Cause and Explanation in Ancient Greek Thought This page intentionally left blank Cause and Explanation in Ancient Greek Thought R. J. Hankinson CLARENDON PRESS · OXFORD 1998 Great Clarendon Street,Oxford OX2 6DP 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 Bangkok Buenos Aires Cape Town Chennai Dar es Salaam Delhi Hong Kong Istanbul Karachi Kolkata Kuala Lumpur Madrid Melbourne Mexico City Mumbai Nairobi São Paulo Shanghai Taipei Tokyo Toronto 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 © R. J. Hankinson 1998 The moral rights of the authors have been asserted Database right Oxford University Press (maker) First published 1998 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 reprographicsrights 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 Hankinson,R. J. Cause and explanation in ancient Greece / R. J. Hankinson. Includes bibliographical references and index. 1. Causation—History. 2. Explanation—History. 3. Philosophy,Ancient. I. Title. B187.C38H36 1998 122 ′ .0938—dc21 98-26743 ISBN 0-19-823745-6 For Jennifer This page intentionally left blank Preface It was first suggested that I write this book in September 1986: it has,accordingly,taken more than a decade to come to fruition. I began by supposing that it would consist in a relatively narrowly focused investigation of the Greek notion of explanation; it has developed into something more like a general account of what the Greeks called phusikē, the inquiry into nature,since I found it impossible to treat of the meta-theoretical issues of how the Greeks viewed the concepts of explanation and cause themselves without also considering the actual explanations and causes that they championed (it also accounts for my ranging beyond the boundaries of natural science and into metaphysics). This partly accounts for its elephantine period of gestation; but I did not in any case set about the writing in earnest until the spring of 1992,when I produced a first draft as work in progress for a graduate seminar: I am grateful to the seminar's students for their patience and flexibility in adapting to an unorthodox format,and for their enthusiasm and input. My interest in questions of cause and explanation dates from the time when,as an undergraduate,I decided to pursue these issues in Galen's philosophy for my doctoral dissertation,and they have continued to be central to my work in Greek philosophy and science. Inevitably,then,much of this volume goes over ground I have covered elsewhere, although nowhere have I simply recycled previously published material,while in several cases my views have changed. Still,it may be appropriate to indicate areas of overlap. I dealt with Alcmaeon's argument (I.3c) in Hankinson (1991a, 1992a),and some of my treatment of Xenophanes in I.3a is paralleled in Hankinson (1995a, ch. III),as is my account of Democritean scepticism in VI.1 e. Some of the Hippocratic discussion of Chapter II is anticipated in Hankinson (1991a, 1992c, 1995e),while the remarks on evidence are expanded in Hankinson (1997). Plato's Alcmaeonian argument in III.3a is developed in Hankinson (1992a). Much of the discussion of Aristotle in Chapters IV and V is adapted from Hankinson (1995b, c),while the Atomist and Stoic accounts of causation and explanation that occupy Chapters VI and VII are rehearsed in Hankinson (1998a, b); also relevant is (1996). The sceptical attack on explanation and cause,the subject of Chapter VIII,is also dealt with in Hankinson (1995a, chs. XI and XII); while ch. XIII of that work,along with Hankinson (1987 b, 1988d, 1990a, 1995d, 1998d),as well as parts of (1998c),all bear on the discussion of the medical tradition in Chapter IX. Hankinson (1988 a, c, 1995a, ch. XV) relate to the viii PREFACE issue of the status of divination discussed in VI.3a, VII.2d, VIII.5,XI.1 b, and XII.2d. Finally,my account of Galen's views in XI.2–5 draws on Hankinson (1987a, 1988b, d, 1989,1991 a, b, c, 1993,1994 a, b, 1998c). Many of these articles were originally presented as papers in various places; I owe much to the perspicacity of their original audiences. Particular thanks are due to several colleagues and friends for their help with individual sections. Alex Mourelatos gave me the benefit of his great learning in Presocratic philosophy in general and atomism in particular (Chapters I and VI); Lesley Dean-Jones commented acutely on the medical material contained in Chapters II and IX; and Paul Woodruff helped me with both Plato and the Sceptics (Chapters III and VIII). Sylvia Berryman made several useful suggestions concerning Theophrastus and Strato (V.3). The argument of Chapter XII owes much to discussions with David Bradshaw,who was also good enough to read and comment in detail on penultimate drafts of that chapter and Chapter X. My largest debt in this regard is owed to Tim O'Keefe,whose doctoral work on Epicurus and Democritus on reduction and emergence,causation and responsibility,determinism and fatalism,caused me to re-evaluate and revise many of my views on these issues,particularly as they affect the argument of VI.1 b, 2b, and 3. It is both a pleasure and a privilege—and one which it is all too easy to take for granted—to work with such generous and genial colleagues. I am grateful also to Peter Momtchiloff of Oxford University Press for taking the book over after the series in which it was originally due to appear was peremptorily cancelled,without either consultation or explanation,by another publisher. An anonymous referee for OUP made several valuable suggestions which I have incorporated into the final version. Finally,my greatest indebtednesses. In the course of a long,presumably insomniac,European rail journey,Jonathan Barnes read and commented upon the whole typescript with admirable expeditiousness and acuity,suggesting numerous improvements ranging from the correction of typographical errors through matters of fact and questions of argumentative substance and rigour to issues of overall strategy and presentation. His influence is evident (to me at least) on virtually every page. And last,but most de finitely not least,my wife,Jennifer,read the manuscript in full,offering many suggestions of both a philosophical and of a stylistic nature. I am also grateful for her support (not to say understanding and forbearance) through a period in which both of us have had to juggle heavy workloads with family responsibilities. Anyone who has had to attempt such feats of domestic dexterity will know what I mean when I say that merely to survive is an achievement; to do so with good will PREFACE ix and good humour intact is little short of miraculous. In recognition of this (and much else),with love and gratitude,I dedicate this book to her. Jim Hankinson Texas, April 1997 This page intentionally left blank Contents Note on Citations xv Introduction 1 I. The Presocratics 7 1. Prehistory 7 2. The Milesians 8 3. Causal Origination 26 4. Pluralism and Emergence 39 5. Conclusions 50 II. Science and Sophistry 51 1. Rational Medicine 51 2. The Sophists 69 3. History 79 4. Conclusions 82 III. Plato 84 1. Metaphysics and Causation 84 2. Causation and the Soul 98 3. Hypothesis and Explanation 102 4. Timaeus: The Model Applied 108 5. Coda: Mathematical and Astronomical Theory 120 6. Conclusions 124 IV. Aristotle: Explanation and Nature 125 1. The Structure of Reality 125 2. Causation and Coincidence 132 3. Teleological Explanation 140 4. The Explanation of Action 153 5. Conclusions 158 V. Aristotle: Explanation and the World 160 1. Demonstration and Explanation 160 2. Observation and Science 171 3. Theophrastus and After 188 4. Conclusions 199 xii CONTENTS VI. The Atomists 201 1. Democritus 201 2. Epicureanism and Explanation 211 3. Freedom and the Explanation of Action 223 4. Later Epicurean Scientific Epistemology 232 5. Conclusions 236 VII. The Stoics 238 1. Stoic Causal Theory 238 2. Freedom and Determinism 252 3. Stoic Cosmology 262 4. Conclusions 266 VIII. The Sceptics 268 1. The Development of Scepticism 268 2. Aenesidemus against the Aetiologists 269 3. The General Attack on Causes 277 4. The Modes of Agrippa 285 5. Scepticism and Science 287 6. Conclusions 293 IX. Explanation in the Medical Schools 295 1. The Limits of Explanation 295 2. Empiricism and Rationalism 306 3. Methodism 318 4. Conclusions 321 X. The Age of Synthesis 323 1. The Origins of Syncretism 323 2. The Convergence of the Schools 328 3. The Emergence of Middle Platonism 339 4. The Revival of Aristotelianism: Alexander of Aphrodisias 353 5. Conclusions 363 XI. Science and Explanation 364 1. Ptolemy 364 2. Galen: The Structure of Causation 373 3. The Aristotelian Influence 379 4. Galen's Teleology 385 5. Powers,Functions,and Activities 392 6. Conclusions 402 CONTENTS xiii XII.