Abstract

In the Tractatus Wittgenstein wrote: “Skepticism is not irrefutable, but obviously nonsensical when it tries to raise doubts where no questions can be asked.” In this paper I show how Wittgenstein developed this insight in On Certainty. My principal aim is to show that this is a logical insight, that it is bound up with the distinction between saying and showing, and that one misses the point of On Certainty if one reads it, as some commentators have, in epistemological terms. Throughout all of this I pay special attention to why Wittgenstein thought that skepticism is nonsensical, and what it might mean to say that philosophy is a logical investigation.