The World in the Wave Function: A Metaphysics for Quantum Physics

289 Pages·2021·11.41 MB·English

by  Alyssa Ney

The World in the Wave Function

The World in the
Wave Function
A Metaphysics for Quantum Physics
ALYSSA NEY
1
3
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. Oxford is a registered trade mark of Oxford University
Press in the UK and certain other countries.
Published in the United States of America by Oxford University Press
198 Madison Avenue, New York, NY 10016, United States of America.
© Oxford University Press 2021
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, by license, or under terms agreed with the appropriate reproduction
rights organization. Inquiries 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 work in any other form
and you must impose this same condition on any acquirer.
Library of Congress Cataloging-i n- Publication Data
Names: Ney, Alyssa, author.
Title: The world in the wave function : a metaphysics
for quantum physics / Alyssa Ney.
Description: New York, NY : Oxford University Press, [2021] |
Includes bibliographical references and index.
Identifiers: LCCN 2020024392 (print) | LCCN 2020024393 (ebook) |
ISBN 9780190097714 (hardback) | ISBN 9780190097738 (epub)
Subjects: LCSH: Wave functions. | Quantum theory.
Classification: LCC QC174.26.W3 N49 2020 (print) | LCC QC174.26.W3 (ebook)
| DDC 530.12/ 4— dc23
LC record available at https://l ccn.loc.gov/ 2020024392
LC ebook record available at https://l ccn.loc.gov/ 2020024393
DOI: 10.1093/oso/9780190097714.001.0001
1 3 5 7 9 8 6 4 2
Printed by Integrated Books International, United States of America
On this day, however, the listener saw something odd
when he glanced at the waveform display. Even experts
had a hard time telling with the naked eye whether a wave-
form carried information. But the listener was so familiar
with the noise of the universe that he could tell that the
wave that now moved in front of his eyes had something
extra. The thin curve, rising and falling, seemed to possess
a soul.
— Liu Cixin, The Three-Body Problem (2006)

Contents
Preface ix
Acknowledgments xiii
1. A Preliminary Case for Wave Function Realism 1
1.1 Wave Function Representations in Quantum
Mechanics 1
1.2 The Measurement Problem 14
1.3 Orthodox Quantum Mechanics 15
1.4 Quantum Mechanics without Measurement 25
1.5 Wave Function Realism 33
1.6 A Higher- Dimensional Reality 47
2. The Argument from Entanglement 49
2.1 Entanglement as the Characteristic Feature of
Quantum Theories 49
2.2 The Necessity of Wave Function Realism? 52
2.3 Rivals: The Primitive Ontology Approach 56
2.4 Rivals: Holisms 63
2.5 Rivals: Relational Approaches 67
2.6 Rivals: Spacetime State Realism 72
2.7 Rivals: The Multi-F ield Approach 74
2.8 The Contingency of Wave Function Realism 76
3. The Virtues of Separability and Locality 80
3.1 The Case for Wave Function Realism 80
3.2 Separability 81
3.3 Separability and Wave Function Realism 87
3.4 A Challenge 90
3.5 Concepts of Locality 96
3.6 Quantum Nonlocality 98
3.7 Locality and Wave Function Realism 104
3.8 Avoiding Nonlocality with Nonseparability 113
3.9 Motivating a Separable and Local Metaphysics 120
3.10 In Defense of Intuitions 129
viii Contents
4. Wave Function Realism in a Relativistic Setting 133
4.1 Removing Idealization 133
4.2 Five Critiques 135
4.3 Wave Function Realism for Relativistic Quantum
Theories 138
4.4 Interpretations and Interpretational Frameworks 149
4.5 Response to Objections 150
4.6 Wave Function Realism in the Limit of Physical
Theorizing 160
5. Must an Ontology for Quantum Theories Contain
Local Beables? 166
5.1 The Constitution Objection 166
5.2 Doing without Macroscopic Objects 169
5.3 The Threat of Empirical Incoherence 173
5.4 Primitive Ontologies and Local Beables 181
5.5 Perception and the Macroscopic 194
6. The Causal Role of Macroscopic Objects 197
6.1 The Macro- Object Problem 197
6.2 An Initial Proposal 199
6.3 Monton’s Challenge 207
6.4 Albert’s Proposal 210
6.5 Troubles with Functionalism 216
6.6 The Decoherence Strategy 219
6.7 From Simulation to Constitution 223
7. Finding the Macroworld 225
7.1 A Constitutive Explanation in Two Stages 225
7.2 The Role of Grounding 226
7.3 Recovering Three-D imensionality Using Symmetries 231
7.4 Parts and Wholes 238
7.5 Partial Instantiation 241
7.6 Tables, Chairs, and the Rest 247
7.7 Finding the World in the Wave Function 248
Postscript: An Incredulous Stare 251
References 255
Index 265
Preface
If quantum theories are true, what kind of truth do they suggest?
What are their ontological implications, that is, what do they tell us
about the fundamental objects that make up our world? How should
quantum theories make us reevaluate our classical conceptions of
the basic constitution of material objects and ourselves? And what
lessons do they carry for the way objects may interact with one an-
other? A century after the development of quantum theories, there
is still nothing like a consensus answer to any of these questions,
nor even a received view. And yet it is natural to wonder what these
theories that have been so remarkably empirically successful may
be telling us about ourselves and the world that surrounds us.
The goal of this book is to develop and defend one framework for
understanding the kind of world described by quantum theories.
This is a framework initially suggested by the wave representa-
tion for quantum theories developed by Erwin Schrödinger in
the 1920s, but only much later explicitly proposed and defended
as an account of reality in the work of the philosophers of physics
David Albert and Barry Loewer in the 1990s. Albert characterized
it as the necessary point of view for those purporting to be realists
about quantum theories (1996, p. 277), that is, for those who re-
gard quantum theories as approximately correct and objective
representations of our world, rather than merely useful math-
ematical tools to predict the results of future experiments. This
framework is what Albert and Loewer have called wave function
realism. It is a way of interpreting quantum theories so that the
central object they describe is the quantum wave function, an ob-
ject they view as a field on an extremely high-d imensional space.