Objective Certainty versus Scepticism

Abstract

What I need to shew is that a doubt is not necessary even when it is possible. That the possibility of a language-game doesn’t depend on everything being doubted that can be doubted.

(OC 392)

A sceptic about x believes there is no knowledge about x. In that (simple) sense of scepticism, Wittgenstein is a sceptic. He believes there is no knowledge about the existence of the external world, about the world being more than five minutes old; he also believes that, in normal circumstances, a person does not know that she has a body, or a hand, or a toothache. We can call this kind of scepticism, with which Wittgenstein agrees: knowledge-scepticism. More commonly, however, scepticism is the belief that doubt about x is always rational. This motivation, Wittgenstein rejects. In On Certainty, Wittgenstein is criticizing the idea that there is no knowledge because everything can be doubted. This chapter is about that kind of scepticism — the obsessive doubt kind of scepticism. We might refer to the kind of scepticism Wittgenstein is rejecting as: doubt-scepticism.