Once, G. E. Moore scorned the “common point of view which takes the world of experience as ultimately real.” The argument Moore followed to this sceptical conclusion in his fledgling 1897 fellowship dissertation was a legacy from Kant's Antinomies. By 1899 Moore had renounced idealist conclusions; he set out both to disengage from Kantian arguments and to reconcile with “the world of experience.” Moore's work for a stable realist basis for knowledge to fulfil both aims occupied his most famous argument, in his 1939 lecture “Proof of an External World.” Moore himself is sometimes supposed to have thought the argument of this masterwork unsatisfactory where it treats a traditional sceptical puzzle posed by dreaming. Critics, including Wittgenstein, have portrayed Moore's best reply to philosophical scepticism as dogmatic mere assertion, unresponsive or as ineffectual as sheer handwaving. However, these critics rate Moore's success against scepticism based on interpretations of “Proof of an External World” that neglect its part in Moore's campaign against Kant. Consequently, some potentially pivotal questions — which in this study I merely broach — remain wide open; for example, why in presenting his famous 1939 proof did Moore state that its purpose was to refute what “Kant declares to be his opinion, that there is only one possible proof of the existence of things outside of us” (PXW, p. 145)? And why did Moore explicitly reject the formula for posing philosophical scepticism in which Kant famously proclaimed this problem “a scandal to philosophy”?