G. E. Moore is known for his attack on idealism and defense of common-sense realism and for being, together with Bertrand Russell and Ludwig Wittgenstein, one of the founders of analytic philosophy. His main stimulus for investigating philosophical problems was what other philosophers had written, rather than the problems of science or the world itself; for this reason he is known as the "philosopher's philosopher." He took pains to analyze what philosophers meant when they enunciated metaphysical theses such as the claim that time is unreal--a position that he himself held in his younger years--and to refute such propositions. In Principia Ethica (1903) he argues for the autonomy of ethical concepts. The book had a strong influence in literary circles, especially on members of the Bloomsbury Group, such as the writer Virginia Woolf and the economist John Maynard Keynes. Writing to a friend in 1940, Woolf asked, "did you ever...