chapter  9
SCEPTICISM, CERTAINTY, MOORE AND WITTGENSTEIN
ByCRISPIN WRIGHT
Pages 21

G.E.Moore’s ‘A Defence of Common Sense’ was first published in 1925 and his ‘Proof of an External World’ fourteen years later.2 Apparently Wittgenstein had a long-standing interest in these papers and in the last eighteen months of his life, stimulated3 by discussions with Norman Malcolm while his house-guest in Ithaca in 1949, he composed the notes we now have as On Certainty. My question here is whether Wittgenstein’s last philosophical thoughts point to a principled and stable response to the issue at which Moore’s papers had been directed-the issue of scepticism, and particularly scepticism about our knowledge of the material world. My eventual and hesitant answer will be: yes, though the development here will be inevitably sketchy. And it will be focused upon one specific-though as disturbing as any, and very general-form of sceptical argument, which I shall begin by eliciting, ironically, from the consideration of something that was supposed to help-Moore’s curious ‘Proof’ itself.