The Oxford Companion to Philosophy Part 78 pps

invention rather than a revelation. With James, the ten- ability of a thesis is determined in terms of its experiential consequences in a far wider than merely observational sense—a sense that embraces the affective sector as well. John Dewey, like Peirce before him, saw inquiry as a self-corrective process whose procedures and norms must be evaluated and revised in the light of subsequent experi- ence. But Dewey regarded this reworking as a social and communal process proceeding in the light of values that are not (as with Peirce) connected specifically to science (viz. prediction and experimental control), but rather values that are more broadly rooted in the psychic disposi- tion of ordinary people at large—the moral and aesthetic dimension now being specifically included. Peirce’s prag- matism is scientifically élitist, James’s is psychologically personalistic, Dewey’s is democratically populist. Pragmatism had a mixed reception in Europe. In Italy Giovanni Papini and Giovanni Vailati espoused the doc- trine and turned it into a party platform for Italian philosophers of science. In Britain, F. C. S. Schiller was an enthusiastic follower of William James, while F. P. Ram- sey and A. J. Ayer endorsed pivotal aspects of Peirce’s thought. Among continental participants, Rudolf Carnap also put pragmatic ideas to work on issues of logic and phil- osophy of language, and Hans Reichenbach reinforced Peirce’s statistical and probabilistic approach to the methodology of induction. However, the reception of pragmatism by other philosophers was by no means uni- versally favourable. F. H. Bradley objected to the subordin- ation of cognition to practice because of the inherent incompleteness of all merely practical interests. G. E. Moore criticized William James’s identification of true beliefs with useful ones—among other reasons because utility is changeable over time. Bertrand Russell objected that beliefs can be useful but yet plainly false. And various continental philosophers have disapprovingly seen in pragmatism’s concern for practical efficacy—for ‘success’ and ‘paying off’—the expression of characteristically American social attitudes: crass materialism and naïve democratism. Pragmatism was thus looked down upon as a quintessentially American philosophy—a philosophical expression of the American go-getter spirit with its success-orientated ideology. However, Americans have had no monopoly on prac- tice-orientated philosophizing. Karl Marx’s ideas regard- ing the role of practice and its relation to theory have had a vast subsequent influence (some of it upon otherwise emphatically non-Marxist thinkers such as Max Scheler). Important recent developments of praxis-orientated phil- osophy within a neo-Marxist frame of reference are rep- resented by Tadeusz Kotarbin´ski in Poland and Jürgen Habermas in Germany. Kotarbin´ski has endeavoured to put the theory of *praxis on a systematic basis within a spe- cial discipline he designates as praxiology. Habermas has pursued the concept of praxis deeply into the domain of the sociological implications of technology. Be this as it may, pragmatism has found its most favourable reception in the USA, and has never since Peirce’s day lacked dedicated advocates there. At Harvard in the next generation after James, C. I. Lewis was con- cerned to apply pragmatism to the validation of logical sys- tems. He focused upon (and in his own work sought to develop) the idea of alternative systems of logic among which one must draw on guides of pragmatic utility. And for all his differences with Lewis, W. V. Quine continued this thinker’s emphasis on the pragmatic dimension of choice among alternative theoretical systems. Richard Rorty has endeavoured to renovate John Dewey’s rejec- tion of abstract logical and conceptual rigidities for the flexibilities of expediency in practice. In a cognate spirit, Joseph Margolis has re-emphasized pragmatism’s anti- absolutism based on the transiencies of historical change. And Nicholas Rescher’s ‘meth-odological pragmatism’ sought to return pragmatism to its Peircian roots by giving the doctrine a specifically methodological turn, seeing that anything methodological—a tool, procedure, instrumen- tality, programme, or policy of action, etc.—is best valid- ated in terms of its ability to achieve the purposes at issue, its success at accomplishing its appropriate task. It follows that even the factual domain can be viewed in such a light that practical reason becomes basic to the theoretical. One overarching and ironic fact pervades the develop- ment of pragmatism, namely that the doctrine can be seen either as a validation of objectively cogent standards or as a subverter of them. There is a Peircian or objective prag- matism of ‘What works impersonally’—though proving efficient and effective for the realization of some appropri- ate purpose in an altogether person-indifferent way (‘suc- cessful prediction’, ‘control over nature’, ‘efficacy in need fulfillment’). And there is a Jamesian or subjective prag- matism of ‘What works for X’ in proving efficient and effective for the realization of a particular person’s (or group’s) wishes and desires. The objective pragmatists stand in the tradition of Peirce and include F. P. Ramsey, C. I. Lewis, Rudolf Carnap; the subjective pragmatists stand in the tradition of William James and include F. C. S. Schiller and Richard Rorty. (John Dewey straddles the fence by going to an social interpersonalism that stops short of impersonalism.) Looking at James, Peirce saw sub- jective pragmatism as a corruption and degradation of the pragmatic enterprise, since its approach is a venture not in validating objective standards but in deconstructing them to dissolve standards as such into the variegated vagaries of idiosyncratic positions and individual inclinations. And this is how objective pragmatists view the matter down to the present day—this writer included. n.r. *American philosophy. D. S. Clarke, Jr., Rational Acceptance and Purposes (Totowa, NJ, 1989). Elizabeth Flower and Murray G. Murphy, A History of Philosophy in America, ii (New York, 1977). Bruce Kuklick, A History of Philosophy in America: 1720–2000 (Oxford, 2001). John P. Murphy, Pragmatism from Peirce to Davidson (Boulder, Colo., 1990). Nicholas Rescher, Methodological Pragmatism (Oxford, 1977). 750 pragmatism —— Cognitive Pragmatism (Pittsburgh, 2001). Richard Rorty, Consequences of Pragmatism (Minneapolis, 1982). John E. Smith, Purpose and Thought: The Meaning of Pragmatism (New Haven, Conn., 1978). Henry S. Thayer, Meaning and Action: A Critical History of American Pragmatism (Indianapolis, 1968). pragmatism, neo-: see neo-pragmatism. praxis. The Greek word for ‘action’. It enters the philo- sophical literature as a quasi-technical term with Aristotle (meaning ‘doing’ rather than ‘making [something]’), is developed by some of the Left Hegelians, and is now pri- marily associated with Marx and Marxism. In the 1960s and 1970s the term characterized the approach of east European (especially Yugoslav) Marxists (known as the Praxis Group), whose central concern was to study and influence the role of free creative activity in changing and shaping ethical, social, political, and economic life along humanistic socialist lines. r.de g. Nicholas Lobkowicz, Theory and Practice: History of a Concept from Aristotle to Marx (Notre Dame, Ind., 1967). predicate: see subject and predicate. predicate calculus. A device (also called the functional calculus, or calculus of relations) for formalizing and sys- tematizing the logical relations between propositions when these are considered not (as for the *propositional calculus) as unanalysed, but as analysed to bring out their structures, so that two different propositions, instead of being identical or totally different, may be partially differ- ent, having something in common, like ‘All cats are black’ and ‘Some cats are black’. This *calculus, like the propos- itional calculus, can be presented either as an axiom sys- tem or as a natural deduction system for the relevant area. Unlike the old Aristotelian logic it takes account of rela- tional predicates (which can be dyadic like ‘greater than’, triadic like ‘between’, or in general n-adic), as well as of non-relational predicates like ‘black’ (which yield the monadic predicate calculus, to which certain special the- orems apply). The predicate calculus is called extended or second-order if its variables range over what its predicates, as well as what its subjects, stand for; otherwise it is called restricted or first-order. (*Higher-order logic.) a.r.l. D. Hilbert and W. Ackerman, Principles of Mathematical Logic (first pub. in German, 1928–38; New York, 1950). predicative theories. Theories which aim to obey the principle that an abstract object exists only if it has a pred- icative definition. (*Vicious-circle principle.) Russell’s *type theory is not one, since it contains an axiom of reducibility which nullifies that principle. The axiom was needed to obtain the classical theory of real numbers, which a predicative theory cannot do. For on the classical theory there are uncountably many real numbers, whereas the predicative universe must be countable, since it cannot outrun the available definitions. H. Weyl produced the first predicative theory of real numbers in Das Kontinuum (1918). His results have since been extended, and it turns out that a surprisingly large amount of the classical theory can be reconstructed. Accordingly, some philosophers have claimed that pred- icative mathematics includes all the mathematics that is actually needed in the sciences, and therefore all that is empirically justified. The intuitionist theory of real numbers is also a pred- icative theory, but further constrained by being restricted to *intuitionist logic. d.b. *impredicative definition. C. S. Chihara, Ontology and the Vicious Circle Principle (Ithaca, NY, 1973). S. Feferman, ‘Systems of Predicative Analysis’, Journal of Symbolic Logic (1964). H. Wang, A Survey of Mathematical Logic (Amsterdam, 1962), esp. chs. 23–5. prediction. The key role of prediction in human affairs inheres in our stake in the future. After all, we are all going to have to spend the rest of our lives there. And from the outset, the existence of Homo sapiens has hinged on predictive knowledge: ‘What will happen when I enter that cave? Will I find shelter or fierce animals?’ ‘What will happen when I eat those mushrooms? Will they nourish or poison me?’ Without some degree of cognitive control over the future, we humans could not exist as the intelli- gent creatures we are. Prediction is literally foretelling, specifying occurrences in advance of the fact. A correct forecast can, of course, be the result of pure accident, of lucky guesswork and pure chance. But only rational prediction that is based on grounds whose merits are discernible prior to the event is of epistemological interest: predictions whose merits are discernible only after the fact are useless. It can be ques- tioned as a matter of principle whether such cogent pre- dictions can be made at all. Every rational prediction is an *induction—a projection of some sort from past experi- ence, though it need not, of course, be a simple linear pro- jection that is at issue. Thus only in the setting of lawful regularity—where occurrences fall into discernible pat- terns—will rational prediction be possible at all. The extent to which this world is such an orderly cosmos is a discussable question. But the course of wisdom is clearly to hope for the best. Two extremes can be contemplated: (1) that of *determinism, of a ‘Laplacian’ cosmos in which literally everything that happens can in principle be pre- calculated, and (2) that of a chaotic world where nothing can be securely predicted because all apparent patterns are at best transitory stabilities. Since classical antiquity, most philosophers have taken an intermediate position, hold- ing that the real world admits of rational prediction in many cases, but with many important exceptions, pre- eminently relating to chance (‘stochastic’) events in phys- ical nature—such as quantum phenomena or the ‘swerve’ of Epicurus—and to the spontaneous decisions that mani- fest the *free will of human beings. prediction 751 Some cogent predictions can be equipped with an explicit explanatory rationale. Others may have no further backing than the unarticulated judgement of an informed expert. But even here rational control is possible through establishing a ‘track record’. The ability to underwrite successful predictions is our best quality-control test of the adequacy of scientific theor- izing. To be truly satisfactory, our scientific explanations must have a rationale that also engenders adequate predictions. (In this regard the linkage of cosmology to quantum theory becomes crucial.) The most important feature of a good prediction, ratio- nal cogency apart, is its specificity or detail. It is safe (and uninteresting) to predict that Henry will die some time, but far more risky (and interesting) to predict that he will die exactly 756 days hence. It is a consequence of *Bayes’s theorem that the more daring a prediction—the lower its a priori likelihood—the more informative it is, other things being equal. To be sure, other things are not in general equal. For example, a great deal more turns on predicting the outcome of a war or the course of a nation’s economy than on the result of a boxing-match. This factor of inher- ent significance of the matter at issue is the third principal consideration in assessing the merit of a prediction. There are many obstacles to predictability. In nature we have volatility and *chance (stochastic phenomena); in human affairs innovation and chance (free will). *Chaos is a phenomenon that straddles both domains. Processes are chaotic whenever minute differences in conditions (so small as to fall beneath the threshold of detectability) can produce large-scale differences in result. (Lightning bolts and smoke swirls are an example in nature, political assassinations and battlefield fatalities in human affairs.) Chaos is to all appearances a more important source of impredictability than any putative indeterminism in physics. Would we want the predictive project to be perfectible? Our psychological and emotional condition is clearly such that we would not want to live in a pre-programmed world where the rest of our fate and future is fully dis- cernible in the realities of the present. The human yearn- ing for novelty—for new experiences and prospects and possibilities—is surely a characteristic aspect of what makes us into the sorts of creatures we are. The feeling of open horizons—of new developments that make for sus- pense and surprises—is integral to our human nature. Without some exposure to chance and uncertainty we cannot function as the creatures we are—the sort of crea- tures we have become under the pressure of evolutionary development. We thrive in the interstices of chance that pervade a world of predominantly lawful order. n.r. John L. Casti, Searching for Certainty: What Scientists can Know about the Future (New York, 1990). Paul Horwich, Asymmetries in Time: Problems in the Philosophy of Science (Cambridge, Mass., 1989). J. R. Lucas, The Future (Oxford, 1989). Nicholas Rescher, The Limits of Science (Berkeley, Calif., 1989). Stephen Toulmin, Foresight and Understanding (New York, 1980). prediction paradox. A variety of distinct puzzles have come to be associated with this name. (1) involves the sen- tence A: ‘Event E will happen tomorrow and it cannot be proven by a sound argument using A as a premiss that E will happen tomorrow’. A begins with a prediction but goes on to deny that A could be a true premiss leading to the prediction. This could only happen if A were not true. So A involves a denial of its own truth, making it a relative of the *liar paradox. (2) A notoriously unreliable speaker can say B: ‘E will happen but you don’t know it will’ and tease his audience by making a prediction which can turn out true even though his audience, being unable to trust him, will not know E is going to happen. In both these cases, the ‘prediction’ can be replaced by a non-predictionPand still leave the same essential problem. So the title ‘prediction paradox’ is not well-deserved. A somewhat better candidate for the title is (3): X needs to stage event E on just one of the next n days without Y (who knows that X is committed to staging Y on these terms) being able to predict in advance which day it will be. The last day looks like a bad choice for X. This tends to make the next-to-last day also look bad, and then the next-to-next, leading to a paradoxical argument ruling out the whole series of days. The contest between X and Y raises interest- ing problems in game theory. Unlike (1) and (2), which cru- cially involve statements (A and B), no statements need be made for the contest to arise between X and Y. j.c. *exam paradox. James Cargile, ‘The Surprise Test Paradox’, Journal of Philosophy (1967). pre-established harmony: see harmony, pre-established. preface paradox. Paradox about belief and rationality. Recognizing his own fallibility, the author writes in the preface, with all sincerity, ‘Though I believe everything I’ve written, no doubt this book contains mistakes (for which I apologize)’. He believes each of the state- ments in the book, yet also believes that at least one of them is false, which is close to believing a contradiction; yet his position seems both modest and rational. The paradox stems from the fact that it cannot be rational to believe a contradiction. r.m.s. A. N. Prior, Objects of Thought, ed. P. T. Geach and A. Kenny (Oxford, 1971), 84ff. prejudice, Burkian: see Burke. prescriptivism. A theory about the meaning of moral terms such as *‘good’, *‘right’, and *‘ought’. Its principal advocate has been R. M. Hare. The theory draws a con- trast between descriptive meaning, whereby language is used for stating facts, and the ‘prescriptive’ meaning which is characteristic of moral language. Moral terms are used primarily for guiding action, for telling people what to do. As such they are similar to imperatives, which also have prescriptive meaning. Moral discourse is not, as the 752 prediction *emotive theory of ethics had seemed to suggest, a mani- pulative process of playing on people’s feelings. It is a rational activity, addressed to others as rational agents. It is, however, logically distinct from the activity of descript- ive discourse, and hence no statements of fact can entail any conclusion about what one ‘ought’ to do. r.j.n. R. M. Hare, The Language of Morals (Oxford, 1952). present: see time. presentism. The presentist maintains that only presently existing objects and presently occurring events are real, thereby excluding from reality past and future objects and events. Indeed, for the presentist, only the present *time is real, so that our talk about past and future times must be interpreted very differently from our talk about the pre- sent. He will be perfectly happy to allow that certain objects did exist or will exist, which do not presently exist and so are not real. What he wants to avoid saying is that there really are past and future times, ontologically on a par with the present time, at which these presently non- existent objects exist. His position may be likened to that of the opponent of *modal realism, who contends that non-actual *possible worlds are not ontologically on a par with the actual world, but are merely maximal consistent sets of propositions representing ways the world could have been. e.j.l. M. J. Loux, Metaphysics: A Contemporary Introduction, 2nd edn. (London, 2001). Pre-Socratic philosophy. The term includes all early Greek theorists, with cosmological or philosophical interests, active before the end of the fifth century bc, except for the *Sophists. This convenient though arbitrary usage recog- nizes that philosophy began in Greece from, or in conjunc- tion with, abstract cosmological theorizing, and was not generally recognized as a separate discipline in this period. Abstract cosmology was founded by the sixth-century Milesians: Thales, Anaximander, and Anaximenes. They aimed to construct probable theories about the universe as a whole. They sought economical explanations in well- defined terms, and used the principle of *sufficient reason as a guide to these. Lacking the means of experimental verification, they tied their theories to the observable world by the concept of phusis (nature), which implied a basic uniformity of behaviour in the natural world. There was an overall teleology (guidance by a supreme intelli- gence identified with the fundamental component of the physical world). This style of ‘natural philosophy’ (phusi- ologia) was continued in the fifth century by Anaxagoras and Democritus among others. Like every ambitious scientific programme, natural philosophy generated philosophical problems. The most pressing was the epistemological one, particularly since the project required the rejection of all traditional author- ities. It is likely that the Milesians were not explicit about their epistemology; but Xenophanes rejected all human claims to knowledge outside the area of immediate experi- ence. Instead he envisaged the construction (and cumula- tive refinement) of ‘better opinion’, the criterion for which was ‘resemblance to truths’, i.e. the truths of imme- diate experience. His own cosmology systematically makes parsimonious extrapolations from ordinary experi- ence. This strain of empiricism, revived in the later fifth century, can be traced in Anaxagoras, some of the medical writings attributed to Hippocrates, and perhaps Socrates. A different type of approach appears in the theology of Xenophanes, which deduced the properties of God from a priori principles of what is ‘fitting’ for a divinity. The out- standing theorists of the late sixth and early fifth centuries claimed to discover truths of which the denial would be in some way unreasonable or unthinkable. Pythagoras pos- sibly appealed to occult or mystical experience. But Hera- clitus and Parmenides (leader of the Eleatics) in their different ways focused on the workings of human reason itself, thereby founding logic and metaphysics. Heraclitus’ logos, to which he appealed for confirmation, reflects or embodies reason. Parmenides, in the first surviving attempt at consciously rigorous argument, claimed to start from a premiss which cannot coherently be denied, and to deduce step by step the properties of any possible object of knowledge. Both Heraclitus and Parmenides were concerned with another systematic legacy of the ‘natural philosophers’: the problem of unity and diversity in the universe, and (arising from that) the problem of appearance and reality. Heraclitus detected a general pattern of ‘unity- in-opposites’, exemplified in the identity of the river which survives the change of its waters. He did not (as some have thought) deny the principle of *non-contradiction, but rather saw ambiguities in the very essence of things. Par- menides, by contrast, argued that anything knowable must be fully determinate and absolutely unified. This led him to a strong form of monism about underlying reality. Parmenides’ ideas, particularly his arguments against ‘coming-to-be’ and ‘ceasing-to-be’, and his insistence on absolutely definite objects of knowledge, were widely influential. His immediate follower Zeno of Elea turned his style of argumentation to destructive ends, exposing the logical inadequacy of certain natural assumptions about the physical world. Another near-contemporary, Empedocles, idiosyncratically blended Parmenidean metaphysics and Pythagorean doctrines of the soul with a cosmology, which, in parallel to the medical theory of Alcmaeon of Croton ( fl. c.450?), explained the diversity of appearances by a finite but plural number of basic ‘roots’ (the first appearance as such of the ‘four elements’) with clearly defined properties. The later part of the fifth century was dominated, in the western Greek world (southern Italy and Sicily), by (real or self-styled) Pythagoreans. Pure mathematics was taken as the paradigm, perhaps the only possible kind, of know- ledge. (A reduction of all sciences to arithmetic seems to have been seriously attempted.) Philolaus ( fl. c.450?) argued for finite units and quantities as the only possible objects of knowledge. Pre-Socratic philosophy 753 early greek philosophy pythagoras, one of the earliest known Greek thinkers: the mythology that attached itself to him in antiquity has made it difficult to affirm much more than that he was a charismatic founder of a religious sect with strong ethical ordinances. heraclitus, was to be a model for various modern Euro- pean philosophers in point of the oracular obscurity of his style, his supposed disregard for his fellow humans, the ambition of his philosophy, and the importace in it of opposition and flux. socrates: Plato paid homage to his mentor by his literary representation and continuation of the Socratic enterprise in a series of philosophical dialogues, in which Socrates seldom meets his match. democritus, perhaps a younger contemporary of Socra- tes, was one of the earliest proponents of an atomic theory of the universe, and seems to have been a forerunner of Epicurus in ethics. In mainland Greece and the Aegean islands, the later fifth century was the age of the Sophists (of whom one, Protagoras, was an original philosopher); and of Socrates. Of those others denominated ‘Pre-Socratics’, most revived the original programme of natural philosophy, taking account of the new situation created above all by the Eleatics and by the new attention to biological theory and psychology. (An isolated figure, Melissus, belongs with the *Eleatics, and is most notable for his radical critique of sense-perception.) The leading figures were Anaxagoras and the early proponent of *atomism, Dem- ocritus. Anaxagoras and Democritus represent opposite, repeatedly recurring tendencies in physics: Anaxagoras is a ‘field theorist’, assuming the continuity and ubiquity of physical forces, while Democritus is a ‘particle theorist’, claiming that they are localized and particulate. Anaxago- ras was closer in spirit and style to the original Milesian enterprise, identifying the cosmic intelligence as ‘Mind’ (*nous) and attributing to it an overall teleological control. The Atomists made a fundamental break in creating reductive *materialism: there are only (lifeless and mind- less) atoms and void with their essential properties. They aimed to derive, from these foundations, not only living and sentient beings of familiar kinds, but ‘gods’ (large, long-lived beings inhabiting intercosmic void) and moral values. Pre-Socratic philosophy never entirely broke free, except with the Eleatics, from its origins in the problems of a scientific programme. Democritus is the first and only Pre-Socratic known to have elaborated an ethical theory, though in Heraclitus and Empedocles ethical values are given a place in the natural world. The scepticism about moral and religious systems associated with the antithesis between nomos (‘custom’) and phusis (‘nature’ or ‘reality’), which figured in the discussions of the Sophists, has its roots in Xenophanes’ attacks on traditional religion and values. Even in the limited sources, an increasing philo- sophical sophistication in ontology and epistemology, and an increasing command of the techniques of argument, can be traced. The interpretation of the Pre-Socratics has been con- troversial at least since the late fifth century bc. (*Craty- lus.) Many of their works were already lost or scarce in late antiquity, and the rest perished thereafter, apart from quotations in surviving writers. In the scarcity of primary sources Aristotle’s remarks on them were generally taken as authoritative from medieval times until recently. Only in the nineteenth century did a new climate of thought, and advances in scholarship, allow some Pre-Socratics to emerge as important philosophers in their own right. Understanding has been both furthered and impeded by the imperialism of those modern philosophers who, like Aristotle, have sought to force the history of philosophy into a preconceived mould. In default of substantial new primary materials, scholarship can advance only by gradu- ally reaching a better (philosophically informed, but not prejudiced) understanding of (a) the nature and aims of the sources; (b) the language and concepts used by the Pre-Socratics and their contemporaries; (c) their philo- sophical intentions, as shown by the totality of the evidence. e.l.h. J. Barnes, Early Greek Philosophy (London, 1987). H. Fränkel, Early Greek Poetry and Philosophy, tr. M. Hadas and J. Willis (Oxford, 1975). E. Hussey, The Presocratics (London, 1972). G. S. Kirk, J. E. Raven, and M. Schofield, The Presocratic Philoso- phers, 2nd edn. (Cambridge, 1983). A. A. Long (ed.), The Cambridge Companion to Early Greek Philoso- phy (Cambridge, 1999). presumption. A concept borrowed by epistemology from law that represents a way of filling in—at least pro tem— certain gaps in our otherwise available information. The ‘presumption of innocence’ is a paradigm case here; a pre- sumption is a matter not of secured facts, of given inform- ation, but rather of answers that are taken in the absence of counter-indications. Presumptions are accordingly defeasible, vulnerable to being overturned—but only by some duly established conflicting considerations. A pre- sumption accordingly has a favourable burden of proof on its side: counter-evidence is needed to effect its undoing. A specific presumption is always grounded in a princi- ple of presumption. Such principles operate in various domains. For example, a cognitive presumption operates in favour of the data of sight (‘Accept what you see to be so’). In communicative contexts we have a presumption to the effect that people are truthful (‘Accept what your interlocutors maintain’); in everyday enquiry we have the presumption that our sources are reliable (‘Accept what encyclopedias and authorities maintain’); in science we have the presumption of evidential sufficiency (‘Accept what the most strongly established theory or explanation maintains’). However, the result of applying such princi- ples of presumption is always tentative and provisional: the rider ‘until such time as indications to the contrary come to view’ is attached to all presumptive principles. The validations of the principle of presumption can be of two sorts. Some are justified a priori and proceed by showing that they are sine qua non prerequisites of a certain cognitive practice. Others are a posteriori and experiential, grounded in the ex post facto consideration of a track record showing that operating on this basis yields better results for the enterprise at issue than would otherwise be available. Practical efficacy is the crux for presumption. Presumptions play a key role in the cyclic justifications at issue in an epistemological coherentism that dispenses with the self-evident certainties of an epistemic founda- tionalism. n.r. N. Rescher, Methodological Pragmatism (Oxford, 1977). E. Ullman-Margalit, ‘On Presumption’, Journal of Philosophy (1983). Price, Henry Habberley (1899–1984). Wykeham Professor of Logic and Fellow of New College, Oxford, 1935–59; a shy, reclusive figure, belonging to no school or group and Price, H. H. 755 seeking no disciples. His major work is Perception, in which, adopting from Russell and Moore the term *‘sense-datum’ for the basic object of perception, he seeks to clarify the sense in which sense-data ‘belong to’ material objects, rejecting, on the one hand, the causal theories of Locke and Russell and, on the other hand, the *phenomenalism of, for example, J. S. Mill. He pursues these issues further in Hume’s Theory of the External World (Oxford, 1940). In Thinking and Experience (London, 1953) he explores the nature of thinking, playing down the then fashionable emphasis on the use of ‘symbols’, and arguing that con- cepts should be seen as ‘recognitional capacities’. g.j.w. H. H. Price, Perception (London, 1932). Price, Richard (1723–91). Welsh dissenting minister noted for his defence of a non-naturalist moral philosophy. His argument for the non-definability of goodness anticipates G. E. Moore, and elements of his intuitionism have reappeared in the work of H. A. Prichard and W. D. Ross. Price’s defence of individual freedom and national inde- pendence figured prominently in his criticism of the British declaration of war against the American colonies, and his advice to the Americans after the war helped to shape their new Constitution. He edited Bayes’s essay on the doctrine of chances, pioneered actuarial theory, and became a Fellow of the Royal Society. His enthusiasm for the cause of the French Revolution provoked Edmund Burke to write his famous and severely critical Reflections on the Revolution in France. o.r.j. *Bayesian confirmation theory. D. O. Thomas, The Honest Mind: The Thought and Work of Richard Price (Oxford, 1977). Prichard, Harold Arthur (1871–1947). Oxford philoso- pher who emphasized the unanalysability of certain epis- temological and ethical concepts, notably knowledge and moral obligation (see his Knowledge and Perception (Lon- don, 1950) and Moral Obligation (London, 1949)). Know- ledge, or being certain, was an infallible state of mind, which its possessor could know that he possessed, though it had to be distinguished from merely feeling certain, or thinking without question. Moral philosophy, he sug- gested, rested on a mistake in that it tried to justify moral obligation by reducing it to something else, such as inter- est, but any such analysis could only succeed by destroy- ing what was supposed to be analysed; like knowledge, moral *obligation presented itself directly to our intu- itions. Prichard’s moral philosophy therefore contains obvious analogues both to Moore’s view of good as unanalysable and to Kant’s view of duty as entirely inde- pendent of interest. a.r.l. H. A. Prichard, Moral Writings, ed. J. MacAdam (Oxford, 2002). Priestley, Joseph (1733–1804). English Utilitarian philosopher, scientist, and unorthodox theologian. Priest- ley’s main political work is his Essay on the First Principles of Government (1768). This work is of interest because it is here that Bentham may have discovered the formula of the *greatest happiness of the greatest number. Priestley, again before Bentham, attempts to bring about the fusion of the principle of utility with democratic ideas. The prob- lem of government is therefore that of finding a way to identify the interest of the governors with the interests of the governed. Priestley’s solution is that identity of inter- ests can be achieved by making it necessary for the rulers to court the favour of the people. ‘It is nothing but the con- tinued fear of a revolt in favour of some rival, that could keep such princes within bounds.’ Priestley is important for many discoveries in chemistry and physics. r.s.d. Elie Halevy, The Growth of Philosophical Radicalism, tr. Mary Morris (London, 1928). prima-facie duties: see duty. primary and secondary qualities. Deriving from the Greek Atomists and common in the seventeenth century (Galileo, Descartes, Boyle) the distinction between these is famously found in Locke’s Essay Concerning Human Understanding, where primary *qualities (e.g. shape) are ‘utterly inseparable from . . . [a] body’, however small (ii. viii. 9) and secondary qualities (e.g. colour) ‘in truth are nothing in . . . objects themselves, but powers to produce various sensations in us’ (ii. viii. 10). It is often supposed to be an epistemological doctrine concerning perceptual error and illusion, and so to depend on some idea that while we often err about the colours of objects we do not do so about their shapes, or that our perception of colour can vary with our position or with our mental and phys- ical states. In fact, however, it is really a corollary of the corpuscular theory of matter, or, more generally, of the ‘mechanical philosophy’. Primary qualities belong not only to observable things such as an almond, but also to the insensible minute cor- puscles which were supposed to make it up. An almond has solidity, extension, shape, mobility, and number, and according to the corpuscular theory the almond’s corpus- cles have these qualities too. Secondary qualities, such as colour and taste, belong to the almond but not to its cor- puscles. They arise from the arrangement of the solid, shaped, and mobile corpuscles themselves. Of course, like its colour, the almond’s primary qualities of solidity and extension also result from its consisting of solid, extended corpuscles. What distinguishes them from secondary qualities is that these are those features which corpuscles need to have in order to account for all the qualities (pri- mary and secondary) of the things they make up. Because material things consist of arrangements of insensible corpuscles, they act on our sense-organs in cer- tain ways. Interaction between an almond’s corpuscles and those of our taste-buds results in the production, in our minds, of a certain idea, that of sweetness; though quite how such causation between the physical and the mental takes place is, Locke says, a mystery. Similarly, via the intermediary of reflected light, interaction between an almond’s corpuscles and those of our eyes produces in 756 Price, H. H. us the idea of its colour. Secondary qualities of objects are those arrangements of its corpuscles which cause certain ideas in us. Fire causes pain in us, and snow causes ideas of coldness and whiteness. However, while we think of pain simply as something caused in us by the interaction between fire and our bodies, we think of snow as being, in itself, white and cold. Locke suggests that the corpuscular account of objects, and our perception of them, gives us no reason to think of snow’s coldness and whiteness like this. We do perceive snow as being cold and white in itself; but since our doing so is a result of the arrangement of primary- qualitied corpuscles, there is no need to suppose snow really is as we perceive it. Snow does have a certain cor- puscular arrangement, which fits it to produce ideas of coldness and of whiteness in us; but just as there is nothing in fire resembling pain, so there need be nothing in snow resembling the whiteness and coldness it appears to have. The case is otherwise with primary qualities. In order to explain how we perceive objects as having shape, and being solid, we need to suppose that objects have those properties in the way they appear to have. r.s.w. *representative theory of perception. Peter Alexander, Ideas, Qualities and Corpuscles (Cambridge, 1985). Margaret D. Wilson, ‘History of Philosophy in Philosophy Today; and the Case of the Sensible Qualities’, Philosophical Review (1992). R. S. Woolhouse, John Locke (Brighton, 1983), ch. 4. prime matter. (Latin materia prima; Greek pro¯te¯ hule¯; ‘first’ or ‘primary’ matter.) Traditionally, *matter which ‘in itself’ has no determinate positive qualities, but the poten- tial to have such qualities. Prime matter is posited as what persists through a *change in which one Aristotelian element (e.g. water) turns into another (e.g. air). This con- ception of prime matter is traditionally ascribed to Aris- totle, although the attribution has been challenged (as has the notion’s intelligibility). p.j.m. *substratum; apeiron. Aristotle, De generatione et corruptione, tr. and ed. C. J. F. Williams (Oxford, 1982), app. prime mover. This is a label given to an ultimate cause of motion or change in the universe; it is an idea of funda- mental importance in rational *cosmology. In ancient philosophy the topic is most fully developed by Plato and Aristotle. Both maintain that the original cause of motion must possess mind. But Aristotle argues against Plato that the prime mover must be itself unmoved. Although criticized by Kant, it re-emerges in current big bang the- ory. The idea has never been more succinctly expressed than in its earliest presentation in Plato’s Phaedrus 245c–e. j.d.g.e. principle. The history of philosophy abounds in prin- ciples: the principle of *sufficient reason, Hume’s prin- ciple (‘No ought from an is’), the principle of *double effect . . . A principle will often be put forward as an allegedly obvious truth from which to derive further truths. The principle or principles may be thought so basic and general that all or most of knowledge, or anyway of philosophical knowledge, can be derived: we then have philosophical *foundationalism, as typified in the work of Spinoza. But Descartes’s ‘I think therefore I am’ is not of the general form required of a principle. Using it, or some- thing like it, as a starting-point would amount to a dif- ferent, epistemological, form of foundationalism. A moral principle is less a starting-point for reasoning than a guide for deliberation and action. In moral philoso- phy, you may find a hybrid of the two—for example, the ‘utility principle’. r.p.l.t. *arkhe¯; utilitarianism; regulative principles; rules. B. de Spinoza, Ethics, in The Chief Works of Benedict de Spinoza, ed. R. H. M. Elwes (New York, 1955). principle of sufficient reason: see sufficient reason, principle of. principles, regulative: see regulative principles. Prior, Arthur Norman (1914–69). New Zealand-born philosopher who taught at the University of Canterbury in New Zealand and the University of Manchester before becoming a Fellow of Balliol College, Oxford. He first gained his reputation in ethics, and then went on to do fundamental work in logic and metaphysics. Prior was a leading figure in the movement to apply modal logic to the formalization of a wide variety of linguistic phenom- ena. In 1953 he invented tense logic, introducing two new modal operators ‘It will be the case that’ and ‘It has been the case that’. Prior used his tense logic to articulate theor- ies about the structure and metaphysics of time, and to mount a robust defence of free will and indeterminism. Tense logic is also employed for the manipulation of time- dependent data and has numerous applications in com- puting. In 1956 Prior and Carew Meredith were the first to give a possible-worlds semantics employing the ‘accessi- bility’ relation between worlds. Their idea, now standard in modal semantics, was that ‘Necessarily p’ is true in a world w iff p is true in every possible world accessible from w. An iconoclast and a resourceful innovator, Prior inspired many to undertake work in tense and modal logic. b.j.c. B. J. Copeland (ed.), Logic and Reality: Essays on the Legacy of Arthur Prior (Oxford, 1996). A. N. Prior, Papers on Time and Tense, new edn. ed. T. Braüner, B. J. Copeland, P. Hasle, and P. Ohrstrom (Oxford, 2003). prioritarianism is the view that gains in the well-being of the worse-off are morally more important than the same size gains for the better-off. This view contrasts with *utili- tarianism, which counts a gain in the well-being of one individual the same as it counts the same size gain for any- one else. Pure *equality in the distribution of well-being is often accused of favouring reducing the well-being of the prioritarianism 757 better-off even when this will not benefit the worse off. Prioritarianism rejects such ‘levelling down’. b.h. M. Clayton and A. Williams (eds.), The Ideal of Equality (London, 2002). prisoner’s dilemma. The prisoner’s dilemma describes a possible situation in which prisoners are offered various deals and prospects of punishment. The options and out- comes are so constructed that it is rational for each person, when deciding in isolation, to pursue a course which each finds to be against his interest and therefore irrational. For example, if I am an employer and you a worker, it may be to my advantage not to pay you (rather than pay you) whether or not you do the work, and for you not to do the work (rather than do it) whether or not I pay you; but it is to the advantage of neither of us that I should not pay and you should not work. Such a scenario postulates a lack of enforced co-operation; and to avoid the undesirable out- come, the actors in the drama need to be forced into co- operation by a system of rules. So it has been argued that we can find in this dilemma a basis for the generation of the insti- tutions of morality—or, at least, of prudent co-operation. But that conclusion is challenged by others who point out that the same choice-theoretic problems also arise with ends that are immoral or prudentially harmful. j.d.g.e. From an immense literature on this topic, I select the collection of essays, classic and modern, edited by David P. Gauthier, Morality and Rational Self-Interest (Englewood Cliffs, NJ, 1970). privacy. In US legal philosophy the area of individual rights. In philosophy of mind the characteristic of each person’s experiences and thoughts that they are known immediately only to that person. Epistemological *foun- dationalists took such supposedly infallible and self- intimating knowledge to be the firm basis they sought. The alleged privacy of each person’s thoughts and experiences gives rise to the *‘other minds’ problem as well as to gen- eral *scepticism regarding knowledge. Attempts to avert such consequences include appeals to the public nature of language, the medium in which thoughts have in any case to be formed. More general attacks on the notion of the mind as an inner realm uniquely accessible to each indi- vidual are found in *Heidegger’s *Dasein from the 1920s and *Ryle’s behavioural analysis of mind from the 1940s. Latterly, *Dennett and *Churchland, respectively, see in the flow of subjective experience but a scrambled version of, and a poor way of accessing, what really happens at more basic ‘sub-personal’ levels. a.h. A. J. Ayer, ‘Basic Propositions’, in Philosophical Essays (London, 1954). G. Ryle, The Concept of Mind (London, 1949). private language problem. Sections 243–315 of Wittgen- stein’s Philosophical Investigations criticize the idea, presup- posed by Cartesianism and empiricism, of a language whose primitive terms signify the speaker’s ‘private’ sen- sations and perceptions, allegedly inalienably owned and truly known only by their bearer. ‘Ownership’ of experi- ence is misconstrued, since different people can have the very same sensation. Private knowledge of experience is misconceived, since neither knowing nor being ignorant of one’s current experience make sense. That the mutual intelligibility of a putative ‘private’ language is problem- atic is obvious. The originality of Wittgenstein’s argu- ment is to show that it must be unintelligible even to its speaker. For it presupposes the possibility of private ostensive definition, of a private (mental) *sample func- tioning as a standard for the correct application of a word, and of a rule which cannot logically be followed by another person, all of which are shown to be incoherent. The consequences of the argument, if it is correct, ramify throughout metaphysics, epistemology, and philosophy of mind. Unsurprisingly, it was heatedly debated in the fol- lowing decades and controverted both by traditional empiricists and by contemporary materialists and func- tionalists. p.m.s.h. P. M. S. Hacker, An Analytical Commentary on the Philosophical Investigations, iii: Wittgenstein: Meaning and Mind (Oxford, 1990), 1–287. privatization is the granting of individual property rights over previously communally owned or unowned resources. Efficiency-based arguments and justice-based arguments are given in its favour. The least plausible just- ice-based argument is from the right to property, since many theorists today agree that distribution of property rights should be derived from principles of justice, rather than vice versa. Justice-based arguments for privatizing communal resources, such as service-providing institu- tions, focus on personal responsibility and increases in freedom of choice which come with competition by providers on a market. It is not clear, however, that all goods allocation should be responsive to individual prefer- ences. Informed choices about education and health care are limited by lack of expertise of precisely the kind sought. Furthermore, even if markets hold individuals responsible for their market choices, those choices are themselves limited by the market advantages and disadvantages that individuals start with. It is also not clear that individuals should be held accountable for all their choices. A moral duty of assistance requires helping those not in a position to help themselves, even if they once were. Arguments from efficiency highlight the state’s moral duty not to waste communal resources. Market competi- tion reduces waste, whilst publicly run services are notori- ously wasteful. So, it is argued, why not improve efficiency through privatizing, whilst giving credits to less advantaged citizens to purchase services? This, however, reduces benefits to market preferences, and efficiency to market efficiency. Market efficiency modifies the goods supplied. For efficient exchange on a market, benefits need clear boundaries, which, for example, are lacked by a ‘good state of public health’. Consequently, privatization encourages ‘commodification’: changes to goods making them more market-friendly, such as turning them into dis- tinctly priced units or solely developing their revenue- 758 prioritarianism yielding properties. This has negative side-effects. Ele- phant populations in Zimbabwe increased after elephants were privatized. Yet, the value inherent in having ‘free- roaming creatures in their natural habitat’ is lost when individuals have control-conferring property rights over these creatures. In the social sphere, it can be argued, all aspects of the provision of goods representing a society’s assistance to its disadvantaged members should be subject to democratic, communal control. s.m g. *economics and morality; socialism. Bo Rothstein, Just Institutions Matter: The Moral and Political Logic of the Universal Welfare State (Cambridge, 1998). privileged access. The supposed special authority pos- sessed by a subject’s beliefs about his or her current men- tal states, as compared with others’ beliefs about those states. Attacked as a myth by Ryle, the idea is still debated. Accounts of first-personal authority vary, ranging from, at one extreme, *incorrigibility, that the subject cannot be wrong, to the subject’s merely being better placed in some respects than others. Recent debate has focused on recon- ciling it with *externalism. p.f.s. *introspection; inner sense. W. Alston, ‘Varieties of Privileged Access’, American Philosophical Quarterly (1971). B. Gertler (ed.), Privileged Access: Philosophical Theories of Self- Knowledge (Aldershot, 2003). probabilistic causality. If classical *determinism is true, every event has a sufficient cause which necessitates its occurrence. However, since the advent of quantum physics, we may have to acknowledge that some events, such as the spontaneous decay of a radium atom, lack any such determining cause. Even setting aside such consider- ations, we are frequently confronted with situations— most obviously in games of chance—in which the outcome of a process cannot be predicted with certainty, but in which some possible outcomes appear to be more probable than others. For these reasons, some philoso- phers of causation have argued that we need to generalize any account of *causality to accommodate the possibility of probabilistic causation. According to one widely adopted approach, to say that an event c was a probabilis- tic cause of another event e is to say that, in the circum- stances in which c occurred, the occurrence of c raised the chance of e occurring—although spelling out what pre- cisely may be meant by this and dealing with various apparent counter-examples is no easy matter, quite apart from the fact that it is difficult to dissociate the notion of causation from that of some kind of necessitation. e.j.l. D. H. Mellor, The Facts of Causation (London, 1995). probability. Although there is a well-established math- ematical calculus of probability, the nature of its subject- matter is still in dispute. Someone who asserts that it will probably rain is not asserting outright that it will: the ques- tion is how such guarded assertions relate to the facts. The modern mathematical treatment of probability owes its origins to Pascal’s treatment of games of chance, and the classical equipossibility theory arises most natur- ally in this context. To say that the probability of a fair die landing six uppermost is one-sixth is to say that among the six equally likely outcomes, the ratio of favourable to unfavourable cases is one to five. But paradoxes arise where there are different, equally possible candidates for the set of equally possible outcomes. And in defining prob- ability in terms of equal possibility the theory runs into circularity. The possibility of deriving probabilities from statistical data has often been thought to require a ‘relative fre- quency’ interpretation. The probability of a 50-year-old man who smokes forty cigarettes a day dying within ten years is, on this view, simply the number of deaths in that period among such men. The attraction of this interpret- ation is that it appears to make the probability of an event as objectively ascertainable as the height of a house. But a given individual will generally belong to various classes with differing life expectancies. In such cases we can no longer speak of the probability of a given individual’s dying: but this may be just what concerns us. Much discussion of the frequency theory has concen- trated on games of chance, where prior assumptions about frequencies rather than actual frequencies take the lead. What happens in the ‘long run’ in ‘roughly’ a given proportion of cases is introduced to bring these into line with each other. But this account owes explanations of what ‘roughly’ means, and of how long a long run is, and these seem to depend on the notion of probability. (It is improbable, not impossible, that a fair coin never shows heads in however long a run.) More sophisticated versions involve the idea of a limit to which actual frequencies tend as the number of events increases; but no data guarantee the existence of this limit. The frequency interpretation has no obvious applica- tion to a statement like that made by John Dalton in 1803 that ‘the most probable opinion’ about the nature of heat was that it was ‘an elastic fluid of great subtilty’. This has led some philosophers to attempt to analyse probability in terms of so-called ‘degrees of belief’. This account has often been thought of not as an alternative to the fre- quency interpretation, but as the analysis of a different concept, the word ‘probability’ being ambiguous. Person- alist theories take probability judgements to be expres- sions of the willingness to make certain bets: to believe that the probability of the coin showing heads is one-tenth is to be willing to stake a pound to win nine if heads show. To avoid this arbitrariness by substituting ‘degree of reasonable belief’ is to invite an explanation of reasonable belief. It is difficult to see how this might be given without reference to probability, hence without circularity. ‘Logical relation’ theories attempt to avoid arbitrari- ness by building evidence into the probability judgement. On this view a probability judgement concerns a logical relation between a statement and the evidence: ‘It will probably rain tomorrow’ is really in shorthand, the probability 759 . well- defined terms, and used the principle of *sufficient reason as a guide to these. Lacking the means of experimental verification, they tied their theories to the observable world by the concept of phusis. it will be. The last day looks like a bad choice for X. This tends to make the next -to- last day also look bad, and then the next -to- next, leading to a paradoxical argument ruling out the whole series. principle. The axiom was needed to obtain the classical theory of real numbers, which a predicative theory cannot do. For on the classical theory there are uncountably many real numbers, whereas the