knowledge and intelligence in the individual. Piaget thought that genetic epistemology could be distinguished from developmental psychology, but the distinction, as he made it, was not clear. It might be argued, however, that just as the prime concern of ordinary *epistemology is to show how knowledge is possible, so the aim of genetic epistemology should be to show how the acquisition and growth of knowledge is possible. This is a matter for genu- ine philosophical concern. The first instance of such a philosophical theory, only partially successful, is to be found in the last chapter of Aristotle’s Posterior Analytics and is a response to an argument in Plato’s Meno that *learning and the acquisition of new knowledge is impossible. d.w.h. D. W. Hamlyn, Experience and the Growth of Understanding (Lon- don, 1978). epistemology, history of. Epistemology, or the theory of knowledge, is that branch of philosophy concerned with the nature of knowledge, its possibility, scope, and general basis. It has been a major interest of many philosophers almost from the beginnings of the subject. Often, but not always, these philosophers have had as their main pre- occupation the attempt to provide a general basis which would ensure the possibility of knowledge. For this reason it is sometimes said that the seventeenth and eighteenth centuries were the age of epistemology, in that Descartes then introduced what is sometimes termed the ‘search for certainty’, seeking a sure foundation for knowledge, and was followed in this by other philosophers of the period. To this end Descartes employed his ‘method of doubt’, a form of systematic *scepticism, in order to ascertain what could not be doubted. He found this in his notorious proposition *‘Cogito ergo sum’ (‘I think, therefore I am’), which, he thought, established the existence of the self as a thinking thing (although it seems, on the face of it, to imply only that a thought must have a thinker, and what that thinker must be like is another matter, as is the ques- tion whether ‘I think’ itself can be doubted). Given the thoughts of that self as he construed it, he then sought to derive from them the existence of God and thereafter that of the external world, as it came to be called (the world being external to the mind, the only thing to which, it was thought, we have direct access). There was in Descartes’s time a renewed interest in scepticism, though it is arguable that his systematic scepti- cism went further than any previous form in that he was prepared to consider the application of doubt to himself and not merely to other things. The interest in scepticism was renewed in that, much earlier, in the period of post- Aristotelian philosophy, a school of sceptical philosophy had been founded by Pyrrho. The Greek Sceptics maintained that they were inquirers, refusing to acknow- ledge claims to knowledge unless a ‘criterion of truth’, as it was called, could be produced. The rival philosophical schools, particularly the *Stoics and *Epicureans, tried to produce such a criterion, something in experience that had the mark of certain truth, in what appears to have been a running debate between them and the Sceptics and members of Plato’s *Academy who were influenced by scepticism. The search for a criterion of truth is obviously a version of the search for certainty. Plato himself had had little of such concerns, although he was interested in the nature of knowledge, and Republic 477e6 seems to suggest that the title of knowledge should be reserved for that over which there cannot be error. By and large, however, Plato was more concerned with the question what distinguishes knowledge from belief (doxa), construed as having something simply before the mind, and considered as true or false. In his middle period, he seems to have been so influenced by metaphysical consid- erations as to be inclined to distinguish knowledge by con- fining it to a particular realm of entities, his Forms or Ideas. Later, however, particularly in his dialogue the Theaetetus, he seems to revert to an idea put forward in the early dia- logue the Meno, that correct belief can be turned into knowledge by fixing it by means of a reason or cause. The Theaetetus gives good reasons for thinking that knowledge is more than true belief, but fails to find an adequate account of what the extra thing required can amount to. (He supposes that it might be some interpretation of the term *logos—speech, enumeration of the parts of a thing, or the determination of the thing’s identity—but finds all three objectionable.) Nevertheless, Plato seems through- out to have in mind by knowledge a state of mind related to an object, and the question is what that state and that relation can be. Aristotle has similar preconceptions, and is hardly at all concerned with the justification of knowledge-claims. He says repeatedly that we think we have knowledge proper (episte¯me¯) of something when we know its reason or cause. In his view that reason is brought out when the subject- matter can be ordered in terms of a demonstrative syllo- gism (where the premisses and conclusions state essential or necessary truths about something), the middle term of which (what the two premisses have in common) gives that reason. Knowledge proper, therefore, entails bring- ing its object within a context of explanatory and reason- giving propositions, which amounts to science as Aristotle conceived it. He thus thought that knowledge of a thing involved understanding it in terms of the reasons for it. (Some recent scholars have said that by ‘knowledge’ Aris- totle meant understanding, but that is not quite right.) There is no concern here about exactly what it is to know that such and such is the case, so-called propositional knowledge, and even less with the attempt to base know- ledge-claims on something absolutely certain. That came in only when the Sceptics, who thought that freedom from care resulted from it, pressed their scepticism. The rival schools such as the Stoics had a similar motivation to some extent in seeking a source of certainty in a ‘criterion of truth’. Although Plato thought, at any rate at one time, that knowledge was reserved for the Forms, and also sug- gested in his ‘Theory of Recollection’, put forward in his Meno and Phaedo, that we are born with such knowledge 260 epistemology, genetic but have to be reminded of it by particular experiences, he put forward otherwise no general theory about the source of our knowledge. It is often said that Aristotle thought that all the materials of knowledge, all the concepts which it involves, are derived from experience. In my opinion, there is some doubt about that, although he did think that the acquisition of knowledge depended in one way or another on experience. On the other hand, Thomas Aquinas, the great medieval Aristotelian, certainly thought that all the materials for knowledge are derived from experience, although he certainly did not claim that all knowledge as such is derived from experience (as his theological concerns indicate). The distinction between knowledge and its materials (the concepts presupposed by it) is important and it became crucial in the eighteenth century. Apart from this, the philosophers of the Middle Ages contributed little to epistemology that was not avail- able from the Greeks. It is perhaps worth noting, how- ever, that Augustine was near enough to the post-Aristotelians to be influenced by scepticism and pro- duced a kind of pre-echo of Descartes’s ‘Cogito ergo sum’ in his own ‘Si fallor sum’ (‘If I err, I exist’). One thing that was novel about the kind of philosophy that Descartes introduced was its first-person approach. The general basis for justification of claims to knowledge was to be found in the individual’s own mind, and the ‘I think’ is, for Descartes, the basis for any confidence an individual can have in believing himself to have know- ledge. The possibility of any further knowledge must be derived from that. Descartes also introduced the ‘way of ideas’ as part of that programme. What we are given is ideas of one kind or another and the problem is how we can justifiably use them as a basis for belief in a world which is outside our minds. Perception is just as much a matter of having ideas as is any other operation of the mind, and the problem is therefore what kind of justifica- tion we have for believing that our ideas are representa- tive of anything. This approach was characteristic of seventeenth- and eighteenth-century philosophy, and although it is conventional to divide the philosophers of the time between those who were rationalists (in empha- sizing the part played by reason in it) and empiricists (in emphasizing the part played by experience) they were not fundamentally at odds in that general approach. Descartes did not think that all our ideas are derived from experience, and the rationalists who followed him, particularly Leibniz, maintained the possibility of innate ideas, or at least ideas which are independent of experi- ence or a priori (a term which goes back to Aristotle’s dis- tinction between knowledge derived from truths which are prior to demonstration and truths which are posterior in that they are as yet undemonstrated and may be arrived at by induction from experience). In fact an a priori idea or truth does not have to be innate, as Kant was to emphasize in saying that while all knowledge begins with experience it does not follow that it all arises out of experience. Thus the thesis that some knowledge is a priori is quite compatible with the thesis that no knowledge is innate. Nevertheless, the rationalists tended to assert the possibil- ity of innate, and not merely a priori, knowledge, as in effect did Plato when, in putting forward his ‘Theory of Recollection’, he claimed that experience reminds us of knowledge with which we are born. Such knowledge might be either knowledge of truths or the knowledge which we may have in having a genuine idea of some- thing. Locke, the first of the so-called British Empiricists, argued vehemently that all our ideas arise from experi- ence, but he did not think, as did some later empiricists, including J. S. Mill, that all knowledge of truths was derived from experience. Some such knowledge, he thought, rests on intuition and some on demonstration. Locke did think, however, that experience is the founda- tion for knowledge in that the simple ideas of sense are the origin of everything else in the understanding. That thought was taken further by Berkeley and Hume. The main epistemological concerns of these philosophers were, thus, the limits and extent of the human under- standing, as typified by the central claim of Hume’s empiricism—that all ideas are derived from impressions of sense, every simple idea being a copy of a correspond- ing impression. The problem for Hume, given this, is what justifies us in going from one impression to another, and thus, since he thought that belief consisted of a lively idea related to or associated with a present impres- sion, what justifies us in belief about anything beyond a present impression. What justifies us, in particular, in belief in causality and in a world apart from present impressions? Hume thought, sceptically, that there was no such justification; we can explain only what, psycho- logically, makes us have those beliefs. This is a matter of custom, producing a determination of the mind, as is involved in the principles of the association of ideas. Apart from what they thought about ideas none of these philosophers thought that knowledge of all truths was derived solely from experience, although the empiri- cists tended to suggest that what were in effect a priori truths were confined to what Hume called ‘relations of ideas’. Kant made a systematic distinction between ana- lytic judgements, the truth of which is a priori in depend- ing on the relations between the ideas involved, and synthetic judgements which go beyond what is implicit in the ideas involved. An empiricist would have no problems about such truths provided that the latter class of judge- ments are confined to what can be justified by reference to experience, and are thus a posteriori. But Kant thought that there were, in addition, synthetic a priori truths— necessary but more than analytic truths involved in math- ematics and in the presuppositions of the sciences and of objective knowledge generally. He also thought, how- ever, that it was impossible to go beyond what was so pre- supposed in human understanding, despite what some philosophers had claimed, and what Hegel, for example, claimed after him, could be achieved by pure reason. Kant argued that the attempt to use pure reason in that way inevitably led to antinomies and other forms of epistemology, history of 261 contradiction; Hegel thought that such apparent logical obstacles could be transcended in higher forms of ratio- nality. The issues can be no more than hinted at here; in Hegelian philosophy epistemology tends to be swallowed up in a certain style of metaphysics. There were almost immediate reactions against Hegel, but most of them were metaphysically orientated. Schopenhauer, who reacted to Hegel in a very bad- tempered and abusive way, urged a return, as far as episte- mology was concerned, to Kant, although he thought that the principles of objective knowledge which Kant had argued for could be reduced to one of four forms of the *principle of sufficient reason, a principle due originally to Leibniz. Nietzsche, who was influenced in some ways by Schopenhauer, even if he misinterpreted him, maintained the doctrine of the subjectivity of truth—truth is in effect power. This is a difficult doctrine, to say the least, but it has had considerable influence on recent continental philoso- phy. None of this, however, is, strictly speaking, episte- mology for its own sake. Outside neo-Kantianism, epistemology in the nine- teenth century remained almost exclusively an Anglo- Saxon phenomenon. J. S. Mill, as already indicated, argued for an extreme empiricism, maintaining that knowledge of all truths was derived from experience, thus putting a great deal of weight on the role of induction in arriving at general truths of all kinds. The end of the century saw the rise of American *pragmatism, initially in the claim by C. S. Peirce that the meaningfulness of our ideas is a function of their contribution to rational conduct. This notion was misleadingly extended to truth by William James. Because knowledge entails truth, this inevitably affected concep- tions of knowledge on the part of these philosophers and their pragmatist descendants. Perhaps the main epistemo- logical tenet inherited from Peirce, however, is that of *‘fallibilism’, the idea that we may always be wrong and that, from the point of view of knowledge, truth is simply an ideal limit. This idea has been extremely influential, although if it is taken to imply that we cannot be certain of anything it seems quite wrong. Twentieth-century empiricism, the main subsequent movement in epistemology, tended to be a kind of rever- sion to Hume without the psychological dress. It was con- cerned, however, less with the basis of our ideas than with the scope and certainty of our knowledge of truths. Logi- cal Positivists, such as A. J. Ayer, asserted that all knowable truths are either analytic or empirical—there is no room for the synthetic a priori. At the same time the problem of our knowledge of the external world remains because all that is ‘given’ is to be found in the individual’s experience, particularly in what have become known as *sense-data (a notion which is close, at any rate in status, to Hume’s impressions). Sense-data propositions are indubitable, if anything is (and Ayer himself vacillated on that point), But there is then a problem about the relation between sense- data and so-called material objects—a problem which gen- erated various epistemological theories of perception, particularly phenomenalism, the doctrine that material objects are either bundles of actual and possible sense-data or what came to be known, following Russell, as logical constructions from these. The whole notion of the *‘given’ has subsequently come under criticism from many sources. But does knowledge need, in any case, an indubitable basis? Knowledge may entail belief and the truth of what is believed, but, whatever else it entails, it is not evident that it is that such truth must be indubitable. Philosophers have thus, for good reason, most often ceased to invoke sense-data as perceptual foundations for knowledge. Interest in that kind of approach to epistemol- ogy has thereby declined. What has remained of consider- able interest for philosophers is perhaps twofold. First, there is the question what knowledge is, what exhaustive account one is to give of that concept. A short paper by Edmund Gettier on whether knowledge amounts to justi- fied true belief (a theory which he supposed was espoused by Plato), arguing that there could be justified true belief which did not amount to knowledge, has generated a whole industry of attempts to give the necessary and suffi- cient truth-conditions for any proposition of the form ‘X knows that p’. This, it has been suggested, may be achieved either by adding further conditions apart from those involved in speaking of justified true belief or by eschewing reference to justification and substituting refer- ence to something like a causal relation between what is known and the belief involved. Pursuit of the industry continues with no firm resolution, although it is clear that, whatever else is entailed, the possibility that the belief is true by chance must be ruled out. Second, there is the question, pursued most indefatiga- bly by some American philosophers, about the general foundations for our system of beliefs—whether there is such a foundation, whether it is all a matter of the coher- ence of our beliefs, or what. So the desire that knowledge should have foundations in some way is still alive. A ques- tion that remains open is whether that desire is based on an illusion concerning the nature of knowledge (whether, that is, it requires foundations, or whether the appeal to that architectural image is just a misleading metaphor) or whether the failure to provide sure foundations is a reason for despair about the whole idea of knowledge. So the two problems are in fact connected—as they always have been, though not equally for every philosopher, as we have seen. d.w.h. *epistemology, problems of. Jonathan Dancy, Introduction to Contemporary Epistemology (Oxford, 1985). Stephen Everson (ed.), Epistemology: Companions to Ancient Thought, i (Cambridge, 1990). D. W. Hamlyn, The Theory of Knowledge (London, 1971). ——The Penguin History of Western Philosophy (London, 1987). R. H. Popkin, The History of Scepticism (1960; 3rd edn. New York, 2003). Richard Rorty, Philosophy and the Mirror of Nature (Princeton, NJ, 1980). B. A. O. Williams, Descartes: The Project of Pure Enquiry (London, 1978). 262 epistemology, history of epistemology, problems of. Epistemology is the study of our right to the beliefs we have. More generally, we start from what we might call our cognitive stances, and ask whether we do well to have those stances. Cognitive stances include both our beliefs and (what we take to be) our knowings; and in another dimension they include our attitudes towards the various strategies and methods we use to get new beliefs and filter out old ones, as well as the products of those strategies and methods. Epistemology, on this showing, is explicitly normative; it is concerned with whether we have acted well or badly (responsibly or irresponsibly) in forming the beliefs we have. In pursuing this enquiry, we do not, of course, ask only about the beliefs and strategies we find ourselves with at the beginning. We also ask whether there are not others which we would do better to have, and whether there are not others which we should have if we have these ones to start off with. The hope is to end up with a full account of how a responsible cognitive agent should behave, with some assurance that we do not fall too far short of that ideal. 1. Justification. We can distinguish between two sorts of belief: the mediated and the unmediated. Mediated beliefs are those which we reach by some strategy which starts from other beliefs we have. Inference is such a strategy (but not the only one); we infer that it will rain soon from our separate beliefs that it is mid-morning and that it is growing very dark outside. Mediated beliefs raise the question of whether the strategy we adopt is one to which we have a right—one we do well to use. Unmediated beliefs are those which we adopt without moving to them from other beliefs we already have. These raise different problems, which concern the source of our right to believe. I open my eyes and, because of what I see, immediately believe that there is a book in front of me. If I do well in adopting that belief, it is justified (or I am justified in adopting it). This focus on justification is one way of expressing the idea that epistemology is normative. What makes it the case, then, that this belief is justified? Various answers suggest themselves. One is the *relia- bilist answer: that the belief is justified because it is the result of a reliable process. Another is the *coherentist answer: that this belief is justified because my world is more coherent with it than it would be without it. A third is the *foundationalist claim (at least in its classical form) that this belief is not in fact unmediated, but inferred from a belief about how things seem to me just now. If this last were true, we are thrown back to two questions. The first is whether, and how, the belief about how things seem to me just now is justified. The second is whether the infer- ence from that belief is justified. We might ask what princi- ple of inference is employed. Suppose it is this: that if things seem to me that way, they probably are that way. What makes it the case that we do well to use this principle? 2. The structure of justification. This brings us to one particu- lar question about justification, which has received much attention. Suppose that we give the justification of a mediated belief A which appeals to its relation to some other belief B. This belief, B, justifies that one, A; my belief that it is Sunday justifies my belief that there will be no mail today. There is a very strong intuition that B can only transmit justification to A if it is itself justified. So the ques- tion whether A is justified has not yet been answered, when we appealed to B, but only shelved. Whether it is justified depends on whether B is. What justified B? We might appeal to some further belief C, but then the prob- lem will simply recur. We have here the beginnings of an infinite regress. The first belief in the series is not justified unless the last one is. But will there ever be a last belief in the series? This is the infinite regress of justification. Foundation- alism takes this regress seriously, and tries to find ‘basic beliefs’ that are capable of stopping it. Promising ways of doing this include the idea that basic beliefs are justified by their source (they are the immediate products of the sense, perhaps), or by their subject-matter (they concern the nature of the believer’s current sensory states). *Empiricism, in this connection, wants in some way to ground basic beliefs in experience. Foundationalism concerns itself with the structure of this empiricist programme. So a concern with the regress of justification is a con- cern with the structure of justification. Coherentism tries to show that a justified set of beliefs need not have the form of a superstructure resting on a base; the idea here is that the foundationalist programme is bound to fail, so that the ‘base’ is left groundless, resting on nothing. If this were the result, and if foundationalists were right about the structure of a justified belief set, the only possible con- clusion would be the sceptical one that none of our beliefs are in fact justified. Coherentists reject the base/superstructure distinc- tion; there are no beliefs which are intrinsically grounds, and none which are intrinsically superstructure. Beliefs about experience can be supported by appeal to theory (which would be going upwards in terms of the founda- tionalist model), as well as vice versa (theories need the support of experience). The whole thing is much more of a mess, and cannot be sorted neatly into layers. 3. Knowledge. Epistemology, as so far explained, focuses on justification. There is a second focus, on knowledge. Someone whose belief is justified does well. But justifica- tion comes in degrees, and so does our epistemic status (determined by how well we are doing). The top status is that of knowledge. Someone who knows that p could not be doing better (at least with respect to p). There is a nat- ural interest in this top status. Two main questions arise: what is the most we can hope for, and in what areas do we get it? The traditional attempts to define knowledge focus on the first of these. These attempts come in two main families. The first tries to see knowledge as some clever form of belief; the best-known form of this view is the ‘tripartite definition’, which takes knowledge to be (1) belief which is both (2) justified and (3) true. The epistemology, problems of 263 second family of views takes knowledge to start where belief gives out. Plato’s version of this was that belief is concerned with the changing (especially the material world), and knowledge with the unchanging (e.g. mathe- matics). Other versions might suggest that we can have knowledge of our surroundings, but only when some physical thing is directly present to the mind. On this approach, knowledge is a direct relation, while belief is conceived as an indirect relation to the thing believed. The second question about knowledge, namely what areas we can get it in, introduces us to the distinction between global and local. In some areas, we might say, knowledge is available, and in others it is not—or at least less freely available. It is common to hear people say that we have no knowledge of the future, of God, or of right and wrong, while allowing that there is at least some sci- entific knowledge and some knowledge of the past (in memory). Similarly, in discussing the justification of belief, we might say that our beliefs about our present surroundings are on firm ground, as firm as that which supports our (rather different) central theoretical beliefs in science, while our beliefs about God and about the future are intrinsically less well supported. 4. Scepticism. Scepticism about knowledge comes in both global and local forms. The knowledge-sceptic holds that we cannot achieve knowledge, and this claim could be made in general (the global variety) or only in certain areas such as those mentioned above (the local form). The belief-sceptic is generally held to be more interesting. This person, in global form, holds that we have no right to any of our beliefs; none are better than others, and none are good enough to count as justified. More locally, a belief- sceptic might say that while we do well in some of our beliefs about things presently hidden from us (e.g. what is in the cupboard), we have no right to any beliefs about right and wrong. Someone who said this would be a moral sceptic, and the difficulty in that position is to make sure that the reasons that underlie one’s moral scepticism do not spread over into other areas. If, for instance, one’s objection to beliefs about moral matters is that they lie beyond the reach of observation, one would have to make the same objection to scientific beliefs about matters too small to be observed. So there is a distinction between local and global scepti- cism, both in the theory of justified belief and in that of knowledge. Both sorts of scepticism need to be supported by argument, and one main problem of epistemology is the attempt to assess and rebut such arguments as they appear. This is one important way in which we can work to establish our right to our beliefs. There have been two classic strands of sceptical argu- ment in the history of epistemology, the Pyrrhonist and the Cartesian. *Pyrrhonism (named after its leading fig- ure, Pyrrho of Elis (c.365–270 bc)) focuses on the justifica- tion of belief, while the scepticism we inherit from Descartes starts with knowledge and attempts to move to belief from there. Descartes argued that we cannot know something if we are unable to distinguish the case where it is true from the case where, though false, it seems to be true. For if we cannot distinguish, then though it may here be true, for all we know it isn’t; this case might, for all we can tell, be one where the appearances are deceiving us, and if so, we can hardly claim to know that they are not. Though persuasive enough as an argument for know- ledge-scepticism, this approach cannot easily be extended to support belief-scepticism; for the fact that I cannot tell when appearances are deceiving me does little to show that I have no (or insufficient) reason for my beliefs. Mat- ters are different with the Pyrrhonist tradition. This is explicitly aimed at showing that the reasons on one side are never better than they are on the other. If so, we would be forced to allow that there is no such thing as a belief that is favoured by the balance of the reasons, and so to admit that we cannot defend our right to our beliefs in the only way available to us, namely that of showing that the evi- dence supports them. Pyrrhonism focuses on the criteria by which we distinguish between the true and the false and argues in various ways that we have no right to those criteria, and so that they cannot be rationally defended. One classic move here is to ask what criteria we can use to evaluate our criteria; if we are to appeal to the very criteria that are under consideration, we beg the question, and we have no further criteria to appeal to. Pyrrhonism is here attacking our cognitive strategies, arguing that none of them can be defended. Hume’s argument attacking the rationality of induction is the classic instance. 5.*Naturalism in epistemology. Being normative, episte- mology is concerned with evaluation—the evaluation of strategies and their products (beliefs). Among the strat- egies it evaluates are those of science. So conceived, episte- mology sits in judgement on all other areas of human enquiry; it counts as *First Philosophy. (The sceptical question above asks how epistemology can succeed in evaluating itself.) Quine attempted to reverse this pos- ition, and to conceive of epistemology as part of science, looking to the results of science to answer the questions of epistemology. This enterprise, called naturalizing episte- mology, is not impossible. Science does sometimes suc- ceed in evaluating its own strategies, just as it evaluates its own instruments. So science is sometimes normative; it may not only examine our perceptual processes, but also pronounce on their reliability. But some of the questions of epistemology seem to resist naturalization, e.g. those which concern reason rather than observation. To say that science is sometimes normative, and that traditional epistemology is a large part of its normative element, might indeed reverse the relation between epis- temology and natural science and thereby ‘naturalize’ it. But this alone would not be enough for many determined naturalizers. I have been presenting epistemology as a normative enterprise, whether or not it is placed within the sphere of natural science. But there are many who sup- pose that if normative claims and assertions make genuine sense and are capable of being true or false, they must be 264 epistemology, problems of somehow identical with natural claims, ones from which the normativity has been removed. The worry here is that if normative facts are not identical with natural facts, we will find ourselves landed with two realms, the realm of nature (where we find such things as particles, electricity, and gravity) and the realm of the normative (where we find such things as duties, responsibilities, and rights), without there being any way of understanding how those two realms are co-present in one and the same world. More aggressively, the question becomes how there is any room for distinct normative facts in a natural world, the world that can be studied by science. If we want norma- tive epistemological facts, then, we will have to show that those facts are also natural. If we succeeded in doing that, we would have naturalized epistemology in a much more dramatic sense. 6. Special areas. There are traditionally four sources of knowledge (or of justified belief): the senses, *memory, *introspection, and *reason. Each of these has its episte- mology. The study of perceptual knowledge asks how perception manages to yield knowledge of our material surroundings. To answer this question one obviously needs to know a certain amount about how the senses actually work. But that knowledge seems to be not enough on its own (so perhaps the epistemology of the senses cannot be naturalized either). There are difficulties to be faced here which cannot be solved with a bit more scientific information. One is the sceptical difficulty some- times called the *veil of perception. If our senses only reveal knowledge about how things seem, how can we hope to use them to find out how things really are? The appearances, on this showing, are obstructing rather than helping us in our attempts to discern the nature of reality; perception casts a veil over the world rather than reveal- ing it to us. Another sceptical difficulty here derives from the *argument from illusion. At the other extreme is the epistemology of reason. The activities of reason are twofold. First there is inference, in which we move from old knowledge to new knowledge. The strongest form of this is valid deductive inference, which occurs when it is not possible that our premisses (what we are moving from) are true if our conclusion (what we are moving to) is false. One question here is how such inference could ever yield new knowledge. Surely the conclusion must be somehow already contained in the premisses, if the premisses cannot be true where the con- clusion is false. The second supposed activity of reason is the direct discovery of new truths. A truth that can be dis- covered by the activity of reason alone is called an *a priori truth, and knowledge of it is a priori knowledge. One of the great questions in epistemology is how a priori know- ledge is possible, and what sorts of truth can be known in this way. Some propositions are true in virtue of their meaning alone, e.g. that all bachelors are people. We know this truth, and not by appeal to the senses, to introspection, or to memory. So we know it by reason. But propositions of this sort (often called analytic) are trivial. They give us no substantial knowledge. Can reason give us substantial knowledge of anything, or is all a priori knowledge analytic and (therefore) trivial? For example, if mathematical knowledge is the product of reason, can it be substantial? Are mathematical truths merely analytic? We appear to be torn between saying that mathematical truths are important and saying that we know them by the activity of reason alone. It was the attempt to avoid this dilemma that led to Kant’s first Critique. 7. The place of epistemology. Where does epistemology come on the philosophical map? I see it as a chapter in the more general enterprise which is called the philosophy of mind; it is the evaluative side of that enterprise. In the phil- osophy of mind we ask about the nature of mental states, in particular (for present purposes) about the nature of belief. Our views in epistemology are sensitive to our answers to that question, just as they are sensitive to sci- entific results about the nature of perceptual processes. For instance, our account of the relation between know- ledge and belief will depend crucially on the way in which we conceive of belief. Is it a closed state, in which we are aware merely of representations of things rather than of things themselves (the veil of belief )? If so, is knowledge to be merely the best form of such a state—the thinnest veil? Or is knowledge to be conceived quite differently? The other philosophical area to which epistemology is tightly tied is the theory of meaning. The question whether we are able to know propositions of a certain sort is sensitive to our account of what those propositions mean. For instance, if we take statements about a material world to be a disguised form of statement about experi- ence, and if we think that our knowledge of experiences is secure from sceptical attack, we may hope to emerge with a defence of our ability to know the nature of the material world. This hope is the hope that *phenomenalism will solve some of our epistemological problems for us. j.d. *epistemology, history of; epistemic justification; epis- temology, genetic; evolutionary epistemology; femi- nist epistemology; naturalized epistemology; relativism, epistemological; knowledge. R. B. Brandom, ‘Insights and Blindspots of Reliabilism’, in Articu- lating Reasons: An Introduction to Inferentialism (Cambridge, Mass., 2000). R. M. Chisholm, Theory of Knowledge, 2nd edn. (Englewood Cliffs, NJ, 1977). J. Dancy, Introduction to Contemporary Epistemology (Oxford, 1985). A. Goldman, Epistemology and Cognition (Cambridge, Mass., 1986). W. V. Quine, ‘Epistemology Naturalised’, in Ontological Relativity (New York, 1969). W. F. Sellars, ‘Empiricism and the Philosophy of Mind’, in Sci- ence, Perception and Reality (London, 1963). L. Wittgenstein, On Certainty (Oxford, 1969). epistemology and psychology. The divorce of philoso- phy and psychology is a relatively recent affair. Histories epistemology and psychology 265 of psychology read like histories of philosophy until the mid-nineteenth century, when the methods and preoccu- pations of philosophers and psychologists began to diverge, and psychologists came to regard themselves as engaged in a fully fledged science emancipated from its empirically feeble predecessors. In 1879, Wilhelm Wundt established the first psychological laboratory at the Uni- versity of Leipzig. Not until well into the twentieth cen- tury, however, did professional associations and university departments of philosophy and psychology become dis- tinct. The disciplines have resisted reconciliation and maintained a respectful distance ever since. Academic departmental boundaries aside, W. V. Quine convinced many philosophers that distinctions between scientific and philosophical endeavours are tenuous; in particular, ‘epistemology . . . is a chapter of psychology’. Traditionally, epistemology sought an unassailable foun- dation for subsequent empirical theorizing: philosophical investigation must be independent of, and prior to, empiri- cal inquiry. The goal was to demonstrate that knowledge of the world around us could be inferred from sensory experiences that mediate access to that world. The grounds for such an inference have proved remarkably dif- ficult to locate, however. Hume demonstrated that they were not to be found in reason alone. One possibility is that talk of a mind-independent world is misplaced: sentences about physical bodies might be reducible to, or translatable into, sentences concerning sense experiences. Quine argues against this possibility, and concludes that the rela- tion we bear to the physical world is best comprehended by empirical psychology. It is not that epistemology is to be replaced by psychology, only that we must cease to regard epistemology as operating in the classical mode, prior to and independently of psychology and the natural sciences. Inspired by Quine, some philosophers have turned to empirical psychological findings in support of conclusions concerning traditional philosophical matters. Stephen Stich, taking the dark view, argues that work in psych- ology undermines philosophers’ time-honoured trust in reason as a vehicle, if not a source, of truth. P. M. Church- land, in dismissing belief and reason as being on a par with ghosts and devils, favours the replacement of theories of mind with a properly hard-nosed neuroscience, leaving little for philosophers to work with. D. C. Dennett finds answers to age-old philosophical questions about con- scious experience and belief in cutting-edge work of psychologists and neuroscientists. In a more moderate vein, A. I. Goldman, a proponent of the ‘naturalizing’ of epistemology and metaphysics, argues that philosophy begins, but does not end, with the consideration of ‘folk theories’, conceptions of ourselves and our world embodied in our language and everyday patterns of thought. Having mapped these folk concep- tions, we turn to psychologists, anthropologists, and others for an explanation of their deployment. Suppose, for instance, that our folk scheme treats colours as objective features of objects on a par with shapes. We might learn from psychology and neurobiology that perceived colours are better regarded as artefacts arising from the operation of our visual apparatus. Having accepted this, we would be in a position both to explain and to revise our naïve ‘pre- theoretical’ conception of colour. We would do so, not on the basis of a priori reflection, however, but by way of an explicit appeal to what we took to be empirical fact. It is by no means universally accepted that philosophy can, or must, be naturalized in any of these ways. Even so, many philosophers now concede it is a mistake to assume that philosophical inquiry could be altogether insulated from empirical findings in psychology and elsewhere, hence the emergence of ‘cognitive science’, a disciplinary hybrid comprising psychologists, computer scientists, lin- guists, philosophers, and others, striving to understand the mind and its place in the natural order. Whether this represents an investigatory advance remains to be seen. While on the whole laudable, interdisciplinary co-operation can serve to blur the focus of research. Philosophers are prone to forget that empirical theories of mind can incorporate substantive philosophical commit- ments with shadowy credentials. These may be recycled back into philosophy, though in a way that disguises their character. Loosely paraphrasing Wittgenstein: philoso- phers nowadays risk taking on board conceptual con- fusions disguised as experimental methods. j.heil. P. M. Churchland, The Engine of Reason, the Seat of the Soul (Cam- bridge, Mass., 1995). D. C. Dennett, Kinds of Minds (New York, 1996). A. I. Goldman, Liaisons: Philosophy Meets the Cognitive and Social Sciences (Cambridge, Mass., 1991). W. V. Quine, ‘Epistemology Naturalized’, in Ontological Relativity and Other Essays (New York, 1969). S. P. Stich, The Fragmentation of Reason (Cambridge, Mass., 1990). epoche¯. ‘Withholding’ of assent and dissent, i.e. suspense of judgement. Ancient *scepticism combined a thesis, ‘There is no knowledge’, with a prescription, ‘Practise epoche¯’. The one leads to the other via a view shared by some non-sceptics that it is stupid to assent to what you do not know. And the outcome is delightful: ‘Freedom from disturbance follows like a shadow’ (Diogenes Laertius on Pyrrho). But there was, and is, controversy whether gen- eral epoche¯ is a practicable option. c.a.k. M. F. Burnyeat, ‘Can the Sceptic Live his Scepticism?’, in M. Schofield, M. F. Burnyeat, and J. Barnes (eds.), Doubt and Dog- matism (Oxford, 1980); repr. in M. F. Burnyeat (ed.), The Skepti- cal Tradition (Berkeley, Calif., 1983). equality. Currently the most controversial of the great social ideals. In the abstract, it means that people who are similarly situated in morally relevant respects should be treated similarly; but everything depends on what kinds of similarity count as relevant, and what constitutes similar treatment. Is a society equal enough if it guarantees all its citizens the same basic political and legal rights, or should it try to foster a much more general equality of condition? Complete equality among persons being impossible, the 266 epistemology and psychology real meaning of the idea is reduction or amelioration of *inequality. Possible interpretations include equality before the law, equality of political power, equality of opportunity for social and economic advancement, equality of resources, equality of welfare, equality of freedom, and equality of respect. Merely abolishing aristocracy and giv- ing everybody the vote is compatible with huge inequali- ties in social condition and political influence. By now it is relatively uncontroversial in Western societies that gov- ernments should not discriminate on the basis of race, religion, sex, or national origin, and that they should dis- courage such discrimination by private parties. Contro- versy arises over the extent to which governments should also aim at greater social and economic equality through policies of collective social provision, public health and education, and redistribution of income or wealth, and whether they should employ policies of affirmative action to produce greater equality among groups if there has been discrimination in the past. The main issue is whether we should regard certain human inequalities and their consequences as natural, and only be concerned not to impose further artificial ones, or whether we should base social policy on the assumption that all persons are equally deserving of a good life, and that their society should try to make it possible for them to have it. This latter goal of positive equality will not be real- ized through mere equality of opportunity, since equal opportunity combined with unequal ability and luck pro- duce very unequal results. An important alternative view is that equality has no value in itself, but is significant only for its effects. *Utili- tarianism, for example, holds that society should be arranged to maximize the total happiness of its members, without regard to how benefits and disadvantages are dis- tributed, except as this affects the total. However, eco- nomic equality is likely to have instrumental value, because of the principle of diminishing marginal utility: a given sum transferred from rich to poor will enhance the welfare of the latter more than it will decrease the welfare of the former. But too strong an effort toward equality can have economic effects which diminish utility. t.n. *liberty and equality; justice; well-being. R. Dworkin, A Matter of Principle (Cambridge, Mass., 1985). T. Nagel, Equality and Partiality (New York, 1991). M. Walzer, Spheres of Justice (New York, 1983). equipollence. The theory of equipollence developed by some medieval logicians, e.g. Peter of Spain (c.1215–77), concerned the equivalences that result from inserting a negation sign before or after a sign of quantity, e.g. ‘Not every A is B’, ‘Every A is not B’. ‘Equipollence’ later became synonymous with *equivalence in general. Tarski, though, defines as ‘equipollent’ two systems of sentences such that any sentence in one can be derived from the sentences in the other. c.w. A. Tarski, Introduction to Logic (New York, 1965), 32–3. equivalence. Relation between two statements p and q when p implies q and q implies p. Material equivalence, in line with *material implication (p implies q unless p is true and q false; q implies p unless q is true and p false), holds between p and q if and only if they have the same truth- value. But equivalence is also often interpreted to require necessary identity of truth-value and/or identity of con- tent and/or identity of meaning. s.w. *equivalence relation. S. Wolfram, Philosophical Logic (London, 1989), ch. 4. 1. equivalence relation. An equivalence relation is a binary, i.e. two-term, relation that is *transitive, *symmetric, and (strongly) *reflexive; for example, being the same age as is an equivalence relation, relative to the domain of things with age. c.a.k. *equivalence of statements. W. Hodges, Logic (Harmondsworth, 1977). equivalences of the form T: see snow is white. equivocation: see ambiguity. equivocation, fallacy of. You equivocate when you mean two things by one or more occurrences of a single word or phrase. Often this is innocuous, as in puns. But it will lead to faulty reasoning when an *argument requires one such meaning in order to entail the intended conclu- sion, another in order to have true premisses. Usually the fault is not deceptive, but sometimes it is thought- provoking, as in: What you are able to do or not do, you are free not to do; you are able to pay or not pay taxes; so you are free not to pay them. c.a.k. *ambiguity. C. L. Hamblin, Fallacies (London, 1970). Erasmus, Desiderius (1466–1536). Born in poor circum- stances in Rotterdam, he attended the University of Paris where he came into contact with many who were due to play a crucial role in the new humanist movement. He rose to become a key figure in *Renaissance humanism, active as a critic of the Church and of contemporary mores, and active also as an editor of major writings from an earlier age, such as the works of the early Fathers of the Church, and above all the Greek text of the New Testa- ment. His edition of the New Testament, though inad- equate in many ways, was a major advance on anything available in the Middle Ages. Many of his writings, such as In Praise of Folly, a powerful satire on society both ecclesi- astical and lay, argue the case for a return to a form of Christian pietism. Though he attacked many abuses com- mitted by the Church, abuses which in due course it tried to stamp out, he was unsympathetic to the Reformation then under way, as is made clear by his attack on Luther. It is an irony of history that his works were placed on the Index by the Council of Trent. a.bro. Roland H. Bainton, Erasmus of Rotterdam (London, 1969). Erasmus, Desiderius 267 Eriugena, John Scotus (c.810–c.877) from Ireland, lived for years in France where he worked at the Court of Charles the Bald. He translated a number of works, includ- ing some by pseudo-Dionysius, from Greek into Latin, and in addition wrote treatises of his own, in particular On the Division of Nature, the first great philosophical system of the Middle Ages. The Division, which was heavily influ- enced by the Neoplatonism of pseudo-Dionysius, is pre- sented as a system of Christian thought, but there is room for dispute over whether it avoids an un-Christian *panthe- ism. He considers nature under four heads: nature which creates and is uncreated, nature which is created and cre- ates, nature which is created and does not create, and nature which neither creates nor is created. Since God is said to fall under the first heading, it might well seem that there is a pantheistic philosophy here, but the distinction that Eriugena draws between uncreated creator and all else is sufficient to convince some commentators that he has found his own way to develop a position which is not far removed from Christian orthodoxy. a.bro. John J. O’Meara, Eriugena (Oxford, 1988). error theory of value is the label given by J. L. Mackie to a position he promoted about the nature of *value. According to Mackie, although moral judgements in their meaning aim at something objective, there are in fact no objective values. Hence our normal moral judgements involve an error. r.h. J. L. Mackie, Ethics (Harmondsworth, 1977), ch. 1. eschatology. That branch of theology concerned with ‘the last things’—death, what follows it for each individ- ual, and the final fate of the universe. According to trad- itional Christian theology, death is followed by resurrection of the dead, God’s judgement on their past life, and their apportionment to heaven or hell. ‘Realized eschatology’ is the view that states analogous to the trad- itional after-death states occur in our present life—e.g. God’s judgement on the past is a feature of life on earth. Scholars have found strains of realized eschatology, as well as traditional eschatology, in the New Testament; a few very radical theologians defend only realized eschatology. r.g.s. R. Swinburne, Responsibility and Atonement (Oxford, 1989), ch. 12. esoteric. ‘Inner’. A word coined in the second century ad to refer to Aristotle’s more difficult works, as contrasted with his accessible *‘exoteric’ ones. The esoteric works were intended for more advanced pupils. Their obscurity gave rise to the story that they concealed Aristotle’s true doctrines, which were a secret to be revealed only to dis- ciples. The word was later applied with the sense ‘secret’, e.g. to the doctrines of Pythagoras’ inner circle. r.j.h. *Pythagoreanism. I. Düring, Aristotle in the Ancient Biographical Tradition (Göteborg, 1957), 426–43. ESP phenomena, philosophical implications of. ESP (extrasensory perception), the supposed ability to receive information about the world without the use of the recog- nized senses, raises questions about various aspects of the physicalistic world-view that dominates current phil- osophical thinking. Apparent occurrences of ESP, while often extremely convincing to participants, are difficult to investigate applying standard scientific canons of repeat- ability, independence of observation, and applicability of quantitative measurement. Thus such occurrences, if genu- ine, question the universality of these canons. Events supposedly learned of by ESP include ones at great dis- tances or even of future events; this would violate known causal relations and so undermine causal theories of per- ception (how can future events cause the perception of such events in the present?). More generally, ESP, if it exists, would appear to be non-physical: ESP is disanalo- gous to the familiar senses (no known organ of sensation, no known physical link with events perceived) and so explanations, perhaps purely mentalistic, outside the cur- rent physicalistic paradigm seem required. g.c. J. R. Smythies (ed.), Science and ESP (London, 1967). esse est percipi. ‘To be is to be perceived.’ Berkeley, in his Treatise Concerning the Principles of Human Knowledge (1710), asserts (para. 3) of ‘unthinking things’ that ‘their esse is percipi, nor is it possible they should have any exist- ence, out of the minds or thinking things which perceive them’—on the ground that unthinking things, ‘sensible objects’, are*‘ideas or sensations’. Note that he affirms this only of ‘unthinking’ things. g.j.w. A. A. Luce, The Dialectic of Immaterialism (London, 1963), ch. 6. essence. There are four grades of *essentialism. According to grade 1, a thing x is allowed to have a property φ essen- tially only relative to some other (implicitly or explicitly) singled-out property that x has (or kind to which it belongs). Such a property φ is thus a ‘relativistic’ essence, and the acceptance of such essences requires only accept- ance of de dicto necessity: that is, it presupposes only the sort of necessary truth that applies to general propositions such as the proposition that if something is square then it has a shape. Locke’s doctrine of ‘nominal essence’ belongs with this grade of essentialism. According to grade 2, in addition to such de dicto neces- sity there is also fundamental *de re necessity. According to this grade, moreover, it is a necessary truth that any property possessed essentially by anything is possessed essentially by everything that possesses it. Thus, necessar- ily if something is a body, then it is necessarily a body. Note well: it is not just necessarily a body relative to some property of it that entails its being a body, it is not just neces- sarily a body ‘under some description’ that yields its being a body. No, the thing itself that is a body has that property not just contingently but necessarily. In a sense essentiality is, for this intermediate grade, fundamentally 268 Eriugena, John Scotus a feature of properties. Some properties are essential prop- erties; and, most would say, some are not. Properties that are thus essential are in a sense ‘absolute essences’, since whatever has them must have them essentially. But there is a higher grade of essentialism, grade 3, according to which in addition to properties had essen- tially in the relativistic fashion of the lowest grade and in the absolute and de re necessary fashion of the second grade, there are properties had essentially by some things while they are had but not essentially by other things. Thus a snowball may be said to be round and necessarily so (it is of the essence of a snowball, part of its essential nature, that it be round), but the constituent piece of snow is round yet not necessarily so. This might be called ‘particularistic’ essentialism, since one and the same property might be of the essence of one particular while it is had by another particular without being of its essence. Finally, a higher-yet grade of essentialism, grade 4, requires that each particular have a property that only it could possibly have had, in any possible world: its ‘thisness’ or *haecceity. Roundness is a sort of essence that, as we have seen, is distinctively of the essence of some (only) of those particulars that have it. A thing’s haecceity, on the other hand, is in a more extreme fashion distinctively of the essence of something: for it is a property that is neces- sarily possessed by that thing in whatever possible world it might have existed, and one that could not possibly have been possessed by any other thing. The higher grades of essentialism give rise to puzzling conundrums. For example, it seems very plausible that if a thing has a differential modal property (one that not everything has or need have), then there must be some actual (non-modal) property of that thing to explain why it has that modal property. But this gives rise to a problem concerning any property that is not only differentially but also ‘distinctively’ essential, it being possible that some- thing have it essentially while something else has it also but not essentially. Take the roundness of a snowball, which it shares with its constituent piece of snow, even though one, the snowball, has it essentially, and the other, the constituent snow, has it also but not essentially. Given the extent and nature of the similarity in actual properties, including roundness, between the snowball and the con- stituent snow, it is hard to see what could possibly explain the possession of that modal property by that snowball. Whatever property of the snowball we might appeal to in order to explain its essential possession of roundness would seem to be shared by the constituent snow, which is supposed to have roundness only accidentally. So what could possibly explain this difference between them, that one has roundness essentially while the other has it only accidentally? e.s. S. Kripke, Naming and Necessity (Cambridge, Mass., 1972). M. Loux (ed.), The Possible and the Actual (Ithaca, NY, 1979). A. Plantinga, The Nature of Necessity (Oxford, 1974). W. V. Quine, From a Logical Point of View (Cambridge, Mass., 1953; 2nd edn. 1961). essence, individual: see haecceity. essentialism. The essentialist claims that we can draw an objective distinction between an object’s essential and accidental properties, which is not simply a reflection of how we choose to describe the object. An essential prop- erty of an object is one that it possesses in every *possible world in which it exists—or, if one favours *counterpart theory, it is one that is possessed by every counterpart of the object in other possible worlds. For example, it may be urged that it was an essential property of Napoleon that he was a human being, but only an accidental property of him that he was Emperor of France. Some supposedly essential properties of objects, such as Napoleon’s prop- erty of being human, are shared by other objects of the same kind, but there may also be essential properties that are unique to the object possessing them—and these are said to constitute that object’s individual *essence. In the case of a human being like Napoleon, one such property may be his property of having originated from the fusion of a particular sperm and egg. e.j.l. E. J. Lowe, A Survey of Metaphysics (Oxford, 2002). essentially contested concepts. It is sometimes claimed that the enduring diversity of opinion over, e.g., moral, political, or religious issues reveals that such questions lie beyond the domain of rational enquiry. In the 1950s, W. B. Gallie challenged this claim, arguing that disputes about concepts like ‘art’, ‘democracy’, and ‘social justice’ are not merely semantic or attitudinal in character, but often involve arguments that aspire to be, and sometimes are, rationally persuasive. None the less, the internal complex- ity of such concepts ensures that dispute is always prone to break out. Thus, from the fact that such concepts are ‘essentially contested’, we should not conclude that their use defies rational assessment. d.bak. W. B. Gallie, ‘Essentially Contested Concepts’, Proceedings of the Aristotelian Society, 56 (1955/6). eternal recurrence. An ancient cosmological idea, seized upon by Nietzsche, to the effect that everything that happens is part of an endlessly repeating cycle or sequence of events. While Nietzsche entertained this idea as an actual cosmological hypothesis, he first introduced it and chiefly employed it hypothetically as a kind of test. One who is able to affirm life even on this supposition will have what it takes to endure and flourish in the aftermath of all disillusionment. (See e.g. The Gay Science, sect. 341; Thus Spoke Zarathustra, pt. 3; The Will to Power, sect. 1066.) r.s. *cosmology. John Stambaugh, Nietzsche’s Thought of Eternal Return (Baltimore, 1972). eternity. Sometimes used to mean simply the whole of *time; but more usually used to mean a timeless realm (with no past or future) in which God lives. Boethius eternity 269 . another matter, as is the ques- tion whether ‘I think’ itself can be doubted). Given the thoughts of that self as he construed it, he then sought to derive from them the existence of God and thereafter. dialogue the Theaetetus, he seems to revert to an idea put forward in the early dia- logue the Meno, that correct belief can be turned into knowledge by fixing it by means of a reason or cause. The Theaetetus. to me just now. If this last were true, we are thrown back to two questions. The first is whether, and how, the belief about how things seem to me just now is justified. The second is whether the