Ancient Philosophy PDF

 Ancient Philosophy This is the remarkable story of the birth of philosophy, its flourishing in the ancient Mediterranean world, and the development of ideas which have shaped the course of Western thought and society. Sir Anthony Kenny’s stimulating account...

 Ancient Philosophy This is the remarkable story of the birth of philosophy, its flourishing in the ancient Mediterranean world, and the development of ideas which have shaped the course of Western thought and society. Sir Anthony Kenny’s stimulating account begins with Pythagoras and Thales, and ends with St Augustine, who handed on the torch of philosophy to the Christian age. At the centre of the narrative are the two great Wgures of Plato and Aristotle, who between them set the agenda for philosophy for the next two millenia, and whose influence is as profound today as ever. The fruit of a lifetime’s scholarship and insight, Ancient Philosophy sets the philosophers and their ideas in historical context, and explains the signiWcance and impact of each wave of new ideas. It is the first volume in a magisterial new series, which brings the history of philosophy alive to anyone who wants to understand the roots of Western civilization. Sir Anthony Kenny has been President of the British Academy, and Pro-Vice-Chancellor of the University of Oxford. He has written many acclaimed books on the philosophy of mind, the philosophy of religion, and the history of philosophy, including both scholarly and popular works on Aristotle, Aquinas, Descartes, and Wittgenstein. A New History of Western Philosophy Anthony Kenny Volume 1: Ancient Philosophy Volume 3: The Rise of Modern Philosophy Volume 2: Medieval Philosophy Volume 4: Philosophy in the Modern World This page intentionally left blank A NEW HISTORY OF WESTERN PHILOSOPHY volume 1 Ancient Philosophy anthony kenny CLARENDON PRESS
OXFORD  3 Great Clarendon Street, Oxford o x 2 6d p Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide in Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With oYces in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries Published in the United States by Oxford University Press Inc., New York ß Sir Anthony Kenny 2004 The moral rights of the author have been asserted Database right Oxford University Press (maker) First published 2004 First published in paperback 2006 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above You must not circulate this book in any other binding or cover and you must impose this same condition on any acquirer British Library Cataloguing in Publication Data Data available Library of Congress Cataloging in Publication Data Data available Typeset by SPI Publisher Services, Pondicherry, India Printed in Great Britain on acid-free paper by Biddles Ltd., King’s Lynn ISBN 0–19–875273–3 978–0–19–875273–8 ISBN 0–19–875272–5 (Pbk.) 978–0–19–875272–1 (Pbk.) 1 3 5 7 9 10 8 6 4 2  SUMMARY OF CONTENTS List of Contents vii Map x Introduction xi 1. Beginnings: From Pythagoras to Plato 1 2. Schools of Thought: From Aristotle to Augustine 65 3. How to Argue: Logic 116 4. Knowledge and its Limits: Epistemology 145 5. How Things Happen: Physics 178 6. What There Is: Metaphysics 199 7. Soul and Mind 229 8. How to Live: Ethics 257 9. God 289 Chronology 317 List of Abbreviations and Conventions 319 Bibliography 323 List of Illustrations 331 Index 335 This page intentionally left blank  CONTENTS Map x Introduction xi 1. Beginnings: From Pythagoras to Plato 1 The Four Causes 1 The Milesians 4 The Pythagoreans 9 Xenophanes 11 Heraclitus 12 Parmenides and the Eleatics 17 Empedocles 20 Anaxagoras 24 The Atomists 26 The Sophists 28 Socrates 32 The Socrates of Xenophon 35 The Socrates of Plato 37 Socrates’ Own Philosophy 41 From Socrates to Plato 45 The Theory of Ideas 49 Plato’s Republic 56 The Laws and the Timaeus 60 2. Schools of Thought: From Aristotle to Augustine 65 Aristotle in the Academy 65 Aristotle the Biologist 69 The Lyceum and its Curriculum 73 Aristotle on Rhetoric and Poetry 75 Aristotle’s Ethical Treatises 79 Aristotle’s Political Theory 82 Aristotle’s Cosmology 87 The Legacy of Aristotle and Plato 89 Aristotle’s School 91 Epicurus 94  CONTENTS Stoicism 96 Scepticism in the Academy 100 Lucretius 101 Cicero 103 Judaism and Christianity 104 The Imperial Stoa 106 Early Christian Philosophy 109 The Revival of Platonism and Aristotelianism 111 Plotinus and Augustine 112 3. How to Argue: Logic 116 Aristotle’s Syllogistic 117 The de Interpretatione and the Categories 123 Aristotle on Time and Modality 129 Stoic Logic 136 4. Knowledge and its Limits: Epistemology 145 Presocratic Epistemology 145 Socrates, Knowledge, and Ignorance 148 Knowledge in the Theaetetus 152 Knowledge and Ideas 156 Aristotle on Science and Illusion 161 Epicurean Epistemology 166 Stoic Epistemology 169 Academic Scepticism 173 Pyrrhonian Scepticism 175 5. How Things Happen: Physics 178 The Continuum 178 Aristotle on Place 182 Aristotle on Motion 184 Aristotle on Time 186 Aristotle on Causation and Change 189 The Stoics on Causality 192 Causation and Determinism 194 Determinism and Freedom 196 6. What There Is: Metaphysics 199 Parmenides’ Ontology 200 viii  CONTENTS Plato’s Ideas and their Troubles 205 Aristotelian Forms 216 Essence and Quiddity 218 Being and Existence 223 7. Soul and Mind 229 Pythagoras’ Metempsychosis 229 Perception and Thought 232 Immortality in Plato’s Phaedo 234 The Anatomy of the Soul 237 Plato on Sense-Perception 240 Aristotle’s Philosophical Psychology 241 Hellenistic Philosophy of Mind 248 Will, Mind, and Soul in Late Antiquity 251 8. How to Live: Ethics 257 Democritus the Moralist 257 Socrates on Virtue 260 Plato on Justice and Pleasure 264 Aristotle on Eudaimonia 266 Aristotle on Moral and Intellectual Virtue 269 Pleasure and Happiness 274 The Hedonism of Epicurus 277 Stoic Ethics 280 9. God 289 Xenophanes’ Natural Theology 289 Socrates and Plato on Piety 290 Plato’s Evolving Theology 293 Aristotle’s Unmoved Movers 296 The Gods of Epicurus and the Stoics 302 On Divination and Astrology 308 The Trinity of Plotinus 311 Chronology 317 List of Abbreviations and Conventions 319 Bibliography 323 List of Illustrations 331 Index 335 ix  INTRODUCTION hy should one study the history of philosophy? There are many W reasons, but they fall into two groups: philosophical and historical. We may study the great dead philosophers in order to seek illumination upon themes of present-day philosophical inquiry. Or we may wish to understand the people and societies of the past, and read their philosophy to grasp the conceptual climate in which they thought and acted. We may read the philosophers of other ages to help to resolve philosophical problems of abiding concern, or to enter more fully into the intellectual world of a bygone era. In this history of philosophy, from the beginnings to the present day, I hope to further both purposes, but in diVerent ways in diVerent parts of the work, as I shall try to make clear in this Introduction. But before outlining a strategy for writing the history of philosophy, one must pause to reXect on the nature of philosophy itself. The word ‘philosophy’ means diVerent things in diVerent mouths, and correspondingly ‘the history of philosophy’ can be interpreted in many ways. What it signiWes depends on what the particular historian regards as being essential to philosophy. This was true of Aristotle, who was philosophy’s Wrst historian, and of Hegel, who hoped he would be its last, since he was bringing philosophy to perfection. The two of them had very diVerent views of the nature of philosophy. Nonetheless, they had in common a view of philosophical progress: philosophical problems in the course of history became ever more clearly deWned, and they could be answered with ever greater accuracy. Aristotle in the Wrst book of his Metaphysics and Hegel in his Lectures on the History of Philosophy saw the teachings of the earlier philosophers they recorded as halting steps in the direction of a vision they were themselves to expound. Only someone with supreme self-conWdence as a philosopher could write its history in such a way. The temptation for most philosopher historians is to see philosophy not as culminating in their own work, but rather as a gradual progress to whatever philosophical system is currently  INTRODUCTION in fashion. But this temptation should be resisted. There is no force that guarantees philosophical progress in any particular direction. Indeed, it can be called into question whether philosophy makes any progress at all. The major philosophical problems, some say, are all still being debated after centuries of discussion, and are no nearer to any deWnitive resolution. In the twentieth century the philosopher Ludwig Wittgenstein wrote: You always hear people say that philosophy makes no progress and that the same philosophical problems which were already preoccupying the Greeks are still troubling us today. But people who say that do not understand the reason why it has to be so. The reason is that our language has remained the same and always introduces us to the same questions.... I read ‘philosophers are no nearer to the meaning of ‘‘reality’’ than Plato got’. What an extraordinary thing! How remark- able that Plato could get so far! Or that we have not been able to get any further! Was it because Plato was so clever? (MS 213/424) The diVerence between what we might call the Aristotelian and the Wittgensteinian attitude to progress in philosophy is linked with two diVerent views of philosophy itself. Philosophy may be viewed as a science, on the one hand, or as an art, on the other. Philosophy is, indeed, uniquely diYcult to classify, and resembles both the arts and the sciences. On the one hand, philosophy seems to be like a science in that the philosopher is in pursuit of truth. Discoveries, it seems, are made in philosophy, and so the philosopher, like the scientist, has the excitement of belonging to an ongoing, cooperative, cumulative intellectual venture. If so, the philosopher must be familiar with current writing, and keep abreast of the state of the art. On this view, we twenty-Wrst-century philosophers have an advantage over earlier practitioners of the discipline. We stand, no doubt, on the shoulders of other and greater philosophers, but we do stand above them. We have superannuated Plato and Kant. On the other hand, in the arts, classic works do not date. If we want to learn physics or chemistry, as opposed to their history, we don’t nowadays read Newton or Faraday. But we read the literature of Homer and Shake- speare not merely to learn about the quaint things that passed through people’s minds in far-oV days of long ago. Surely, it may well be argued, the same is true of philosophy. It is not merely in a spirit of antiquarian curiosity that we read Aristotle today. Philosophy is essentially the work xii  INTRODUCTION of individual genius, and Kant does not supersede Plato any more than Shakespeare supersedes Homer. There is truth in each of these accounts, but neither is wholly true and neither contains the whole truth. Philosophy is not a science, and there is no state of the art in philosophy. Philosophy is not a matter of expanding knowledge, of acquiring new truths about the world; the philosopher is not in possession of information that is denied to others. Philosophy is not a matter of knowledge, it is a matter of understanding, that is to say, of organizing what is known. But because philosophy is all-embracing, is so universal in its Weld, the organization of knowledge it demands is some- thing so diYcult that only genius can do it. For all of us who are not geniuses, the only way in which we can hope to come to grips with philosophy is by reaching up to the mind of some great philosopher of the past. Though philosophy is not a science, throughout its history it has had an intimate relation to the sciences. Many disciplines that in antiquity and in the Middle Ages were part of philosophy have long since become inde- pendent sciences. A discipline remains philosophical as long as its concepts are unclariWed and its methods are controversial. Perhaps no scientiWc concepts are ever fully clariWed, and no scientiWc methods are ever totally uncontroversial; if so, there is always a philosophical element left in every science. But once problems can be unproblematically stated, when con- cepts are uncontroversially standardized, and where a consensus emerges for the methodology of solution, then we have a science setting up home independently, rather than a branch of philosophy. Philosophy, once called the queen of the sciences, and once called their handmaid, is perhaps better thought of as the womb, or the midwife, of the sciences. But in fact sciences emerge from philosophy not so much by parturition as by Wssion. Two examples, out of many, may serve to illustrate this. In the seventeenth century philosophers were much exercised by the problem which of our ideas are innate and which are acquired. This problem split into two problems, one psychological (‘What do we owe to heredity and what do we owe to environment?’) and one belonging to the theory of knowledge (‘How much of our knowledge depends on experi- ence and how much is independent of it?’). The Wrst question was handed over to scientiWc psychology, the second question remained philosophical. xiii  INTRODUCTION But the second question itself split into a number of questions, one of which was ‘Is mathematics merely an extension of logic, or is it an independent body of truth?’ The question whether mathematics could be derived from pure logic was given a precise answer by the work of logicians and mathematicians in the twentieth century. The answer was not philo- sophical, but mathematical. So here we had an initial, confused, philosoph- ical question which ramiWed in two directions—towards psychology and towards mathematics. There remains in the middle a philosophical residue to be churned over, concerning the nature of mathematical propositions. An earlier example is more complicated. A branch of philosophy given an honoured place by Aristotle is ‘theology’. When today we read what he says, the discipline appears a mixture of astronomy and philosophy of religion. Christian and Muslim Aristotelians added to it elements drawn from the teaching of their sacred books. It was when St Thomas Aquinas, in the thirteenth century, drew a sharp distinction between natural and revealed theology that the Wrst important Wssion took place, removing from the philosophical agenda the appeals to revelation. It took rather longer for the astronomy and the natural theology to separate out from each other. This example shows that what may be sloughed oV by philoso- phy need not be a science but may be a humanistic discipline such as biblical studies. It also shows that the history of philosophy contains examples of fusion as well as of Wssion. Philosophy resembles the arts in having a signiWcant relation to a canon. A philosopher situates the problems to be addressed by reference to a series of classical texts. Because it has no speciWc subject matter, but only characteristic methods, philosophy is deWned as a discipline by the activities of its great practitioners. The earliest people whom we recognize as philosophers, the Presocratics, were also scientists, and several of them were also religious leaders. They did not yet think of themselves as belonging to a common profession, the one with which we twenty- Wrst-century philosophers claim continuity. It was Plato who in his writings Wrst used the word ‘philosophy’ in some approximation to our modern sense. Those of us who call ourselves philosophers today can genuinely lay claim to be the heirs of Plato and Aristotle. But we are only a small subset of their heirs. What distinguishes us from the other heirs of the great Greeks, and what entitles us to inherit their name, is that unlike the physicists, the astronomers, the medics, the linguists, we phil- xiv  INTRODUCTION osophers pursue the goals of Plato and Aristotle only by the same methods as were already available to them. If philosophy lies somewhere between the sciences and the arts, what is the answer to the question ‘Is there progress in philosophy?’ There are those who think that the major task of philosophy is to cure us of intellectual confusion. On this, modest, view of the philosopher’s role, the tasks to be addressed diVer across history, since each period needs a diVerent form of therapy. The knots into which the undisciplined mind ties itself diVer from age to age, and diVerent mental motions are necessary to untie the knots. A prevalent malady of our own age, for instance, is the temptation to think of the mind as a computer, whereas earlier ages were tempted to think of it as a telephone exchange, a pedal organ, a homun- culus, or a spirit. Maladies of earlier ages may be dormant, such as belief that the stars are living beings; or they may return, such as the belief that the stars enable one to predict human behaviour. The therapeutic view of philosophy, however, may seem to allow only for variation over time, not for genuine progress. But that is not necessarily true. A confusion of thought may be so satisfactorily cleared up by a philosopher that it no longer oVers temptation to the unwary thinker. One such example will be considered at length in the Wrst volume of this history. Parmenides, the founder of the discipline of ontology (the science of being), based much of his system on a systematic confusion between diVerent senses of the verb ‘to be’. Plato, in one of his dialogues, sorted out the issues so successfully that there has never again been an excuse for mixing them up: indeed, it now takes a great eVort of philosophical imagination to work out exactly what led Parmenides into confusion in the Wrst place. Progress of this kind is often concealed by its very success: once a philosophical problem is resolved, no one regards it as any more a matter of philosophy. It is like treason in the epigram: ‘Treason doth never prosper, what’s the reason? j For if it prosper none dare call it treason.’ The most visible form of philosophical progress is progress in philosoph- ical analysis. Philosophy does not progress by making regular additions to a quantum of information; as has been said, what philosophy oVers is not information but understanding. Contemporary philosophers, of course, know some things that the greatest philosophers of the past did not know; but the things that they know are not philosophical matters but the truths xv  INTRODUCTION that have been discovered by the sciences begotten of philosophy. But there are also some things that philosophers of the present day understand which even the greatest philosophers of earlier generations failed to understand. For instance, philosophers clarify language by distinguishing between diVerent senses of words; and once a distinction has been made, future philosophers have to take account of it in their deliberations. Take, as an example, the issue of free will. At a certain point in the history of philosophy a distinction was made between two kinds of human freedom: liberty of indiVerence (ability to do otherwise) and liberty of spontaneity (ability to do what you want). Once this distinction has been made the question ‘Do human beings enjoy freedom of the will?’ has to be answered in a way that takes account of the distinction. Even someone who believes that the two kinds of liberty coincide has to provide arguments to show this; he cannot simply ignore the distinction and hope to be taken seriously on the topic. It is unsurprising, given the relationship of philosophy to a canon, that one notable form of philosophical progress consists in coming to terms with, and interpreting, the thoughts of the great philosophers of the past. The great works of the past do not lose their importance in philosophy— but their intellectual contributions are not static. Each age interprets and applies philosophical classics to its own problems and aspirations. This is, in recent years, most visible in the Weld of ethics. The ethical works of Plato and Aristotle are as inXuential in moral thinking today as the works of any twentieth-century moralists—this is easily veriWed by taking any citation index—but they are being interpreted and applied in ways quite diVerent from the ways in which they were applied in the past. These new inter- pretations and applications do eVect a genuine advance in our understand- ing of Plato and Aristotle; but of course it is understanding of quite a diVerent kind from what is given by a new study of the chronology of Plato’s dialogues or a stylometric comparison between Aristotle’s various ethical works. The new light we receive resembles rather the enhanced appreciation of Shakespeare we may get by seeing a new and intelligent production of King Lear. The historian of philosophy, whether primarily interested in philosophy or primarily interested in history, cannot help being both a philosopher and a historian. A historian of painting does not have to be a painter; a historian of medicine does not, qua historian, practise medicine. But a xvi  INTRODUCTION historian of philosophy cannot help doing philosophy in the very writing of history. It is not just that someone who knows no philosophy will be a bad historian of philosophy; it is equally true that someone who has no idea of how to cook will be a bad historian of cookery. The link between philosophy and its history is a far closer one. The historical task itself forces historians of philosophy to paraphrase their subjects’ opinions, to oVer reasons why past thinkers held the opinions they did, to speculate on the premisses left tacit in their arguments, and to evaluate the coherence and cogency of the inferences they drew. But the supplying of reasons for philosophical conclusions, the detection of hidden premisses in philosophical arguments, and the logical evaluation of philosophical inferences are themselves full-blooded philosophical activities. Consequently, any serious history of philosophy must itself be an exercise in philosophy as well as in history. On the other hand, the historian of philosophy must have a knowledge of the historical context in which past philosophers wrote their works. When we explain historical actions, we ask for the agent’s reasons; if we Wnd a good reason, we think we have understood his action. If we conclude he did not have good reason, even in his own terms, we have to Wnd, diVerent, more complicated explanations. What is true of action is true of taking a philosophical view. If the philosophical historian Wnds a good reason for a past philosopher’s doctrine, then his task is done. But if he concludes that the past philosopher has no good reason, he has a further and much more diYcult task, of explaining the doctrine in terms of the context in which it appeared—social, perhaps, as well as intellectual.1 History and philosophy are closely linked even in the Wrst-hand quest for original philosophical enlightenment. In modern times this has been most brilliantly illustrated by the masterpiece of the great nineteenth- century German philosopher Gottlob Frege, The Foundations of Arithmetic. Almost half of Frege’s book is devoted to discussing and refuting the view of other philosophers and mathematicians. While he is discussing the opinions of others, he ensures that some of his own insights are artfully insinuated, and this makes easier the eventual presentation of his own theory. But the main purpose of his lengthy polemic is to convince readers of the seriousness of the problems to which he will later oVer solutions. 1 The magnitude of this task is well brought out by Michael Frede in the introduction to his Essays in Ancient Philosophy (Oxford: Clarendon Press, 1987). xvii  INTRODUCTION Without this preamble, he says, we would lack the Wrst prerequisite for learning anything: knowledge of our own ignorance. Most histories of philosophy, in this age of specialization, are the work of many hands, specialists in diVerent Welds and periods. In inviting me to write, single-handed, a history of philosophy from Thales to Derrida, Oxford University Press gave expression to the belief that there is something to be gained by presenting the development of philosophy from a single viewpoint, linking ancient, medieval, early modern, and contemporary philosophy into a single narrative concerned with con- nected themes. The work will appear in four volumes: the Wrst will cover the centuries from the beginning of philosophy up to the conver- sion of St Augustine in a d 387. The second will take the story from Augustine up to the Lateran Council of 1512. The third will end with the death of Hegel in 1831. The fourth and Wnal volume will bring the narrative up to the end of the second millennium. Obviously, I cannot claim to be an expert on all the many philosophers whom I will discuss in the volumes of this work. However, I have published books on major Wgures within each of the periods of the four volumes: on Aristotle (The Aristotelian Ethics and Aristotle on the Perfect Life), on Aquinas (Aquinas on Mind and Aquinas on Being), on Descartes (Descartes: A Study of his Philosophy and Descartes: Philosophical Letters), and on Frege and Wittgenstein (Frege and Wittgenstein as Penguin introductions and The Legacy of Wittgenstein). I hope that the work that went into the writing of these books gave me an insight into the philosophical style of four diVerent eras in the history of philosophy. It certainly gave me a sense of the perennial importance of certain philosophical problems and insights. I hope to write my history in a manner that takes account of the points I have raised in this Introduction. I do not suVer from any Whiggish illusion that the current state of philosophy represents the highest point of philosophical endeavour yet reached. On the contrary, my primary pur- pose in writing the book is to show that in many respects the philosophy of the great dead philosophers has not dated, and that today one may gain philosophical illumination by a careful reading of the great works that we have been privileged to inherit. The kernel of any kind of historiography of philosophy is exegesis: the close reading and interpretation of philosophical texts. Exegesis may be of two kinds, internal or external. In internal exegesis the interpreter tries to xviii  INTRODUCTION render the text coherent and consistent, making use of the principle of charity in interpretation. In external exegesis the interpreter seeks to bring out the signiWcance of the text by comparing it and contrasting it with other texts. Exegesis may form the basis of the two quite diVerent historical endeav- ours that I described at the beginning of this Introduction. In one, which we may call historical philosophy, the aim is to reach philosophical truth, or philosophical understanding, about the matter or issue under discussion in the text. Typically, historical philosophy looks for the reasons behind, or the justiWcation for, the statements made in the text under study. In the other endeavour, the history of ideas, the aim is not to reach the truth about the matter in hand, but to reach the understanding of a person or an age or a historical succession. Typically the historian of ideas looks not for the reasons so much as the sources, or causes, or motives, for saying what is said in the target text. Both of these disciplines base themselves on exegesis, but of the two, the history of ideas is the one most closely bound up with the accuracy and sensitivity of the reading of the text. It is possible to be a good philosopher while being a poor exegete. At the beginning of his Philosophical Investigations Wittgenstein oVers a discussion of St Augustine’s theory of language. What he writes is very dubious exegesis; but this does not weaken the force of his philosophical criticism of the ‘Augustinian’ theory of language. But Witt- genstein did not really think of himself as engaged in historical philosophy, any more than he thought of himself as engaged in the historiography of ideas. The invocation of the great Augustine as the author of the mistaken theory is intended merely to indicate that the error is one that is worth attacking. In diVerent histories of philosophy the skills of the historian and those of the philosopher are exercised in diVerent proportions. The due proportion varies in accordance with the purpose of the work and the Weld of philosophy in question. The pursuit of historical understanding and the pursuit of philosophical enlightenment are both legitimate approaches to the history of philosophy, but both have their dangers. Historians who study the history of thought without being themselves involved in the philosophical problems that exercised past philosophers are likely to sin by superWciality. Philosophers who read ancient, medieval, or early modern texts without a knowledge of the historical context in which they were xix  INTRODUCTION written are likely to sin by anachronism. Rare is the historian of philosophy who can tread Wrmly without falling into either trap. Each of these errors can nullify the purpose of the enterprise. The historian who is unconcerned by the philosophical problems that troubled past writers has not really understood how they themselves conducted their thinking. The philosopher who ignores the historical background of past classics will gain no fresh light on the issues that concern us today, but merely present contemporary prejudices in fancy dress. The two dangers threaten in diVerent proportions in diVerent areas of the history of philosophy. In the area of metaphysics it is superWciality which is most to be guarded against: to someone without a personal interest in fundamental philosophical problems the systems of the great thinkers of the past will seem only quaint lunacy. In political philosophy the great danger is anachronism: when we read Plato’s or Aristotle’s criticisms of democracy, we shall not make head or tail of them unless we know something about the institutions of ancient Athens. In between metaphysics and political philosophy stand ethics and philosophy of mind: here both dangers threaten with roughly equal force. I shall attempt in these volumes to be both a philosophical historian and a historical philosopher. Multi-authored histories are sometimes struc- tured chronologically and sometimes structured thematically. I shall try to combine both approaches, oVering in each volume Wrst a chronological survey, and then a thematic treatment of particular philosophical topics of abiding importance. The reader whose primary interest is historical will focus on the chronological survey, referring where necessary to the thematic sections for ampliWcation. The reader who is more concerned with the philosophical issues will concentrate rather on the thematic sections of the volumes, referring back to the chronological surveys to place particular issues in context. Thus in this Wrst volume I oVer in the Wrst part a conventional chrono- logical tour from Pythagoras to Augustine, and in the second part a more detailed treatment of topics where I believe we have still much to learn from our predecessors in classical Greece and imperial Rome. The topics of these thematic sections have been chosen partly with an eye to the development of the same themes in the volumes that are yet to come. xx  INTRODUCTION The audience I have in mind is at the level of second- or third-year undergraduate study. I realize, however, that many of those interested in the history of philosophy may themselves be enrolled in courses that are not primarily philosophical. Accordingly, I shall do my best not to assume a familiarity with contemporary philosophical techniques or terminology. I aim also to write in a manner clear and light-hearted enough for the history to be enjoyed by those who read it not for curricular purposes but for their own enlightenment and entertainment. xxi This page intentionally left blank  1 Beginnings: From Pythagoras to Plato he history of philosophy does not begin with Aristotle, but the T historiography of philosophy does. Aristotle was the Wrst philosopher who systematically studied, recorded, and criticized the work of previous philosophers. In the Wrst book of the Metaphysics he summarizes the teachings of his predecessors, from his distant intellectual ancestors Pythagoras and Thales up to Plato, his teacher for twenty years. To this day he is one of the most copious, and most reliable, sources of our information about philosophy in its infancy. The Four Causes Aristotle oVers a classiWcation of the earliest Greek philosophers in accordance with the structure of his system of the four causes. ScientiWc inquiry, he believed, was above all inquiry into the causes of things; and there were four diVerent kinds of cause: the material cause, the eYcient cause, the formal cause, and the Wnal cause. To give a crude illustration of what he had in mind: when Alfredo cooks a risotto, the material causes of the risotto are the ingredients that go into it, the eYcient cause is the chef himself, the recipe is the formal cause, and the satisfaction of the clients of his restaurant is the Wnal cause. Aristotle believed that a scientiWc understanding of the universe demanded an inquiry into the operation in the world of causes of each of these kinds (Metaph. A 3. 983a24–b17).  PYTHAGORAS TO PLATO Early philosophers on the Greek coast of Asia Minor concentrated on the material cause: they sought the basic ingredients of the world we live in. Thales and his successors posed the following question: At a fundamen- tal level is the world made out of water, or air, or Wre, or earth, or a combination of some or all of these? (Metaph. A 3. 983b20–84a16). Even if we have an answer to this question, Aristotle thought, that is clearly not enough to satisfy our scientiWc curiosity. The ingredients of a dish do not put themselves together: there needs to be an agent operating upon them, by cutting, mixing, stirring, heating, or the like. Some of these early philosophers, Aristotle tells us, were aware of this and oVered conjectures about the agents of change and development in the world. Sometimes it would be one of the ingredients themselves—Wre was perhaps the most promising suggestion, as being the least torpid of the elements. More often it would be some agent, or pair of agents, both more abstract and more picturesque, such as Love or Desire or Strife, or the Good and the Bad (Metaph. A 3–4. 984b8–31). Meanwhile in Italy—again according to Aristotle—there were, around Pythagoras, mathematically inclined philosophers whose inquiries took quite a diVerent course. A recipe, besides naming ingredients, will contain a lot of numbers: so many grams of this, so many litres of that. The Pythagoreans were more interested in the numbers in the world’s recipe than in the ingredients themselves. They supposed, Aristotle says, that the elements of numbers were the elements of all things, and the whole of the heavens was a musical scale. They were inspired in their quest by their discovery that the relationship between the notes of the scale played on a lyre corresponded to diVerent numerical ratios between the lengths of the strings. They then generalized this idea that qualitative diVerences might be the upshot of numerical diVerences. Their inquiry, in Aristotle’s terms, was an inquiry into the formal causes of the universe. (Metaph. A 5. 985b23– 986b2) Coming to his immediate predecessors, Aristotle says that Socrates preferred to concentrate on ethics rather than study the world of nature, while Plato in his philosophical theory combined the approaches of the schools of both Thales and Pythagoras. But Plato’s Theory of Ideas, while being the most comprehensive scientiWc system yet devised, seemed to Aristotle—for reasons that he summarizes here and develops in a number of his treatises—to be unsatisfactory on several grounds. There 2  PYTHAGORAS TO PLATO were so many things to explain, and the Ideas just added new items calling for explanation: they did not provide a solution, they added to the problem (Metaph. A 5. 990b1 V.). Most dissertations that begin with literature searches seek to show that all work hitherto has left a gap that will now be Wlled by the author’s original research. Aristotle’s Metaphysics is no exception. His not too hidden agenda is to show how previous philosophers neglected the remaining member of the quartet of causes: the Wnal cause, which was to play a most signiWcant role in his own philosophy of nature (Metaph. A 5. 988b6–15). The earliest philosophy, he concluded, is, on all subjects, full of babble, since in its beginnings it is but an infant (Metaph. A 5. 993a15–7.) A philosopher of the present day, reading the surviving fragments of the earliest Greek thinkers, is impressed not so much by the questions they were asking, as by the methods they used to answer them. After all, the book of Genesis oVers us answers to the four causal questions set by Aristotle. If we ask for the origin of the Wrst human being, for instance, we are told that the eYcient cause was God, that the material cause was the dust of the earth, that the formal cause was the image and likeness of God, and that the Wnal cause was for man to have dominion over the Wsh of the sea, the fowl of the air, and every living thing on earth. Yet Genesis is not a work of philosophy. On the other hand, Pythagoras is best known not for answering any of the Aristotelian questions, but for proving the theorem that the square on the hypotenuse of a right-angled triangle is equal in area to the sum of the squares on the other two sides. Thales, again, was believed by later Greeks to have been the Wrst person to make an accurate prediction of an eclipse, in the year 585 bc. These are surely achievements in geometry and astronomy, not philosophy. The fact is that the distinction between religion, science, and philosophy was not as clear as it became in later centuries. The works of Aristotle and his master Plato provide a paradigm of philosophy for every age, and to this day anyone using the title ‘philosopher’ is claiming to be one of their heirs. Writers in twenty-Wrst-century philosophy journals can be seen to be using the same techniques of conceptual analysis, and often to be repeating or refuting the same theoretical arguments, as are to be found in the writings of Plato and Aristotle. But in those writings there is much else that would 3  PYTHAGORAS TO PLATO not nowadays be thought of as philosophical discussion. From the sixth century bc onwards elements of religion, science, and philosophy ferment together in a single cultural cauldron. From our distance in time philoso- phers, scientists, and theologians can all look back to these early thinkers as their intellectual forefathers. The Milesians Only two sayings are recorded of Thales of Miletus (c.625–545 bc), trad- itionally the founding father of Greek philosophy. They illustrate the mélange of science and religion, for one of them was ‘All things are full of gods’, and the other was ‘Water is the Wrst principle of everything’. Thales was a geometer, the Wrst to discover the method of inscribing a right-angled triangle in a circle; he celebrated this discovery by sacriWcing an ox to the gods (D.L. 1. 24–5). He measured the height of the pyramids by measuring their shadows at the time of day when his own shadow was as long as he was tall. He put his geometry to practical use: having proved that triangles with one equal side and two equal angles are congruent, he used this result to determine the distance of ships at sea. Thales also had a reputation as an astronomer and a meteorologist. In addition to predicting the eclipse, he is said to have been the Wrst to show that the year contained 365 days, and to determine the dates of the summer and winter solstices. He studied the constellations and made estimates of the sizes of the sun and moon. He turned his skill as a weather forecaster to good account: foreseeing an unusually good olive crop, he took a lease on all the oil mills and made a fortune through his monopoly. Thus, Aristotle said, he showed that philosophers could easily be rich if they wished (Pol. 1. 11. 1259a6–18). If half the stories current about Thales in antiquity are true, he was a man of many parts. But tradition’s portrait of him is ambiguous. On the one hand, he Wgures as a philosophical entrepreneur, and a political and military pundit. On the other hand, he became a byword for unworldly absent-mindedness. Plato, among others, tells the following tale: Thales was studying the stars and gazing into the sky, when he fell into a well, and a jolly and witty Thracian servant girl made fun of him, saying that he was crazy to 4  PYTHAGORAS TO PLATO know about what was up in the heavens while he could not see what was in front of him beneath his feet. (Theaetetus 174a) An unlikely story went around that he had met his death by just such a fall while stargazing. Thales was reckoned as one of the Seven Sages, or wise men, of Greece, on a par with Solon, the great legislator of Athens. He is credited with a number of aphorisms. He said that before a certain age it was too soon for a man to marry; and after that age it was too late. When asked why he had no children, he said ‘Because I am fond of children.’ Thales’ remarks heralded many centuries of philosophical disdain for marriage. Anyone who makes a list of a dozen really great philosophers is likely to discover that the list consists almost entirely of bachelors. One plausible list, for instance, would include Plato, Augustine, Aquinas, Scotus, Descartes, Locke, Spinoza, Hume, Kant, Hegel, and Wittgenstein, none of whom were married. Aristotle is the grand exception that dis- proves the rule that marriage is incompatible with philosophy. Even in antiquity people found it hard to understand Thales’ adoption of water as the ultimate principle of explanation. The earth, he said, rested on water like a log Xoating in a stream—but then, asked Aristotle, what does the water rest on? (Cael. 2. 13. 294a28–34). He went further and said that everything came from and was in some sense made out of water. Again, his reasons were obscure, and Aristotle could only conjecture that it was because all animals and plants need water to live, or because semen is moist (Metaph. A 3. 983b17–27). It is easier to come to grips with the cosmology of Thales’ junior compatriot Anaximander of Miletus (d. c.547 bc). We know rather more about his views, because he left behind a book entitled On Nature, written in prose, a medium just beginning to come into fashion. Like Thales he was credited with a number of original scientiWc achievements: the Wrst map of the world, the Wrst star chart, the Wrst Greek sundial, and an indoor clock as well. He taught that the earth was cylindrical in shape, like a stumpy column no higher than a third of its diameter. Around the world were gigantic tyres full of Wre; each tyre was punctured with a hole through which the Wre could be seen from outside, and the holes were the sun and moon and stars. Blockages in the holes accounted for eclipses of the sun and phases of the moon. The celestial Wre which is nowadays 5  PYTHAGORAS TO PLATO Anaximander with his sundial, in a Roman mosaic largely hidden was once a great ball of Xame around the infant earth; when this ball exploded, the fragments grew tyres like bark around themselves. Anaximander was much impressed by the way trees grow and shed their bark. He used the same analogy to explain the origin of human beings. Other animals, he observed, can look after themselves soon after birth, but humans need a long nursing. If humans had always been as they are now, the race would not have survived. In an earlier age, he conjectured, humans had spent their childhood encased in a prickly bark, so that they looked like Wsh and lived in water. At puberty they shed their bark, and 6  PYTHAGORAS TO PLATO stepped out onto dry land, into an environment in which they could take care of themselves. Because of this, Anaximander, though not otherwise a vegetarian, recommended that we abstain from eating Wsh, as the ancestors of the human race (KRS 133–7). Anaximander’s cosmology is more sophisticated than Thales’ in several ways. First of all, he does not look for something to support the earth: it stays where it is because it is equidistant from everything else and there is no reason why it should move in any direction rather than any other (DK 12 A11; Aristotle, Cael. 2. 13. 295b10). Secondly, he thinks it is an error to identify the ultimate material of the universe with any of the elements we can see around us in the contem- porary world, such as water or Wre. The fundamental principle of things, he said, must be boundless or undeWned (apeiron). Anaximander’s Greek word is often rendered as ‘the InWnite’, but that makes it sound too grand. He may or may not have thought that his principle extended for ever in space; what we do know is that he thought it had no beginning and no end in time and that it did not belong to any particular kind or class of things. ‘Everlasting stuV’ is probably as close a paraphrase as we can get. Aristotle was later to reWne the notion into his concept of prime matter.1 Thirdly, Anaximander oVered an account of the origin of the present world, and explained what forces had acted to bring it into existence, inquiring, as Aristotle would say, into the eYcient as well as the material cause. He saw the universe as a Weld of competing opposites: hot and cold, wet and dry. Sometimes one of a pair of opposites is dominant, sometimes the other: they encroach upon each other and then withdraw, and their interchange is governed by a principle of reciprocity. As Anaximander put it poetically in his one surviving fragment, ‘they pay penalty and render reparation to each other for their injustice under the arbitration of time’ (DK 12 B1). Thus, one surmises, in winter the hot and the dry make reparation to the cold and the wet for the aggression they committed in summer. Heat and cold were the Wrst of the opposites to make their appearance, separating oV from an original cosmic egg of the everlasting indeterminate stuV. From them developed the Wre and earth which, we have seen, lay at the origin of our present cosmos. 1 See Ch. 5 below. 7  PYTHAGORAS TO PLATO Anaximenes (X. 546–525 bc), a generation younger than Anaximander, was the last of the trio of Milesian cosmologists. In several ways he is closer to Thales than to Anaximander, but it would be wrong to think that with him science is going backwards rather than forwards. Like Thales, he thought that the earth must rest on something, but he proposed air, rather than water, for its cushion. The earth itself is Xat, and so are the heavenly bodies. These, instead of rotating above and below us in the course of a day, circle horizontally around us like a bonnet rotating around a head (KRS 151–6). The rising and setting of the heavenly bodies is explained, apparently, by the tilting of the Xat earth. As for the ultimate principle, Anaximenes found Anaximander’s boundless matter too rareWed a concept, and opted, like Thales, for a single one of the existing elements as fundamental, though again he opted for air rather than water. In its stable state air is invisible, but when it is moved and condensed it becomes Wrst wind and then cloud and then water, and Wnally water condensed becomes mud and stone. RareWed air became Wre, thus com- pleting the gamut of the elements. In this way rarefaction and condensa- tion can conjure everything out of the underlying air (KRS 140–1). In support of this claim Anaximenes appealed to experience, and indeed to experiment—an experiment that the reader can easily carry out for herself. Blow on your hand, Wrst with the lips pursed, and then from an open mouth: the Wrst time the air will feel cold, and the second time hot. This, argued Anaximenes, shows the connection between density and tempera- ture (KRS 143). The use of experiment, and the insight that changes of quality are linked to changes of quantity, mark Anaximenes as a scientist in embryo. Only in embryo, however: he has no means of measuring the quantities he invokes, he devises no equations to link them, and his fundamental principle retains mythical and religious properties.2 Air is divine, and generates deities out of itself (KRS 144–6); air is our soul, and holds our bodies together (KRS 160). The Milesians, then, are not yet real physicists, but neither are they myth-makers. They have not yet left myth behind, but they are moving away from it. They are not true philosophers either, unless by ‘philosophy’ 2 See J. Barnes, The Presocratic Philosophers, rev. edn. (London: Routledge, 1982), 46–8. 8  PYTHAGORAS TO PLATO one simply means infant science. They make little use of conceptual analysis and the a priori argument that has been the stock-in-trade of philosophers from Plato to the present day. They are speculators, in whose speculations elements of philosophy, science, and religion mingle in a rich and heady brew. The Pythagoreans In antiquity Pythagoras shared with Thales the credit for introducing philosophy into the Greek world. He was born in Samos, an island oV the coast of Asia Minor, about 570 bc. At the age of 40 he emigrated to Croton on the toe of Italy. There he took a leading part in the political aVairs of the city, until he was banished in a violent revolution about 510 bc. He moved to nearby Metapontum, where he died at the turn of the century. During his time at Croton he founded a semi- religious community, which outlived him until it was scattered about 450 bc. He is credited with inventing the word ‘philosopher’: instead of claiming to be a sage or wise man (sophos) he modestly said that he was only a lover of wisdom (philosophos) (D.L. 8. 8). The details of his life are swamped in legend, but it is clear that he practised both mathematics and mysticism. In both Welds his intellectual inXuence, acknowledged or implicit, was strong throughout antiquity, from Plato to Porphyry. The Pythagoreans’ discovery that there was a relationship between musical intervals and numerical ratios led to the belief that the study of mathematics was the key to the understanding of the structure and order of the universe. Astronomy and harmony, they said, were sister sciences, one for the eyes and one for the ears (Plato, Rep. 530d). However, it was not until two millennia later that Galileo and his successors showed the sense in which it is true that the book of the universe is written in numbers. In the ancient world arithmetic was too entwined with number mysticism to promote scientiWc progress, and the genuine scientiWc advances of the period (such as Aristotle’s zoology or Galen’s medicine) were achieved without beneWt of mathematics. Pythagoras’ philosophical community at Croton was the prototype of many such institutions: it was followed by Plato’s Academy, Aristotle’s 9  PYTHAGORAS TO PLATO Pythagoras commending vegetarianism, as imagined by Rubens Lyceum, Epicurus’ Garden, and many others. Some such communities were legal entities, and others less formal; some resembled a modern research institute, others were more like monasteries. Pythagoras’ associates held their property in common and lived under a set of ascetic and ceremonial rules: observe silence, do not break bread, do not pick up crumbs, do not poke the Wre with a sword, always put on the right shoe before the left, and so on. The Pythagoreans were not, to begin with, complete vegetarians, but they avoided certain kinds of meat, Wsh, and poultry. Most famously, they were forbidden to eat beans (KRS 271–2, 275–6). The dietary rules were connected with Pythagoras’ beliefs about the soul. It did not die with the body, he believed, but migrated elsewhere, perhaps into an animal body of a diVerent kind.3 Some Pythagoreans extended this into belief in a three-thousand-year cosmic cycle: a human soul after death would enter, one after the other, every kind of land, sea, or 3 See Ch. 7 below. 10  PYTHAGORAS TO PLATO air creature, and Wnally return into a human body for history to repeat itself (Herodotus 2. 123; KRS 285). Pythagoras himself, however, after his death was believed by his followers to have become a god. They wrote biographies of him full of wonders, crediting him with second sight and the gift of bilocation; he had a golden thigh, they said, and was the son of Apollo. More prosaically, the expression ‘Ipse dixit’ was coined in his honour. Xenophanes The death of Pythagoras, and the destruction of Miletus in 494, brought to an end the Wrst era of Presocratic thought. In the next generation we encounter thinkers who are not only would-be scientists, but also philoso- phers in the modern sense of the word. Xenophanes of Colophon (a town near present-day Izmir, some hundred miles north of Miletus) straddles the two eras in his long life (c.570–c.470 bc). He is also, like Pythagoras, a link between the eastern and the western centres of Greek cultures. Expelled from Colophon in his twenties, he became a wandering minstrel, and by his own account travelled around Greece for sixty-seven years, giving recitals of his own and others’ poems (D.L. 9. 18). He sang of wine and games and parties, but it is his philosophical verses that are most read today. Like the Milesians, Xenophanes propounded a cosmology. The basic element, he maintained, was not water nor air, but earth, and the earth reaches down below us to inWnity. ‘All things are from earth and in earth all things end’ (D.K. 21 B27) calls to mind Christian burial services and the Ash Wednesday exhortation ‘remember, man, thou art but dust and unto dust thou shalt return’. But Xenophanes elsewhere links water with earth as the original source of things, and indeed he believed that our earth must at one time have been covered by the sea. This is connected with the most interesting of his contributions to science: the observation of the fossil record. Seashells are found well inland, and on mountains too, and in the quarries in Syracuse impressions of Wsh and seaweed have been found. An impression of a bay leaf was found in Paros deep in a rock, and in Malta there are Xat shapes of all kinds of sea creatures. These were produced when everything was covered with mud long ago, and the impressions dried in the mud. (KRS 184) 11  PYTHAGORAS TO PLATO Xenophanes’ speculations about the heavenly bodies are less impressive. Since he believed that the earth stretched beneath us to inWnity, he could not accept that the sun went below the earth when it set. On the other hand, he found implausible Anaximenes’ idea of a horizontal rotation around a tilting earth. He put forward a new and ingenious explanation: the sun, he maintained, was new every day. It came into existence each morning from a congregation of tiny sparks, and later vanished oV into inWnity. The appearance of circular movement is due simply to the great distance between the sun and ourselves. It follows from this theory that there are innumerable suns, just as there are innumerable days, because the world lasts for ever even though it passes through aqueous and terrestrial phases (KRS 175, 179). Though Xenophanes’ cosmology is ill-founded, it is notable for its naturalism: it is free from the animist and semi-religious elements to be found in other Presocratic philosophers. The rainbow, for instance, is not a divinity (like Iris in the Greek pantheon) nor a divine sign (like the one seen by Noah). It is simply a multicoloured cloud (KRS 178). This natural- ism did not mean that Xenophanes was uninterested in religion: on the contrary, he was the most theological of all the Presocratics. But he despised popular superstition, and defended an austere and sophisticated monotheism.4 He was not dogmatic, however, either in theology or in physics. God did not tell us mortals all when time began Only through long-time search does knowledge come to man. (KRS 188) Heraclitus Heraclitus was the last, and the most famous, of the early Ionian philoso- phers. He was perhaps thirty years younger than Xenophanes, since he is reported to have been middle-aged when the sixth century ended (D.L. 9. 1). He lived in the great metropolis of Ephesus, midway between Miletus and Colophon. We possess more substantial portions of his work than of any previous philosopher, but that does not mean we Wnd him easier to 4 See Ch. 9 below. 12  PYTHAGORAS TO PLATO understand. His fragments take the form of pithy, crafted prose aphorisms, which are often obscure and sometimes deliberately ambiguous. Heraclitus did not argue, he pronounced. His delphic style may have been an imita- tion of the oracle of Apollo which, in his own words, ‘neither speaks, nor conceals, but gestures’ (KRS 244). The many philosophers in later centuries who have admired Heraclitus have been able to give their own colouring to his paradoxical, chameleon-like dicta. Even in antiquity Heraclitus was found diYcult. He was nicknamed ‘the Enigmatic One’ and ‘Heraclitus the Obscure’ (D.L. 9. 6). He wrote a three-book treatise on philosophy—now lost—and deposited it in the great temple of Artemis (St Paul’s ‘Diana of the Ephesians’). People could not make up their minds whether it was a text of physics or a political tract. ‘What I understand of it is excellent,’ Socrates is reported as saying. ‘What I don’t understand may well be excellent also; but only a deep sea diver could get to the bottom of it’ (D.L. 2. 22). The nineteenth-century German idealist Hegel, who was a great admirer of Heraclitus, used the same marine metaphor to express an opposite judgement. When we reach Heraclitus after the Xuctuating speculations of the earlier Presocratics, Hegel wrote, we come at last in sight of land. He went on to add, proudly, ‘There is no proposition of Heraclitus which I have not adopted in my own Logic.’5 Heraclitus, like Descartes and Kant in later ages, saw himself as making a completely new start in philosophy. He thought the work of previous thinkers was worthless: Homer should have been eliminated at an early stage of any poetry competition, and Hesiod, Pythagoras, and Xenophanes were merely polymaths with no real sense (D.L. 9. 1). But, again like Descartes and Kant, Heraclitus was more inXuenced by his predecessors than he realized. Like Xenophanes, he was highly critical of popular religion: oVering blood sacriWce to purge oneself of blood guilt was like trying to wash oV mud with mud. Praying to statues was like whispering in an empty house, and phallic processions and Dionysiac rites were simply disgusting (KRS 241, 243). Again like Xenophanes, Heraclitus believed that the sun was new every day (Aristotle, Mete. 2. 2355b13–14), and, like Anaximander, he thought the 5 Lectures on the History of Philosophy, ed. and trans. E. S. Haldane and F. H. Simpson (London: Routledge, 1968), 279. 13  PYTHAGORAS TO PLATO sun was constrained by a cosmic principle of reparation (KRS 226). The ephemeral theory of the sun is indeed in Heraclitus expanded into a doctrine of universal Xux. Everything, he said, is in motion, and nothing stays still; the world is like a Xowing stream. If we step into the same river twice, we cannot put our feet twice into the same water, since the water is not the same two moments together (KRS 214). That seems true enough, but on the face of it Heraclitus went too far when he said that we cannot even step twice into the same river (Plato, Cra. 402a). Taken literally, this seems false, unless we take the criterion of identity for a river to be the body of water it contains rather than the course it Xows. Taken allegorically, it is presumably a claim that everything in the world is composed of constantly changing constituents: if this is what is meant, Aristotle said, the changes must be imperceptible ones (Ph. 8. 3. 253b9 V.). Perhaps this is what is hinted at in Heraclitus’ aphorism that hidden harmony is better than manifest harmony—the harmony being the underlying rhythm of the universe in Xux (KRS 207). Whatever Heraclitus meant by his dictum, it had a long history ahead of it in later Greek philosophy. A raging Wre, even more than a Xowing stream, is a paradigm of constant change, ever consuming, ever refuelled. Heraclitus once said that the world was an ever-living Wre: sea and earth are the ashes of this perpetual bonWre. Fire is like gold: you can exchange gold for all kinds of goods, and Wre can turn into any of the elements (KRS 217–19). This Wery world is the only world there is, not made by gods or men, but governed throughout by Logos. It would be absurd, he argued, to think that this glorious cosmos is just a piled-up heap of rubbish (DK 22 B124). ‘Logos’ is the everyday Greek term for a written or spoken word, but from Heraclitus onwards almost every Greek philosopher gave it one or more of several grander meanings. It is often rendered by translators as ‘Reason’—whether to refer to the reasoning powers of human individuals, or to some more exalted cosmic principle of order and beauty. The term found its way into Christian theology when the author of the fourth gospel proclaimed, ‘In the begin- ning was the Logos, and the Logos was with God, and the Logos was God’ (John 1: 1). This universal Logos, Heraclitus says, is hard to grasp and most men never succeed in doing so. By comparison with someone who has woken up to the Logos, they are like sleepers curled up in their own dream-world instead of facing up to the single, universal truth (S.E., M. 7. 132). Humans 14  PYTHAGORAS TO PLATO fall into three classes, at various removes from the rational Wre that governs the universe. A philosopher like Heraclitus is closest to the Wery Logos and receives most warmth from it; next, ordinary people when awake draw light from it when they use their own reasoning powers; Wnally, those who are asleep have the windows of their soul blocked up and keep contact with nature only through their breathing (S.E., M. 7. 129–30).6 Is the Logos God? Heraclitus gave a typically quibbling answer. ‘The one thing that alone is truly wise is both unwilling and willing to be called by the name of Zeus.’ Presumably, he meant that the Logos was divine, but was not to be identiWed with any of the gods of Olympus. The human soul is itself Wre: Heraclitus sometimes lists soul, along with earth and water, as three elements. Since water quenches Wre, the best soul is a dry soul, and must be kept from moisture. It is hard to know exactly what counts as moisture in this context, but alcohol certainly does: a drunk, Heraclitus says, is a man led by a boy (KRS 229–31). But Heraclitus’ use of ‘wet’ also seems close to the modern slang sense: brave and tough men who die in battle, for instance, have dry souls that do not suVer the death of water but go to join the cosmic Wre (KRS 237).7 What Hegel most admired in Heraclitus was his insistence on the coinci- dence of opposites, such as that the universe is both divisible and indivisible, generated and ungenerated, mortal and immortal. Sometimes these iden- tiWcations of opposites are straightforward statements of the relativity of certain predicates. The most famous, ‘The way up and the way down are one and the same’, sounds very deep. However, it need mean no more than that when, skipping down a mountain, I meet you toiling upward, we are both on the same path. DiVerent things are attractive at diVerent times: food when you are hungry, bed when you are sleepy (KRS 201). DiVerent things attract diVerent species: sea-water is wholesome for Wsh, but poison- ous for humans; donkeys prefer rubbish to gold (KRS 199). Not all Heraclitus’ pairs of coinciding opposites admit of easy resolution by relativity, and even the most harmless-looking ones may have a more profound signiWcance. Thus Diogenes Laertius tells us that the sequence Wre–air–water–earth is the road downward, and the sequence earth– water–air–Wre is the road upward (D.L. 9. 9–11). These two roads can 6 Readers of Plato are bound to be struck by the anticipation of the allegory of the Cave in the Republic. 7 See the discussion in KRS 208. 15  PYTHAGORAS TO PLATO only be regarded as the same if they are seen as two stages on a continuous, everlasting, cosmic progress. Heraclitus did indeed believe that the cosmic Wre went through stages of kindling and quenching (KRS 217). It is presumably also in this sense that we are to understand that the universe is both generated and ungenerated, mortal and immortal (DK 22 B50). The underlying process has no beginning and no end, but each cycle of kindling and quenching is an individual world that comes into and goes out of existence. Though several of the Presocratics are reported to have been politically active, Heraclitus has some claim, on the basis of the fragments, to be the Wrst to produce a political philosophy. He was not indeed interested in practical politics: an aristocrat with a claim to be a ruler, he waived his claim and passed on his wealth to his brother. He is reported to have said that he preferred playing with children to conferring with politicians. But he was perhaps the Wrst philosopher to speak of a divine law—not a physical law, but a prescriptive law, that trumped all human laws. There is a famous passage in Robert Bolt’s play about Thomas More, A Man for All Seasons. More is urged by his son-in-law Roper to arrest a spy, in contravention of the law. More refuses to do so: ‘I know what’s legal, not what’s right; and I’ll stick to what’s legal.’ More denies, in answer to Roper, that he is setting man’s law above God’s. ‘I’m not God,’ he says, ‘but in the thickets of the law, there I am a forester.’ Roper says that he would cut down every law in England to get at the Devil. More replies, ‘And when the last law was down, and the Devil turned round on you—where would you hide, Roper, the laws all being Xat?’8 It is diYcult to Wnd chapter and verse in More’s own writings or recorded sayings for this exchange. But two fragments of Heraclitus express the sentiments of the participants. ‘The people must Wght on behalf of the law as they would for the city wall’ (KRS 249). But though a city must rely on its law, it must place a much greater reliance on the universal law that is common to all. ‘All the laws of humans are nourished by a single law, the divine law’ (KRS 250). What survives of Heraclitus amounts to no more than 15,000 words. The enormous inXuence he has exercised on philosophers ancient and modern is a matter for astonishment. There is something Wtting about his position 8 Robert Bolt, A Man for All Seasons (London: Heinemann, 1960), 39. 16  PYTHAGORAS TO PLATO in Raphael’s fresco in the Vatican stanze, The School of Athens. In this monumental scenario, which contains imaginary portraits of many Greek philosophers, Plato and Aristotle, as is right and just, occupy the centre stage. But the Wgure to which one’s eye is immediately drawn on entering the room is a late addition to the fresco: the booted, brooding Wgure of Heraclitus, deep in meditation on the lowest step.9 Parmenides and the Eleatics In Roman times Heraclitus was known as ‘the weeping philosopher’. He was contrasted with the laughing philosopher, the atomist Democritus. A more appropriate contrast would be with Parmenides, the head of the Italian school of philosophy in the early Wfth century. For classical Athens, Heraclitus was the proponent of the theory that everything was in motion, and Parmenides the proponent of the theory that nothing was in motion. Plato and Aristotle struggled, in diVerent ways, to defend the audacious thesis that some things were in motion and some things were at rest. Parmenides, according to Aristotle (Metaph. A 5. 986b21–5), was a pupil of Xenophanes, but he was too young to have studied under him in Colo- phon. He spent most of his life in Elea, seventy miles or so south of Naples. There he may have encountered Xenophanes on his wanderings. Like Xenophanes, he was a poet: he wrote a philosophical poem in clumsy verse, of which we possess about 120 lines. He is the Wrst philosopher whose writing has come down to us in continuous fragments that are at all substantial. The poem consists of a prologue and two parts, one called the path of truth, the other the path of mortal opinion. The prologue shows us the poet riding in a chariot with the daughters of the Sun, leaving behind the halls of night and travelling towards the light. They reach the gates which lead to the paths of night and day; it is not clear whether these are the same as the paths of truth and opinion. At all events, the goddess who welcomes him on his quest tells him that he must learn both: 9 The Wgure traditionally regarded as Heraclitus does not Wgure on cartoons for the fresco. Michelangelo is said to have been Raphael’s model, though R. Jones and N. Penny, Raphael, (London: Yale University Press, 1983) 77, doubt both traditions. 17  PYTHAGORAS TO PLATO Besides trustworthy truth’s unquaking heart Learn the false Wctions of poor mortals’ art. (KRS 288. 29–30) There are only two possible routes of inquiry: Two ways there are of seeking how to see One that it is, and is not not to be— That is the path of Truth’s companion Trust— The other it is not, and not to be it must. (KRS 291. 2–5) (I must ask the reader to believe that Parmenides’ Greek is as clumsy and as baZing as this English text.) Parmenides’ Way of Truth, thus riddlingly introduced, marks an epoch in philosophy. It is the founding charter of a new discipline: ontology or metaphysics, the science of Being. Whatever there is, whatever can be thought of, is for Parmenides nothing other than Being. Being is one and indivisible: it has no beginning and no end, and it is not subject to temporal change. When a kettle of water boils away, this may be, in Heraclitus’ words, the death of water and the birth of air; but for Parmenides it is not the death or birth of Being. Whatever changes may take place, they are not changes from being to non- being; they are all changes within Being. But for Parmenides there are not, in fact, any real changes at all. Being is everlastingly the same, and time is unreal because past, present, and future are all one.10 The everyday world of apparent change is described in the second part of Parmenides’ poem, the Way of Seeming, which his goddess introduces thus: I bring to an end my trusty word and thought, The tale of Truth. The rest’s another sort— A pack of lies expounding men’s beliefs. (KRS 300) It is not clear why Parmenides feels obliged to reproduce the false notions that are entertained by deluded mortals. If we took the second part of his poem out of its context, we would see in it a cosmology very much in the tradition of the Ionian thinkers. To the normal pairs of opposites Parmenides adds light and darkness, and he is given credit by Aristotle for introducing Love as the eYcient cause of everything (Metaph. A 3. 984b27). The Way of Seeming in fact includes two truths not hitherto 10 A detailed examination of Parmenides’ ontology will be found in Ch. 6 below. 18  PYTHAGORAS TO PLATO generally known: Wrst, that the earth is a sphere (D.L. 9. 21), and secondly, that the Morning Star is the same as the Evening Star. Parmenides’ disowned discovery was to provide philosophers of a later generation with a paradigm for identity statements.11 Parmenides had a pupil, Melissus, who came from Pythagoras’ island of Samos and who was said to have studied also with Heraclitus. He was active in politics, and rose to the rank of admiral of the Samos Xeet. In 441 bc Samos was attacked by Athens, and though Athens was Wnally victorious in the war Melissus is recorded as having twice inXicted defeat on the Xeet of Pericles (Plutarch, Pericles 166c–d; D.L. 9. 4). Melissus expounded the philosophy of Parmenides’ poem in plain prose, arguing that the universe was unlimited, unchangeable, immovable, indivis- ible, and homogeneous. He was remembered for drawing two consequences from this monistic view: (1) pain was unreal, because it implied (impossibly) a deWciency of being; (2) there was no such thing as a vacuum, since it would have to be a piece of Unbeing. Local motion was therefore impossible, for the bodies that occupy space have no room to move into (KRS 534). Another pupil of Parmenides was Zeno of Elea. He produced a set of more famous arguments against the possibility of motion. The Wrst went like this: ‘There is no motion, for whatever moves must reach the middle of its course before it reaches the end.’ To get to the far end of a stadium, you have to run to the half-way point, to get to the half-way point you must reach the point half-way to that, and so ad inWnitum. Better known is the second argument, commonly known as Achilles and the tortoise. ‘The slower’, Zeno said, ‘will never be overtaken by the swifter, for the pursuer must Wrst reach the point from which the fugitive departed, so that the slower must necessarily remain ahead.’ Let us suppose that Achilles runs four times as fast as the tortoise, and that the tortoise is given a forty- metre start when they run a hundred-metre race against each other. According to Zeno’s argument, Achilles can never win. For by the time he reaches the forty-metre mark, the tortoise is ahead by ten metres. By the time Achilles has run those ten, the tortoise is still ahead by two and a half metres. Each time Achilles makes up a gap, the tortoise opens up a new, shorter, gap, so he can never overtake him (Aristotle, Ph. 5. 9. 239b11–14). 11 The 19th-century philosopher Gottlob Frege used the example to introduce his celebrated distinction between sense and reference. 19  PYTHAGORAS TO PLATO These and other similar arguments of Zeno assume that distances and motions are inWnitely divisible. His arguments have been dismissed by some philosophers as ingenious but sophistical paradoxes. Others have admired them greatly: Bertrand Russell, for instance, claimed that they provided the basis of the nineteenth-century mathematical renaissance of Weierstrass and Cantor.12 Aristotle, who preserved Zeno’s puzzles for us, claimed to disarm them, and to re-establish the possibility of motion, by distinguishing between two forms of inWnity: actual inWnity and potential inWnity.13 But it was not for many centuries that the issues raised by Zeno were given solutions that satisWed both philosophers and mathematicians. Empedocles The most Xamboyant of the early philosophers of Greek Italy was Empedo- cles, who Xourished in the middle of the Wfth century. He was a native of Acragas, the town on the south coast of Sicily which is now Agrigento. The town’s port today bears the name Porto Empedocle, but this testiWes not to an enduring veneration of the philosopher, but to the Risorgimento’s passion for renaming sites in honour of Italy’s past glories. Empedocles came of an aristocratic family which owned a stud of prizewinning horses. In politics, however, he is reputed to have been a democrat; he is said to have foiled a plot to turn the city into a dictatorship. The grateful citizens, the story goes on, oVered to make him king, but he refused the oYce, preferring his frugal life as a physician and counsellor (D.L. 8. 63). If free of ambition, however, he was not devoid of vanity, and in one of his poems he boasts that wherever he goes men and women throng to him for advice and healing. He claimed to possess drugs to ward oV old age, and to know spells to control the weather. In the same poem he frankly professed himself to have achieved divine status (D.L. 8. 66). DiVerent biographical traditions, not all chronologically possible, make Empedocles a pupil of Pythagoras, of Xenophanes, and of Parmenides. Certainly he imitated Parmenides by writing a hexameter poem On Nature; this poem, dedicated to his friend Pausanias, contained about 2,000 lines, of which we possess about a Wfth. He also wrote a religious poem, PuriWcations, 12 The Principles of Mathematics (London: Allen & Unwin, 1903), 347. 13 See Ch. 5 below. 20  PYTHAGORAS TO PLATO of which less has been preserved. Scholars do not agree to which poem should be attached the many disjointed citations that survive; some, indeed, think that the two poems belonged to a single work. Further pieces of the textual jigsaw were recovered when forty papyrus fragments were identiWed in the archives of the University of Strasbourg in 1994. As a poet, Empedocles was more Xuent than Parmenides, and also more versatile. According to Aristotle, he wrote an epic on Xerxes’ invasion of Greece, and according to other traditions he was the author of several tragedies (D.L. 8. 57). Empedocles’ philosophy of nature can be regarded, from one point of view, as a synthesis of the thought of the Ionian philosophers. As we have seen, each of them had singled out some one substance as the basic or dominant stuV of the universe: Thales had privileged water, Anaximenes air, Xenophanes earth, and Heraclitus Wre. For Empedocles all four of these substances stood on equal terms as the fundamental ingredients, or ‘roots’ as he put it, of the universe. These roots had always existed, he maintained, but they mingle with each other in various proportions in such a way as to produce the familiar furniture of the world and also the denizens of the heavens. From these four sprang what was and is and ever shall: Trees, beasts, and human beings, males and females all, Birds of the air, and Wshes bred by water bright; The age-old gods as well, long worshipped in the height. These four are all there is, each other interweaving And, intermixed, the world’s variety achieving. (KRS 355) What Empedocles called ‘roots’ were called by Plato and later Greek thinkers stoicheia, a word earlier used to indicate the syllables of a word. The Latin translation elementum, from which our ‘element’ is derived, compares the roots not to syllables, but to letters of the alphabet: an elementum is an LMNtum. Empedocles’ quartet of elements was assigned a fundamental role in physics and chemistry by philosophers and scientists until the time of Boyle in the seventeenth century. Indeed, it can be claimed that it is still with us, in altered form. Empedocles thought of his elements as four diVerent kinds of matter; we think of solid, liquid, and gas as three states of matter. Ice, water, and steam would be, for Empedo- cles, speciWc instances of earth, water, and air; for us they are three diVerent 21  PYTHAGORAS TO PLATO states of the same substance, H2O. It was not unreasonable to think of Wre, and especially the Wre of the sun, as a fourth element of equal importance. One might say that the twentieth-century emergence of the science of plasma physics, which studies the properties of matter at the sun’s tem- perature, has restored Empedocles’ fourth element to parity with the other three. Aristotle praised Empedocles for having realized that a cosmological theory must not just identify the elements of the universe, but must assign causes for the development and intermingling of the elements to make the living and inanimate compounds of the actual world. Empedo- cles assigns this role to Love and Strife: Love combines the elements, and Strife forces them apart. At one time the roots grow to be one out of many, at another time they split to be many out of one. These things, he said, never cease their continual interchange, now through love coming together into one, now carried apart from each other by Strife’s hatred (KRS 348). Love and Strife are the picturesque ancestors of the forces of attraction and repulsion which have Wgured in physical theory throughout the ages. For Empedocles, history is a cycle in which sometimes Love is dominant, and sometimes Strife. Under the inXuence of Love the elements combine into a homogeneous, harmonious, and resplendent sphere, rem- iniscent of Parmenides’ universe. Under the inXuence of Strife the elements separate out, but when Love begins to regain the ground it had lost, all the diVerent species of living beings appear (KRS 360). All compound beings, such as animals and birds and Wsh, are temporary creatures that come and go; only the elements are everlasting, and only the cosmic cycle goes on for ever. To explain the origin of living species, Empedocles put forward a remarkable theory of evolution by survival of the Wttest. First Xesh and bone emerged as chemical mixtures of the elements, Xesh being consti- tuted by Wre, air, and water in equal parts, and bone being two parts water to two parts earth and four parts Wre. From these constituents unattached limbs and organs were formed: unsocketed eyes, arms without shoulders, and faces without necks (KRS 375–6). These roamed around until they chanced to Wnd partners; they formed unions, which were often, at this preliminary stage, quite unsuitable. Thus there arose various monstrosities: human-headed oxen, ox-headed humans, androgynous creatures with 22  PYTHAGORAS TO PLATO faces and breasts on front and back (KRS 379). Most of these fortuitous organisms were fragile or sterile; only the Wttest structures survived to be the human and animal species we know. Their Wtness to reproduce was a matter of chance, not design (Aristotle, Ph. 2. 8. 198b29). Aristotle paid tribute to Empedocles for being the Wrst to grasp the important biological principle that diVerent parts of dissimilar living organ- isms might have homologous functions: e.g. olives and eggs, leaves and feathers (Aristotle, GA 1. 23. 731a4). But he was contemptuous of his attempt to reduce teleology to chance, and for many centuries biologists followed Aristotle rather than Empedocles. Empedocles had the last laugh when Darwin saluted him for ‘shadowing forth the principle of natural selection’.14 Empedocles employed his quartet of elements in giving an account of sense-perception, based on the principle that like is known by like. In his poem PuriWcations he combined his physical theory with the Pythagorean doctrine of metempsychosis.15 Sinners—divine or human—are punished when Strife casts their souls into diVerent kinds of creatures on land and sea. A cycle of reincarnation held out a hope of eventual deiWcation for privileged classes of men: seers, bards, doctors, and princes (KRS 409). Empedocles, of course, had a claim to identify himself with all these professions. In his writing, Empedocles moves seamlessly between an austerely mechanistic mode and a mystically religious one. He sometimes uses divine names for his four elements (Zeus, Hera, Aidoneus, and Nestis) and identiWes his Love with the goddess Aphrodite, whom he celebrates in terms anticipating Schiller’s great ‘Ode to Joy’ (KRS 349). No doubt his own claim to divinity can be deXated in the same way as he demythologizes the Olympian gods. But it caught the attention of posterity, especially in the legend of his death. A woman called Pantheia, the story goes, given up for dead by the physicians, was miraculously restored to life by Empedocles. To celebrate, he oVered a sacriWcial banquet to eighty guests in a rich man’s house at the foot of Etna. When the other guests went to sleep, he heard his name called from heaven. He hastened to the summit of the volcano, and then, in Milton’s words, 14 Appendix to 6th edn. of The Origin of Species, quoted in A. Gottlieb, The Dream of Reason: A History of Western Philosophy from the Greeks to the Renaissance (London: Allen Lane, 2000), 80. 15 See Ch. 7 below. 23  PYTHAGORAS TO PLATO to be deemed A god, leaped fondly into Aetna Xames. (Paradise Lost iii. 470) Matthew Arnold dramatized this story in his Empedocles on Etna. He places these verses in the mouth of the philosopher at the crater’s rim: This heart will glow no more; thou art A living man no more, Empedocles! Nothing but a devouring Xame of thought— But a naked, eternally restless mind! To the elements it came from Everything will return Our bodies to earth, Our blood to water, Heat to Wre, Breath to air. They were well born, they will be well entomb’d— But mind? (lines 326 –38) Arnold gives the philosopher, before his Wnal leap, the hope that in reward for his love of truth his intellect will never wholly perish. Anaxagoras If Empedocles achieved a kind of immortality as a precursor of Darwin, his contemporary Anaxagoras is sometimes regarded as an intellectual ances- tor of the currently popular cosmology of the big bang. Anaxagoras was born around 500 bc in Clazomenae, near Izmir, and was possibly a pupil of Anaximenes. After the end of the wars between Persia and Greece, he came to Athens and was a client of the statesman Pericles. He thus stands at the head of the distinguished series of philosophers whom Athens either bred or welcomed. When Pericles fell from favour, Anaxagoras too became a target of popular attack. He was prosecuted for treason and impiety, and Xed to Lampsacus on the Hellespont, where he lived in honourable exile until his death in 428. 24  PYTHAGORAS TO PLATO Here is his account of the beginning of the universe: ‘All things were together, inWnite in number and inWnite in smallness; for the small too was inWnite. While all things were together, nothing was recognizable because of its smallness. Everything lay under air and ether, both inWnite’ (KRS 467). This primeval pebble began to rotate, throwing oV the surrounding ether and air and forming out of them the stars and the sun and the moon. The rotation caused the separation of dense from rare, of hot from cold, of dry from wet, and bright from dark. But the separation was never com- plete, and to this day there remains in every single thing a portion of everything else. There is a little whiteness in what is black, a little cold in what is hot, and so on: things are named after the item that is dominant in it (Aristotle, Ph. 1. 4. 187a23). This is most obvious in the case of semen, which must contain hair and Xesh, and much, much more; but it must also be true of the food we eat (KRS 483–4, 496). In this sense, as things were in the beginning, so now they are all together. The expansion of the universe, Anaxagoras maintained, has continued in the present and will continue in the future (KRS 476). Perhaps it has already generated worlds other than our own. As a result of the presence of everything in everything, he says, men have been formed and the other ensouled animals. And the men possess farms and inhabit cities just as we do, and they have a sun and a moon and the rest just like us. The earth produces things of every sort for them to be harvested and stored, as it does for us. I have said all this about the process of separating oV, because it would have happened not only here with us, but elsewhere too. (KRS 498) Anaxagoras thus has a claim to be the originator of the idea, later proposed by Giordano Bruno and popular again today in some quarters, that our cosmos is just one of many which may, like ours, be inhabited by intelli- gent creatures. The motion that sets in train the development of the universe is, according to Anaxagoras, the work of Mind. ‘All things were together: then Mind came and gave them order’ (D.L. 2. 6). Mind is inWnite and separate, and has no part in the general commingling of elements; if it did, it would get drawn into the evolutionary process and could not control it. This teaching, placing mind Wrmly in control of matter, so struck his contemporaries that they nicknamed Anaxagoras himself the 25  PYTHAGORAS TO PLATO Mind. It is diYcult, however, to assess exactly what his doctrine, though it greatly impressed both Plato and Aristotle, actually meant in practice. In Plato’s dialogue Phaedo, Socrates, in his last days in prison, is made to express his gradual disillusionment with the mechanistic explanations of natural science to be found in the early philosophers. He was pleased, he said, when he heard that Anaxagoras had explained everything by nous, or mind; but he was disappointed by the total absence of reference to value in his work. Anaxagoras was like someone who said that all Socrates’ actions were performed with his intelligence, and then gave the reason why he was sitting here in prison by talking about the constitution of his body from bones and sinews, and the nature and properties of these parts, without mentioning that he judged it better to sit there in obedience to the Athenian court’s sentence. Teleological explanation was more profound than mechanistic explanation. ‘If anyone wants to Wnd out the reason why each thing comes to be or perishes or exists, this is what he must Wnd out about it: how is it best for that thing to exist, or to act or be acted upon in any way?’ (Phd. 97d). Anaxagoras speaks about his Mind in ways appropriate to divinity, and this could have made him vulnerable to a charge, in the Athenian courts, of introducing strange gods. But in fact the charge of impiety seems to have been based on his scientiWc conjectures. The sun, he said, was a Wery lump of metal, somewhat larger than the Peloponnesus. This was taken to be incompatible with the veneration appropriate to the sun as divine. In exile in Lampsacus, Anaxagoras made his Wnal benefaction to humanity: the invention of the school holiday. Asked by the authorities of the city how they should honour him, he said that children should be let oV school in the month of his death. He had already earned the gratitude of students of science by being the Wrst writer to include diagrams in his text. The Atomists The Wnal and most striking anticipation of modern science in the Presoc- ratic era was made by Leucippus of Miletus and Democritus of Abdera. Though they are always named together, like Tweedledum and Tweedle- dee, and considered joint founders of atomism, nothing really is known about Leucippus except that he was the teacher of Democritus. It is on the 26  PYTHAGORAS TO PLATO surviving writings of the latter that we principally depend for our know- ledge of the theory. Democritus was a polymath and a proliWc writer, author of nearly eighty treatises on topics ranging from poetry and harmony to military tactics and Babylonian theology. All these treatises are lost, but we do possess a copious collection of fragments from Democri- tus, more than from any previous philosopher. Democritus was born in Abdera, on the coast of Thrace, and was thus the Wrst signiWcant philosopher to be born on the Greek mainland. The date of his birth is uncertain, but it was probably between 470 and 460 bc. He is reported to have been forty years younger than Anaxagoras, from whom he took some of his ideas. He travelled widely and visited Egypt and Persia, but was not over-impressed by the countries he visited. He once said that he would prefer to discover a single scientiWc explanation than to become king of Persia (D.L. 9. 41; DK 68 B118). Democritus’ fundamental thesis is that matter is not inWnitely divisible. We do not know his exact argument for this conclusion, but Aristotle conjectured that it ran as follows. If we take a chunk of any kind of stuV and divide it up as far as we can, we will have to come to a halt at tiny bodies which are indivisible. We cannot allow matter to be divisible to inWnity: for let us suppose that the division has been carried out and then ask: what would ensue if the division was carried out? If each of the inWnite number of parts has any magnitude, then it must be further divisible, which contradicts our hypothesis. If, on the other hand, the surviving parts have no magnitude, then they can never have amounted to any quantity: for zero multiplied by inWnity is still zero. So we have to conclude that divisibility comes to an end, and the smallest possible fragments must be bodies with sizes and shapes. These tiny, indivisible bodies were called by Democritus ‘atoms’ (which is just the Greek word for ‘indivisible’) (Aristotle, GC 1. 2. 316a13–b16).16 Atoms, Democritus believed, are too small to be detected by the senses; they are inWnite in number and come in inWnitely many varieties, and they have existed for ever. Against the Eleatics, he maintained that there was no contradiction in admitting a vacuum: there was a void, and in this inWnite empty space atoms were constantly in motion, just like motes in a sunbeam. They come in diVerent forms: they may diVer in shape (as the letter A diVers from the letter N), in order (as AN diVers from NA), and in posture (as N 16 For Aristotle’s counter to this argument, see Ch. 5 below. 27  PYTHAGORAS TO PLATO diVers from Z). Some of them are