  An important aspect of Moore's rejection of idealism was his affirmation of a ‘common sense’ realist position, according to which our ordinary common-sense view of the world is largely correct. Moore first explicitly championed this position in his 1910-11 lectures Some Main Problems of Philosophybut he made it his own when he responded in 1925 to an invitation to describe his ‘philosophical position’ by setting this out as ‘A Defence of Common Sense’. Moore begins the paper by listing a large number of ‘truisms’ such as that ‘the earth had existed also for many years before my body was born’. Concerning these truisms he then asserts, first, that he knows them for certain, second, that other people likewise know for certain the truth of comparable truisms about themselves and, third, that he knows this second general truth (and, by implication, others do too). So the truth and general knowledge of these truisms is a matter of common sense. Having set out these truisms, Moore then acknowledges that some philosophers have denied their truth or, more commonly, denied our knowledge of them (even though, according to Moore, they also know them) and he attempts to show that these denials are incoherent or unwarranted. These claims might seem to leave little space for radical philosophical argument. But in the last part of the paper Moore argues that his defence of common sense leaves completely undecided the question as to how the truistic propositions which make up the common sense view of the world are to be analysed; the analysis may be as radical as one likes as long as it is consistent with the truth and knowability of the propositions analysed. Thus, for example, he is content to allow that philosophical argument may show that a phenomenalist analysis of propositions about the physical world is correct.