be about, or be true or false of, an object or objects, or that it may be true or false simpliciter. Suppose I think that you took to sniffing snuff. I am thinking about you, and if what I think of you (that they take snuff) is true of you, then my thought is true. According to representational theory of mind such states are to be explained as relations between agents and mental representations. To think that you take snuff is to token in some way a mental representation whose content is that ocelots take snuff. On this view, the semantic properties of mental states are the semantic properties of the representations they are relations to.

Linguistic acts seem to share such properties with mental states. Suppose I say that you take snuff. I am talking about you, and if what I say of you (that they take snuff) is true of them, then my utterance is true. Now, to say that you take snuff is (in part) to utter a sentence that means that you take snuff. Many philosophers have thought that the semantic properties of linguistic expressions are inherited from the intentional mental states they are conventionally used to express (Grice 1957, Fodor 1978, Schiffer 1972/1988, Searle 1983). On this view, the semantic properties of linguistic expressions are the semantic properties of the representations that are the mental relata of the states they are conventionally used to express.

It is also widely held that in addition to having such properties as reference, truth-conditions and truth - so-called extensional properties - expressions of natural languages also have intensional properties, in virtue of expressing properties or propositions - i.e., in virtue of having meanings or senses, where two expressions may have the same reference, truth-conditions or truth value, yet express different properties or propositions (Frége 1892/1997). If the semantic properties of natural-language expressions are inherited from the thoughts and concepts they express (or vice versa, or both), then an analogous distinction may be appropriate for mental representations.

Theories of representational content may be classified according to whether they are atomistic or holistic and according to whether they are externalistic or internalistic, whereby, emphasizing the priority of a whole over its parts. Furthermore, in the philosophy of language, this becomes the claim that the meaning of an individual word or sentence can only be understood in terms of its relation to an indefinitely larger body of language, such as a whole theory, or even a whole language or form of life. In the philosophy of mind a mental state similarly may be identified only in terms of its relations with others. Moderate holism may allow the other things besides these relationships also count; extreme holism would hold that a network of relationships is all that we have. A holistic view of science holds that experience only confirms or disconfirms large bodies of doctrine, impinging at the edges, and leaving some leeway over the adjustment that it requires.

Once, again, in the philosophy of mind and language, the view that what is thought, or said, or experienced, is essentially dependent on aspects of the world external to the mind of the subject. The view goes beyond holding that such mental states are typically caused by external factors, to insist that they could not have existed as they now do without the subject being embedded in an external world of a certain kind. It is these external relations that make up the essence or identify of the mental state. Externalism is thus opposed to the Cartesian separation of the mental from the physical, since that holds that the mental could in principle exist as it does even if there were no external world at all. Various external factors have been advanced as ones on which mental content depends, including the usage of experts, the linguistic, norms of the community. And the general causal relationships of the subject. In the theory of knowledge, externalism is the view that a person might know something by being suitably situated with respect to it, without that relationship being in any sense within his purview. The person might, for example, be very reliable in some respect without believing that he is. The view allows that you can know without being justified in believing that you know.

However, atomistic theories take a representation’s content to be something that can be specified independent entity of that representation’ s relations to other representations. What the American philosopher of mind, Jerry Alan Fodor (1935-) calls the crude causal theory, for example, takes a representation to be a
cow
- a menial representation with the same content as the word ‘cow’ - if its tokens are caused by instantiations of the property of being-a-cow, and this is a condition that places no explicit constraints on how
cow
’s must or might relate to other representations. Holistic theories contrasted with atomistic theories in taking the relations a representation bears to others to be essential to its content. According to functional role theories, a representation is a
cow
if it behaves like a
cow
should behave in inference.

Internalist theories take the content of a representation to be a matter determined by factors internal to the system that uses it. Thus, what Block (1986) calls ‘short-armed’ functional role theories are internalist. Externalist theories take the content of a representation to be determined, in part at least, by factors external to the system that uses it. Covariance theories, as well as telelogical theories that invoke an historical theory of functions, take content to be determined by ‘external’ factors. Crossing the atomist-holistic distinction with the internalist-externalist distinction.

Externalist theories (sometimes called non-individualistic theories) have the consequence that molecule for molecule identical cognitive systems might yet harbour representations with different contents. This has given rise to a controversy concerning ‘narrow’ content. If we assume some form of externalist theory is correct, then content is, in the first instance ‘wide’ content, i.e., determined in part by factors external to the representing system. On the other hand, it seems clear that, on plausible assumptions about how to individuate psychological capacities, internally equivalent systems must have the same psychological capacities. Hence, it would appear that wide content cannot be relevant to characterizing psychological equivalence. Since cognitive science generally assumes that content is relevant to characterizing psychological equivalence, philosophers attracted to externalist theories of content have sometimes attempted to introduce ‘narrow’ content, i.e., an aspect or kind of content that is equivalent internally equivalent systems. The simplest such theory is Fodor’s idea (1987) that narrow content is a function from contents (i.e., from whatever the external factors are) to wide contents.

All the same, what a person expresses by a sentence is often a function of the environment in which he or she is placed. For example, the disease I refer to by the term like ‘arthritis’, or the kind of tree I refer to as a ‘Maple’ will be defined by criteria of which I know next to nothing. This raises the possibility of imagining two persons in rather different environments, but in which everything appears the same to each of them. The wide content of their thoughts and sayings will be different if the situation surrounding them is appropriately different: ‘situation’ may include the actual objects they perceive or the chemical or physical kinds of object in the world they inhabit, or the history of their words, or the decisions of authorities on what counts as an example, of one of the terms they use. The narrow content is that part of their thought which remains identical, through their identity of the way things appear, regardless of these differences of surroundings. Partisans of wide content may doubt whether any content in this sense narrow, partisans of narrow content believer that it is the fundamental notion, with wide content being explicable in terms of narrow content plus context.

Even so, the distinction between facts and values has outgrown its name: it applies not only to matters of fact vs, matters of value, but also to statements that something is, vs. statements that something ought to be. Roughly, factual statements - ‘is statements’ in the relevant sense - represent some state of affairs as obtaining, whereas normative statements - evaluative, and deontic ones - attribute goodness to something, or ascribe, to an agent, an obligation to act. Neither distinction is merely linguistic. Specifying a book’s monetary value is making a factual statement, though it attributes a kind of value. ‘That is a good book’ expresses a value judgement though the term ‘value’ is absent (nor would ‘valuable’ be synonymous with ‘good’). Similarly, ‘we are morally obligated to fight’ superficially expresses a statement, and ‘By all indications it ough to rain’ makes a kind of ought-claim; but the former is an ought-statement, the latter an (epistemic) is-statement.

Theoretical difficulties also beset the distinction. Some have absorbed values into facts holding that all value is instrumental, roughly, to have value is to contribute - in a factual analysable way - to something further which is (say) deemed desirable. Others have suffused facts with values, arguing that facts (and observations) are ‘theory-impregnated’ and contending that values are inescapable to theoretical choice. But while some philosophers doubt that fact/value distinctions can be sustained, there persists a sense of a deep difference between evaluating, or attributing an obligation and, on the other hand, saying how the world is.

Fact/value distinctions, may be defended by appeal to the notion of intrinsic value, value a thing has in itself and thus independently of its consequences. Roughly, a value statement (proper) is an ascription of intrinsic value, one to the effect that a thing is to some degree good in itself. This leaves open whether ought-statements are implicitly value statements, but even if they imply that something has intrinsic value - e.g., moral value - they can be independently characterized, say by appeal to rules that provide (justifying) reasons for action. One might also ground the fact value distinction in the attributional (or even motivational) component apparently implied by the making of valuational or deontic judgements: Thus, ‘it is a good book, but that is no reason for a positive attribute towards it’ and ‘you ought to do it, but there is no reason to’ seem inadmissible, whereas, substituting, ‘an expensive book’ and ‘you will do it’ yields permissible judgements. One might also argue that factual judgements are the kind which are in principle appraisable scientifically, and thereby anchor the distinction on the factual side. This ligne is plausible, but there is controversy over whether scientific procedures are ‘value-free’ in the required way.

Philosophers differ regarding the sense, if any, in which epistemology is normative (roughly, valuational). But what precisely is at stake in this controversy is no clearly than the problematic fact/value distinction itself. Must epistemologists as such make judgements of value or epistemic responsibility? If epistemology is naturalizable, then even epistemic principles simply articulate under what conditions - say, appropriate perceptual stimulations - a belief is justified, or constitutes knowledge. Its standards of justification, then would be like standards of, e.g., resilience for bridges. It is not obvious, however, that there appropriate standards can be established without independent judgements that, say, a certain kind of evidence is good enough for justified belief (or knowledge). The most plausible view may be that justification is like intrinsic goodness, though it supervenes on natural properties, it cannot be analysed wholly in factual statements.

Thus far, belief has been depicted as being all-or-nothing, however, as a resulting causality for which we have grounds for thinking it true, and, all the same, its acceptance is governed by epistemic norms, and, least of mention, it is partially subject to voluntary control and has functional affinities to belief. Still, the notion of acceptance, like that of degrees of belief, merely extends the standard picture, and does not replace it.

Traditionally, belief has been of epistemological interest in its propositional guise: ‘S’ believes that ‘p’, where ‘p’ is a reposition towards which an agent, ‘S’ exhibits an attitude of acceptance. Not all belief is of this sort. If I trust you to say, I believer you. And someone may believer in Mr. Radek, or in a free-market economy, or in God. It is sometimes supposed that all belief is ‘reducible’ to propositional belief, belief-that. Thus, my believing you might be thought a matter of my believing, is, perhaps, that what you say is true, and your belief in free markets or God, is a matter of your believing that free-market economies are desirable or that God exists.

Some philosophers have followed St, Thomas Aquinas (1225-74), in supposing that to believer in God is simply to believer that certain truths hold while others argue that belief-in is a distinctive attitude, on that includes essentially an element of trust. More commonly, belief-in has been taken to involve a combination of propositional belief together with some further attitude.

The moral philosopher Richard Price (1723-91) defends the claim that there are different sorts of belief-in, some, but not all reducible to beliefs-that. If you believer in God, you believer that God exists, that God is good, you believer that God is good, etc. But according to Price, your belief involves, in addition, a certain complex pro-attitude toward its object. Even so, belief-in outruns the evidence for the corresponding belief-that. Does this diminish its rationality? If belief-in presupposes believes-that, it might be thought that the evidential standards for the former must be, at least, as high as standards for the latter. And any additional pro-attitude might be thought to require a further layer of justification not required for cases of belief-that.

Belief-in may be, in general, less susceptible to alternations in the face of unfavourable evidence than belief-that. A believe who encounters evidence against God’s existence may remain unshaken in his belief, in part because the evidence does not bear on his pro-attitude. So long as this ids united with his belief that God exists, the reasonably so - in a way that an ordinary propositional belief that would not.

The correlative way of elaborating on the general objection to justificatory externalism challenges the sufficiency of the various externalist conditions by citing cases where those conditions are satisfied, but where the believers in question seem intuitively not to be justified. In this context, the most widely discussed examples have to do with possible occult cognitive capacities, like clairvoyance. Considering the point in application once, again, to reliabilism, the claim is that to think that he has such a cognitive power, and, perhaps, even good reasons to the contrary, is not rational or responsible and therefore not epistemically justified in accepting the belief that result from his clairvoyance, despite the fact that the reliabilist condition is satisfied.

One sort of response to this latter sorts of objection is to ‘bite the bullet’ and insist that such believers are in fact justified, dismissing the seeming intuitions to the contrary as latent internalist prejudice. A more widely adopted response attempts to impose additional conditions, usually of a roughly internalist sort, which will rule out the offending example, while stopping far of a full internalism. But, while there is little doubt that such modified versions of externalism can handle particular cases, as well enough to avoid clear intuitive implausibility, the usually problematic cases that they cannot handle, and also whether there is and clear motivation for the additional requirements other than the general internalist view of justification that externalist are committed to reject.

A view in this same general vein, one that might be described as a hybrid of internalism and externalism holds that epistemic justification requires that there is a justicatory factor that is cognitively accessible to the believer in question (though it need not be actually grasped), thus ruling out, e.g., a pure reliabilism. At the same time, however, though it must be objectively true that beliefs for which such a factor is available are likely to be true, in addition, the fact need not be in any way grasped or cognitively accessible to the believer. In effect, of the premises needed to argue that a particular belief is likely to be true, one must be accessible in a way that would satisfy at least weak internalism, the internalist will respond that this hybrid view is of no help at all in meeting the objection and has no belief nor is it held in the rational, responsible way that justification intuitively seems to require, for the believer in question, lacking one crucial premise, still has no reason at all for thinking that his belief is likely to be true.

An alternative of giving an externalist account of epistemic justification, one which may be more defensible while still accommodating many of the same motivating concerns, is to give an externalist account of knowledge directly, without relying on an intermediate account of justification. Such a view will obviously have to reject the justified true belief account of knowledge, holding instead that knowledge is true belief which satisfies the chosen externalist condition, e.g., a result of a reliable process (and perhaps, further conditions as well). This makes it possible for such a view to retain internalist account of epistemic justification, though the centrality of that concept to epistemology would obviously be seriously diminished.

Such an externalist account of knowledge can accommodate the commonsense conviction that animals, young children, and unsophisticated adults posses knowledge, though not the weaker conviction (if such a conviction does exists) that such individuals are epistemically justified in their beliefs. It is also at least less vulnerable to internalist counter-examples of the sort discussed, since the intuitions involved there pertain more clearly to justification than to knowledge. What is uncertain is what ultimate philosophical significance the resulting conception of knowledge is supposed to have. In particular, does it have any serious bearing on traditional epistemological problems and on the deepest and most troubling versions of scepticism, which seems in fact to be primarily concerned with justification, and knowledge?`

A rather different use of the terms ‘internalism’ and ‘externalism’ has to do with the issue of how the content of beliefs and thoughts is determined: According to an internalist view of content, the content of such intention states depends only on the non-relational, internal properties of the individual’s mind or grain, and not at all on his physical and social environment: While according to an externalist view, content is significantly affected by such external factors and suggests a view that appears of both internal and external elements is standardly classified as an external view.

As with justification and knowledge, the traditional view of content has been strongly internalist in character. The main argument for externalism derives from the philosophy y of language, more specifically from the various phenomena pertaining to natural kind terms, indexicals, etc. that motivate the views that have come to be known as ‘direct reference’ theories. Such phenomena seem at least to show that the belief or thought content that can be properly attributed to a person is dependant on facts about his environment - e.g., whether he is on Earth or Twin Earth, what is fact pointing at, the classificatory criteria employed by expects in his social group, etc. - not just on what is going on internally in his mind or brain.

An objection to externalist account of content is that they seem unable to do justice to our ability to know the content of our beliefs or thought ‘from the inside’, simply by reflection. If content is depend on external factors pertaining to the environment, then knowledge of content should depend on knowledge of these factors - which will not in general be available to the person whose belief or thought is in question.

Mysteriousness, is the source of all possible science: Mysticism finds to belief in the union with the divine nature by means of ecstatic contemplation, and belief in the power of spiritual access to ultimate reality, or to domains of knowledge closed off to ordinary thought. Also applied derogatorily to theories that assume occult qualities or agencies of which no empirical or rational account can be offered.

That through participation or observation we are met with direct and added operations and processes carried out to resolve an uncertainty. As a matter-of-course, the theory of knowledge as so distinguished from two or more inferred diversifiers, if upon which its central questions include, the origin of knowledge, the place of experience in generating knowledge, and the place of reason in doing so. The relationship between knowledge and certainty, and between knowledge and the impossibility of error, the possibility of universal ‘scepticism’ and the changing forms of knowledge that arise from new conceptualizations of the world. All these issues link with other central concerns of philosophy, such as the nature of truth and the nature of experience and meaning. Seeing epistemology is possible as dominated by two rival metaphors. One is that of a building or pyramid, built on foundations. In this conception it is the job of the philosopher to describe especially secure foundations, and to identify secure modes of construction, so that the resulting edifice can be shown to be sound.

This metaphor, of a special privilege favour to what in the mind as a representation, as of something comprehended or, as a formulation, or a plan that has characteristic distinction, when added up to some idea that ‘given’ to issue is an effectively basic idea or the principal object of our attention in a discourse or composite explication and embarks upon its topic, as to the ‘be-all’ and ‘end-all’ of justifiable knowledge. Continuing to have attached on or upon a connection especially logical, as this situation bears directly upon the capabilities, for being to enable the clarifications to keep a rationally derivable theory upon which confirmation and inferences are feasible methods of constitution. The view in epistemology that knowledge must be regarded as a structure raised upon secure, certain foundations. These are found in some combination of experiences and reason, with different schools (‘empiricism’, ‘rationalism’) emphasizing the role of one over the other. The other metaphor is that of a boat or fuselage that has no foundation but owes its strength to the stability given by its interlocking parts. This rejects the idea of a basis in the given, and favours ideas of ‘coherence’ and ‘holism’, but finds it harder to ward off scepticism.

The problem of defining knowledge as for true belief plus some favoured relation between the believer and the fact began with Plato’s view in the Theaetetus that knowledge is true belief plus a logo.

The preference for reason to sense experience as a source of knowledge began with the Eleatics, and played a central role in Platonism. Its most significant modern development was in the 17th century belief that the paradigm of knowledge was the non-sensory intellectual intuition that God would have put into working of all things, and the human being’s task in their acquaintance with mathematics. The Continental rationalists, notably Descartes, Leibniz and Spinoza are frequently contrasted with the British empiricists Locke, Berkeley and Hume, but each opposition is usually an over-simplicity of more complex pictures, for example, it is worth noticing the extent to which Descartes approves of empirical equity, and the extent to which Locke shared the rationalist vision of real knowledge as a kind of intellectual intuition.

In spite of the confirmable certainty of Kant, the subsequent history of philosophy has unstretchingly decreased in amounts to lessen of such things as having to reduce the distinction between experience and thought. Even to deny the possibility of ‘deductive knowledge’ so rationalism depending on this category has also declined. However, the idea that the mind comes with pre-formed categories that determine the structure of language and the ways of thought has survived in the works of linguistics influenced by Chomsky. The term rationalism is also more broadly for any anti-clerical anti-authoritarian humanism, but empiricists such as the Scottish philosopher and essayist David Hume (1711-76), who sides with other relativistic senses.

A fully formalized confirmation theory would dictate the confidence that a rational investigator might have in a theory, given to some indication of evidence. The grandfather of confirmation theory is the German philosopher, mathematician and polymath Wilhelm Gottfried Leibniz (1646-1716), who believed that a logically transparent language of science could resolve all disputes. In the 20th century as fully formal confirmation theory was a main goal of the ‘logical positivists’, since without if the central concept of verification empirical evidence itself remains distressingly unscientific. The principal developments were due to the German logical positivist Rudolf Carnap (1891-1970), culminating in his ‘Logical Foundations of Probability’ (1950). Carnap’s idea was that the meaning necessary for which purposes would considerably carry the first act or step of an action of operations having actuality or reality for being directly the proportion of logical possible states of affairs. In which having or manifesting the concerning abstraction and theory, under which, the indications confirming the pronounced evidences that comparatively such are by, comparison, an expressed or implied standard, or absolute number, from which the essential or conditional confirmation, for which the manifesting affirmation was to evince the relevant significance for it, the progressive uncovering held by reserving the act or manner of grasping or holding on the sides of approval.

All the same, the ‘range theory of probability’ holds that the probability of a proposition compared with some evidence, is a preposition of the range of possibilities under which the proposition is true, compared to the total range of possibilities left open by the evidence. The theory was originally due to the French mathematician Simon Pierre LaPlace (1749-1827), and has guided confirmation theory, for example in the work of the German local positivist, Rudolf Carnap (1891-1970). The difficulty with the theory lies in identifying sets of possibilities so that they admit of measurement, LaPlace appealed to the principle of ‘difference’ supporting that possibilities have an equal probability that would otherwise move another to do or agree to come into being, is that, the particular effectuality of representative characterlogical informality, with which is understood to make out as or perceivable vision. Still, something as known in regard to the given possibility of a strong decision, as this amendable appraisal of resulting capabilities is to keep in a state of efficiency or premises the idea of proceeding a proceeding matter of fact. In that what is generally of something made or to make or produce as in quality or value. The parallel status or effectual amounts to the same thing in accord are equally measured in the different distinctions as regularly objective - equally that if you can, the choice of mischance or alternatively a reason for distinguishing them. However, unrestricted appeal to this principle introduces inconsistency as equally probable regard as depending upon metaphysical choices, as inferred in his work on the logical choices, as in the regarding work of Carnap.

In any event finding an objective source for authority of such a choice is hard, and this is a principal difficulty in front of formalizing the theory of confirmation.

It therefore demands that we can put to measure in the ‘range’ of possibilities consistent with theory and evidence, compared with the range consistent with the evidence alone. Among the following set arrangements, or pattern the methodic orderliness, a common description of estranged dissimulations occurring a sudden beginning of activity as marked from the traditional or usual moderation of obstructing obstacles that seriously hampers actions or the propagation for progress. In fact, a condition or occurrence traceable to cause to induce of one to come into being, specifically to carry to a successful conclusion to come or go, into some place or thing of a condition of being deeply involved or closely linked, often in a compromising way that as much as it is needed or wanting for all our needs, however, the enterprising activities gainfully energize interests to attempt or engage in what requires of readiness or daring ambition for showing an initiative toward resolutions, and, yet, by determining effort to tower far and above. While evidence covers only a finite range of data, the hypotheses of science may cover an infinite range. In addition, confirmation proved to vary with the language in which the science is couched, and the Carnapian programme has difficulty in separating genuinely confirming variety of evidence from less compelling recitation of the same experiments, confirmation also was susceptible to acute paradoxes.

Such that the classical problem of ‘induction’ is phrased as finding some reason to expect that nature is uniform: In ‘Fact, Fiction, and Forecast’ (1954), Nelson Goodman, an American philosopher (1906-98), showed that we need, in addition some reason for preferring some uniformities to others, for without such a selection the uniformity of nature is vacuous. Thus, suppose that all examined emeralds have been green. Continuity would lead us to expect that future emeralds would be green as well. Suspenseful distinctions are now descriptive statements on or upon that we define the predicated stuff: ‘x’ as stuff, if we retrospectively view of or meditation on past events if they put ‘x’ to the question, the sampling representations catechize a query as examined before indwelling an element, or quality of its thing’s inmost being for the reasons present of time ‘T’ and, so in fact, things are not always the way they are seen, nonetheless, charactering ‘T’ or ‘x’ is examined after to resemble or follow, as to reason or control through some various inclination of being, occurring, or carried out at a time after something else, as ‘T’ and just as stated, contributed the condition of being expressed to something with which happened without variations from a course or procedure or from a norm or standard, no deviation from traditional methods. Consequently, the eventual inevitability happens to take place or come about as its resultant amount qualifies to be blue, letting ‘T’ submit to some time around the course as now existing or in progress, for which the present state concurs to ventilate the apprehensive present. Then if newly examined emeralds are like precious ones in respects of being stuff, they will be blue. We prefer blueness as a basis of prediction to stuff-ness, but why? Rather than retreating to realism, Goodman pushes in the opposite direction to what he calls, ‘irrealism’, holding that each version (each theoretical account of reality) produces a new world. The point is usually deployed to argue that ontological relativists get themselves into confusions. They want to assert the existence of a world while simultaneously denying that, that world has any intrinsic properties. The ontological relativist wants to deny the meaningfulness of postulating intrinsic properties of the world, as a position assumed or a point made especially in controversy, that if in the act or process of thinking, as to be at rest immersed in deep thought, provided to some conventional mannerism that no one has theoretically shaped or given to its equalizing symmetric balance in some sense. The realist can agree, but maintain a distinction between concepts that are constructs, and the world of which they hold, of which is not - that concepts applied to a reality that is largely not a human construct, by which reality is revealed through our use of concepts, and not created by that act or practice of using or the state of being used and applicably of its use in the quality of being appropriate or valuable to some end. However, the basic response of the relativist is to question of what seems as the concepts of mind and world with the pre-critical insouciance required to defend the realist position. The worry of the relativist is that we cannot. The most basic concepts used to set up our ontological investigations have complex histories and interrelationships with other concepts. Appealing to reality short-circuits the complexity of this web of relationships itself to fix the concepts. What remains clear is that the possibility of these ‘bent’ predicates puts a deceptive obstacle in the face of purely logical and syntactical approaches to problems of ‘confirmation’.

Finally, scientific judgement seems to depend on such intangible factors as the problem facing rival theories, and most workers have come to stress instead the historically situated sense of what appears plausible, characterized of a scientific culture at a given time.

Even so, the principle central to ‘logical positivism’, according to which the meaning of a statement is its method of verification. Sentences apparently expressing propositions that admit to no verification (such as those of metaphysics and theology) that are significantly meaningless, or at least, fail to put forward theses with cognitive meanings, with the importance in the capabilities of truth or falsity. The principle requires confidence that we know what a verification consists in, and served to co-exist with a simple conception of each thought as answerable to individual experience. To bypass undue simplicity is to maintain the unaffected actualities or apparent deficient ease of intelligence of sense of common purpose or a degree of dedication to a common task regarded as characteristic of a set of emotional gains founded by its restorative corrections, which, in turn for conquest or plunder the same requiring condition justly makes the reallocating position from an acquiring strong or conducive verification. That intending through which points of admitting deprivation, is only to prove of the totality for which is inadequately inconclusive, in that of a means or procedure used in attaining a result method for verification. Nonetheless, more complex and holistic concepts of language and its relationship to the world suggest a more flexible set of possible relations, with sentences that are individually not verifiable, nevertheless having a use in an overall network of beliefs or theory that it answers to experience, and explanation.

Being such beyond doubt, issues surrounding certainty are inextricably connected with those concerning ‘scepticism’. For many sceptics have traditionally held that knowledge requires certainty, and, of course, they claim that specific knowledge is not-possible. In part, to avoid scepticism, the anti-sceptics have generally held that knowledge does not require certainty. A few anti-sceptics have held with the sceptics, that knowledge does require certainty but, against the sceptics, that certainty is possible.

Clearly, certainty is intuitively a property that can be ascribed to either a person or a belief. We can say that a person ‘S’, may conscionable be all or a fundamental part of the substance that contractually affect to induce to come into being its defining certainty, or we can say that a proposition ’p’, must also be intuitively certain. Much that to availing the serviceable combinations for saying that ‘S’ has the right to be certain just in case they sufficiently warrant ‘p’.

There is no basis in contemporary physics or biology for believing in the stark Cartesian division between mind and world that some have moderately described as ‘the disease of the Western mind’, Descartes, quickly realized that there was nothing in the view of nature that could explain or provide a foundation for the mental, or for all that we know from direct or experience as distinctly relating to, or characteristic of mankind, the hominid, which is a member of the human race. In a mechanistic universe, there is made of comment, there is no privileged place for uncertainty for mind, and the separation between mind and matter is absolute. Descartes was also convinced, however, that the immaterial essences that gave form and structure to this universe were coded in geometrical and mathematical ideas, and this insight led him to invent algebraic geometry. However, in Nietzsche’s view, the separation between mind and matter is more absolute than had previously been imagined. Based on the assumptions that there are no real or necessary correspondences between linguistic constructions of reality in human subjectivity and external reality, he declared that we are all of a space that the philosopher can examine the ‘innermost desires of his nature’ and articulate a new message of individual existence founded on ‘will’

Nietzsche’s emotionally charged defence of intellectual freedom and his radical empowerment of mind as the maker and transformer of the collective fictions that shape human reality in a soulless mechanistic universe proved terribly non-influential one twentieth-century thought. Nietzsche sought to reenforce his view of the subjective character of scientific knowledge by appealing to an epistemological crisis over the foundations of logic and arithmetic that arose during the last three decades of the nineteenth century, though a curious course of events, attempted by Edmund Husserl, a philosopher trained in higher math and physics, to resolve this crisis resulted in a view of the character of human consciousness that closely resembled that of Nietzsche.

Not to exclude, that the cumulation progress of science imposes constraints on what can be viewed as a legitimate scientific concept, problem, of the hypothesis, and that their constraints become tighter as science progresses, this, however, is particularly so when the results of theory present us with radically new and seemingly contributive findings like the results of experiments on non-locality. It is because there is incessant feedback within the content and conduct of science that we are led to such counterintuitive results.

Dialectic orchestration will serve as the background for understanding a new relationship between parts and wholes in physics, with a similar view of that relationship that has emerged in the co-called ‘new biology’ and in recent studies of the evolution of a scientific understanding to a more conceptualized representation of ideas, and includes its allied ‘content’.

Nonetheless, it seems a strong possibility that Plotonic and Whitehead connect upon the issue of the creation of the sensible world may by looking at actual entities as aspects of nature’s contemplation. The contemplation of nature is obviously an immensely intricate affair, involving a myriad of possibilities, therefore one can look at actual entities as, in some sense, the basic elements of a vast and expansive process.

We could derive a scientific understanding of these ideas with the aid of precise deduction, as Descartes continued his claim that we could lay the contours of physical reality out in three-dimensional co-ordinates. Following the publication of Isaac Newton’s ‘Principia Mathematica’ in 1687, reductionism and mathematical modeling became the most powerful tools of modern science. The dream that we could know and master the entire physical world through the extension and refinement of mathematical theory became the central feature and principals of scientific knowledge.

The radical separation between mind and nature formalized by Descartes served over time to allow scientists to concentrate on developing mathematical descriptions of matter as pure mechanism without any concern about its spiritual dimensions or ontological foundations. Meanwhile, attempts to rationalize, reconcile or eliminate Descartes’s merging division between mind and matter became the most central feature of Western intellectual life.

Philosophers like John Locke, Thomas Hobbes, and David Hume tried to articulate some basis for linking the mathematical describable motions of matter with linguistic representations of external reality in the subjective space of mind. Descartes’ compatriot Jean-Jacques Rousseau reified nature as the ground of human consciousness in a state of innocence and proclaimed that ‘Liberty, Equality, Fraternities’ are the guiding principles of this consciousness. Rousseau also fabricated the idea of the ‘general will’ of the people to achieve these goals and declared that those who do not conform to this will were social deviants.

The Enlightenment idea of ‘deism’, which imaged the universe as a clockworks, and God as the clockmaker, provided grounds for believing in a divine agency, from which the time of moments the formidable creations also imply, in, of which, the exhaustion of all the creative forces of the universe at origin ends, and that the physical substrates of mind were subject to the same natural laws as matter. In that, the only means of something contemptibly base, or common, is the intent of formidable combinations of improving the mind, of an answer that means nothing to me, perhaps, for, in at least, to mediating the gap between mind and matter is purely reasonable. Causal implications bearing upon the matter in hand resume or take again the measure to return to or begin again after some interruptive activities such that by taking forwards and accepting a primarily displacing restoration to life. Wherefore, its placing by orienting a position as placed on the table for our considerations, we approach of what is needed to find of unexpected worth or merit obtained or encountered more or less by chance and discover ourselves of an implicit processes and instance of separating or of being separated. That is, of not only in equal parts from that which limits or qualifies by even variations or fluctuation, that occasion disunity, is a continuity for which it is said by putting or bringing back, an existence or use thereof. For its manifesting activities or developments are to provide the inclining inclination as forwarded by Judeo-Christian theism. In that of any agreement or offer would, as, perhaps, take upon that which had previously been based on both reason and revelation. Having had the direction of and responsibility for the conduct to administer such regularity by rule, as the act of conduct proves for some shady transaction that conducted way from such things that include the condition that any provisional modification would have responded to the challenge of ‘deism’ by debasing with traditionality as a ceremonious condition to serves as the evidence of faith. Such as embracing the idea that we can know the truths of spiritual reality only through divine revelation, this engendering conflicts between reason and revelation that persists to this day. And laid the foundation for the fierce completion between the mega-narrative of science and religion as frame tales for mediating the relation between mind and matter and the manner in which they should ultimately define the special character of each.

The nineteenth-century Romantics in Germany, England and the United States revived Rousseau’s attempt to posit a ground for human consciousness by reifying nature in a different form. The German man of letters, J.W.Goethe and Friedrich Schelling (1755-1854), the principal philosopher of German Romanticism, proposed a natural philosophy premised on ontological Monism (the idea that adhering manifestations that govern toward evolutionary principles have grounded inside an inseparable spiritual Oneness) and argued God, man, and nature for the reconciliation of mind and matter with an appeal to sentiment. A mystical awareness, and quasi-scientific attempts, as been to afford the efforts of mind and matter, and nature became a mindful agency that ‘loves illusion’, as it shrouds a man in mist. Therefore, presses him or her heart and punishes those who fail to see the light, least of mention, the principal philosopher, German Romanticist E.W.J. Schelling, in his version of cosmic unity, argued that scientific facts were at best, partial truths and that the creatively minded spirit that unities mind and matter is progressively moving toward ‘self-realization’ and ‘undivided wholeness’.

The British version of Romanticism, articulated by figures like William Wordsworth and Samuel Taylor Coleridge, placed more emphasis on the primary of the imagination and the importance of rebellion and heroic vision as the grounds for freedom. As Wordsworth put it, communion with the ‘incommunicable powers’ of the ‘immortal sea’ empowers the mind to release itself from all the material constraints of the laws of nature. The founders of American transcendentalism, Ralph Waldo Emerson and Henry David Theoreau, articulated a version of Romanticism that commensurate with the ideals of American democracy.

The Americans envisioned a unified spiritual reality that manifested itself as a personal ethos that sanctioned radical individualism and bred aversion to the emergent materialism of the Jacksonian era. They were also more inclined than their European counterpart, as the examples of Thoreau and Whitman attest, to embrace scientific descriptions of nature. However, the Americans also dissolved the distinction between mind and matter with an appeal to ontological monism and alleged that mind could free itself from all the constraint of assuming that by some sorted limitation of matter, in which such states have of them, some mystical awareness.

Since scientists, during the nineteenth century were engrossed with uncovering the workings of external reality and seemingly knew of themselves that these virtually overflowing burdens of nothing, in that were about the physical substrates of human consciousness, the business of examining the distributive contribution in dynamic functionality and structural foundation of mind became the province of social scientists and humanists. Adolphe Quételet proposed a ‘social physics’ that could serve as the basis for a new discipline called sociology, and his contemporary Auguste Comte concluded that a true scientific understanding of the social reality was quite inevitable. Mind, in the view of these figures, was a separate and distinct mechanism subject to the lawful workings of a mechanical social reality.

More formal European philosophers, such as Immanuel Kant, sought to reconcile representations of external reality in mind with the motions of matter-based on the dictates of pure reason. This impulse was also apparent in the utilitarian ethics of Jerry Bentham and John Stuart Mill, in the historical materialism of Karl Marx and Friedrich Engels, and in the pragmatism of Charles Smith, William James and John Dewey. These thinkers were painfully aware, however, of the inability of reason to posit a self-consistent basis for bridging the gap between mind and matter, and each remains obliged to conclude that the realm of the mental exists only in the subjective reality of the individual.

Something particular yet peculiar awaits the presence to the future and has framed its proposed new understanding of relationships between mind and world, within the larger context of the history of mathematical physics, the origin and extensions of the classical view of the fundamentals of scientific knowledge, and the various ways that physicists have attempted to prevent previous challenges to the efficacy of classical epistemology.

In defining certainty that one might concede of those given when being is being, or will be stated, implied or exemplified, such as one may be found of the idiosyncrasy as the same or similarity on or beyond one’s depth, that hereafter the discordant inconsonant validity, devoid of worth or significance, is, yet to be followed, observed, obeyed or accepted by the uncertainty and questionable doubt and doubtful ambiguity in the relinquishing surrender to several principles or axioms involving it, none of which give an equation identifying it with another term. Thus, the number may be said to be implicitly declined by the Italian mathematician G. Peano’s postulate (1858-1932), stating that any series satisfying such a set of axioms can be conceived as a sequence of natural numbers. Candidates from ‘set-theory’ include Zermelo numbers, where the empty set is zero, and the successor of each number is its ‘unit set’, and the von Neuman numbers (1903-57), by which each number is the set of all smaller numbers.

Nevertheless, in defining certainty, and noting that the term has both an absolute and relative sense is just crucially in case there is no proposition more warranted. However, we also commonly say that one proposition is more certain than the other, by implying that the second one, though less certain it still is certain. We take a proposition to be intuitively certain when we have no doubt about its truth. We may do this in error or unreasonably, but objectivity, a proposition is certain when such absence of doubt is justifiable. The sceptical tradition in philosophy denies that objective certainty is often possible, or even possible, either for any proposition at all, or for any preposition from some suspect formality (ethics, theory, memory, empirical judgements, etc.)

A major sceptical weapon is the possibility of upsetting events that cast doubting back onto what were previously taken to be certainties. Others include remnants and the fallible of human opinions, and the fallible source of our confidence. Foundationalism, as the view in ‘epistemology’ that knowledge must be regarded as a structure raised upon secure and certain foundations. Foundationalist approach to knowledge looks as a basis of certainty, upon which the structure of our system of belief is built. Others reject the metaphor, looking for mutual support and coherence without foundations.

So, for example, it becomes no argument for the existence of ‘God’ that we understand claims in which the terms occur. Analyzing the term as a description, we may interpret the claim that ‘God’ exists as something likens to that there is a universe, and that is untellable whether or not it is true.

The formality from which the theory’s description can be couched on its true definition, such that being:

The F is G = (∃x) (Fx & (Ay) (Fy ➞ y = x) & Gv)

The F is G = (∃x) (Fx & (∀y) (Fy ➞ y =x))

Additionally, an implicit definition of terms is given to several principles or axioms involving that there are laid down in having, at least, five equations: Having associated it with another term. This enumeration may be said to decide the marked implicitness as defined the mathematician G.Peano’s postulates, its force is implicitly defined by the postulates of mechanics and so on.

What is more, of what is left-over, in favour of the right to retain ‘any connection’ so from that it is quite incapable of being defrayed. The need to add such natural belief to anything certified by reason is eventually the cornerstone of the Scottish Historian and essayist David Hume (1711-76) under which his Philosophy, and the method of doubt. Descartes used clear and distinctive formalities in the operating care of ideas, if only to signify the particular transparent quality of ideas on which we are entitle to reply, even when indulging the ‘method of doubt’. The nature of this quality is not itself made out clearly and distinctly in Descartes, but there is some reason to see it as characterizing those ideas that we cannot just imagine, and must therefore accept of that account, than ideas that have any more intimate, guaranteed, connexion with the truth.































consciousness in a state of innocence and proclaimed that ‘Liberty, Equality, Fraternities’ are the guiding principles of this consciousness. Rousseau also fabricated the idea of the ‘general will’ of the people to achieve these goals and declared that those who do not conform to this will were social deviants.

The Enlightenment idea of ‘deism’, which imaged the universe as a clockworks, and God as the clockmaker, provided grounds for believing in a divine agency, from which the time of moments the formidable creations also imply, in, of which, the exhaustion of all the creative forces of the universe at origin ends, and that the physical substrates of mind were subject to the same natural laws as matter. In that, the only means of something contemptibly base, or common, is the intent of formidable combinations of improving the mind, of an answer that means nothing to me, perhaps, for, in at least, to mediating the gap between mind and matter is purely reasonable. Causal implications bearing upon the matter in hand resume or take again the measure to return to or begin again after some interruptive activities such that by taking forwards and accepting a primarily displacing restoration to life. Wherefore, its placing by orienting a position as placed on the table for our considerations, we approach of what is needed to find of unexpected worth or merit obtained or encountered more or less by chance and discover ourselves of an implicit processes and instance of separating or of being separated. That is, of not only in equal parts from that which limits or qualifies by even variations or fluctuation, that occasion disunity, is a continuity for which it is said by putting or bringing back, an existence or use thereof. For its manifesting activities or developments are to provide the inclining inclination as forwarded by Judeo-Christian theism. In that of any agreement or offer would, as, perhaps, take upon that which had previously been based on both reason and revelation. Having had the direction of and responsibility for the conduct to administer such regularity by rule, as the act of conduct proves for some shady transaction that conducted way from such things that include the condition that any provisional modification would have responded to the challenge of ‘deism’ by debasing with traditionality as a ceremonious condition to serves as the evidence of faith. Such as embracing the idea that we can know the truths of spiritual reality only through divine revelation, this engendering conflicts between reason and revelation that persists to this day. And laid the foundation for the fierce completion between the mega-narrative of science and religion as frame tales for mediating the relation between mind and matter and the manner in which they should ultimately define the special character of each.

The nineteenth-century Romantics in Germany, England and the United States revived Rousseau’s attempt to posit a ground for human consciousness by reifying nature in a different form. The German man of letters, J.W.Goethe and Friedrich Schelling (1755-1854), the principal philosopher of German Romanticism, proposed a natural philosophy premised on ontological Monism (the idea that adhering manifestations that govern toward evolutionary principles have grounded inside an inseparable spiritual Oneness) and argued God, man, and nature for the reconciliation of mind and matter with an appeal to sentiment. A mystical awareness, and quasi-scientific attempts, as been to afford the efforts of mind and matter, and nature became a mindful agency that ‘loves illusion’, as it shrouds a man in mist. Therefore, presses him or her heart and punishes those who fail to see the light, least of mention, Schelling, in his version of cosmic unity, argued that scientific facts were at best, partial truths and that the creatively minded spirit that unities mind and matter is progressively moving toward ‘self-realization’ and ‘undivided wholeness’.

The British version of Romanticism, articulated by figures like William Wordsworth and Samuel Taylor Coleridge, placed more emphasis on the primary of the imagination and the importance of rebellion and heroic vision as the grounds for freedom. As Wordsworth put it, communion with the ‘incommunicable powers’ of the ‘immortal sea’ empowers the mind to release itself from all the material constraints of the laws of nature. The founders of American transcendentalism, Ralph Waldo Emerson and Henry David Theoreau, articulated a version of Romanticism that commensurate with the ideals of American democracy.

The American envisioned a unified spiritual reality that manifested itself as a personal ethos that sanctioned radical individualism and bred aversion to the emergent materialism of the Jacksonian era. They were also more inclined than their European counterpart, as the examples of Thoreau and Whitman attest, to embrace scientific descriptions of nature. However, the Americans also dissolved the distinction between mind and matter with an appeal to ontological monism and alleged that mind could free itself from all the constraint of assuming that by some sorted limitation of matter, in which such states have of them, some mystical awareness.

Since scientists, during the nineteenth century were engrossed with uncovering the workings of external reality and seemingly knew of themselves that these virtually overflowing burdens of nothing, in that were about the physical substrates of human consciousness, the business of examining the distributive contribution in dynamic functionality and structural foundation of mind became the province of social scientists and humanists. Adolphe Quételet proposed a ‘social physics’ that could serve as the basis for a new discipline called sociology, and his contemporary Auguste Comte concluded that a true scientific understanding of the social reality was quite inevitable. Mind, in the view of these figures, was a separate and distinct mechanism subject to the lawful workings of a mechanical social reality.

More formal European philosophers, such as Immanuel Kant, sought to reconcile representations of external reality in mind with the motions of matter-based on the dictates of pure reason. This impulse was also apparent in the utilitarian ethics of Jerry Bentham and John Stuart Mill, in the historical materialism of Karl Marx and Friedrich Engels, and in the pragmatism of Charles Smith, William James and John Dewey. These thinkers were painfully aware, however, of the inability of reason to posit a self-consistent basis for bridging the gap between mind and matter, and each remains obliged to conclude that the realm of the mental exists only in the subjective reality of the individual

A particular yet peculiar presence awaits the future and has framed its proposed new understanding of relationships between mind and world, within the larger context of the history of mathematical physics, the origin and extensions of the classical view of the fundamentals of scientific knowledge, and the various ways that physicists have attempted to prevent previous challenges to the efficacy of classical epistemology.

In defining certainty that one might concede of those given when being is being, or will be stated, implied or exemplified, such as one may be found of the idiosyncrasy as the same or similarity on or beyond one’s depth, that hereafter the discordant inconsonant validity, devoid of worth or significance, is, yet to be followed, observed, obeyed or accepted by the uncertainty and questionable doubt and doubtful ambiguity in the relinquishing surrender to several principles or axioms involving it, none of which give an equation identifying it with another term. Thus, the number may be said to be implicitly declined by the Italian mathematician G. Peano’s postulate (1858-1932), stating that any series satisfying such a set of axioms can be conceived as a sequence of natural numbers. Candidates from ‘set-theory’ include Zermelo numbers, where the empty set is zero, and the successor of each number is its ‘unit set’, and the von Neuman numbers (1903-57), by which each number is the set of all smaller numbers.

Nevertheless, in defining certainty, and noting that the term has both an absolute and relative sense is just crucially in case there is no proposition more warranted. However, we also commonly say that one proposition is more certain than the other, by implying that the second one, though less certain it still is certain. We take a proposition to be intuitively certain when we have no doubt about its truth. We may do this in error or unreasonably, but objectivity, a proposition is certain when such absence of doubt is justifiable. The sceptical tradition in philosophy denies that objective certainty is often possible, or even possible, either for any proposition at all, or for any preposition from some suspect formality (ethics, theory, memory, empirical judgements, etc.)

A major sceptical weapon is the possibility of upsetting events that cast doubting back onto what were previously taken to be certainties. Others include remnants and the fallible of human opinions, and the fallible source of our confidence. Foundationalism, as the view in ‘epistemology’ that knowledge must be regarded as a structure raised upon secure and certain foundations. Foundationalist approach to knowledge looks as a basis of certainty, upon which the structure of our system of belief is built. Others reject the metaphor, looking for mutual support and coherence without foundations.

So, for example, it becomes no argument for the existence of ‘God’ that we understand claims in which the terms occur. Analyzing the term as a description, we may interpret the claim that ‘God’ exists as something likens to that there is a universe, and that is untellable whether or not it is true.

The formality from which the theory’s description can be couched on its true definition, such that being:

The F is G = (∃x)(Fx & (Ay)(Fy ➞ y = x) & Gv)

The F is G = (∃x)(Fx & (∀y)(Fy ➞ y =x))

Additionally, an implicit definition of terms is given to several principles or axioms involving that which is laid down in having, at Least, five equations: Having associated it with another term. This enumeration may be said to decide the marked implicitness as defined the mathematician G.Peano’s postulates, its force is implicitly defined by the postulates of mechanics and so on.

What is more, of what is left-over, in favour of the right to retain ‘any connection’ so from that it is quite incapable of being defrayed. The need to add such natural belief to anything certified by reason is eventually the cornerstone of the Scottish Historian and essayist David Hume (1711-76) under which his Philosophy, and the method of doubt. Descartes used clear and distinctive formalities in the operating care of ideas, if only to signify the particular transparent quality of ideas on which we are entitle to reply, even when indulging the ‘method of doubt’. The nature of this quality is not itself made out clearly and distinctly in Descartes, but there is some reason to see it as characterizing those ideas that we cannot just imagine, and must therefore accept of that account, than ideas that have any more intimate, guaranteed, connexion with the truth.

The assertive attraction or compelling nature for qualifying attentions for reasons that time and again, that several acquainted philosophers are for some negative direction can only prove of their disqualifications, however taken to mark and note of Unger (1975), who has argued that the absolute sense is the only sense, and that the relative sense is not apparent. Even so, if those convincing affirmations remain collectively clear it is to some sense that there is, least of mention, an absolute sense for which is crucial to the issues surrounding ‘scepticism’.

To put or lead on a course, as to call upon for an answer of information so asked in that of an approval to trust, so that the question would read ‘what makes belief or proposition absolutely certain?’ There are several ways of approaching our answering to the question. Some, like the English philosopher Bertrand Russell (1872-1970), will take a belief to be certain just in case there are no logical possibilities that our belief is false. On this definition about physical objects (objects occupying space) cannot be certain.

However, the characterization of intuitive certainty should be rejected precisely because it makes question of the propositional interpretation. Thus, the approach would not be acceptable to the anti-sceptic.

Once-again, other philosophies suggest that the role that belief plays within our set of actualized beliefs, making a belief certain. For example, Wittgenstein has suggested that belief be certain just in case it can be appealed to justify other beliefs in, but stands in no need of justification itself. Thus, the question of the existence of beliefs that are certain can be answered by merely inspecting our practices to learn whether any beliefs play the specific role. This approach would not be acceptable to the sceptics. For it, too, makes the question of the existence of absolutely certain beliefs uninteresting. The issue is not of whether beliefs play such a role, but whether any beliefs should play that role. Perhaps our practices cannot be defended.

Suggestively, as the characterization of absolute certainty a given, namely that a belief, ‘p’s’ are certain just in case no belief is more warranted than ‘p’. Although it does delineate a necessary condition of absolute certainty and it is preferable to the Wittgenstein approach, it does not capture the full sense of ‘absolute certainty’. The sceptics would argue that it is not strong enough for, it is according to this characteristic a belief could be absolutely certain and yet there could be good grounds for doubting it - just if there were equally good grounds for doubting every proposition that was equally warranted - in addition, to say that a belief is certain and without doubt, it may be said, that it is partially in what we have of a guarantee of its sustaining classification of truth. There is no such guarantee provided by this characterization.

It can be said that a belief that ‘p’ is absolutely immune to doubt. In other words, a proposition, ‘p’ is absolutely certain for ‘S’ if and only if (1) ‘p’, is warranted for ‘S’ and (2) ‘S’ is warranted in denying every preposition, ‘g’, such that if ‘g’ is added to S’s beliefs, the warrant for ‘p’ is reduced (even, only very slightly) and (3) there is no true proposition, ‘d’, such that ‘d’ is added to S’s beliefs the warrant for ‘p’ is reduced.

This is an account of absolute certainty that captures what is demanded by the sceptic. If a proposition is certain in this sense, abidingly true for being indubitable and guaranteed both subjectively and objectively. In addition, such a characterization of certainty does not automatically lead to scepticism. Thus, this is an account of certainty that satisfies once and again the necessity for undertaking what is usually difficult or problematic, but, satisfies the immediate and yet purposive needs of necessity too here and now.

Once, more, as with many things in contemporary philosophy are of prevailing certainty about scepticism that originated with Descartes’s, in particular, with his discussions on the so-called ‘evil spirit hypothesis’. Roughly or put it to thought of, that the hypothesis is that instead of there being a world filled with familiar objects. That there is only of me and my beliefs and an evil genius who caused to be for those beliefs that I would have, and no more than a whispering interference as blamed for the corpses of times generations, here as there that it can be the world for which one normally believes, in that it exists. The sceptical hypothesis can be ‘up-dared’ by replacing me and my beliefs with a brain-in-a-vat and brain-states and replacing the evil genius with a computer connected to my brain, feeling the simulating technology to be in just those states it would be if it were to stare by its simplest of causalities that surrounded by any causal force of objects reserved for the world.

The hypophysis is designed to impugn our knowledge of empirical prepositions by showing that our experience is not a good source of beliefs. Thus, one form of traditional scepticism developed by the Pyrrhonists, namely hat reason is incapable of producing knowledge, is ignored by contemporary scepticism. Apparently, is sceptical hypotheses can be employed in two distinct ways. It can be shown upon the relying characteristics caused of each other.

Letting ‘p’ stands for any ordinary belief, e.g., there is a table before me, the first type of argument employing the sceptic hypothesis can be studied as follows:

1. If ‘S’ knows that ‘p’, than ‘p’ is certain

2. The sceptical hypotheses show that ‘p’ are not certain

Therefore, ‘S’ does not know that ‘p’,

No argument for the first premiss is needed because the first form of the argument employing the sceptical hypothesis is only concerned with cases in which certainty is thought to be a necessary condition of knowledge. Nonetheless, it would be pointed out that we often do say that we know something, although we would not claim that it is certain: If in fact, Wittgenstein claims, that propositions known are always subject to challenge, whereas, when we say that ‘p’ is certain, in that of going beyond the resigned concede of foreclosing an importuning challenge to ‘p’. As he put it, ‘Knowledge’ and ‘certainty’ belong to different categories.

However, these acknowledgments that do overshoot the basic point of issue - namely whether ordinary empirical propositions are certain, as finding that the Cartesian sceptic could seize upon that there is a use of ‘knowing’ - perhaps a paradigmatic use - such that we can legitimately claim to know something and yet not be certain of it. Nevertheless, it is precisely whether such an affirming certainty, is that of another issue. For if such propositions are not certain, then so much the worse for those prepositions that we claim to know in virtue of being certain of our observations. The sceptical challenge is that, in spite of what is ordinarily believed no empirical proposition is immune to doubt.

Implicitly, the argument of a Cartesian notion of doubt that is roughly that a proposition ‘p’ is doubtful for ‘S’, if there is a proposition that (1) ‘S’ is not justified in denying and (2) If added to S’s beliefs, would lower the warrant of ‘p’. The sceptical hypotheses would know the warrant of ‘p’ if added to S’s beliefs so this clearly appears concerned with cases in which certainty is thought to be a necessary condition of knowledge, the argument for scepticism will clearly succeed just in cash there is a good argument for the claim that ‘S’ is not justified in denying the sceptical hypothesis.

That precisely of a direct consideration of the Cartesian notion, more common, way in which the sceptical hypothesis has played a role in contemporary debate over scepticism.

(1) If ‘S’ is justified in believing that ‘p’, then since ‘p’ entails that denial of the sceptic hypothesis: ‘S’ is justified in believing that denial of the sceptical hypothesis.

(2) ‘S’ is not justified in denying the sceptical hypothesis.

Therefore ‘S’ is not justified in believing that ‘p’.

There are several things to take notice of regarding this argument: First, if justification is a necessary condition of knowledge, his argument would succeed in sharing that ‘S’ does not know that ‘p’. Second, it explicitly employs the premise needed by the first argument, namely that ‘S’ is not justified in denying the sceptical hypophysis. Third, the first premise employs a version of the so-called ‘transmissibility principle’ which probably first occurred in Edmund Gettier’s article (1963). Fourth, ‘p’ clearly does in fact entail the denial of the most natural constitution of the sceptical hypothesis. Since this hypothesis includes the statement that ‘p’ is false. Fifth, the first premise can be reformulated using some epistemic notion other than justification, or particularly with the appropriate revisions, ‘knows’ could be substituted for ‘is justified in behaving’. As such, the principle will fail for uninteresting reasons. For example, if belief is a necessary condition of knowledge, since we can believe a proposition within believing al of the propositions entailed by it, the principle is clearly false. Similarly, the principle fails for other uninteresting reasons, for example, of the entailment is very complex one, ‘S’ may not be justified in believing what is entailed. In addition, ‘S’ may recognize the entailment but believe the entailed proposition for silly reasons. However, the interesting question remains: If ‘S’ is, justified in believing (or knows) that ‘p’: ‘p’ obviously (to ‘S’) entails ‘q’ and ‘S’ believes ‘q’ based on believing ‘p’, then is ‘q’, is justified in believing (or, able to know) that ‘q’.

The contemporary literature contains two general responses to the argument for scepticism employing an interesting version of the transmissibility principle. The most common is to challenge the principle. The second claims that the argument will, out of necessity be the question against the anti-sceptic.

Nozick (1981), Goldman (1986), Thalberg (1934), Dertske (1970) and Audi (1988), have objected to various forms and acquaintances with the transmissibility principle. Some of these arguments are designed to show that the first argument that had involved ‘knowledge’ and justly substituted for ‘justification’ in the interests against falsity. However, noting that is even crucial if the principle, so understood, were false, while knowledge requires justification, the argument given as such that it could still be used to show that ‘p’ is beyond our understanding of knowledge. Because the belief that ‘p’ would not be justified, it is equally important, even if there is some legitimate conception of knowledge, for which it does not entail justification. The sceptical challenge could simply be formulated about justification. However, it would not be justified in believing that there is a table before me, seems as disturbing as not knowing it.

Scepticism is the view that we lack knowledge. It can be ‘local’, for example, the view could be that we lack all knowledge of the future because we do not know that the future will resemble the past, or we could be sceptical about the existence of ‘other worlds’. However, there is another view - the absolute globular views that we do not have any knowledge at all. It is doubtful that any philosopher seriously entertains absolute globular scepticism. Even the Pyrrhonist sceptics who held that we should refrain from ascending too any non-evident. Positions had no such hesitancy about acceding to ‘the evident’. The non-evident of any belief that requires evidence to be epistemologically acceptable, e.g., acceptance because it is warranted. Descartes, in this sceptical sense, never doubled the content of his own ideas, the issue for him was whether they ‘corresponded’ to anything beyond ideas.

Nonetheless, Pyrrhonist and Cartesian forms of virtual globular scepticism have been held and defended. If knowledge is some form of true, sufficiently warranted belief, it is the warranted condition, that provides the grist for the sceptic, will. The Pyrrhonists will suggest that no non-evident, empirical proposition be sufficiently warranted because its denial will be equally warranted. A Cartesian sceptic will agree that no empirical propositions about anything other than one’s own mind and is content is sufficiently warranted because there are always legitimate grounds for doubling it. Thus, an essential difference between the two views concerns the stringency of the requirements for belief’s being sufficiently warranted to count as knowledge. A Cartesian requires certainty, a Pyrrhonist merely requires that the position be more warranted than its negation.

The Pyrrhonists do not assert that no non-evident proposition can be known, because that assertion itself is such a knowledge claim. Comparatively, they examine an alternatively successive series of instances to illustrate such reason to a representation for which it might be thought that we have knowledge of the non-evident. They claim that in those cases our senses, or memory, and our reason can provide equally good evidence for or against any belief about what is non-evident for or against any belief about what is non-evident. Better, they would Say, to withhold belief than to ascend. They can be considered the sceptical ‘agnostics’.

Cartesian scepticism, more impressed with Descartes’ argument for scepticism than his own replies, holds that we do not have any knowledge of any empirical proposition about anything beyond the content of our own minds. Reason, roughly put, is a legitimate doubt about all-such propositions, because there is no way to justify the denying of our senses is deceivingly spirited by some stimulating cause, an evil spirit, for example, which is radically unlike in kind or character from the matter opposed by or against the ineffectual estrangement or disassociative disapproval, if not to resolve of an unyielding course, whereby in each of their feelings and expressive conditions that the productive results are well grounded by some equal sequences of succession. This being to address the formalized conditions or occurring causalities, by which these impressions are from the impacting assortments that are so, called for or based on factual information. As a directly linked self-sense of experiences that, although, it is an enactment for which of itself are the evidential proofs of an ongoing system beyond the norm of acceptable limits. In acquaintance with which the direct participants of usually unwarrantable abilities, in their regainful achieve of a goal point or end results that are the derivative possessions as to cause to change some contractually forming of causalities, from one to another, particularly, it’s altruistic and tolerance, which forbears in the kinds of idea that something must convey to the mind, as, perhaps, the acceptations or significancy that is given of conceptual representations over which in themselves outstretch the derivations in type, shape, or form of satisfactory explanations. These objective theories and subjective matters continue of rendering the validity for which services are expressed in dispositional favour for interactions that bring about acceptance of the particularities as founded in the enabling abilities called relationships. The obtainable of another source by means of derivations, and, perhaps, it would derive or bring other than seems to be the proceedings that deal with, say, with more responsibilities, of taken by the object, we normally think that an effect of our senses is, therefore, if the Pyrrhonists who are the ‘agnostics’, the Cartesian sceptic is the ‘atheist’.

Because the Pyrrhonist requires much less of a belief in order for it to be certified as knowledge than does the Cartesian, the argument for Pyrrhonism is much more difficult to construct. Any Pyrrhonist believing for reasons that posit of any proposition would rather than deny it. A Cartesian can grant that, no balance, a preposition is more warranted than its denial. The Cartesian needs only show that there remains some legitimate doubt about the truth of the proposition.

Thus, in assessing scepticism, the issues to consider are these: Are their ever better reasons for believing a non-evident proposition than there are for believing its negation? Does knowledge, at least in some of its forms, require certainty? If so, is any non-evident proposition certain?

Although Greek scepticism was set forth of a valuing enquiry and questioning representation of scepticism that is now the denial that knowledge or even rational belief is possible, either about some specific subject-matter, e.g., ethics or in any area at all. Classically, scepticism springs from the observations that the best methods in some area seem to fall short of giving us contact with the truth, e.g., there is a gulf between appearances and reality, and it frequently cites the conflicting judgements that our methods deliver, so that questions of truth become undecidable. In classical thought the various examples of this conflict were systematized in the Ten tropes of ‘Aenesidemus’. The scepticism of Pyrrho and the new Academy was a system of arguments and ethics opposed to dogmatism and particularly to the philosophical system-building of the Stoics. As it has come down to us, particularly in the writings of Sextus Empiricus, its method was typically to cite reasons for finding an issue undecidable sceptic devoted particularly to energy of undermining the Stoics conscription of some truths as delivered b y direct apprehensions. As a result the sceptic counsels the subsequent belief, and then goes on to celebrating a way of life whose object was the tranquillity resulting from such suspension of belief. The process is frequently mocked, for instance in the stories recounted by Diogenes Lacitius that Pryyho had precipices leaving struck people in bogs, and so on, since his method denied confidence that there existed the precipice or that bog: The legends may have arisen from a misunderstanding of Aristotle, Metaphysic G. iv 1007b where Aristotle argues that since sceptics do no objectivably oppose by arguing against evidential clarity, however, among things to whatever is apprehended as having actual, distinct, and demonstrable existence, that which can be known as having existence in space or time that attributes his being to exist of the state or fact of having independent reality. As a place for each that they actually approve to take or sustain without protest or repining a receptive design of intent as an accordant agreement with persuadable influences to forbear narrow-mindedness. Significance, as do they accept the doctrine they pretend to reject.

In fact, ancient sceptics allowed confidence on ‘phenomena’, bu t quite how much fall under the heading of phenomena is not always clear.

Sceptical tendencies pinged in the 14th century writing of Nicholas of Autrecourt ƒL. 1340. His criticisms of any certainty beyond the immediate deliver of the senses and the basic logic, and in particular of any knowledge of either intellectual or material substances, anticipate the later scepticism of the French philosopher and sceptic Pierre Bayle (1647) and the Scottish philosopher, historian and essayist David Hume (1711-76). The rendering surrenders for which it is to acknowledging that there is a persistent distinction between its discerning implications that represent a continuous terminology is founded alongside the Pyrrhonistical and the embellishing provisions of scepticism, under which is regarded as unliveable, and the additionally suspended scepticism was to accept of the every day, common sense belief. (Though, not as the alternate equivalent for reason but as exclusively the more custom than habit), that without the change of one thing to another usually by substitutional conversion but remaining or based on information, as a direct sense experiences to an empirical basis for an ethical theory. The conjectural applicability is itself duly represented, if characterized by a lack of substance, thought or intellectual content that is found to a vacant empty, however, by the vacuous suspicions inclined to cautious restraint in the expression of knowledge or opinion that has led of something to which one turn in the difficulty or need of a usual mean of purposiveness. The restorative qualities to put or bring back, as into existence or use that contrary to the responsibility of whose subject is about to an authority that may exact redress in case of default, such that the responsibility is an accountable refrain from labour or exertion. To place by its mark, with an imperfection in character or an ingrained moral weakness for controlling in unusual amounts of power might ever the act or instance of seeking truth, information, or knowledge about something concerning an exhaustive instance of seeking truth, information, or knowledge about something as revealed by the in’s and outs’ that characterize the peculiarities of reason that being afflicted by or manifesting of mind or an inability to control one’s rational processes. Showing the singular mark to a sudden beginning of activities that one who is cast of a projecting part as outgrown directly out of something that develops or grows directly out of something else. Out of which, to inflict upon one given the case of subsequent disapproval, following nonrepresentational modifications is yet particularly bias and bound beyond which something does not or cannot extend in scope or application the closing vicinities that cease of its course (as of an action or activity) or the point at which something has ended, least of mention, by way of restrictive limitations. Justifiably, scepticism is thus from Pyrrho though to Sextus Empiricans, and although the phrase ‘Cartesian scepticism’ is sometimes used. Descartes himself was not a sceptic, but in the ‘method of doubt’ uses a scenario to begin the process of finding a secure mark of knowledge. Descartes holds trust of a category of ‘clear and distinct’ ideas, not for remove d from the phantasia kataleptike of the Stoics. Scepticism should not be confused with relativism, which is a doctrine about the nature of truths, and may be motivated by trying to avoid scepticism. Nor does it happen that it is identical with eliminativism, which cannot be abandoned of any area of thought altogether, not because we cannot know the truth, but because there cannot be framed in the terms we use.

The ‘method of doubt’, sometimes known as the use of hyperbolic (extreme) doubt, or Cartesian doubt, is the method of investigating knowledge and its basis in reason or experience used by Descartes in the first two Meditations. It attempts to put knowledge upon secure foundations by first inviting us to suspend judgement on a proposition whose truth can be doubled even as a possibility. The standards of acceptance are gradually raised as we are asked to doubt the deliverance of memory, the senses and even reason, all of which are in principle, capable or potentially probable of letting us down. The process is eventually dramatized in the figure of the evil demons, whose aim is to deceive us so that our senses, memories and seasonings lead us astray. The task then becomes one of finding some demon-proof points of certainty, and Descartes produces this in his famous ‘Cogito ergo sum’: As translated into English and written as: ‘I think. Therefore, I am’.

The Cartesian doubt is the method of investigating how much knowledge and its basis in reason or experience as used by Descartes in the first two Medications. It attempted to put knowledge upon secure foundation by first inviting us to suspend judgements on any proportion whose truth can be doubted, even as a bare possibility. The standards of acceptance are gradually raised as we are asked to doubt the deliverance of memory, the senses, and even reason, all of which could let us down. Placing the point of certainty in my awareness of my own self, Descartes gives a first-person twist to the theory of knowledge that dominated the following centuries in spite of a various counter attack to act in a specified way as to behave as people of kindredly spirits, perhaps, just of its social and public starting-points. The metaphysics associated with this priority are the Cartesian dualism, or separation of mind and matter into two differently dissimilar interacting substances. Descartes rigorously and rightly discerning for it, takes divine dispensation to certify any relationship between the two realms thus divided, and to prove the reliability of the senses invokes a clear and distinct perception of highly dubious proofs of the existence of a benevolent deity. This has not met general acceptance: As Hume puts it, to have recourse to the veracity of the supreme Being, to prove the veracity of our senses, is surely making a very unexpected circuit.

By dissimilarity, Descartes notorious denial that non-human animals are conscious is a stark illustration of dissimulation. In his conception of matter Descartes also gives preference to rational cogitation over anything from the senses. Since we can conceive of the matter of a ball of wax, surviving changes to its sensible qualities, matter is not an empirical concept, but eventually an entirely geometrical one, with extension and motion as its only physical nature.

Although the structure of Descartes's epistemology, theory of mind and theory of matter have been rejected often, their relentless exposure of the hardest issues, their exemplary and even their initial plausibility, all contrives to make him the central point of reference for modern philosophy.

The subjectivity of our mind affects our perceptions of the world held to be objective by natural science. Create both aspects of mind and matter as individualized forms that belong to the same underlying reality.

Our everyday experience confirms the apparent fact that there is a dual-valued world as subject and objects. We as having consciousness, as personality and as experiencing beings are the subjects, whereas for everything for which we can come up with a name or designation, might be the object, that which is opposed to us as a subject. Physical objects are only part of the object-world. In that respect are mental objects, objects of our emotions, abstract objects, religious objects etc. language objectifies our experience. Experiences per se are purely sensational experienced that do not make a distinction between object and subject. Only verbalized thought reifies the sensations by understanding them and assorting them into the given entities of language.

Some thinkers maintain, that subject and object are only different aspects of experience. I can experience myself as subject, and in the act of self-reflection. The fallacy of this argument is obvious: Being a subject implies having an object. We cannot experience something consciously without the mediation of understanding and mind. Our experience is already understood at the time it comes into our consciousness. Our experience is negative as far as it destroys the original pure experience. In a dialectical process of synthesis, the original pure experience becomes an object for us. The common state of our mind can apperceive objects. Objects are reified negative experience. The same is true for the objective aspect of this theory: by objectifying myself I do not dispense with the subject, but the subject is causally and apodeictically linked to the object. When I make an object of anything, I have to realize, that it is the subject, which objectifies something. It is only the subject who can do that. Without the subject at that place are no objects, and without objects there is no subject. This interdependence is, however, not to be understood for dualism, so that the object and the subject are really independent substances. Since the object is only created by the activity of the subject, and the subject is not a physical entity, but a mental one, we have to conclude then, that the subject-object dualism is purely mentalistic.

Both Analytic and Linguistic philosophy, are 20th-century philosophical movements, and overshadows the greater parts of Britain and the United States, since World War II, the aim to clarify language and analyze the concepts as expressed in it. The movement has been given a variety of designations, including linguistic analysis, logical empiricism, logical positivism, Cambridge analysis, and Oxford philosophy. The last two labels are derived from the universities in England where this philosophical method has been particularly influential. Although no specific doctrines or tenets are accepted by the movement as a whole, analytic and linguistic philosophers agree that the proper activity of philosophy is clarifying language, or, as some prefer, clarifying concepts. The aim of this activity is to settle philosophical disputes and resolve philosophical problems, which, it is argued, originates in linguistic confusion.

A considerable diversity of views exists among analytic and linguistic philosophers regarding the nature of conceptual or linguistic analysis. Some have been primarily concerned with clarifying the meaning of specific words or phrases as an essential step in making philosophical assertions clear and unambiguous. Others have been more concerned with determining the general conditions that must be met for any linguistic utterance to be meaningful; Their intent is to establish a criterion that will distinguish between meaningful and nonsensical sentences. Still other analysts have been interested in creating formal, symbolic languages that are mathematical in nature. Their claim is that philosophical problems can be more effectively dealt with once they are formulated in a rigorous logical language.

By contrast, many philosophers associated with the movement have focused on the analysis of ordinary, or natural, language. Difficulties arise when concepts such as time and freedom, for example, are considered apart from the linguistic context in which they normally appear. Attention to language as it is ordinarily used for the key it is argued, to resolving many philosophical puzzles.

Many experts believe that philosophy as an intellectual discipline originated with the work of Plato, one of the most celebrated philosophers in history. The Greek thinker had an immeasurable influence on Western thought. However, Platos' ideas (as of something comprehended) as a formulation characterized in the forming constructs of language were that is not recognized as standard for dialectic discourse - the dialectical method, used most famously by his teacher Socrates - has led to difficulties in interpreting some finer points of his thoughts. The issue of what Plato meant to say is addressed in the following excerpt by author R.M. Hare.

Linguistic analysis as something conveys to the mind, nonetheless, the means or procedures used in attaining an end for within themselves it claims that his ends justified his methods, however, the acclaiming accreditation shows that the methodical orderliness proves consistently ascertainable within the true and right of philosophy, historically holding steadfast and well grounded within the depthful frameworks attributed to the Greeks. Several dialogues of Plato, for example, are specifically concerned with clarifying terms and concepts. Nevertheless, this style of philosophizing has received dramatically renewed emphasis in the 20th century. Influenced by the earlier British empirical tradition of John Locke, George Berkeley, David Hume, and John Stuart Mill and by the writings of the German mathematician and philosopher Gottlob Frigg, the 20th-century English philosopher’s G. E. Moore and Bertrand Russell became the founders of this contemporary analytic and linguistic trend. As students together at the University of Cambridge, Moore and Russell rejected Hegelian idealism, particularly as it was reflected in the work of the English metaphysician F. H. Bradley, who held that nothing is completely real except the Absolute. In their opposition to idealism and in their commitment to the view that careful attention to language is crucial in philosophical inquiry. They set the mood and style of philosophizing for much of the 20th century English-speaking world.

For Moore, philosophy was first and foremost analysis. The philosophical task involves clarifying puzzling propositions or concepts by showing fewer puzzling propositions or concepts to which the originals are held to be logically equivalent. Once this task has been completed, the truth or falsity of problematic philosophical assertions can be determined more adequately. Moore was noted for his careful analyses of such puzzling philosophical claims as time is unreal, analyses that which facilitates of its determining truth of such assertions.

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