On Dummett’s “Proof-Theoretic Justifications of Logical Laws”

Abstract

This paper deals with Michael Dummett’s attempts at a proof-theoretic justification of the laws of (intuitionistic) logic, pointing to several critical problems inherent in this approach. It discusses in particular the role played by “boundary rules” in Dummett’s semantics. For a revised approach based on schematic validity it is shown that the rules of intuitionistic logic can indeed be justified, but it is argued that a schematic conception of validity is problematic for Dummett’s philosophy of logic.