The Nature Of Explanation

The Nature of Explanation This page intentionally left blank THE NATURE OF EXPLANATION PETER A C H I N S T E I N New York Oxford OXFORD U N I V E R S I T Y PRESS Oxford University Press Oxford New York Toronto Delhi Bombay Calcutta Madras Karachi Petaling Jaya Singapore Hong Kong Tokyo Nairobi Dar es Salaam Cape Town Melbourne Auckland and associated companies in Beirut Berlin Ibadan Nicosia Copyright © 1983 by Oxford University Press, Inc. First published in 1983 by Oxford University Press, Inc., 200 Madison Avenue, New York, New York 10016 First issued as an Oxford University Press paperback, 1985 Oxford is a registered trademark of Oxford University Press. 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, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Library of Congress Cataloging in Publication Data Achinstein, Peter. The nature of explanation. Includes index. 1. Explanation (Philosophy) Addresses, essays, lectures. I. Title. BD237.A25 1983 121 82-22571 ISBN 0-19-503215-2 0-19-503743-X (pbk.) Printing (last digit): 9 8 7 6 5 4 3 2 Printed in the United States of America For my son Jonathan This page intentionally left blank Preface For more than a third of a century philosophical discussions of explanation have been dominated by various formal "models." Included among these are the deductive and statistical models of Hempel and variants proposed by others, and the statistical model of Salmon. Yet there are well-known counterexamples to these models, and good reasons for supposing that they fail to provide even necessary conditions. The typical response is to add more conditions to the model or to modify others. But each new variation on the old theme is simply an invitation to philosophical sharpshooters to hit the mark with fresh counterexamples. What this book presents is not another variation but a different theme. Unlike the standard theories, it focuses, to begin with, on the explaining act itself—the act in which by uttering or writing words someone explains something. From that act a "product" emerges: an explanation. To characterize what kind of entity that product is, as well as how it can be evaluated, essential reference must be made to the concept of an explaining act. Otherwise, I argue, we will be unable to distinguish explanations from products of non-explaining acts; and we will be unable to say why various explanations, particularly in the sciences, deserve praise or blame. A theory of the explaining act, of the product and its ontological status, and of the evaluation of explanations, is presented in the second, third, and fourth chapters. Following this the theory is brought to bear on a number of issues: why have the standard models of explanation been unsuccessful (are they seeking the impossible)? What is a causal expl