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Reply to Valentini, ‘De Broglie–Bohm Pilot‐Wave Theory: Many Worlds in Denial?’

Harvey R. Brown

Published Jun 24, 2010• 7 citations
Publisher

Abstract

Abstract The reality of the patterns in the wave-function representing different worlds is not like that of locality and the uncertainty relations, which hold only for the equilibrium distribution. Nor, in the light of the Deutsch–Wallace representation theorem for the Born rule, is the appeal to non-equilibrium probability distributions as the ground for the distinction between pilot-wave theory and many-worlds theory well-motivated. Finally, Valentini's counter-claim, that the latter is motivated by eigenvalue realism, ignores the need to give an account of macroscopic superpositions.

DOI
10.1093/acprof:oso/9780199560561.003.0020

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De Broglie-Bohm Pilot-Wave Theory: Many Worlds in Denial?

Antony Valentini

We reply to claims (by Deutsch, Zeh, Brown and Wallace) that the pilot-wave theory of de Broglie and Bohm is really a many-worlds theory with a superfluous configuration appended to one of the worlds. Assuming that pilot-wave theory does contain an ontological pilot wave (a complex-valued field in configuration space), we show that such claims arise from not interpreting pilot-wave theory on its own terms. Specifically, the theory has its own ('subquantum') theory of measurement, and in general describes a 'nonequilibrium' state that violates the Born rule. Furthermore, in realistic models of the classical limit, one does not obtain localised pieces of an ontological pilot wave following alternative macroscopic trajectories: from a de Broglie-Bohm viewpoint, alternative trajectories are merely mathematical and not ontological. Thus, from the perspective of pilot-wave theory itself, many worlds are an illusion. It is further argued that, even leaving pilot-wave theory aside, the theory of many worlds is rooted in the intrinsically unlikely assumption that quantum measurements should be modelled on classical measurements, and is therefore unlikely to be true.

arXiv:0811.0810•Nov 5, 2008•38 citations

Comment on Valentini, "De Broglie-Bohm Pilot-Wave Theory: Many Worlds in Denial?"

Harvey R. Brown

Valentini has recently defended the de Broglie-Bohm pilot-wave version of quantum theory from the claim that it is essentially Everett theory encumbered with the redundant postulation of point particles. In this note, Valentini’s central arguments are questioned. 1

•Jan 1, 2009•8 citations

Comment on Valentini, "De Broglie-Bohm Pilot-Wave Theory: Many Worlds in Denial?" [arXiv:0811.0810]

Harvey R. Brown

Valentini [arXiv:0811.0810] has recently defended the de Broglie-Bohm pilot-wave version of quantum theory from the claim that it is essentially Everett theory encumbered with the redundant postulation of point particles. In this note, Valentini's central arguments are questioned.

arXiv:0901.1278•Jan 9, 2009•7 citations

De Broglie–Bohm Pilot‐Wave Theory: Many Worlds in Denial?

Antony Valentini

Abstract This chapter replies to claims that the pilot-wave theory of de Broglie and Bohm is really a many-worlds theory with a superfluous configuration appended to one of the worlds. Assuming that pilot-wave theory does contain an ontological pilot wave (a complex-valued field in configuration space), the chapter shows that such claims arise from not interpreting pilot-wave theory on its own terms. Specifically, the theory has its own (‘subquantum’) theory of measurement, and in general describes a ‘non-equilibrium’ state that violates the Born rule. Furthermore, in realistic models of the classical limit, one does not obtain localised pieces of an ontological pilot wave following alternative macroscopic trajectories: from a de Broglie–Bohm viewpoint, alternative trajectories are merely mathematical and not ontological. Thus, from the perspective of pilot-wave theory itself, many worlds is an illusion. It is further argued that, even leaving pilot-wave theory aside, the theory of many worlds is rooted in the intrinsically unlikely assumption that quantum measurements should be modelled on classical measurements, and is therefore unlikely to be true.

•Jun 24, 2010•33 citations

Many worlds or one: reply to Steeger

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Abstract Steeger (Synthese 200(2), 2022) has recently claimed that Bohmians are able to make use of the Deutsch-Wallace derivation of quantum-mechanical chance values. I argue that Steeger’s proposal does not succeed, but a close cousin of it—for de Broglie-Bohm epistemic probabilities—does. This clarifies the relationship between Born rule probabilities in Everettian quantum mechanics and de Broglie-Bohm theory, as well as the scope of the Deutsch-Wallace theorem.

Synthese•Apr 10, 2025•0 citations

Foundations of Statistical Mechanics and the Status of the Born Rule in de Broglie-Bohm Pilot-Wave Theory

Antony Valentini

We compare and contrast two distinct approaches to understanding the Born rule in de Broglie-Bohm pilot-wave theory, one based on dynamical relaxation over time (advocated by this author and collaborators) and the other based on typicality of initial conditions (advocated by the 'Bohmian mechanics' school). It is argued that the latter approach is inherently circular and physically misguided. The typicality approach has engendered a deep-seated confusion between contingent and law-like features, leading to misleading claims not only about the Born rule but also about the nature of the wave function. By artificially restricting the theory to equilibrium, the typicality approach has led to further misunderstandings concerning the status of the uncertainty principle, the role of quantum measurement theory, and the kinematics of the theory (including the status of Galilean and Lorentz invariance). The restriction to equilibrium has also made an erroneously-constructed stochastic model of particle creation appear more plausible than it actually is. To avoid needless controversy, we advocate a modest 'empirical approach' to the foundations of statistical mechanics. We argue that the existence or otherwise of quantum nonequilibrium in our world is an empirical question to be settled by experiment.

arXiv:1906.10761•WORLD SCIENTIFIC eBooks•Apr 21, 2020•34 citations
Abstract The reality of the patterns in the wave-function representing different worlds is not like that of locality and the uncertainty relations, which hold only for the equilibrium distribution. Nor, in the light of the Deutsch–Wallace representation theorem for the Born rule, is the appeal to non-equilibrium probability distributions as the ground for the distinction between pilot-wave theory and many-worlds theory well-motivated. Finally, Valentini's counter-claim, that the latter is motivated by eigenvalue realism, ignores the need to give an account of macroscopic superpositions.
We reply to claims (by Deutsch, Zeh, Brown and Wallace) that the pilot-wave theory of de Broglie and Bohm is really a many-worlds theory with a superfluous configuration appended to one of the worlds. Assuming that pilot-wave theory does contain an ontological pilot wave (a complex-valued field in configuration space), we show that such claims arise from not interpreting pilot-wave theory on its own terms. Specifically, the theory has its own ('subquantum') theory of measurement, and in general describes a 'nonequilibrium' state that violates the Born rule. Furthermore, in realistic models of the classical limit, one does not obtain localised pieces of an ontological pilot wave following alternative macroscopic trajectories: from a de Broglie-Bohm viewpoint, alternative trajectories are merely mathematical and not ontological. Thus, from the perspective of pilot-wave theory itself, many worlds are an illusion. It is further argued that, even leaving pilot-wave theory aside, the theory of many worlds is rooted in the intrinsically unlikely assumption that quantum measurements should be modelled on classical measurements, and is therefore unlikely to be true.
Abstract This chapter replies to claims that the pilot-wave theory of de Broglie and Bohm is really a many-worlds theory with a superfluous configuration appended to one of the worlds. Assuming that pilot-wave theory does contain an ontological pilot wave (a complex-valued field in configuration space), the chapter shows that such claims arise from not interpreting pilot-wave theory on its own terms. Specifically, the theory has its own (‘subquantum’) theory of measurement, and in general describes a ‘non-equilibrium’ state that violates the Born rule. Furthermore, in realistic models of the classical limit, one does not obtain localised pieces of an ontological pilot wave following alternative macroscopic trajectories: from a de Broglie–Bohm viewpoint, alternative trajectories are merely mathematical and not ontological. Thus, from the perspective of pilot-wave theory itself, many worlds is an illusion. It is further argued that, even leaving pilot-wave theory aside, the theory of many worlds is rooted in the intrinsically unlikely assumption that quantum measurements should be modelled on classical measurements, and is therefore unlikely to be true.
We compare and contrast two distinct approaches to understanding the Born rule in de Broglie-Bohm pilot-wave theory, one based on dynamical relaxation over time (advocated by this author and collaborators) and the other based on typicality of initial conditions (advocated by the 'Bohmian mechanics' school). It is argued that the latter approach is inherently circular and physically misguided. The typicality approach has engendered a deep-seated confusion between contingent and law-like features, leading to misleading claims not only about the Born rule but also about the nature of the wave function. By artificially restricting the theory to equilibrium, the typicality approach has led to further misunderstandings concerning the status of the uncertainty principle, the role of quantum measurement theory, and the kinematics of the theory (including the status of Galilean and Lorentz invariance). The restriction to equilibrium has also made an erroneously-constructed stochastic model of particle creation appear more plausible than it actually is. To avoid needless controversy, we advocate a modest 'empirical approach' to the foundations of statistical mechanics. We argue that the existence or otherwise of quantum nonequilibrium in our world is an empirical question to be settled by experiment.