Thought Experiments

THOUGHT EXPERIMENTS

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THOUGHT EXPERIMENTS ROY A. SORENSEN

OXFORD UNIVERSITY PRESS New York Oxford

Oxford University Press Oxford New York Athens Auckland Bangkok Bogota Buenos Aires Calcutta Cape Town Chennai Dar es Salaam Delhi Florence Hong Kong Istanbul Karachi Kuala Lumpur Madrid Melbourne Mexico City Mumbai Nairobi Paris Sao Paulo Singapore Taipei Tokyo Toronto Warsaw and associated companies in Berlin Ibadan

Copyright ©1992 by Roy A. Sorensen First published in 1992 by Oxford University Press, Inc. 198 Madison Avenue, New York, New York 10016 First Issued as an Oxford University Press paperback, 1998 Oxford is a registered trademark of Oxford University Press, Inc. 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 Sorensen, Roy A. Thought expriments Roy A. Sorensen p. cm. Includes bibliographical references and index. ISBN 0-19-507422-X ISBN 0-19-512913-X (pbk.) 1 Thought and thinking. 2. Logic 3. Philosophy and science 1. Title B105.T54S67 1992 101-dc20 9136760

135798642 Printed in the United States of America on acid-free paper

For Julia, a woman of fine distinctions

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ACKNOWLEDGMENTS

This book has indebted me to many people. The first group consists of the individuals who attended colloquia given at the Graduate Center of the City University of New York, Columbia University, Dartmouth College, Rutgers University, the State University of New York at Stony Brook, Virginia Tech, and the 1990 Inter-University Conference for Philosophy of Science in Dubrovnik. Several of my colleagues at New York University have earned my gratitude for their encouragement and advice, among them Raziel Abelson, Frances Kamm, John Richardson, William Ruddick, Peter Unger, and especially John Carroll. I have also acquired far-flung debts to Lars Bergstrom, James Robert Brown, and Martin Bunzl, who scrutinized earlier drafts. Since I used the latter in philosophy of science courses, this book has benefited from student input. Anonymous, detailed referee reports led me to make painful but necessary excisions, precisifications and elaborations. This book has been through enough drafts to win rave reviews from lumberjacks! A New York University presidential Fellowship allowed me to experience the hospitality of the Virginia Tech philosophy department. Richard Burian guided me through the ins and outs of evolutionary theory and philosophy of biology (though I may still have zigged where I should have zagged); Joseph Pitt was my Galileo hotline; Peter Barker and Roger Ariew filled in assorted gaps in my knowledge of the history of science; and John Christman, Julia Driver, and Jim Klagge kept me in focus about ethical thought experiments. My last group of creditors are editors. I thank the editor of the American Scientist for permission to use a portion of "Thought Experiments" in chapters 3 and 6 and the editors of Philosophical Studies for the use of parts of "Moral Dilemmas, Thought Experiments, and Conflict Vagueness" in chapter 7. Finally, at Oxford University Press I thank senior editor Cynthia Read and assistant editor Peter Ohlin for shepherding this book into its final form. New York September 1991

R.A.S.

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CONTENTS

Introduction, 7

1. Our Most Curious Device, 3 I The Instrument of Choice, 7 II

Scientific Thought Experiments, 8

III

The Bridge to Philosophical Thought Experiments, 11

IV

Analytic Philosophy's Commitment to Thought Experiment, 75

2. Scepticism About Thought Experiments, 21 I

Introspection on the Sly? 27 A. The Internal Horizon, 27 B. Complaints About Introspection, 22 C. The Parallel Plight of Thought Experiments, 26

II

A Repackaged Appeal to Ordinary Language? 41 A. How the Appeal to Ordinary Language Is Supposed to Work, 42 B. Strong Scepticism About the Appeal to Ordinary Language, 42 C. Moderate Scepticism About the Appeal to Ordinary Language, 43 D. Semantic Descent to Thought Experiments, 45

III

Thought Experiments and the Dilemma of Informativeness, 46

3. Mach and Inner Cognitive Africa, 51 I II III

Instinctive Knowledge, 57 The Continuum of Cognitive Bargain Hunters, 58 Mach's Response to the Problem of Informativeness, 61

CONTENTS