A type-theoretical Curry paradox and its solution.

The Curry–Howard correspondence, according to which propositions are types, suggests that every paradox formulable in natural deduction has a type-theoretical counterpart. I will give a purely type-theoretical formulation of Curry's paradox. On the basis of the definition of a type |$\Gamma (A)$|⁠ ,...

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Bibliographic Details
Published in:Philosophical Quarterly Vol. 75; no. 2; pp. 763 - 775
Main Author: Klev, Ansten
Format: Article
Published: Oxford University Press / USA Apr2025
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Online Access:View this record in EBSCOhost
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Summary:The Curry–Howard correspondence, according to which propositions are types, suggests that every paradox formulable in natural deduction has a type-theoretical counterpart. I will give a purely type-theoretical formulation of Curry's paradox. On the basis of the definition of a type |$\Gamma (A)$|⁠ , Curry's reasoning can be adapted to show the existence of an object of the arbitrary type A. This is paradoxical for several reasons, among others that A might be an empty type. The solution to the paradox consists in seeing that |$\Gamma (A)$| is not a well-defined type.