Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Philosophical Studies

Free will in the many-worlds interpretation of quantum mechanics

David John Baker

Published Apr 1, 2025• 0 citations
Publisher

Abstract

Abstract David Wallace has argued that there is no special problem for free will in the many-worlds interpretation of quantum mechanics, beyond the well-known problem of reconciling free will with physical determinism. I argue to the contrary that, on the plausible and popular “deep self” approach to compatibilism, the many-worlds interpretation does face a special problem. It is not clear on the many-worlds picture how our actions can issue from our most central character traits, given that copies of us in other branches are certain to act differently than we do.

DOI
10.1007/s11098-025-02314-y

Related papers

Not Just Many Worlds but Many Universes? A Problem for the Many Worlds View of Quantum Mechanics

Peter Baumann

Abstract The many-worlds view is one of the most discussed “interpretations” of quantum mechanics. As is well known, this view has some very controversial and much discussed aspects. This paper focuses on one particular problem arising from the combination of quantum mechanics with Special Relativity. It turns out that the ontology of the many-worlds view – the account of what there is and what branches of the universe exist – is relative to inertial frames. If one wants to avoid relativizing ontology, one has to argue either that there is an additional source of branching due to Special Relativity and thus additional branches or worlds. Or one has to argue that there are not only many worlds but also many universes (sets of worlds or world-branches); there is thus not only one tree of many world-branches but many frame-specific trees, a “forest” of many world-trees. The main problem here is how one can understand all or any of this.

Metaphysica•Aug 3, 2022•0 citations

Why the Many-Worlds Interpretation?

Lev Vaidman A

A brief (subjective) description of the state of the art of the many-worlds interpretation of quantum mechanics (MWI) is presented. It is argued that the MWI is the only interpretation which removes action at a distance and randomness from quantum theory. Limitations of the MWI regarding questions of probability which can be legitimately asked are specified. The ontological picture of the MWI as a theory of the universal wave function decomposed into a superposition of world wave functions, the important parts of which are defined in three-dimensional space, is presented from the point of view of our particular branch. Some speculations about misconceptions, which apparently prevent the MWI from being in the consensus, are mentioned.

arXiv:2208.04618•Quantum Reports•Aug 4, 2022•22 citations

The Many Worlds Interpretation of QM

Robert Charles Koons

A group of philosophers and physicists at Oxford have recently crafted, in light of developments in the theory of decoherence, a new version of the Everett or Many Worlds interpretation of quantum mechanics. I will focus on the work of David Wallace, who identifies the quasi-classical domains making up the various “worlds” or “branches” of the interpretation with macroscopic patterns that are functionally realized (to an approximate degree good enough for practical purposes) by the quantum wavefunction of the universe. I argue that Wallace’s reliance on Savage’s pragmatic account of probability fails, due to the unreasonableness of Savage’s Sure Thing Principle in a many-worlds setting. I also argue that Wallace’s program is vulnerable to a version of Putnam’s model-theoretic indeterminacy argument, with the result that almost any conceivable macroscopic “world” is in fact realized by that function and so is (by Wallace’s light) as real as our own. I offer a hylomorphic revision of the many-worlds model, the “traveling forms” interpretation of Alexander Pruss, and I argue that this revision solves both the indeterminacy problem and the problem of interpreting quantum probabilities.

Routledge eBooks•Oct 19, 2017•8 citations

Many Worlds?

Simon W. Saunders

Abstract What does realism about the quantum state imply? What follows when quantum theory is applied without restriction, if need be, to the whole universe? These are the questions which are debated in this book. All the chapters start from the point of realism, and based on the need, or the aspiration, for a theory that unites micro- and macroworlds, at least in principle. But the further claim argued by some is that if you allow the Schrödinger equation unrestricted application, supposing the quantum state to be something physically real, then this universe is one of countlessly many others, constantly branching in time, all of which are real. The result is the many worlds theory, also known as the Everett interpretation of quantum mechanics. The contrary claim sees this picture of many worlds as in no sense inherent in quantum mechanics, even when the latter is allowed unrestricted scope and even given that the quantum state itself is something physically real. For this picture of branching worlds fails to make physical sense, let alone common sense, even on its own terms. The status of these worlds, what they are made of, is never adequately explained. Ordinary ideas about time and identity over time become hopelessly compromised. The concept of probability itself is brought into question. This picture of many branching worlds is inchoate, it is a vision, an error. There are realist alternatives to many worlds, some even that preserve the Schrödinger equation unchanged. Twenty chapters, accompanied by commentaries and discussions, examine these claims and counterclaims in depth. They focus first on the question of ontology, the existence of worlds, second on the interpretation of probability, and third on alternatives or additions to many worlds. The introduction offers a helpful guide to the arguments for the Everett interpretation, particularly as they have been formulated in the last two decades.

•Jun 24, 2010•352 citations

The Emergent Multiverse

David Wallace

Presenting a striking new account of the 'many worlds' approach to quantum theory, aka the Everett interpretation, David Wallace offers a clear and up-to-date survey of work on this theory in physics and in philosophy of science.

Oxford University Press eBooks•May 24, 2012•528 citations

An Envariance-based Objection to the Many Worlds Interpretation of Quantum Mechanics

Robert Verrill

In this paper, I argue that there is a problem with the Many Worlds Interpretation of quantum mechanics (MWI). I show this by relying on the notion of envariance. Zurek's work on envariance was intended to strengthen the MWI by providing a non-circular derivation of the Born rule within the MWI framework. However, I will argue that envariance actually undermines the MWI by showing that in many situations, the system-environment terms in the entangled universal quantum state don't correspond to distinct entities as MWI-advocates such as David Wallace claim they do. After making my envariance-based objection to the MWI, I show that three other interpretations—the Relational Quantum Mechanics interpretation, the de Broglie-Bohm (aka the Pilot Wave) interpretation, and the GRW interpretation—do not adopt all the assumptions needed for envariance, and so can sidestep the problem that envariance presents to the MWI. My argument against the MWI is of relevance to the philosophy of middle-sized objects since it highlights a problem with the claim that a multiplicity of middle-sized objects emerge in different worlds from a universal quantum state.

Topoi•Aug 6, 2026•0 citations
Abstract David Wallace has argued that there is no special problem for free will in the many-worlds interpretation of quantum mechanics, beyond the well-known problem of reconciling free will with physical determinism. I argue to the contrary that, on the plausible and popular “deep self” approach to compatibilism, the many-worlds interpretation does face a special problem. It is not clear on the many-worlds picture how our actions can issue from our most central character traits, given that copies of us in other branches are certain to act differently than we do.
Abstract The many-worlds view is one of the most discussed “interpretations” of quantum mechanics. As is well known, this view has some very controversial and much discussed aspects. This paper focuses on one particular problem arising from the combination of quantum mechanics with Special Relativity. It turns out that the ontology of the many-worlds view – the account of what there is and what branches of the universe exist – is relative to inertial frames. If one wants to avoid relativizing ontology, one has to argue either that there is an additional source of branching due to Special Relativity and thus additional branches or worlds. Or one has to argue that there are not only many worlds but also many universes (sets of worlds or world-branches); there is thus not only one tree of many world-branches but many frame-specific trees, a “forest” of many world-trees. The main problem here is how one can understand all or any of this.
A brief (subjective) description of the state of the art of the many-worlds interpretation of quantum mechanics (MWI) is presented. It is argued that the MWI is the only interpretation which removes action at a distance and randomness from quantum theory. Limitations of the MWI regarding questions of probability which can be legitimately asked are specified. The ontological picture of the MWI as a theory of the universal wave function decomposed into a superposition of world wave functions, the important parts of which are defined in three-dimensional space, is presented from the point of view of our particular branch. Some speculations about misconceptions, which apparently prevent the MWI from being in the consensus, are mentioned.
A group of philosophers and physicists at Oxford have recently crafted, in light of developments in the theory of decoherence, a new version of the Everett or Many Worlds interpretation of quantum mechanics. I will focus on the work of David Wallace, who identifies the quasi-classical domains making up the various “worlds” or “branches” of the interpretation with macroscopic patterns that are functionally realized (to an approximate degree good enough for practical purposes) by the quantum wavefunction of the universe. I argue that Wallace’s reliance on Savage’s pragmatic account of probability fails, due to the unreasonableness of Savage’s Sure Thing Principle in a many-worlds setting. I also argue that Wallace’s program is vulnerable to a version of Putnam’s model-theoretic indeterminacy argument, with the result that almost any conceivable macroscopic “world” is in fact realized by that function and so is (by Wallace’s light) as real as our own. I offer a hylomorphic revision of the many-worlds model, the “traveling forms” interpretation of Alexander Pruss, and I argue that this revision solves both the indeterminacy problem and the problem of interpreting quantum probabilities.
Abstract What does realism about the quantum state imply? What follows when quantum theory is applied without restriction, if need be, to the whole universe? These are the questions which are debated in this book. All the chapters start from the point of realism, and based on the need, or the aspiration, for a theory that unites micro- and macroworlds, at least in principle. But the further claim argued by some is that if you allow the Schrödinger equation unrestricted application, supposing the quantum state to be something physically real, then this universe is one of countlessly many others, constantly branching in time, all of which are real. The result is the many worlds theory, also known as the Everett interpretation of quantum mechanics. The contrary claim sees this picture of many worlds as in no sense inherent in quantum mechanics, even when the latter is allowed unrestricted scope and even given that the quantum state itself is something physically real. For this picture of branching worlds fails to make physical sense, let alone common sense, even on its own terms. The status of these worlds, what they are made of, is never adequately explained. Ordinary ideas about time and identity over time become hopelessly compromised. The concept of probability itself is brought into question. This picture of many branching worlds is inchoate, it is a vision, an error. There are realist alternatives to many worlds, some even that preserve the Schrödinger equation unchanged. Twenty chapters, accompanied by commentaries and discussions, examine these claims and counterclaims in depth. They focus first on the question of ontology, the existence of worlds, second on the interpretation of probability, and third on alternatives or additions to many worlds. The introduction offers a helpful guide to the arguments for the Everett interpretation, particularly as they have been formulated in the last two decades.
In this paper, I argue that there is a problem with the Many Worlds Interpretation of quantum mechanics (MWI). I show this by relying on the notion of envariance. Zurek's work on envariance was intended to strengthen the MWI by providing a non-circular derivation of the Born rule within the MWI framework. However, I will argue that envariance actually undermines the MWI by showing that in many situations, the system-environment terms in the entangled universal quantum state don't correspond to distinct entities as MWI-advocates such as David Wallace claim they do. After making my envariance-based objection to the MWI, I show that three other interpretations—the Relational Quantum Mechanics interpretation, the de Broglie-Bohm (aka the Pilot Wave) interpretation, and the GRW interpretation—do not adopt all the assumptions needed for envariance, and so can sidestep the problem that envariance presents to the MWI. My argument against the MWI is of relevance to the philosophy of middle-sized objects since it highlights a problem with the claim that a multiplicity of middle-sized objects emerge in different worlds from a universal quantum state.