Organon F
Volume 33, May 2026, Issue 2, Pages 196–217
ISSN 2585-7150 (online)
Research Article
Time Travel and the Limits of Logic: Why the Grandfather Paradox Continues to Resist Solution
Yael Loewenstein
David Lewis’s influential solution to the grandfather paradox treats time traveler Tim’s failure to kill his infant grandfather as an ordinary case of unsuccessful action. Relative to the facts at the time of the attempt, Tim can succeed, and his failure is no more mysterious than missing a basketball shot. I argue that Lewis’s solution is mistaken, and that a more recent alternative—the “strategy by analogy with the impossible,” which likens Tim’s failure to other failures to achieve logically or mathematically impossible tasks (e.g., crossing each of Königsberg’s seven bridges exactly once)—also fails. Drawing a distinction between self-explicable and self-enforcing failures on the one hand, and Tim’s failure on the other, it is shown that Tim’s failure differs from ordinary failures to achieve the impossible insofar as the latter require no causal intervention: the impossibility itself fully explains and brings about the failure. Tim’s case is structurally different. While it is impossible for his grandfather to both survive and not survive, nothing in the impossibility itself explains why his grandfather must survive rather than die—a selection between two contingent-seeming alternatives that ordinarily falls outside logic's purview and within causation’s. The grandfather paradox therefore occupies an unrecognized middle ground: a necessary failure (relative to any facts) that nonetheless seems to demand causal enforcement, leaving the puzzle’s deepest difficulty unresolved by either of the two leading strategies.
Time travel; Grandfather Paradox; David Lewis; closed causal loops; backward causation; logical explanation; explanation.
Author
Yael Loewenstein
Affiliation
University of Houston
Address
Philosophy Department, University of Houston, 3553 Cullen Boulevard, Houston, TX 77204-3004, USA
Received
5 August 2025
Accepted
21 March 2026
Publishers
Institute of Philosophy of the Slovak Academy of Sciences
Institute of Philosophy of the Czech Academy of Sciences
APA
Loewenstein, Y. (2026). Time Travel and the Limits of Logic: Why the Grandfather Paradox Continues to Resist Solution. Organon F, 33(2), 196–217. https://doi.org/10.31577/orgf.2026.33205
Chicago
Loewenstein, Yael. 2026. "Time Travel and the Limits of Logic: Why the Grandfather Paradox Continues to Resist Solution." Organon F 33 (2): 196–217. https://doi.org/10.31577/orgf.2026.33205
Harvard
Loewenstein, Y. (2026). Time Travel and the Limits of Logic: Why the Grandfather Paradox Continues to Resist Solution. Organon F, 33(2), pp. 196–217. https://doi.org/10.31577/orgf.2026.33205
© Yael Loewenstein
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