Counterfactuals and Scientific Realism

Counterfactuals and Scientific Realism

New Directions in the Philosophy of Science Series Editor: Steven French, Philosophy, University of Leeds, UK The philosophy of science is going through exciting times. New and productive relationships are being sought with the history of science. Illuminating and innovative comparisons are being developed between the philosophy of science and the philosophy of art. The role of mathematics in science is being opened up to renewed scrutiny in the light of original case studies. The philosophies of particular sciences are both drawing on and feeding into new work in metaphysics and the relationships between science, metaphysics and the philosophy of science in general are being re-examined and reconfigured. The intention behind this new series from Palgrave Macmillan is to offer a new, dedicated, publishing forum for the kind of exciting new work in the philosophy of science that embraces novel directions and fresh perspectives. To this end, our aim is to publish books that address issues in the philosophy of science in the light of these new developments, including those that attempt to initiate a dialogue between various perspectives, offer constructive and insightful critiques, or bring new areas of science under philosophical scrutiny. Titles include: Sorin Bangu THE APPLICABILITY OF MATHEMATICS IN SCIENCE Indispensability and Ontology Melinda Fagan PHILOSOPHY OF STEM CELL BIOLOGY Knowledge in Flesh and Blood P.D. Magnus SCIENTIFIC ENQUIRY AND NATURAL KINDS From Planets to Mallards Michael J. Shaffer COUNTERFACTUALS AND SCIENTIFIC REALISM Adam Toon MODELS AS MAKE-BELIEVE Imagination, Fiction and Scientific Representation Forthcoming titles include: Alex Broadbent THE PHILOSOPHY OF EPIDEMIOLOGY Gabriele Contessa SCIENTIFIC MODELS AND REPRESENTATION Douglas Kutach CAUSATION AND ITS BASIS IN FUNDAMENTAL PHYSICS Matteo Morganti BETWEEN SCIENCE, METAPHYSICS AND COMMON SENSE Matthew Slater ARE SPECIES REAL? John S. Wilkins and Malte C. Ebach THE NATURE OF CLASSIFICATION New Directions of the Philosophy of Science Series Standing Order ISBN 978 0 230 20210 8 (hardcover) (outside North America only) You can receive future titles in this series as they are published by placing a standing order. Please contact your bookseller or, in case of difficulty, write to us at the address below with your name and address, the title of the series and the ISBN quoted above. Customer Services Department, Macmillan Distribution Ltd, Houndmills, Basingstoke, Hampshire RG21 6XS, England

Counterfactuals and Scientific Realism Michael J. Shaffer St. Cloud State University, USA

Michael J. Shaffer 2012 Softcover reprint of the hardcover 1st edition 2012 978-0-230-30845-9 All rights reserved. No reproduction, copy or transmission of this publication may be made without written permission. No portion of this publication may be reproduced, copied or transmitted save with written permission or in accordance with the provisions of the Copyright, Designs and Patents Act 1988, or under the terms of any licence permitting limited copying issued by the Copyright Licensing Agency, Saffron House, 6 10 Kirby Street, London EC1N 8TS. Any person who does any unauthorized act in relation to this publication may be liable to criminal prosecution and civil claims for damages. The author has asserted his right to be identified as the author of this work in accordance with the Copyright, Designs and Patents Act 1988. First published 2012 by PALGRAVE MACMILLAN Palgrave Macmillan in the UK is an imprint of Macmillan Publishers Limited, registered in England, company number 785998, of Houndmills, Basingstoke, Hampshire RG21 6XS. Palgrave Macmillan in the US is a division of St Martin s Press LLC, 175 Fifth Avenue, New York, NY 10010. Palgrave Macmillan is the global academic imprint of the above companies and has companies and representatives throughout the world. Palgrave and Macmillan are registered trademarks in the United States, the United Kingdom, Europe and other countries ISBN 978-1-349-33906-8 DOI 10.1057/9781137271587 ISBN 978-1-137-27158-7 (ebook) This book is printed on paper suitable for recycling and made from fully managed and sustained forest sources. Logging, pulping and manufacturing processes are expected to conform to the environmental regulations of the country of origin. A catalogue record for this book is available from the British Library. A catalog record for this book is available from the Library of Congress. 10 9 8 7 6 5 4 3 2 1 21 20 19 18 17 16 15 14 13 12

SAL. All these difficulties and objections which you urge are so well founded that it is impossible to remove them; and, our Author would also do. I grant that these conclusions proved in the abstract will be different when applied to the concrete and will be fallacious to this extent, that neither will the horizontal motion be uniform nor the natural acceleration be in the ratio assumed, nor the path of the projectile a parabola, etc. But, on the other hand, I ask you not to begrudge our Author that which other eminent men have assumed even if not strictly true. Galileo Galilei, Dialogues Concerning Two New Sciences

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Contents Series Editor s Foreword x Introduction 1 I.1 Preliminaries and outline of project 1 1 The Concept of Idealization 11 1.1 Idealization and the sciences 11 1.2 The function of idealization 14 1.3 Truth and idealization 17 1.4 Idealization and simplification 19 1.5 Model/world complexity and simplicity 21 1.6 Idealization and representation 24 1.7 The is an idealization of relation 26 1.8 Admissible idealizing assumptions 26 1.9 More on the representational nature of idealization 27 1.10 Basic terminology 29 1.11 Prediction, explanation, and idealization 30 1.12 Theoretical idealizations 32 1.13 Non-constructive idealizations 35 1.14 Constructive idealizations 40 1.15 Non-theoretical idealizations 41 2 The Ubiquity of Idealization and Its Logic 47 2.1 Introduction 47 2.2 Cartwright s anti-realism and the ubiquity of idealizing assumptions 49 2.3 The ineliminability of idealizations thesis 52 2.4 An aside on the use of the terms idealization and abstraction 54 2.5 The ubiquity thesis and the logic of idealization 56 2.6 The strong ubiquity thesis and the weak ubiquity thesis 58 2.7 A problem for scientific realism 60 2.8 More on the idealization-based attacks on realism 62 2.9 Ubiquity, eliminability, and representation 63 2.10 The virtues of simplicity and the nature of theoretical claims 64 vii

viii Contents 2.11 Nowak s objection 69 2.12 Idealization and counterfactuals 81 2.13 The rightness of counterfactuals and idealizing counterfactuals 83 2.14 The logic of idealization: VI 86 2.15 The completeness of possible worlds 89 2.16 The idealization relation 90 2.17 Why accept VI as the logic of idealization? 95 3 Epistemic Access, Confirmation, and Idealization 101 3.1 Confirmation, idealization, and the epistemic access problem 101 3.2 The ubiquity thesis and de facto confirmation 105 3.3 Hypothetico-deductivism 109 3.4 The instance theory of confirmation and Hempel s theory of confirmation 111 3.5 Frequencies of idealized events 113 3.6 Probabilities and confirming idealizing counterfactuals 115 3.7 Bayesianism and idealizing counterfactuals 116 3.8 The basics of Bayesian confirmation theory 117 3.9 A problem for Bayesian confirmation theory 122 3.10 Prospects for a solution to the Bayesian problem of idealization 124 3.11 Lewis concept of imaging 125 3.12 The AGM/Levi approach to conditionals 127 3.13 Bennett s hybrid view 131 3.14 Jones defense of Bayesianism 133 3.15 A Nowakian response 137 3.16 Provisional conclusions and prognoses 139 4 Idealization, Inference to the Best Explanation, and Scientific Realism 145 4.1 Idealization and inference to the best explanation 145 4.2 Desiderata for a theory of inference to the best explanation 146 4.3 What is an explanation? 147 4.4 The best answers to why-questions 149 4.5 Contextualism and degrees of explanatoriness 149 4.6 A formal account of inference to the best explanation 155 4.7 What it takes (minimally) to be an explanation 157

Contents ix 4.8 The contextual aspects of explanation 159 4.9 When are we justified in claiming that something has been explained? 160 4.10 The probative nature of inference to the best explanation, likelihoods, and the acceptance of theories 163 4.11 Further norms, evidence, and the variety of explanatory practices 167 4.12 Answering the explanatory regress argument and the argument from unconfirmability 171 4.13 Refuting the argument form misrepresentation 173 4.14 Scientific realism and its varieties 176 4.15 Realisms 178 4.16 The ontological status of idealized models/worlds 185 4.17 The realism/anti-realism debate and the many aims of science 187 References 194 Index 207

Series Editor s Foreword The intention behind this series is to offer a new, dedicated publishing forum for the kind of exciting new work in the philosophy of science that embraces novel directions and fresh perspectives. To this end, our aim is to publish books that address issues in the philosophy of science in the light of these new developments, including those that attempt to initiate a dialogue between various perspectives, offer constructive and insightful critiques, or bring new areas of science under philosophical scrutiny. Michael Shaffer offers an ambitious and innovative work that certainly meets the aims of the series. Idealization is one of the most significant and powerful features of science but fully understanding its nature and role remains elusive. Shaffer tackles this issue together with its philosophical ramifications by deploying a formal analysis backed up with case studies from scientific practice. The central idea is to characterize idealization in terms of incomplete possible worlds and then to represent those incomplete worlds via a framework of partial models. This analysis is then used as a hook with which to engage a wide range of issues in the philosophy of science, from the nature of truth to scientific realism and the methodology of Bayesian confirmation. In particular, Shaffer challenges certain views of the way idealization supposedly undermines claims that theories may be regarded as approximately true and his arguments offer a useful corrective to the current hegemony that takes the presence of idealization as a problem for scientific realism. More generally, he offers a new perspective on the realist-antirealism debate, noting that the anti-realists emphasis on the instrumental features of scientific theories leads them to neglect the crucial point that many practically useful but strictly false theories can still be regarded as true when appropriately understood as having the form of counterfactuals. On the other hand, realists have erred in focussing on truth or its approximate variant as the only aim of science and as a result have failed to note how idealization can be used to secure instrumentality by sacrificing unconditional truth. Dismissing the idea that all idealizations are ultimately eliminable as unfeasible in practice, Shaffer suggests a way forward for both sides in the debate through balancing the twin aims of computational tractability and representational accuracy. x

Series Editor s Foreword xi He goes on to argue that standard accounts of theory confirmation in science such as the hypothetico-deductive approach, the instance theory of confirmation, Hempel s theory, and, significantly, given its current dominance, Bayesian confirmation theory cannot, in fact, adequately account for the acceptance of theoretical claims that depend on idealizations. In place of these accounts he offers an alternative theory of conditional acceptance incorporating the crucial notion of simplicity in science that then serves as the appropriate theory of rational acceptance for theoretical claims that are true only under the relevant idealizing assumptions. The core of his proposal is that such claims should be regarded as a special sort of counterfactual about what occurs in worlds that are simplifications of less idealized worlds and thus reasoning about these claims can be understood as fundamentally suppositional in form. This is a bold and exciting project that, as I have just sketched, casts new light on a range of core topics in the philosophy of science. It is precisely the sort of proposal that the editorial board and I aim to support through the New Directions series and we are sure that Shaffer s book will have a major impact on the field. Steven French Professor of Philosophy of Science University of Leeds