About this topic
Summary Everettians understand quantum mechanics in a straightforwardly realist way, interpreting macroscopic superpositions as multiplicity rather than as indeterminateness. Instead of Schrodinger's cat being half-alive and half-dead, there are two cats - one alive, one dead. Modern versions of Everettianism rely heavily on the process of decoherence to explain how multiplicity arises; some previous advocates added an additional set of fundamental branching worlds to the quantum formalism.
Key works Wallace 2012 provides a comprehensive treatment of contemporary Everettian quantum mechanics. An anthology covering a wide variety of perspectives on the interpretation is Saunders et al 2010. Everett's original proposal is available in its full form in Everett 1973
Introductions Vaidman 2008
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  1. The Quantum Mechanics of Minds and Worlds.Jeffrey A. Barrett - 2001 - Oxford University Press UK.
    Jeffrey Barrett presents the most comprehensive study yet of a problem that has puzzled physicists and philosophers since the 1930s. Quantum mechanics is in one sense the most successful physical theory ever, accurately predicting the behaviour of the basic constituents of matter. But it has an apparent ambiguity or inconsistency at its heart; Barrett gives a careful, clear, and challenging evaluation of attempts to deal with this problem.
  2. The Quantum Mechanics of Minds and Worlds.Jeffrey A. Barrett - 1999 - Oxford University Press UK.
    Jeffrey Barrett presents the most comprehensive study yet of a problem that has puzzled physicists and philosophers since the 1930s. The standard theory of quantum mechanics is in one sense the most successful physical theory ever, predicting the behaviour of the basic constituents of all physical things; no other theory has ever made such accurate empirical predictions. However, if one tries to understand the theory as providing a complete and accurate framework for the description of the behaviour of all physical (...)
  3. The Problem of Confirmation in the Everett Interpretation.Emily Adlam - 2014 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 47:21-32.
    I argue that the Oxford school Everett interpretation is internally incoherent, because we cannot claim that in an Everettian universe the kinds of reasoning we have used to arrive at our beliefs about quantum mechanics would lead us to form true beliefs. I show that in an Everettian context, the experimental evidence that we have available could not provide empirical confirmation for quantum mechanics, and moreover that we would not even be able to establish reference to the theoretical entities of (...)
  4. Many-Measurements or Many-Worlds? A Dialogue.Diederik Aerts & Massimiliano Sassoli de Bianchi - 2015 - Foundations of Science 20 (4):399-427.
    Many advocates of the Everettian interpretation consider that theirs is the only approach to take quantum mechanics really seriously, and that this approach allows to deduce a fantastic scenario for our reality, one that consists of an infinite number of parallel worlds that branch out continuously. In this article, written in dialogue form, we suggest that quantum mechanics can be taken even more seriously, if the many-worlds view is replaced by a many-measurements view. This allows not only to derive the (...)
  5. Causal Decision Theory and EPR Correlations.Arif Ahmed & Adam Caulton - 2014 - Synthese 191 (18):4315-4352.
    The paper argues that on three out of eight possible hypotheses about the EPR experiment we can construct novel and realistic decision problems on which (a) Causal Decision Theory and Evidential Decision Theory conflict (b) Causal Decision Theory and the EPR statistics conflict. We infer that anyone who fully accepts any of these three hypotheses has strong reasons to reject Causal Decision Theory. Finally, we extend the original construction to show that anyone who gives any of the three hypotheses any (...)
  6. On the Phenomenology of Quantum-Mechanical Superpositions.D. Albert - 1997 - Poznan Studies in the Philosophy of the Sciences and the Humanities 55:196-215.
  7. On What It Takes to Be a World.David Z. Albert & Jeffrey A. Barrett - 1995 - Topoi 14 (1):35-37.
    A many-worlds interpretation is of quantum mechanics tells us that the linear equations of motion are the true and complete laws for the time-evolution of every physical system and that the usual quantum-mechanical states provide complete descriptions of all possible physical situations. Such an interpretation, however, denies the standard way of understanding quantum-mechanical states. When the pointer on a measuring device is in a superposition of pointing many different directions, for example, we are to understand this as many pointers, each (...)
  8. Symposiums Papers: Two No-Collapse Interpretations of Quantum Theory.David Albert & Barry Loewer - 1989 - Noûs 23 (2):169-186.
  9. Interpreting the Many-Worlds Interpretation.David Albert & Barry Loewer - 1988 - Synthese 77 (November):195-213.
  10. Many Worlds and Schrodinger's First Quantum Theory.V. Allori, S. Goldstein, R. Tumulka & N. Zanghi - 2011 - British Journal for the Philosophy of Science 62 (1):1-27.
    Schrödinger’s first proposal for the interpretation of quantum mechanics was based on a postulate relating the wave function on configuration space to charge density in physical space. Schrödinger apparently later thought that his proposal was empirically wrong. We argue here that this is not the case, at least for a very similar proposal with charge density replaced by mass density. We argue that when analyzed carefully, this theory is seen to be an empirically adequate many-worlds theory and not an empirically (...)
  11. Primitive Ontology and the Classical World.Valia Allori - 2016 - In R. Kastner, J. Jeknic-Dugic & G. Jaroszkiewicz (eds.), Quantum Structural Studies: Classical Emergence from the Quantum Level. World Scientific. pp. 175-199.
    In this paper I present the common structure of quantum theories with a primitive ontology, and discuss in what sense the classical world emerges from quantum theories as understood in this framework. In addition, I argue that the primitive ontology approach is better at answering this question than the rival wave function ontology approach or any other approach in which the classical world is nonreductively ‘emergent:’ even if the classical limit within this framework needs to be fully developed, the difficulties (...)
  12. Primitive Ontology in a Nutshell.Valia Allori - 2015 - International Journal of Quantum Foundations 1 (2):107-122.
    The aim of this paper is to summarize a particular approach of doing metaphysics through physics - the primitive ontology approach. The idea is that any fundamental physical theory has a well-defined architecture, to the foundation of which there is the primitive ontology, which represents matter. According to the framework provided by this approach when applied to quantum mechanics, the wave function is not suitable to represent matter. Rather, the wave function has a nomological character, given that its role in (...)
  13. On the Metaphysics of Quantum Mechanics.Valia Allori - 2013 - In Soazig Lebihan (ed.), Precis de la Philosophie de la Physique. Vuibert.
    What is quantum mechanics about? The most natural way to interpret quantum mechanics realistically as a theory about the world might seem to be what is called wave function ontology: the view according to which the wave function mathematically represents in a complete way fundamentally all there is in the world. Erwin Schroedinger was one of the first proponents of such a view, but he dismissed it after he realized it led to macroscopic superpositions (if the wave function evolves in (...)
  14. La storia del gatto che era sia vivo che morto.Valia Allori - 2009 - In Enrico Giannetto (ed.), Da Archimede a Majorana: la fisica nel suo divenire. Guaraldi. pp. 273-283.
    Questa è la breve storia , forse un poco romanzata, del gatto che, se non forse il più citato, è di sicuro il più bistrattato della storia della fisica e della filosofia: il gatto di Schrödinger.
  15. Fundamental Physical Theories: Mathematical Structures Grounded on a Primitive Ontology.Valia Allori - 2007 - Dissertation, Rutgers
    In my dissertation I analyze the structure of fundamental physical theories. I start with an analysis of what an adequate primitive ontology is, discussing the measurement problem in quantum mechanics and theirs solutions. It is commonly said that these theories have little in common. I argue instead that the moral of the measurement problem is that the wave function cannot represent physical objects and a common structure between these solutions can be recognized: each of them is about a clear three-dimensional (...)
  16. Barrett, Jeffrey Allan. The Quantum Mechanics of Minds and Worlds. [REVIEW]Aristidis Arageorgis - 2001 - Review of Metaphysics 54 (4):904-905.
  17. Should We Fear Quantum Torment?István Aranyosi - 2012 - Ratio 25 (3):249-259.
    The prospect, in terms of subjective expectations, of immortality under the no-collapse interpretation of quantum mechanics is certain, as pointed out by several authors, both physicists and, more recently, philosophers. The argument, known as quantum suicide, or quantum immortality, has received some critical discussion, but there hasn't been any questioning of David Lewis's point that there is a terrifying corollary to the argument, namely, that we should expect to live forever in a crippled, more and more damaged state, that barely (...)
  18. Worlds Galore?Guido Bacciagaluppi - unknown
    This is an Essay Review of "Many Worlds? Everett, Quantum Theory, & Reality", edited by Simon Saunders, Jonathan Barrett, Adrian Kent, and David Wallace. A much shortened version of this review is appearing in "Metascience" under the title "The Many Facets of Everett’s Many Worlds".
  19. Jeffrey A. Barrett and Peter Byrne, Eds.The Everett Interpretation of Quantum Mechanics: Collected Works 1955–1980 with Commentary. Princeton, NJ: Princeton University Press, 2012. Pp. 392. $75.00. [REVIEW]Guido Bacciagaluppi - 2013 - Hopos: The Journal of the International Society for the History of Philosophy of Science 3 (2):348-352.
  20. The Everett Interpretation of Quantum Mechanics. Collected Works 1955-1980 with Commentary. Hugh Everett III, Edited by Jeffrey A. Barrett & Peter Byrne. Princeton: Princeton University Press. [REVIEW]Guido Bacciagaluppi - unknown
    This is a review of Barrett and Byrne's commented edition of Everett's collected works, originally published in HOPOS 3, 348-352, but here including footnotes and references.
  21. The Many Facets of Everett's Many Worlds.Guido Bacciagaluppi - 2013 - Metascience 22 (3):575-582.
  22. The Role of Decoherence in Quantum Mechanics.Guido Bacciagaluppi - 2008 - Stanford Encyclopedia of Philosophy.
    Interference phenomena are a well-known and crucial feature of quantum mechanics, the two-slit experiment providing a standard example. There are situations, however, in which interference effects are (artificially or spontaneously) suppressed. We shall need to make precise what this means, but the theory of decoherence is the study of (spontaneous) interactions between a system and its environment that lead to such suppression of interference. This study includes detailed modelling of system-environment interactions, derivation of equations (‘master equations’) for the (reduced) state (...)
  23. Remarks on Space-Time and Locality in Everett's Interpretation.Guido Bacciagaluppi - 2002 - In T. Placek & J. Butterfield (eds.), Non-Locality and Modality. Kluwer Academic Publishers. pp. 105--122.
    Interpretations that follow Everett's idea that the universal wave function contains a multiplicity of coexisting realities, usually claim to give a completely local account of quantum mechanics. That is, they claim to give an account that avoids both a non-local collapse of the wave function, and the action at a distance needed in hidden variable theories in order to reproduce the quantum mechanical violation of the Bell inequalities. In this paper, I sketch how these claims can be substantiated in two (...)
  24. Making Sense of Approximate Decoherence.Guido Bacciagaluppi & Meir Hemmo - 1994 - PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association 1994:345 - 354.
    In realistic situations where a macroscopic system interacts with an external environment, decoherence of the quantum state, as derived in the decoherence approach, is only approximate. We argue that this can still give rise to facts, provided that during the decoherence process states that are, respectively, always close to eigenvectors of pointer position and record observable are correlated. We show in a model that this is always the case.
  25. Essay Review: David Wallace, The Emergent Multiverse.Guido Bacciagaluppi & Jenann Ismael - unknown
    We review and discuss the recent monograph by David Wallace on Everettian Quantum Mechanics. This book is a high point of two decades of work on Everett in both physics and philosophy. It is also a beautiful and welcome exemplar of a modern way of doing metaphysics. We discuss certain aspects more critically, and take the opportunity to sketch an alternative pragmatist approach to probability in Everett, to be fully developed elsewhere.
  26. Measurement Outcomes and Probability in Everettian Quantum Mechanics.David Baker - 2007 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 38 (1):153-169.
    The decision-theoretic account of probability in the Everett or many-worlds interpretation, advanced by David Deutsch and David Wallace, is shown to be circular. Talk of probability in Everett presumes the existence of a preferred basis to identify measurement outcomes for the probabilities to range over. But the existence of a preferred basis can only be established by the process of decoherence, which is itself probabilistic.
  27. Measurement Outcomes and Probability in Everettian Quantum Mechanics.David J. Baker - 2007 - Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 38 (1):153-169.
  28. Can the Statistical Postulate of Quantum Theory Be Derived?—A Critique of the Many-Universes Interpretation.L. E. Ballentine - 1973 - Foundations of Physics 3 (2):229-240.
    The attempt to derive (rather than assume) the statistical postulate of quantum theory from the many-universes interpretation of Everett and De Witt is analyzed The many-universes interpretation is found to be neither necessary nor sufficient for the task.
  29. The Feynman Path Integrals and Everett's Universal Wave Function.D. Bar - 1998 - Foundations of Physics 28 (8):1383-1391.
    We study here the properties of some quantum mechanical wave functions, which, in contrast to the regular quantum mechanical wave functions, can be predetermined with certainty (probability 1) by performing dense measurements (or continuous observations). These specific “certain” states are the junction points through which pass all the diverse paths that can proceed between each two such neighboring “sure” points. When we compare the properties of these points to the properties of the well-known universal wave functions of Everett we find (...)
  30. The Many-Worlds Interpretation of Quantum Mechanics: Psychological Versus Physical Bases for the Multiplicity of "Worlds".Howard Barnum - unknown
    This unpublished 1990 preprint argues that a crucial distinction in discussions of the many-worlds interpretation of quantum mechanics (MWI) is that between versions of the interpretation positing a physical multiplicity of worlds, and those in which the multiplicity is merely psychological, and due to the splitting of consciousness upon interaction with amplified quantum superpositions. It is argued that Everett's original version of the MWI belongs to the latter class, and that most of the criticisms leveled against the MWI, in particular (...)
  31. Dieks' Realistic Interpretation of Quantum Mechanics: A Comment.Howard Barnum - unknown
    D. Dieks has proposed a semantical rule which he claims yields a realistic interpretation of the formalism of quantum mechanics without the projection postulate. I argue that his proposal is unacceptable because it violates a natural requirement of psychophysical parallelism. His "semantical rule" is not an acceptable interpretive rule because it does not identify structures in the theory with structures in our experience, but postulates a merely probabilistic relationship between the two. Dieks' interpretation is contrasted with Everett's relative state interpretation, (...)
  32. Everett's Pure Wave Mechanics and the Notion of Worlds.Jeffrey Barrett - 2011 - European Journal for Philosophy of Science 1 (2):277-302.
    Everett (1957a, b, 1973) relative-state formulation of quantum mechanics has often been taken to involve a metaphysical commitment to the existence of many splitting worlds each containing physical copies of observers and the objects they observe. While there was earlier talk of splitting worlds in connection with Everett, this is largely due to DeWitt’s (Phys Today 23:30–35, 1970) popular presentation of the theory. While the thought of splitting worlds or parallel universes has captured the popular imagination, Everett himself favored the (...)
  33. Everett's Relative-State Formulation of Quantum Mechanics.Jeffrey Barrett - 2008 - Stanford Encyclopedia of Philosophy.
    Everett's relative-state formulation of quantum mechanics is an attempt to solve the measurement problem by dropping the collapse dynamics from the standard von Neumann-Dirac theory of quantum mechanics. The main problem with Everett's theory is that it is not at all clear how it is supposed to work. In particular, while it is clear that he wanted to explain why we get determinate measurement results in the context of his theory, it is unclear how he intended to do this. There (...)
  34. Quantum Worlds.Jeffrey A. Barrett - unknown
    Because of the conceptual difficulties it faces, quantum mechanics provides a salient example of how alternative metaphysical commitments may clarify our understanding of a physical theory and the explanations it provides. Here we will consider how postulating alternative quantum worlds in the context of Hugh Everett III's pure wave mechanics may serve to explain determinate measurement records and the standard quantum statistics. We will focus here on the properties of such worlds, then briefly consider other metaphysical options available for interpreting (...)
  35. Pure Wave Mechanics and the Very Idea of Empirical Adequacy.Jeffrey A. Barrett - 2015 - Synthese 192 (10):3071-3104.
    Hugh Everett III proposed his relative-state formulation of pure wave mechanics as a solution to the quantum measurement problem. He sought to address the theory’s determinate record and probability problems by showing that, while counterintuitive, pure wave mechanics was nevertheless empirically faithful and hence empirical acceptable. We will consider what Everett meant by empirical faithfulness. The suggestion will be that empirical faithfulness is well understood as a weak variety of empirical adequacy. The thought is that the very idea of empirical (...)
  36. On the Faithful Interpretation of Pure Wave Mechanics.Jeffrey A. Barrett - 2011 - British Journal for the Philosophy of Science 62 (4):693-709.
    Given Hugh Everett III's understanding of the proper cognitive status of physical theories, his relative-state formulation of pure wave mechanics arguably qualifies as an empirically acceptable physical theory. The argument turns on the precise nature of the relationship that Everett requires between the empirical substructure of an empirically faithful physical theory and experience. On this view, Everett provides a weak resolution to both the determinate record and the probability problems encountered by pure wave mechanics, and does so in a way (...)
  37. The Preferred-Basis Problem and the Quantum Mechanics of Everything.Jeffrey A. Barrett - 2005 - British Journal for the Philosophy of Science 56 (2):199-220.
    argued that there are two options for what he called a realistic solution to the quantum measurement problem: (1) select a preferred set of observables for which definite values are assumed to exist, or (2) attempt to assign definite values to all observables simultaneously (1810–1). While conventional wisdom has it that the second option is ruled out by the Kochen-Specker theorem, Vink nevertheless advocated it. Making every physical quantity determinate in quantum mechanics carries with it significant conceptual costs, but it (...)
  38. On Everett's Formulation of Quantum Mechanics.Jeffrey A. Barrett - 1997 - The Monist 80 (1):70 - 96.
    Everett wanted a formulation of quantum mechanics that (i) took the linear dynamics to be a complete and accurate description of the time-evolution of all physical systems and (ii) logically entailed the same subjective appearances predicted by the standard formulation of quantum mechanics. While most everyone would agree with this description of Everett's project, there is little agreement on exactly how his relative-state formulation was supposed to work. In this paper, I consider two very different readings of Everett: the bare (...)
  39. On the Nature of Experience in the Bare Theory.Jeffrey A. Barrett - 1997 - Synthese 113 (3):347-355.
    Quantum mechanics without the collapse postulate, the bare theory, was proposed by Albert (1992) as a way of understanding Everett's relative-state formulation of quantum mechanics. The basic idea is to try to account for an observer's beliefs by appealing to a type of illusion predicted by the bare theory. This paper responds to some recent objections to the bare theory by providing a more detailed description of the sense in which it can and the sense in which it cannot account (...)
  40. Empirical Adequacy and the Availability of Reliable Records in Quantum Mechanics.Jeffrey A. Barrett - 1996 - Philosophy of Science 63 (1):49-64.
    In order to judge whether a theory is empirically adequate one must have epistemic access to reliable records of past measurement results that can be compared against the predictions of the theory. Some formulations of quantum mechanics fail to satisfy this condition. The standard theory without the collapse postulate is an example. Bell's reading of Everett's relative-state formulation is another. Furthermore, there are formulations of quantum mechanics that only satisfy this condition for a special class of observers, formulations whose empirical (...)
  41. The Single-Mind and Many-Minds Versions of Quantum Mechanics.Jeffrey A. Barrett - 1995 - Erkenntnis 42 (1):89-105.
    There is a long tradition of trying to find a satisfactory interpretation of Everett's relative-state formulation of quantum mechanics. Albert and Loewer recently described two new ways of reading Everett: one we will call the single-mind theory and the other the many-minds theory. I will briefly describe these theories and present some of their merits and problems. Since both are no-collapse theories, a significant merit is that they can take advantage of certain properties of the linear dynamics, which Everett apparently (...)
  42. The Suggestive Properties of Quantum Mechanics Without the Collapse Postulate.Jeffrey A. Barrett - 1994 - Erkenntnis 41 (2):233 - 252.
    Everett proposed resolving the quantum measurement problem by dropping the nonlinear collapse dynamics from quantum mechanics and taking what is left as a complete physical theory. If one takes such a proposal seriously, then the question becomes how much of the predictive and explanatory power of the standard theory can one recover without the collapse postulate and without adding anything else. Quantum mechanics without the collapse postulate has several suggestive properties, which we will consider in some detail. While these properties (...)
  43. The Quantum Mechanics of Minds and Worlds.Jeffrey Alan Barrett - 1999 - Oxford University Press.
    Jeffrey Barrett presents the most comprehensive study yet of a problem that has puzzled physicists and philosophers since the 1930s.
  44. Quantum Mechanics Without the Collapse Postulate.Jeffrey Alan Barrett - 1992 - Dissertation, Columbia University
    Because of the measurement problem, the standard theory of quantum mechanics is at best incomplete and at worst logically inconsistent. Everett suggested that the measurement problem could be resolved by taking the linear dynamics to be a complete and accurate description of the time-evolution of every physical system. The purpose of this dissertation is to see what happens when one takes Everett's proposal seriously. This dissertation includes a discussion of the standard theory of quantum mechanics and its origins, the measurement (...)
  45. Combining Relativity and Quantum Mechanics: Schrödinger's Interpretation of Ψ. [REVIEW]A. O. Barut - 1988 - Foundations of Physics 18 (1):95-105.
    The incongruence between quantum theory and relativity theory is traced to the probability interpretation of the former. The classical continium interpretation of ψ removes the difficulty. How quantum properties of matter and light, and in particular the radiative problems, like spontaneous emission and Lamb shift, may be accounted in a first quantized Maxwell-Dirac system is discussed.
  46. The Quantum Mechanics of Minds and Worlds.L. Becker - 2001 - Philosophical Review 110 (3):482-484.
  47. The Quantum Mechanics of Minds and Worlds.Lon Becker & Jeffrey Alan Barrett - 2001 - Philosophical Review 110 (3):482.
  48. Speakable and Unspeakable in Quantum Mechanics: Collected Papers on Quantum Philosophy.J. S. Bell - 2004 - Cambridge University Press.
    This book comprises all of John Bell's published and unpublished papers in the field of quantum mechanics, including two papers that appeared after the first edition was published. It also contains a preface written for the first edition, and an introduction by Alain Aspect that puts into context Bell's great contribution to the quantum philosophy debate. One of the leading expositors and interpreters of modern quantum theory, John Bell played a major role in the development of our current understanding of (...)
  49. Six Possible Worlds of Quantum Mechanics.J. S. Bell - 1992 - Foundations of Physics 22 (10):1201-1215.
  50. 6 Possible Worlds of Quantum-Mechanics (Reprinted From Possible Worlds in Humanities Arts and Sciences, Pg 359-373, 1989). [REVIEW]Js Bell - 1992 - Foundations of Physics 22 (10):1201-1215.
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