Philosophy and Foundations of Physics Series Editors: Dennis Dieks and Miklos Redei In this series: Vol. 1: The Ontology of Spacetime Edited by Dennis Dieks Vol. 2: The Structure and Interpretation of the Standard Model By Gordon McCabe Vol. 3: Symmetry, Structure, and Spacetime By Dean Rickles Vol. 4: The Ontology of Spacetime II Edited by Dennis Dieks The Ontology of Spacetime II Edited by Dennis Dieks Institute for History and Foundations of Science Utrecht University Utrecht, The Netherlands Amsterdam – Boston – Heidelberg – London – New York – Oxford – Paris San Diego – San Francisco – Singapore – Sydney – Tokyo Elsevier Radarweg 29, PO Box 211, 1000 AE Amsterdam, The Netherlands The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK First edition 2008 Copyright © 2008 Elsevier B.V. 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 written permission of the publisher Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone (+44) (0) 1865 843830; fax (+44) (0) 1865 853333; email: [email protected]. Alternatively you can submit your request online by visiting the Elsevier web site at http://elsevier.com/locate/permissions, and selecting Obtaining permission to use Elsevier material Notice No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein. Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN-13: 978-0-444-53275-6 Series ISSN: 1871-1774 For information on all Elsevier publications visit our website at books.elsevier.com Printed and bound in Hungary 080910111210987654321 CONTENTS List of Contributors vii Preface ix 1. A Trope-Bundle Ontology for Field Theory 1 2. Is Structural Spacetime Realism Relationism in Disguise? The Supererogatory Nature of the Substantivalism/Relationism Debate 17 3. Identity, Spacetime, and Cosmology 39 4. Persistence and Multilocation in Spacetime 59 5. Is Spacetime a Gravitational Field? 83 6. Structural Aspects of Space-Time Singularities 111 7. Who’s Afraid of Background Independence? 133 8. Understanding Indeterminism 153 9. Conventionality of Simultaneity and Reality 175 10. Pruning Some Branches from “Branching Spacetimes” 187 11. Time Lapse and the Degeneracy of Time: Gödel, Proper Time and Becoming in Relativity Theory 207 12. On Temporal Becoming, Relativity, and Quantum Mechanics 229 13. Relativity, the Passage of Time and the Cosmic Clock 245 14. Time and Relation in Relativity and Quantum Gravity: From Time to Processes 255 15. Mechanisms of Unification in Kaluza–Klein Theory 275 16. Condensed Matter Physics and the Nature of Spacetime 301 Subject Index 331 Author Index 337 v LIST OF CONTRIBUTORS Richard T.W. Arthur, Department of Philosophy, McMaster University, Hamilton, Canada Jonathan Bain, Humanities and Social Sciences, Polytechnic University, Brooklyn, USA Yuri Balashov, Department of Philosophy, University of Georgia, Athens, USA Tomasz Bigaj, Institute of Philosophy, Warsaw University, Warsaw, Poland Carolyn Brighouse, Department of Philosophy, Occidental College, Los Angeles, USA Mauro Dorato, Department of Philosophy, University of Rome 3, Rome, Italy John Earman, Department of History and Philosophy of Science, University of Pittsburgh, Pittsburgh, USA Jan Faye, Department of Media, Cognition, and Communication, University of Copenhagen, Copenhagen, Denmark Peter Forrest, School of Social Science, University of New England, Armidale, Australia Vincent Lam, Department of Philosophy and Centre Romand for Logic, History and Philosophy of Science, University of Lausanne, Lausanne, Switzerland Dennis Lehmkuhl, Oriel College, Oxford University, Oxford, UK Ioan Muntean, Department of Philosophy, University of California, San Diego, USA Vesselin Petkov, Department of Philosophy, Concordia University, Montreal, Canada Dean Rickles, History and Philosophy of Science, The University of Sydney, Sydney, Australia Alexis de Saint-Ours, University of Paris VIII and Laboratory “Pensée des Sciences”, École Normale Supérieure, Paris, France Andrew Wayne, Department of Philosophy, University of Guelph, Canada vii PREFACE The sixteen papers collected in this volume are expanded and revised versions of talks delivered at the Second International Conference on the Ontology of Space- time, organized by the International Society for the Advanced Study of Spacetime (John Earman, President) at Concordia University (Montreal) from 9 to 11 June 2006. In the First Conference, held in 2004, the majority of the papers were devoted to topics relating to Becoming and the Flow of Time.1 Although this subject is still well represented in the present volume, it has become less dominant. Most papers are now devoted to subjects directly relating to the title of the conference: the ontology of spacetime. The book starts with four papers that discuss the ontological status of space- time and the processes occurring in it from a point of view that is first of all conceptual and philosophical. The focus then slightly shifts in the five papers that follow, to considerations more directly involving technical considerations from rel- ativity theory. After this, Time, Becoming and Change take centre stage in the next five papers. The book ends with two excursions into relatively uncharted terri- tory: a consideration of the status of Kaluza–Klein theory, and an investigation of possible relations between the nature of spacetime and condensed matter physics, respectively. The marked differences between the programs of the First and the Second Con- ference, respectively, and the large audiences assembled on both occasions, bear witness to the vitality of the field of Philosophy and Foundations of Spacetime. Preparations for the Third Conference, in 2008, are already well on their way! Dennis Dieks History and Foundations of Science, Utrecht University, Utrecht, The Netherlands 1 See: Dieks, D. (Ed.), 2006. The Ontology of Spacetime. Elsevier, Amsterdam. ix CHAPTER 1 A Trope-Bundle Ontology for Field Theory Andrew Wayne* Field theories have been central to physics over the last 150 years, and there are several theories in contemporary physics in which physical fields play key causal and explanatory roles. This chapter proposes a novel field trope-bundle (FTB) ontology on which fields are composed of bundles of particularized property in- stances, called tropes (Section 2) and goes on to describe some virtues of this ontology (Section 3). It begins with a critical examination of the dominant view about the ontology of fields, that fields are properties of a substantial substratum (Section 1). 1. FIELDS AS PROPERTIES OF A SUBSTANTIAL SUBSTRATUM The dominant view about the ontology of field theory over the last two centuries has been that fields are properties of a substantial substratum. In the 19th century this substance was taken to be a material ether. In the 20th century, the immaterial spacetime manifold took on the role of substantial substratum. For most of the 19th century, the causal and explanatory functions of field theories were assumed by a material, mechanical ether. Field theories of optics, electricity, magnetism and later electromagnetism were developed in which the field corresponded to a collection of properties of a material ether. Scientists ar- ticulated the hope that a unified theory could be extended to gravitational and other phenomena, where a single material ether would be the seat of all physical action. George Green and Lord Kelvin, for example, developed optical theories in which light was the vibration of a mechanical, elastic, solid ether (Green, 1838; Kelvin, 1904). This ether was made up of tiny ether particles. Lagrangian me- chanics, augmented with a few auxiliary hypotheses, were used to obtain many * Department of Philosophy, University of Guelph, Guelph, ON, N1G 2W1, Canada E-mail: [email protected] The Ontology of Spacetime II © Elsevier BV ISSN 1871-1774, DOI: 10.1016/S1871-1774(08)00001-6 All rights reserved 1 2 A Trope-Bundle Ontology for Field Theory sophisticated optical results: derivation of Fresnel’s laws of reflection and refrac- tion of light, phase shifts on reflection and elliptical polarization. From the start, however, these theories were extremely complex and ultimately only able to ac- count for a narrow range of optical phenomena. As they were extended to new domains, ad hoc hypotheses were needed to make them work. For example, the value of the ether’s resistance to distortion (shearing) needed to be set at one value to account for double refraction and another to account for Fresnel’s laws. Yet none of these difficulties was seen to impugn the mechanical ether hypoth- esis itself. The approach was extended to Maxwell’s unified dynamical theory of light, electric and magnetic phenomena. Thus in the 1890s Joseph Larmor devel- oped a sophisticated theory in which the ether is a kind of primitive continuous matter