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Forever is a Day: Supertasks in Pitowsky and Malament-Hogarth Spacetimes

Published online by Cambridge University Press:  01 April 2022

John Earman  and
John D. Norton
John D. Norton*
Affiliation:
Department of History and Philosophy of Science, University of Pittsburgh
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Abstract

The standard theory of computation excludes computations whose completion requires an infinite number of steps. Malament-Hogarth spacetimes admit observers whose pasts contain entire future-directed, timelike half-curves of infinite proper length. We investigate the physical properties of these spacetimes and ask whether they and other spacetimes allow the observer to know the outcome of a computation with infinitely many steps.

Type
Research Article
Information
Philosophy of Science , Volume 60 , Issue 1 , March 1993 , pp. 22 - 42
Copyright
Copyright © Philosophy of Science Association 1993

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Footnotes

†

We are grateful to David Malament and an anonymous referee for helpful suggestions on earlier drafts of this paper.

‡

Send reprint requests to the authors, Department of History and Philosophy of Science, 1017 Cathedral of Learning, University of Pittsburgh, Pittsburgh, PA 15260, USA.

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