difference between plagiarism and forgery is that a person plagiarizes when he tries to pass off another’s work as his own, but he forges when he tries to pass off his own work as another’s. Both are prima facie morally wrong, but the more difficult question is the aesthetic one: Is there any- thing prima facie aesthetically wrong with either (or both)? Some have argued for a Yes answer on the basis of the role that knowledge of authorship plays in aesthetic perception and discrimination, while others have argued for a No answer on the basis of the irrelevance of plagiar- ism and forgery to aesthetic judgements respecting such things as cheques and articles in reference works, such as this one. Now I wonder who the author of this article really is? m.w. There is very little philosophical literature on plagiarism, but Denis Dutton (ed.), The Forger’s Art: Forgery and the Philosophy of Art (Berkeley, Calif., 1983) contains a number of good papers on forgery. Planck, Max (1858–1947). German physicist who dis- covered the formula for black-body radiation. Taking his cue from Boltzmann’s statistical reformulation of the second law of thermodynamics, he found that radiant energy may be treated statistically as if it exchanged only in discrete amounts involving a new constant h, subse- quently known as Planck’s constant. This prepared the way for Einstein’s discovery that light could be treated as both wave and particle, the two aspects being related through Planck’s constant. This constant took on a uni- versal significance when physicists later extended the the- ory from light to matter generally, proposing that energy possessed by matter can be changed into radiant energy only in integral multiples of quanta. This set the founda- tion for *quantum mechanics, which inaugurated a revo- lutionary break with classical physics. Planck was awarded a Nobel Prize for his contribution to physics in 1918. The arrival of quantum mechanics gave rise to a variety of philosophical problems; it presented difficulties for *traditional logic, constituted a challenge to scientific *real- ism, and undermined deterministic views of the universe, with further repercussions in epistemology. o.r.j. *determinism; determinism, scientific. Thomas Kuhn, Black-Body Theory and the Quantum Discontinuity 1894–1912 (Oxford, 1978). Hilary Putnam, Mathematics, Matter and Method: Philosophical Papers, i (Cambridge, 1975). Plantinga, Alvin (1932– ). American philosopher known for the way in which he applies results of his work in other areas of analytic philosophy to traditional issues in phil- osophy of religion. In God and Other Minds (1967), he defended the view that belief in *other minds and belief in *God are, epistemically speaking, on a par: if the former is rational, so is the latter. In The Nature of Necessity (1974), he used contemporary modal logic and metaphysics to for- mulate a valid *ontological argument for the existence of God and a rigorous freewill defence of the logical consist- ency of the existence of God and the existence of *evil. In more recent work in epistemology, Plantinga has argued for the view that belief in God can, in certain circum- stances, be rational and warranted even if it is not based on propositional evidence. p.l.q. *philosophy of religion, problems of. A. Plantinga, Warrant and Proper Function (New York, 1993). J. E. Tomberlin and P. van Inwagen (eds.), Alvin Plantinga (Dor- drecht, 1985). Plato (c.428–347 bc). The best known and most widely studied of all the ancient Greek philosophers. He was an Athenian, born into a noble family, and might have been expected to play a part in the politics of that city. But in fact he came under the influence of Socrates, who fired him with an enthusiasm for philosophy. When Socrates was condemned to death and executed in 399, Plato gave up all thought of a political career, and left Athens in disgust. It is said that he then travelled to various places, including Egypt, but we have no trustworthy information on this part of his life, until we come to his first visit to Italy and Sicily in 387. From that visit he returned to Athens, and soon after founded his *Academy, just outside the city. This may be regarded as the first ‘university’. Apart from two further visits to Sicily, in 367 and 361, he remained at the Academy until his death in 347. It is often assumed that his first philosophical work was the Apology; this purports to be a record of the speeches that Socrates delivered at his trial. Apart from this one example, all Plato’s philosophical works are dialogues. They are standardly divided into three periods: early, mid- dle, and late. On the usual chronology, the early period includes Crito, Ion, Hippias minor, Euthyphro, Lysis, Laches, Charmides, Hippias major, Meno, Euthydemus, Protagoras, Gorgias. Many of these dialogues are short. They are listed here in order of length, from the Crito at 9 pages, to the Euthydemus at 36, the Protagoras at 53, and the Gorgias at 80. No one is confident of their order of composition. The usual chronology for the middle period includes Phaedo, Symposium, Republic, Phaedrus, in that order. The Republic is very long, and is divided into ten books. Some count the Cratylus as belonging to this period (placed after the Republic); some count it as an early dialogue. Finally, on the usual chronology for the late period, it begins with Parmenides and Theaetetus, and then (after a break) it contains Sophist,Statesman, Timaeus(and Critias),Philebus, Laws. Again there is one work which is very long, namely the Laws , which is divided into twelve books. The orthodox view is that this may be counted as Plato’s last work, though in fact the evidence for this claim is very insecure. Another important dispute concerns the date of the Timaeus, which some would classify as a middle dialogue (after the Republic). A great deal of work has been done, and is still being done, towards estab- lishing the order of the dialogues, but one cannot say that a consensus has been reached. (The above list simply omits all works whose authenticity may be considered doubtful.) 720 plagiarism I. The early dialogues are our only worthwhile source for the philosophy of Socrates. They illustrate his preoccupa- tion with ethics, and his insistence that it is vitally import- ant to find correct definitions for ethically significant concepts, since otherwise we will not know how to live. No doubt Plato himself shared these views at the time. But he shows a more independent attitude to the Socratic claim that virtue (*arete¯) is knowledge, and to its associ- ated paradoxes, e.g. that all wrongdoing must be due to ignorance (so that no one does wrong on purpose), and that all *virtues must somehow be the same (so that one cannot have one but lack another). The dialogues show Plato to be very interested in these claims, but he is not clearly endorsing them. On the contrary, he seems rather to be exploring them, and recognizing the problems they involve. He can achieve this neutral stance partly because he is writing dialogues, between Socrates and other speak- ers, and we need not suppose that Plato believes whatever he makes his character Socrates say; and partly because most of the dialogues are anyway inconclusive. They will begin by propounding some problem for discussion, and during the discussion several answers will be proposed, but all will be rejected, so that officially no conclusion is reached. (Often one is tempted to read between the lines, to find an answer that Plato is recommending, despite its official rejection; but even so one should suppose that he is recommending it for further consideration, not for accept- ance.) In these early dialogues, then, Plato is mainly con- cerned with Socrates’ philosophy, but he is trying out lines of thought, and objections to them, and he is not confident that he has found answers. In a few cases (notably the Meno and the Gorgias) one can see that his confidence is growing, and that he has something to say which he very much wants his audience to believe. But that is because the middle period is dawning. II. In the middle period Plato’s interests broaden very considerably, and we find the metaphysical and epistemo- logical doctrines for which he is best known. They now form the background against which he works out his new thoughts on how one ought to live, and on a number of other topics, ranging from the true role of *love (Sympo- sium, Phaedrus) to the structure of the physical world (Timaeus—assuming that to be a middle dialogue). There is space here only for a brief account of some of the better- known doctrines. Although Socrates remains the chief speaker of these dialogues (except for the Timaeus), still one can now be quite confident that the views put into his mouth are Plato’s own views, and often they owe very lit- tle to the historical Socrates. Knowledge and the Forms. Socrates had insisted that we must be able to answer the question ‘What is X?’ before we can say anything else about X. He understood this ques- tion as asking for the one thing common to all the many instances or examples of X, and he continued to stress its importance for ethical inquiry, even though he never found any answers that satisfied him. One may conjecture that this led Plato to ask why the search was yielding no results, and that he came to the conclusion that it was because even the supposed instances and examples of X were unreliable. At any rate, he certainly did come to hold that, in interesting cases such as *justice and goodness and *beauty, every instance of X will also be an instance of the opposite to X. But this provokes a problem, for instances and examples seem to be crucial for language-learning. That is, one could not come to understand the word ‘red’ if there were no examples of red things, nor if every example of something red were at the same time an example of something non-red. How, then, do we manage to attach any meaning at all to words such as ‘just’, ‘good’, and ‘beautiful’? This problem led Plato to suppose that there must be an unambiguous example of justice, not in this world but in some other, and that we must once have been acquainted with it. This is what he calls the ‘Form’ of justice. So his theory is that we are born into this world with a dim recollection of this Form, and that is why we do have some conception of what justice is, though it is only an imperfect conception, which explains why we cannot now answer the Socratic question ‘What is justice?’ This is the theory of Phaedo73–7. It significantly extends a line of thought introduced earlier in the Meno, which had noted that there is such a thing as *a priori knowledge (since mathematics is an example), and had offered to explain this as really recollection of what we had once known in an earlier existence. The Meno had hoped that philosophical inquiry could yield similar knowledge of justice and the like, obtained by examination of what was already latent within us, but had offered no ground for such a hope. The Phaedo provides a ground, at the same time adding a new conception of what it is that must be known (or recalled), namely a paradigm example of X, a reliable and unambiguous guide to what X is, which the perceptible things of this world ‘imitate’, but always ‘fall short of’. These are the Forms. Yet at the same time, and inconsistently, the Forms are thought of as themselves being the answers to the question ‘What is X?’, i.e. as being the one thing common to all the many instances of X , that in which they all ‘participate’. In other words, the Forms are both perfect paradigms and universals. This ambivalent conception is found in all the middle dialogues (including the Timaeus). The associated theory of recol- lection (*anamne¯sis) is not so constantly mentioned; in fact it is restated only once after the Phaedo, i.e. at Phaedrus 249. The Soul (psukhe¯ or psyche) and Morality. In the Apology Socrates had been portrayed as agnostic on the immortal- ity of the soul. In the Phaedo he is convinced of it, and the dialogue is as a whole a sustained argument for that claim. We find further arguments for the immortality of the soul in Republic x and in the Phaedrus, but in those dialogues there is also a more complex view of what the soul is. Whereas the Phaedo, like the early dialogues, had been content with a simple opposition between soul and body, in Republic iv the soul itself is divided into three ‘parts’, which roughly correspond to reason, emotion, Plato 721 and desire. (But in Republic viii–ix the ‘reasoning’ part is associated with the desire for knowledge, the so-called ‘spirited’ part with the desire for honour and prestige, and the ‘desiring’ part—itself recognized to be ‘many- headed’—is clearly confined to bodily desires.) An explicit motive for this division is to allow for conflict within the soul, and one consequence of this is that Plato is no longer tempted by the Socratic claim that all virtue is knowledge, and its associated paradoxes. He does retain the early view that virtue is a condition of the soul, but wisdom is now viewed as a virtue of the reasoning part, whereas courage is a virtue of the spirited part, and justice is explained as a suitable ‘harmony’ between all three parts. Another con- sequence of the threefold division of the soul is that Plato seems to have become uncertain how much of the soul is immortal. (Republic x. 611–12 is deliberately evasive; Phaedrus 245–9 clearly claims that the team of all three parts is immortal; Timaeus 69–72 is equally clear in its claim that only the reasoning part is immortal.) Plato thinks of the immortal soul as subject to reincarnation from one life to another. Those who live virtuous lives will be somehow rewarded, but the detail differs from one treatment to another. Political Theory. In the Republic Plato sets out his ‘ideal state’. It is very decidedly authoritarian. He begins from the premiss that only those who know what the good is are fit to rule, and he prescribes a long and rigorous period of intellectual training, which he thinks will yield this knowledge. In a famous analogy, it will loose the bonds that keep most men confined in a *cave underground, and allow us to ascend to the ‘real’ world outside, which is a world of Forms, available to the intellect but not to the senses. This is to be accomplished by a full study of math- ematics, which will turn one’s attention towards the Forms, since it is an a priori study and does not concern itself with what is perceptible; and after that a study in *‘dialectic’, i.e. in philosophical debate. Those who com- plete this training successfully, and so know what the good is, will form the ruling élite. From time to time they will be required to give up their intellectual delights and go back into the cave to govern it. They will govern with a view to maximizing the happiness of the state as a whole, but Plato thinks that the way to achieve this is to impose a strict censorship to prevent wrong ideas being expressed, to ensure that each person sticks to his own allotted job, so that he does not meddle with affairs that are not his con- cern, and so on. Plato was firmly against democracy, and seems to have seen no connection between happiness and individual liberty. III. The late dialogues open with two criticisms of the the- ories of the middle period, in the Parmenides and the Theaetetus. The Parmenides is concerned with meta- physics, and its first part raises a series of objections to the middle period’s theory of Forms. The most famous of these is the so-called *third man argument, which evi- dently exploits the fact that Forms are supposed to be both universals and perfect paradigms. Scholars differ in their view of how Plato himself reacted to these objections. Provided that the Timaeus is regarded as a middle dia- logue, one can hold that Plato saw that the objections depend upon Forms being both universals and paradigms, and thereupon ceased to think of them as paradigms. But if the Timaeus is later than the Parmenides, as stylometric studies appear to indicate, then one is forced to conclude that Plato made no such modification to his theory. The second part of the Parmenides is a riddle. It draws a bewil- dering array of contradictory conclusions, first from the hypothesis ‘The One is’ and then from its negation ‘The One is not’, and then it just ends without further com- ment. There have been many attempts to extract a serious moral that Plato may have intended, but none have won general approval. As the Parmenides attacks the metaphysics of the middle dialogues, so the Theaetetus attacks their epistemology, but again the attack has its puzzling features. The middle dialogues (and in particular the Timaeus) claim that per- ceptible things are not stable, and for that reason there can be no knowledge of them; rather, only Forms can be known. The first part of the Theaetetus, however, argues that it is self-refuting to ascribe such radical instability to perceptible things, and it proceeds to assume that we do know about them. But it nevertheless insists upon distin- guishing this knowledge from perception, on the ground that knowledge requires belief (or judgement) while mere perception does not. The second part of the dialogue then professes to be exploring the claims that knowledge is to be identified with true belief, or with true belief plus an ‘account’. But what is puzzling about this discussion is that it appears to focus not upon knowledge of facts (savoir) but upon knowledge of objects (connaître), and on the face of it the latter does not involve belief or judgement at all. Again, the solution to this puzzle is a matter of controversy. Although the late dialogues begin with two enigmatic and self-critical pieces, in which Plato’s own position is once more unclear, in subsequent writings he has evi- dently recovered the confidence of his middle period. In the Sophist he gives us a new metaphysics and a more sophisticated investigation of language, in the course of a long investigation of ‘not being’. This includes the import- ant point that even in the simplest sentences one may dis- tinguish two expressions, *subject and predicate, that have different roles to play. In the Statesman he reaffirms his view that ruling is a task for experts, and argues that the expert should not be bound either by law or by the wishes of the people. But it is admitted that law is a second best, where no expert is available. Of constitutions bound by law he considers that monarchy is best, oligarchy in the middle, and democracy worst. But in the absence of law this order is reversed. In the Philebus he once more weighs the claims of knowledge and of pleasure to be the good, and at the same time undertakes a full examination of what pleasure is. He does not award victory to either con- testant, arguing instead for the mixed life, but knowledge is ranked higher. 722 Plato In all three of these dialogues Plato pays much attention to what he calls the method of ‘collection and division’. At an earlier stage he had recommended the different method of ‘hypothesis’. This is introduced in the Meno, apparently as a device which allows us to make progress with philosophical problems without first having to answer the awkward question ‘What is X?’ Then in the Phaedo and the Republic it receives a much fuller expos- ition, and becomes Plato’s account of how a priori know- ledge is possible. This method makes its final appearance in the Parmenides, and one way of reading the second part of that dialogue is as a prolonged demonstration of its inad- equacy. Meanwhile, the new method of ‘collection and division’ has been introduced in the Phaedrus, and it is then both preached and practised at some length in the Sophist and the Statesman. It is presented as a method of finding definitions, though it is clear from what those dialogues say about it that it must be handled very carefully if it is not to lead us astray. The version in the Philebus introduces some new, and very puzzling, considerations concerning ‘the indefinite’. This appears to connect with what Aris- totle tells us about Plato’s so-called ‘unwritten doctrines’, but that topic is too obscure to be pursued here. Finally, in the Laws we find Plato again building an ideal state, but now in a very different mood from that of the Republic and the Statesman. He is now much more ready to compromise with principle in order to find something that will work in practice, and he puts a very high value on the law. In fact the work is remarkable for proposing a great deal of extremely detailed legislation. But Plato’s general attitude remains very authoritarian, and he still pays no attention to individual *liberty. It is justly said that the ‘Nocturnal Council’, which turns out to be the supreme authority in this state, would certainly not have tolerated the subversive ideas of Socrates, from which Plato began. d.b. *Platonism; Good, Form of the; knowledge; psyche. greek text Platonis Opera, ed. J. Burnet (5 vols., Oxford Classical Texts 1900–7). translation E. Hamilton and H. Cairns (eds.), The Collected Dialogues of Plato (New York, 1961). commentary I. M. Crombie, An Examination of Plato’s Doctrines, 2 vols. (Lon- don, 1962–3). G. M. A. Grube, Plato’s Thought, 2nd edn. (London, 1980). T. Irwin, Plato’s Moral Theory (Oxford, 1977). R. Krant (ed.), The Cambridge Companion to Plato (Cambridge, 1993). R. Robinson, Plato’s Earlier Dialectic, 2nd edn. (Oxford, 1953). W. D. Ross, Plato’s Theory of Ideas (Oxford, 1951). N. P. White, Plato on Knowledge and Reality (Indianapolis, 1976). Platonism. ‘Platonism’ refers to (1) the doctrines held by Plato; (2) some central doctrine of Plato, especially the the- ory of Forms, or Ideas, or a doctrine relevantly similar to it, such as the view (contrasting with ‘constructivism’) that logical and/or mathematical entities subsist independently both of the empirical world and of human thought (Frege); (3) the tradition of thinkers claiming allegiance to Plato, whether or not their doctrines were in fact held by him. Plato’s literary career spanned fifty years, and, apart from some letters of doubtful authenticity, he wrote only dialogues in which he himself never appears, but is, at best, represented by a leading participant, usually, but not invariably, Socrates. The dialogues are commonly placed in three groups: (1) The early dialogues consider a ques- tion such as how we are to define virtue or whether it is teachable, and examine various answers to it, but do not usually endorse a positive conclusion; these dialogues and their characteristic procedures are commonly known as ‘Socratic’ rather than ‘Platonic’. (2) The middle dialogues, such as the Republic, expound metaphysical, political, and psychological doctrines. It is these doctrines which are most usually associated with Plato and known as ‘Pla- tonic’. (3) The late dialogues, such as the Sophist, reassess and modify the doctrines of the middle period. Even within each of the two latter periods, dialogues dif- fer significantly in method and doctrine. Thus it is not easy to extract from Plato’s works a single consistent set of doc- trines. (The Neoplatonist Olympiodorus reports that Plato dreamt that he had become a swan which flew from tree to tree, eluding the arrows of its hunters. This means that Plato eludes his interpreters, and his works must be ‘under- stood in many senses, both physically, and ethically, and theologically, and literally’.) But it is tempting to suppose that Plato had a coherent view on the questions asked and the doctrines expounded by his characters, or at least more tempting than it is to suppose that Shakespeare had a coherent doctrine that can be extracted from the utter- ances of his characters. Many interpreters have attempted to elicit a system from Plato, among them Hegel, who, regarding (unlike Schleiermacher) the dialogue form as inessential, attributed to him a tripartite system consisting of *dialectics, philosophy of nature, and philosophy of spirit. Most ‘Platonists’ have seen themselves as such by reason of their adherence to supposedly Platonic doctrines rather than to Plato’s methods or his dialogue form. But different thinkers stress different aspects of his legacy. Platonism as a tradition falls into six broad periods: (1) the Old Academy; (2) the Hellenistic (‘Middle’ and ‘New’) Academy; (3) ancient *Neo-platonism; (4) medieval Pla- tonism; (5) the Renaissance; (6) the modern period. 1. After Plato’s death, his nephew Speusippus (405–335 bc) became head of the *Academy, and he was succeeded in 339 by Xenocrates (396–314 bc). (The reason why Plato’s most distinguished pupil, Aristotle, did not suc- ceed him is probably that, as a non-citizen, he was unable to own property in Athens, rather than, as Anscombe sug- gests, his heterosexuality.) They continued to work, in the manner of Plato’s later work, on metaphysics, logic, and mathematics. 2. Under its sixth head, Arcesilaus, the Academy espoused *scepticism and deployed it especially against Platonism 723 Stoicism. Carneades continued and extended this approach. Academic scepticism stressed its continuity with the early aporetic dialogues, and persisted for two centuries. Augustine’s Contra Academicos (ad 386) is directed against the scepticism that he knew from Cicero’s Academica, but he attempted to reconcile this with the Neoplatonism he had learned from Plotinus by arguing that the Academy had a secret doctrine which they did not reveal to outsiders. Under Antiochus of Ascalon (c.130–68 bc) the Academy abandoned scepticism and adopted a synthesis of Platonism, *Stoicism, and *Aristotelianism. 3. Antiochus prepared the ground for so-called ‘Middle Platonism’, represented by, among others, the anti- Christian Celsus (late second century ad). In the second century Numenius of Apamea attempted to purge Platon- ism of later accretions and regarded the result as identical to *Pythagoreanism. But the greatest Middle Platonists were in Alexandria: Philo (c.25 bc–ad 50), who combined Platonism with Judaism, Clement (c.ad 150–215) and, later, Origen (185–254), who, like Plotinus, was a pupil of Ammonius Saccas (c.175–242), generally regarded as the founder of Neoplatonism. (The distinction between Mid- dle Platonism and Neoplatonism is not, however, sharp: from the first century bc Platonism was transformed into a metaphysical or theological system, involving, for example, ideas as thoughts in God’s mind, the ideal of assimilation to God, and demonic intermediaries between men and God; the aporetic element in Plato was ignored.) The Alexandrians became Christian, and were less inclined to theurgy than the pagan Athenians. Plotinus, the greatest of the Neoplatonists, was not a member of the Academy, nor was his follower Porphyry (c.232–304), the author of an introduction (Isagoge) to Aristotle’s Categories, which in Boethius’ Latin translation, became a standard medieval work, nor Iamblichus (d. c.330). Iamblichus was responsi- ble for many of the concepts, especially the triads, that appear in Proclus. The Academy was closed by Justinian in ad 529 (whereas the Alexandrian school survived the Arab conquest of 641), but through the works of Augustine (Plotinus) and pseudo-Dionysius the Areopagite (Proclus) Neoplatonism entered medieval Christianity. 4. Platonism persisted in the three main spheres of the medieval world: Islam, Byzantium, and the Latin West. Its impact on the Arabs, with their predominantly scientific interests, was less than that of Aristotle. But al-Fa¯ra¯bı¯ was influenced not only by the ideal state of Plato’s Republic, but also by the entirely apolitical Plotinus. His follower Avicenna developed Neoplatonism further. In Byzan- tium, Plato’s dialogues continued to be read, and the revival of Platonism by Michael Psellos (1018–78/96) pre- pared the way for the later champions of Plato against Aristotle, Basilius Bessarion (1403–72) and Georgios Gemistos Pletho (c.1355–1450). They propagated Platon- ism in Italy, and Pletho inspired Cosimo dei Medici to found a new Platonic Academy in Florence in 1459. It was headed by Marsilio Ficino (1433–99) and attracted Greek refugees from Constantinople, who brought with them hitherto unknown Platonic texts. It lasted until 1521. In the West, the philosophical works originally available were Platonic: Plato’s Timaeus, Boethius, Apuleius (the author of works on Socrates and Plato, as well as of The Golden Ass), and Augustine. Later John Scotus Eriugena (c.810–77) translated Dionysius. (That The Divine Names etc. were not the work of the Athenian converted by St Paul was suspected by Lorenzo Valla (1405–57) and finally established by Erasmus. Earlier it was widely believed that Platonists such as Proclus had stolen his ideas.) But by the thirteenth century, despite more trans- lations of Plato and Proclus, Aristotle eclipsed Platonism. 5. In the Renaissance, Plato became a focus of rebellion against scholasticism, and the need was felt for direct acquaintance with his texts. Eventually, though not imme- diately, this tended to undermine the so-far-unquestioned Neoplatonic interpretation of Plato. Petrarch (1304–74), though he had ‘no Greek’, championed Plato, ‘the prince of philosophy’, against Aristotle. Ficino translated Plato, Plotinus, and Hermes Trismegistus (the supposed author of a body of early post-Christian writings, which Ficino believed to be the work of an ancient Egyptian priest and one of the sources of Platonism). He produced a sustained defence of Plato’s doctrine of the immortality of the soul, and regarded him as a forerunner of Christianity, in a tradition of ‘pious philosophy’ extending from Zoroaster to Nicholas of Cusa. Pico della Mirandola was also influenced by, among others, Plato, and was associated with Ficino’s Academy. Platonism migrated to England through Erasmus, Thomas More (1478–1535), and others, giving rise to the *Cambridge Platonists, who, as Coleridge observed, could as well be called the ‘Cam- bridge Plotinists’, since they revered Plotinus and did not doubt his interpretation of Plato. 6. In Ficino’s day the only rival to the Neoplatonist interpretation of Plato was the persistent, if sometimes muted, tradition that Plato was a New Academic sceptic. This view, backed by the authority of Cicero, revived in the late fifteenth century: among its adherents were the Lutheran reformer Philip Melanchthon (1497–1560) and the French sceptic Michel de Montaigne (1533–92). But a third view now began to form, namely that Plato had a positive doctrine, distinct from Neoplatonism, and that this could be discerned from his original texts. This view appealed to Protestants, who deplored the Neoplatonic influence on Christianity but often found Plato himself more tolerable. One of its pioneers was Jean de Serres (Ioannes Serranus) (1540–98), a Calvinist Huguenot, who contributed a Latin translation and an introduction to Henricus Stephanus’ famous 1578 edition of Plato. Its most distinguished adherent was Leibniz, who on several occasions bemoaned the tendency to read not Plato but his commentators: we can recover such valuable doc- trines as the theory of Ideas and recollection only if we remove the Neoplatonic covering. This view was con- firmed by the history of philosophy, which emerged, especially in Germany, as a distinct discipline, alongside theology and philosophy itself: Jakob Brucker (1696–1770), Dietrich Tiedemann (1748–1803), Wilhelm 724 Platonism Tennemann (1761–1819), and Hegel, whatever the faults of their own attempts to reconstruct Plato’s doctrines, finally demolished the Neoplatonic interpretation. (Like Friedrich Schleiermacher (1768–1834), Hegel dismisses Tennemann’s view—which still finds supporters—that Plato had an *‘esoteric’ system which he did not commit to writing.) The discovery of the ‘real’ Plato also put an end to Platonism as a distinct and credible large-scale doc- trine, partly because the dialogues cannot be plausibly read as advocating a definitive creed, and partly because they are usually interpreted as presenting a primitive ver- sion of some more developed modern philosophy, such as Kantianism (Tennemann) or Hegelianism (Hegel), which the interpreter believes in preference to Plato himself. However, Plato provides an ingredient, often an essen- tial ingredient, in much of subsequent Western philoso- phy. Galileo, for example, was a Platonist, not in the sense that he endorsed the mathematical theories of the Timaeus, but because he distinguished between the appearances of nature and its true mathematical struc- ture, the latter being the object of true knowledge. Quasi- Platonic ideas play an important role in Kant and Schelling. In Schopenhauer ideas are what art, apart from music, portrays, and (contrary to Plato’s own intentions) Plato has often been of service both to artists and to philosophers of art. Moreover, even in modern times Plato is often seen as containing in embryo the whole of Western philosophy; thus any serious philosopher must come to terms with him, whether as an ally or as an oppon- ent. J. F. Ferrier (1808–64) claimed that ‘all philosophic truth is Plato rightly divined; all philosophic error is Plato misunderstood’, and Whitehead saw later philosophy as a series of *footnotes to Plato. Nietzsche regarded Plato in this light (e.g. ‘Christianity is Platonism for the people’), but since he rejected Plato’s claim to a non-perspectival insight into true being, he saw his own thought as ‘inverted Platonism’. For Heidegger, Plato initiated the decline of truth from ‘unhiddenness’ to ‘correctness’, and thus gave rise to the metaphysics and humanism that afflicted all later philosophy, including Nietzsche’s. He also lectured, in 1924–5, on Plato’s Sophist, in preparation for his revival of the ‘question of *being’. Jaspers inter- preted Plato in terms of his own thought, and saw him as the ‘representative of philosophy in general’, an open- ended thinker more concerned with philosophizing as a way of life than with the advocacy of specific doctrines. (Sartre’s Being and Nothingness, by contrast, refers only fleetingly to Plato’s Sophist; but his early story Er the Armenian was inspired by the Myth of Er in the Republic.) While Platonism as a full-scale doctrine is no longer a live option, modern philosophers, including analytical philosophers such as Ryle, have often developed their own ideas, and their powers of argumentation and inter- pretation, in interaction with Plato. m.j.i. M. J. B. Allen, The Platonism of Marsilio Ficino (Berkeley, Calif., 1984). V. Goldschmidt, Platonisme et pensée contemporaine (Paris, 1970). E. N. Tigerstedt, The Decline and Fall of the Neoplatonic Inter- pretation of Plato: An Outline and Some Observations (Helsinki, 1974). J L. Vieillard-Baron, Platon et l’idéalisme allemand (1770– 1830) (Paris, 1979). C. M. Woodhouse, Gemistos Plethon: The Last of the Hellenes (Oxford, 1986). Platonism, Neo-: see Neoplatonism. plausibility. A weaker counterpart to *truth. It turns on a claim’s credibility via the acceptance-justifying backing that a duly weighty source (human, instrumental, or methodological) can provide. Thus if we think of informa- tive sources as being graded by reliability, then the plausi- bility of a contention is determined by the best authority that speaks for it. A proposition’s plausibility accordingly depends on its probative status rather than on its specific content in relation to alternatives. In this regard it differs crucially from *probability. The plausibility status of a group of conjoined propositions (unlike its probability sta- tus) is that of the least plausible of its members: plausibility is a chain that is as exactly strong as its weakest link. n.r. George Polya, Patterns of Plausible Inference (Princeton, NJ, 1954). Nicholas Rescher, Plausible Reasoning (Amsterdam, 1976). pleasure. Philosophers have discussed the nature of pleas- ure from an interest either in *hedonism, or in *philoso- phy of mind. The former was the main interest up to the mid-twentieth century. Ancient Greece. A popular early view was to see pleasure as the replenishment of a natural lack; for instance, quench- ing thirst. This was modified by adding that the replenish- ment must be noticed. It was then realized that some pleasures involved no replenishment, as those of anticipa- tion, or enjoying the exercise of abilities. Aristotle came to see pleasure as the perfect actualization of a sentient being’s natural capacities, operating on their proper objects. This, however, is the account of ‘real’ pleasure, and other pleasures are approximations to this on the part of beings not in perfect condition. With humans, Aristotle holds that those who enjoy something are aware of that fact. This makes it natural to suppose that those who experi- ence pleasure believe that they are actualizing in good condition—correctly in the case of those who are, falsely in other cases. The Stoics, taking familiar pleasures as their model, thought of pleasure as such a belief, and as false. Later. These views set the parameters for later discussions up to the time of Descartes. The latter’s sceptical argu- ments led the Empiricists in particular to concentrate on the inner data of the mind as what we really know. Since it seems that subjects know what they enjoy, it seemed nat- ural to class pleasure as one of the inner givens of the mind. To English-speakers this seemed the more natural because pleasure would be classified as a feeling. Pleasure now becomes the experience of a feeling from some source or other. Then either all these feelings feel alike, or pleasure 725 they share some hedonic tone, or they have the character- istic of being wanted for their own sake, or preferred. Early to Modern. In the early period there is no sharp dis- tinction made between an interest in the concept of pleas- ure and in what it is that occurs when pleasure occurs. The latter, however, seems to predominate. By the time of Hume matters are muddier. In the twentieth century, interest shifted to philosophy of mind, to whether attribu- tions of pleasure are attributions of publicly accessible facts or of inner events. Given that the attributions are in a public language, philosophers have turned to consider the meanings of various pleasure-expressions, with the assumption that criteria for their application will be pub- licly accessible. Attributing pleasure has been variously thought to be attributing a manner of indulging or a rela- tion of the indulgence to a subject’s desire or preference. The discussion has been complicated by distinctions between enjoyment and pleasure, and the variety of pleas- ure-expressions. There are methodological problems: how do we determine that the expressions cover the same concept? or that different uses of the same expressions are genuine examples of the concept? None of the above questions have won agreed answers, but the answers clearly affect one’s attitude to hedonism. Different answers on the nature of pleasure give hedon- ism a different air; different selections of pleasure- expression give arguments for different forms of hedon- ism. None of them work. j.c.b.g. *pain; pushpin and poetry; happiness; well-being. Roger Crisp, Mill on Utilitarianism (London, 1997). Fred Feldman, Pleasure and the Good Life (Oxford, 2004). J. C. B. Gosling, Pleasure and Desire (Oxford, 1969). —— and C. C. W. Taylor, The Greeks on Pleasure (Oxford, 1982). Gilbert Ryle, The Concept of Mind (London, 1949). John Skorupski, John Stuart Mill (London, 1989). Plekhanov, Georgii Valentinovich (1856–1918). The leading Russian Marxist theoretician in the two decades before 1914, Plekhanov is chiefly known as the teacher of Lenin and the first to have given serious formulation to the doctrine of *dialectical materialism. In his major work The Development of the Monist View of History, he gave an account of modern social and philosophical thought as culminating in Hegel and Marx and seen through the materialism of Feuerbach, for whom Plekhanov had a high regard. He consistently applied this dialectical materialist method to all branches of human knowledge, thus helping to create the subsequent philosophical orthodoxy of the Soviet Union. d.m cl. S. Baron, Plekhanov: The Father of Russian Marxism (London, 1963). plenitude, principle of. ‘If a proposition P is possible then at some time P is true.’ The principle, accepted by Aristotle, clashes with a common intuition that the non-realization of a *possibility does not imply that the possibility did not exist. The question how to interpret Aristotle’s principle in such a way that it squares with the common intuition has proved a fertile debating-ground. a.bro. Arthur O. Lovejoy, The Great Chain of Being (Cambridge, Mass., 1936). Plotinus (204/5–270). Platonist philosopher, initiator of what we call *Neoplatonism. We do not know his origins. He studied for over eleven years at Alexandria. Then he joined a Roman military expedition to the East, in order to learn from Persian and Indian philosophers (so says his editor and biographer Porphyry). But the expedition was aborted, and he came to Rome, aged 40. There he earned court patronage and spent the rest of his life teaching. From the age of 50 he wrote in Greek a series of essays and shorter articles, chatty in style but at the same time diffi- cult and earnest, and enriched with superb similes. After his death Porphyry chopped them up and gathered them into six groups of nine, the Enneads. Plotinus was a contemplative, who sought contact with a supreme principle, the Good, or One. He tells us that he often achieved momentary success. Religious rites were useless for the purpose; what was needed was an ascent of the soul, away from bodily things. It demanded personal goodness—and Plotinus appears to have been conscien- tious and competent in his help and advice to friends, though he deprecated involvement in public affairs. It also demanded hard philosophical inquiry. His teaching defended the metaphysics that made this ascent desirable, and to the defence he brought a good scholar’s knowledge of the state of his subject and also a good teacher’s willingness to share and examine his pupils’ difficulties on a footing of equality. Even his defer- ence to Plato, whom he used only selectively but revered as faultless, does not really imprison Plotinus’ thought, though it sometimes strains the ingenuity of his interpret- ations. He takes no notice of Christianity. The essence of his metaphysics is: It is only possible to make things by thinking them, and to think things as a maker by being them. (It is backwards to regard thinking as imagining; it is realizing what the manufacturer then makes an image of.) Bodies are phantoms (*‘idols’), pre- sent in matter as an image is in a mirror, and the realities behind them are Forms. But even a thinker will produce only an idol unless the Forms he thinks are in him, and thus collectively are him. Original thought, which does not reason from previous thoughts, Plotinus calls Intel- lect. So Intellect is a maker. But there is no process in its making, only the timeless activity of thinking the intelligi- ble Forms that it is. Everything that has power must exercise it, by what he calls emanating (or ‘beaming’) something less powerful. Such ‘procession’ (as it is also called) accounts for the exist- ence of the perceptible ‘here’ (our world), beamed from the intelligible ‘there’. ‘Here’ contains *souls as well as bodies, because many bodies—including the perceptible universe itself—are alive (i.e. ensouled), and their souls have spontaneously descended from, and can return to, ‘there’. Human souls have parts, and the highest part is 726 pleasure still linked with Intellect ‘there’. We humans choose which part our souls shall ‘incline’ to, and thereby we gain different future lives as plants or animals or demons (in no bad sense) or gods. These future lives will reward and pun- ish us, so keeping the moral balance in our necessarily imperfect but providentially ordered ‘here’. Soul is the lowest of Plotinus’ three universal principles, or ‘hypostases’. It depends on Intellect, which in turn depends on the One, or Good. The One himself is ‘beyond being’, because attribution of being or any other predicate would make him more than One. The other hypostases are multiple (for example, the thoughts that Intellect is are composite), and therefore could not exist independently of this Unity. Desire to touch him is the pang of being smitten by ‘beauty above beauty’. c.a.k. A. H. Armstrong (ed.), The Cambridge History of Later Greek and Early Medieval Philosophy (Cambridge, 1967), chs. 12–16. L. Gerson (ed.), The Cambridge Companion to Plotinus (Cambridge, 1996). D. J. O’Meara, Plotinus (Oxford, 1993). J. M. Rist, Plotinus: The Road to Reality (Cambridge, 1967). pluralism: see monism and pluralism. pluralism, political. A condition marked by the multipli- city of religions, ethnic groups, auto-nomous regions, or functional units within a single state; or a doctrine that holds such a multiplicity to be a good thing. The alterna- tive is a unitary state where one religion or ethnicity is dominant and the central government rules everywhere. Pluralism can be an adaptation to an existing and unavoid- able multiplicity for the sake of peace (*toleration) or it can be a programme aimed at sustaining cultural differ- ence, conceived as a good in itself or as the legitimate product of communal *self-determination. A considerable variety of institutional arrangements are consistent with pluralism in either of these senses, including decentralized government (federalism), functional autonomy (particu- larly with regard to education and family law), and volun- tary association. The hard questions posed by political pluralism mostly have to do with its limits. It isn’t only a multiplication of groups but also of loyalties that pluralism legitimizes. And in the case of individual men and women, multiplication is also division. Attachment and obligation are both divided: what then is the individual to do when their various versions come into conflict? At what point is division incompatible with a common citizenship? States commit- ted to pluralism will set this point fairly far along the con- tinuum that extends from unity to disintegration. None the less, they are likely to defend some significant com- monalities: a single public language or a civic education for all children or a ‘civil religion’ with its own holidays and ceremonies. Political pluralism also refers to the existence of legal opposition parties or competing interest groups in a unitary state, where what is pluralized is not culture or religion but political opinions and conceptions of material interest. The ruling group, whatever its character, con- cedes that its ideas about how to govern are not the only legitimate ideas and that its understanding of the common good must incorporate some subset of more particular understandings. m.walz. *liberalism. Arthur Bentley, The Process of Government (Chicago, 1908). W. Kymlicka (ed.), The Rights of Minority Cultures (Oxford, 1995). Arend Lijphart, Democracy in Plural Societies (New Haven, Conn., 1977). D. Miller and M. Walzer (eds.), Pluralism, Justice, and Equality (Oxford, 1995). David Nichols, The Pluralist State (New York, 1975). plurality of causes. A term sometimes used where more than one cause is required for a particular effect, e.g. igni- tion plus oxygen for an explosion, or (more frequently) where alternative causes can produce the same (type of) effect, e.g. poisoning or decapitation cause death. Arguably, such cases are only apparent, and further analy- sis would indicate the ‘true’ causal relationship, which is claimed to be always one–one. The latter view—not required by counterfactual analyses of *causality—encour- ages, for example, monetarism in economics. a.j.l. J. L. Mackie, The Cement of the Universe (Oxford, 1974). pneuma. Breath, sometimes equated by the Greeks with air, the breath of the cosmos. Aristotle thought that heat in the pneuma enables the transmission of sensitive soul to the embryo, and that it is located near the heart in the mature organism, serving to mediate movement and per- ception. The Stoics thought of it as a fine, subtle body forming the *soul of the cosmos, and explaining growth, behaviour, and rationality. Descartes used the Latin equivalent, spiritus, from which come ‘spirit’ and ‘sprite’ in English. o.r.j. *psyche. Martha Craven Nussbaum, Aristotle’s De Motu Animalium (Princeton, NJ, 1978). poetry. No satisfactory single-concept theory of poetry has been produced: a poem is not essentially a representa- tion, or essentially expression, or essentially a formal or ‘organic’ unity. Not because none of these functions is relevant to poetry, but because no one of them does justice to its complexity and many-levelled nature. Poetry can indeed represent or describe: but it may also celebrate, praise, mourn, present alternative worlds. It certainly expresses, but it can also transform, the emo- tions of ordinary life, and display emotions with more than usual precision, not least because of the discipline and constraints of poetic form. Distinctive of poetry at its best is an ‘all-in’, maximally dense, simultaneous deployment of linguistic resources— sound and rhythm as well as sense, the bringing-together of numerous strands of meaning, through metaphor and other figures, through ambiguities (often unresolved), poetry 727 controlled associations and resonances, allusions: all of these contributing to a well-integrated, unified effect. The reference a poem makes to the world is often given a heightened, pregnant character through symbolical or allegorical or mythical language—in some cases the per- sonal mythology of the poet. (William Blake and W. B. Yeats are notable examples.) Given the total dependence of the poem’s meaning and effect on the precise words in their order, any attempt at paraphrase must become ‘heresy’. A poem is not a dispos- able wrapping for a detachable and re-expressible message. Now, this emphasis on the thinglike integrity of a poem makes for suggestive analogies between poems and non- linguistic artefacts (a vase, sculpture, or melody): hence a claim like ‘A poem should not mean but be’ (MacLeish). But this exaggerates: meaning is indispensable—as is ref- erence to the world beyond the poem—if poetry is not to be impoverished: and, in any case, the sound of words can hardly work in sustained disregard of their sense. The subject-matter of poetry is limitlessly varied. Often enough a poem presents some vividly imagined concrete particular, a momentary, fugitive sensory impression or a recollected emotion, but also—and no less legitimately— its concern may be with abstract ideas and relationships, or with a wide-ranging religious or metaphysical perspec- tive. Crucial here is the absence of any hierarchy of poetic subject-matter: ‘ontological parity’, in Justus Buchler’s phrase: ‘All appearances are realities for the poet.’ The relevance to philosophy of the study of the lan- guage of poetry is already obvious enough. But there is more to note. Poetry is forever fighting against the pres- sures and seductive power of ordinary language to falsify experience in easy, slack cliché. Poetry feels itself often up against the ‘limits of language’, and forced to modify, maybe do violence to, normal syntax. Theory of know- ledge and philosophy of religion cannot ignore poets’ claims to ‘timeless (visionary) moments’—‘epiphanies’. That is easy to say: but to distinguish veridical from illu- sory in this area is notoriously hard. r.w.h. *expression; music; representation. Justus Buchler, The Main of Light (New York, 1974). Poincaré, Jules Henri (1854–1912). A leading contributor to the brilliant French tradition of applied mathematics and physics, Poincaré also wrote extensively on *method- ology and the philosophy of science, in which he is usually classified as a conventionalist. He regarded scientific struc- tures as containing conventional elements which either are principles held to be true by definition or are selected from competing alternatives on pragmatic grounds of *simplicity and convenience. But science must also be empirically adequate, and so Poincaré could also be called a metaphysical realist, since science is based on a belief in the unity and simplicity of nature, and it is the (endless) task of science to discover the most general order. But like Duhem, Poincaré distinguished sharply between scien- tific and metaphysical claims. Although never fully developed, Poincaré’s ideas were influential on scientists like Einstein and on later positivist and pragmatist philoso- phers of science. a.bel. *conventionalism; pragmatism; Duhem. Peter Alexander, ‘The Philosophy of Science 1850–1910’, in D. J. O’Connor (ed.), A Critical History of Western Philosophy (New York, 1964). polar concepts. When a pair of *concepts opposite in meaning is such that neither of the pair can be understood unless the other is understood also, as with ‘genuine– counterfeit’, ‘straight–crooked’, ‘up–down’, they are said to form a ‘conceptual polarity’. Ryle used the notion in an attempt to refute scepticism by arguing that if, as the scep- tic’s argument requires, we understand the concept of error, we must also understand that of being right; which Ryle thought proved that we must sometimes be so. Ryle misses the sceptical point, however. The sceptic can grant that we might have to understand the concep- tual polarity ‘error–correctness’ in order to understand the concept of error, but simply demands how we know on any given occasion that we are not in error. And the sceptic need not even grant so much: he can point to apparent polarities which are such that one of the poles has no clear application, as in ‘mortal–immortal’, ‘per- fect–imperfect’, ‘finite–infinite’, where we can only be said properly to understand one of the poles, the other being merely its indefinite negation, possessed of no unequivocal sense or use. a.c.g. *scepticism. Gilbert Ryle, Dilemmas (Cambridge, 1954), 94 ff. Polish notation. Logical symbolism devised by Łukasiewicz. Propositional constants represented by cap- ital letters: Kpq is ‘p and q’, Apq is ‘p or q’, Cpq is ‘If p, q’, and so on. Similar devices are used for quantifiers and modal- ities. Because *constants are written before their *argu- ments, the ambiguity of expressions like ‘p and q or r’ is removed without using brackets: ‘(p and q) or r’ is AKpqr, while ‘p and (q or r)’ is KpAqr. c.w. A. N. Prior, Formal Logic, 2nd edn. (Oxford, 1962). Polish philosophy. Political philosophy, especially con- cerning nationhood, and formal logic—these have been two areas of distinction for Polish philosophy. Although philosophy in Poland goes back to the thirteenth century and Witelo, famous for his works on optics and the meta- physics of light, its real academic life began at the Univer- sity of Cracow (established in 1364) in the fifteenth century. Subsequently all the controversies of medieval philosophy were addressed in Poland. Jan of Głogów, Michał of Wrocław, Jan of Stobnica, and Benedykt Hesse were among the most important Polish schoolmen. Con- ciliarism became a dominant position among writers working on political matters. Paweł Włodkowic (Paulus Wladimirus) was perhaps the most famous Polish thinker of that time. He developed the concept of just war, which 728 poetry influenced the development of international law. Accord- ing to Paweł, it is prohibited by natural law to convert pagans to Christianity by war. During the *Renaissance (the golden period of Polish culture), Copernicus was the nation’s most remarkable thinker. Although he was not particularly interested in typical philosophical questions, his astronomical work had obvious philosophical sources. His mathematical approach to astronomy had its roots in Padua in Italy, where he studied and became influenced by Platonism. He combined this view with the Aristotelian empiricism of his Cracow teachers. A famous controversy as to whether he was an instrumentalist or realist in his approach to heliocentric astronomy influenced many sub- sequent scientific discussions. The Polish Renaissance was also a period of intensive development in political and social philosophy. Andrzej Frycz-Modrzewski wrote a treatise De republica emendanda (1551) in which he pro- posed a deep programme of reforms of the state, church, and society. Similarly, as in Western European countries, the Renaissance brought a revival of *Stoicism in Poland (Dialectica Ciceronis by Adam Burski is a particularly valu- able work in this tradition). The Reformation brought into being another import- ant stream of philosophical thought, namely Socinian- ism, a movement established by Faustus Socius, who came to Poland (then the most tolerant country in Europe) from Italy, and developed by the Polish Brethren. Joachim Stegmann, Samuel Przypkowski, and Andrzej Wiszowaty contributed to Socinian philosophy: they focused on ethics and social philosophy, basing their doc- trines on the ideals of non-violence, justice, and tolerance. The Counter-Reformation policy forced the Socinians to emigrate from Poland. They moved to the Netherlands and England, and influenced several great European philosophers, including Grotius and Locke. The early post-Renaissance period in Poland was marked by the return of *Aristotelianism with Sebastian Petrycy of Pilzno, the first translator of Aristotle into Polish. The period of 1650–1750 witnessed a deep political and cultural crisis in Poland. The *Enlightenment brought a major change. It happened in close connection with attempts to save Polish independence, which was imperilled by Russia, Prussia, and Austria. Stanis¢aw Staszic and Hugo Ko¢¢åtaj were the most important polit- ical thinkers in Poland in the eighteenth century. Their ideas considerably influenced the content of the 3 May Con- stitution (1791), the second constitution in nation’s history. A type of *positivism (Jan S ´ niadecki) was the most popular philosophy of the Polish Enlightenment, but *Kantianism and *Scottish philosophy were also fairly influential. Poland finally lost its independence in 1795. Subse- quent philosophy was largely a response to the national tragedy, deepened by the defeat of the national uprising in 1830–1. The philosophy of this period (approximately until 1863) is called the Polish national philosophy. This philosophy was related to *Romanticism and to German *idealism. Polish Messianism, which originated with Józef Hoene-Wron´ski (also a famous mathematician) and was represented by great Polish national poets (notably Adam Mickiwicz and Juliusz Słowacki), attributed to Poland a special historical role as the Christ of nations and promised a new era. Józef Gołuchowski, Józef Kremer, Karol Libelt, Bronisław Trentowski, and August Cieszkowski (he invented the term ‘Historiosophie’) developed other kinds of the Polish national thought, more akin to academic philosophy. The defeat of the national uprising (1863–4) led to a strong criticism of the national philosophy in Poland. It was accused of unrealis- tic and irresponsible political claims, harmful to nation and individuals. The group of Warsaw positivists, influ- enced by the ideas of *Comte, *Mill, and *Spencer, demanded that Polish thought be sober and strongly rooted in reality. Polish positivism recommended a pro- gramme of foundational work in all domains important for society. Philosophical life in Poland intensified at the turn of nineteenth century, and this continued in independent Poland after 1918. Kazimierz Twardowski, a student of Brentano, established an analytic movement at the Uni- versity of Lvov, and between 1918 and 1939 the Lvov group grew into the Lvov–Warsaw School, in which the main figures were Jan ·ukasiewicz, Stanis¢aw Les´niewski, and *Alfred Tarski. Polish mathematical logic developed partly as a result of Twardowski’s programme of *analytic philosophy, partly out of the interests of Polish math- ematicians in set theory and topology. Its innovations included many-valued logic, general metamathematics, the *semantic definition of truth, Les´niewski’s systems, and Chwistek’s systems. The Lvov–Warsaw School had affinities with the *Vienna Circle, but eschewed its anti-metaphysical radicalism and was more sympa- thetic toward the philosophical tradition. *Kazimierz Ajdukiewicz and *Tadeusz Kotarbin´ski were other distin- guished exponents of Polish analytic philosophy. *Phe- nomenology flourished in Poland—it was *Roman Ingarden who introduced Husserl’s ideas and developed a realistic version of phenomenology. Neo-Thomism was also influential. Afyer 1945 Poland became part of the Communist bloc. While Marxism was dominant, other currents persisted in Polish philosophical life, and this phenomenon, unique in Eastern Europe, contributed to the anti-Communist revolt in 1989. At present, analytic philosophy, phenom- enology, and Catholic philosophy are the main features of the philosophical map. But pluralism, respect for logic, and sensitivity to the essential problems of national life remain characteristic of Polish philosophy. In spite of honouring idealistic Messianism as the glorious past, most Polish philosophers are inclined to realistic and anti- speculative thinking. j.wol. J. Czerkawski, A. B. Stępien´, and S. Wielgus, ‘Philosophy in Poland’, in E. Craig (ed.), Routledge Encyclopedia of Philosophy (London, 1998). G. Krzywicki-Herburt, ‘Polish Philosophy’, in P. Edwards (ed.), The Encyclopedia of Philosophy (New York, 1967). Polish philosophy 729 . lack another). The dialogues show Plato to be very interested in these claims, but he is not clearly endorsing them. On the contrary, he seems rather to be exploring them, and recognizing the problems. what the good is, will form the ruling élite. From time to time they will be required to give up their intellectual delights and go back into the cave to govern it. They will govern with a view to. modification to his theory. The second part of the Parmenides is a riddle. It draws a bewil- dering array of contradictory conclusions, first from the hypothesis The One is’ and then from its negation The One