Alyssa Ney - The World in the Wave Function

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Library of Congress Cataloging-in-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 530.12/4dc23

LC record available at https://lccn.loc.gov/2020024392

LC ebook record available at https://lccn.loc.gov/2020024393

DOI: 10.1093/oso/9780190097714.001.0001

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 waveform 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)

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 another? 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 representation for quantum theories developed by Erwin Schrdinger 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 regard quantum theories as approximately correct and objective representations of our world, rather than merely useful mathematical 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 object they view as a field on an extremely high-dimensional space. According to wave function realism, we and all of the objects around us are ultimately constituted out of the wave function and although we may seem to occupy a three-dimensional space of the kind described by classical physics, the more fundamental spatial framework of quantum worlds like ours is instead quite different, one of very many dimensions, with no three of these dimensions corresponding to the heights, widths, and depths of our ordinary experience.

In this book, I will not try to make the case that wave function realism is a necessaryframework one must adopt if one is to be a realist about quantum theories.

While wave function realism has been defended for more than twenty years now, it is still a rather minority position among those working in physics and philosophy of physics.