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Decoherence and Ontology, or: How I Learned To Stop Worrying And Love FAPP

Wallace, David (2010) Decoherence and Ontology, or: How I Learned To Stop Worrying And Love FAPP. [Published Article]

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    Abstract

    I make the case that the Universe according to unitary (no-collapse) quantum theory has a branching structure, and so can literally be regarded as a "many-worlds" theory. These worlds are not part of the <em>fundamental</em> ontology of quantum theory - instead, they are to be understood as structures, or patterns, emergent from the underlying theory, through the dynamical process of decoherence. That they are structures in this sense does not mean that they are in any way unreal: indeed, pretty much all higher-level ontology in science, from tables to phonons to tigers, is likewise emergent. Unitary quantum theory is therefore a "many-worlds" theory without any modification of the mathematical structure of the theory: the Everett interpretation does not consist in adding worlds to the formalism, but in realising that they are there already. Our grounds for accepting the reality of those worlds is no more, but no less, than our grounds for accepting any other not-directly observable consequence of an empirically very successful theory.


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    Item Type: Published Article
    Additional Information: In S. Saunders, J. Barrett, A. Kent and D. Wallace (eds.), "Many Worlds? Everett, Quantum Theory, and Reality"
    Keywords: Emergence Decoherence Quantum Theory Everett Interpretation Many Worlds Interpretation
    Subjects: Specific Sciences > Physics > Quantum Mechanics
    General Issues > Reductionism/Holism
    Depositing User: David Wallace
    Date Deposited: 09 Nov 2011 20:59
    Last Modified: 09 Nov 2011 20:59
    Item ID: 8891
    Journal or Publication Title: S. Saunders, J. Barrett, A. Kent and D. Wallace (eds.), "Many Worlds? Everett, Quantum Theory, and Reality"
    Publisher: Oxford University Press
    URI: http://philsci-archive.pitt.edu/id/eprint/8891

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