ABSTRACT
In his famous discussion of Wittgenstein on rules and private language, Kripke describes Wittgenstein as having "invented the most radical and original skeptical problem that philosophy has seen to date". Many commentators have held that Kripke's skeptical problem is exclusively, or at least fundamentally, metaphysical or constitutive. Kripke, it is thought, presents this problem in the guise of an epistemological problem, or using the language of epistemological skepticism, but the weight of it rests on the metaphysical question of what constitutes the fact of someone's meaning something by an expression, or of the expression having a meaning. Commentators have disagreed about the relation between epistemological and metaphysical elements in the skeptical problem. There has indeed been disagreement, within this broad consensus, about whether epistemological considerations are relevant to the skeptical challenge insofar as they impose constraints on possible answers to the metaphysical question.
