ABSTRACT
Hilary Putnam has suggested that intuitionistic logic provides a solution to the sorites paradox, and is therefore appropriate for vague languages. This chapter argues that a new sorites paradox arises from the combination of intuitionistic logic with Putnam's epistemic account of truth, on which the true is what would be justified under optimal conditions. To reject the consequences of the epistemic account of truth on which the new sorites paradox depends is to move towards an epistemic account of vagueness. The epistemic account of truth and intuitionistic semantics has a similar effect. That is hardly surprising in light of the intuitionists’ constructivist account of truth. Propositional Failure is in any case intuitively implausible. Propositional Failure is therefore both intrinsically implausible as an account of vagueness and inconsistent with the role that Putnam assigns to intuitionistic logic. Intuitionism itself provides no reason to reject the Tarskian biconditionals.
