*Jeffrey Alan Barrett*

- Published in print:
- 2001
- Published Online:
- March 2012
- ISBN:
- 9780199247431
- eISBN:
- 9780191697661
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199247431.003.0006
- Subject:
- Philosophy, Philosophy of Science, Metaphysics/Epistemology

This chapter explains the many-worlds interpretations, particularly the DeWitt–Graham interpretation — the splitting-worlds interpretation. The splitting-worlds theory proposes that one must choose ...
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This chapter explains the many-worlds interpretations, particularly the DeWitt–Graham interpretation — the splitting-worlds interpretation. The splitting-worlds theory proposes that one must choose what physical quantities one wants to be determinate in a world, which amounts to choosing a physically preferred basis. It discusses several traditional and real problems encountered with the splitting-worlds theory. It also describes another theory, where one might stipulate that the global state always evolves in the usual linear way, selects a preferred basis that makes observers' records always determinate in each local state, and then chooses a connection rule that will link local states at different times into trajectories — the many threads theory.Less

This chapter explains the many-worlds interpretations, particularly the DeWitt–Graham interpretation — the splitting-worlds interpretation. The splitting-worlds theory proposes that one must choose what physical quantities one wants to be determinate in a world, which amounts to choosing a physically preferred basis. It discusses several traditional and real problems encountered with the splitting-worlds theory. It also describes another theory, where one might stipulate that the global state always evolves in the usual linear way, selects a preferred basis that makes observers' records always determinate in each local state, and then chooses a connection rule that will link local states at different times into trajectories — the many threads theory.

*Lev Vaidman*

- Published in print:
- 2010
- Published Online:
- September 2010
- ISBN:
- 9780199560561
- eISBN:
- 9780191721380
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199560561.003.0024
- Subject:
- Philosophy, Metaphysics/Epistemology, Philosophy of Science

This chapter reviews an attempt to solve the collapse problem in the framework of a time-symmetric quantum formalism. Although the proposal does not look very attractive, its concept — a world ...
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This chapter reviews an attempt to solve the collapse problem in the framework of a time-symmetric quantum formalism. Although the proposal does not look very attractive, its concept — a world defined by two quantum states, one evolving forwards and one evolving backwards in time — is found to be useful in modifying the many-worlds picture of Everett's theory.Less

This chapter reviews an attempt to solve the collapse problem in the framework of a time-symmetric quantum formalism. Although the proposal does not look very attractive, its concept — a world defined by two quantum states, one evolving forwards and one evolving backwards in time — is found to be useful in modifying the many-worlds picture of Everett's theory.

*Jeffrey A. Barrett*

- Published in print:
- 2019
- Published Online:
- July 2020
- ISBN:
- 9780198844686
- eISBN:
- 9780191889196
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198844686.003.0010
- Subject:
- Philosophy, Philosophy of Science

We consider a number of radically different ways that Everett’s pure wave mechanics has been understood. Each of these reconstructions aims to provide a stronger variety of empirical adequacy than ...
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We consider a number of radically different ways that Everett’s pure wave mechanics has been understood. Each of these reconstructions aims to provide a stronger variety of empirical adequacy than Everett’s own formulation of the theory. Among the alternative formulations of quantum mechanics we consider are splitting worlds, decohering worlds, many minds, many threads, and many maps. Each of these differs in its metaphysical commitments and, hence, in how it explains determinate measurement records and probabilities. We focus, in particular, on the problem of accounting for the standard quantum probabilities. To this end, we consider the relationship between typicality and probability and contrast synchronic and forward-looking probabilities. We conclude with a brief discussion of epistemological, pragmatic, and information-theoretic formulations of quantum mechanics. A recurring issue in this chapter concerns what it should mean for a physical theory to be empirically adequate.Less

We consider a number of radically different ways that Everett’s pure wave mechanics has been understood. Each of these reconstructions aims to provide a stronger variety of empirical adequacy than Everett’s own formulation of the theory. Among the alternative formulations of quantum mechanics we consider are splitting worlds, decohering worlds, many minds, many threads, and many maps. Each of these differs in its metaphysical commitments and, hence, in how it explains determinate measurement records and probabilities. We focus, in particular, on the problem of accounting for the standard quantum probabilities. To this end, we consider the relationship between typicality and probability and contrast synchronic and forward-looking probabilities. We conclude with a brief discussion of epistemological, pragmatic, and information-theoretic formulations of quantum mechanics. A recurring issue in this chapter concerns what it should mean for a physical theory to be empirically adequate.