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The Nature of the Controversy over Time-Symmetric Quantum Counterfactuals

Published online by Cambridge University Press:  01 January 2022

Abstract

It is proposed that the recent controversy over “time-symmetric quantum counterfactuals” (TSQCs), based on the Aharonov-Bergmann-Lebowitz Rule for measurements of pre- and post-selected systems, can be clarified by taking TSQCs to be counterfactuals with a specific type of compound antecedent. In that case, inconsistency proofs such as that of Sharp and Shanks (1993) are not applicable, and the main issue becomes not whether such statements are true, but whether they are nontrivial. The latter question is addressed and answered in the negative. Thus it is concluded that TSQCs, understood as counterfactuals with a compound antecedent, are true but only trivially so, and provide no new contingent information about specific quantum systems (except in special cases already identified in literature).

Type
Research Article
Copyright
Copyright © The Philosophy of Science Association

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Footnotes

The author gratefully acknowledges helpful comments and suggestions from two anonymous referees. This work was supported in part by grant no. SES-0115185 of the National Science Foundation.

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