Wittgenstein on Scepticism and Nonsense

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.