G. E. Moore

George Edward Moore was, with Russell and Wittgenstein, an initiator of analytic philosophy. Born in Upper Norwood, south-east London, in 1873, he was the middle of seven children of a medical doctor. After Dulwich College he went up to Trinity College, Cambridge, in 1892, taking a double first in classics and moral sciences. He became a Fellow of Trinity in 1898 and held the Cambridge Chair of Mental Philosophy and Logic from 1925 to 1939, influencing the Bloomsbury Group while keeping his distance from it.

His Principia Ethica (1903) launched modern metaethics. Its central move is the naturalistic fallacy: when ethicists identify "good" with a natural property — pleasure, fitness, complexity — the open question "is the pleasant always good?" remains intelligible, so the two notions are not identical. Goodness, Moore argues, is a simple, unanalysable, non-natural property grasped by intuition. The accompanying theory is ideal utilitarianism: a plurality of intrinsic goods rather than pleasure alone. Principia Ethica was formative for Keynes and Virginia Woolf in Bloomsbury.

In epistemology Moore was the chief opponent of British idealism. His 1903 paper "The Refutation of Idealism" argued that consciousness and its objects must be distinguished. In 1939 his "Proof of an External World" presented the famous demonstration: he held up one hand, then the other, and concluded that at least two external objects exist. Replying to scepticism with commonsense certainties became known as commonsense philosophy.

In philosophy of language he is remembered for Moore's paradox: "It is raining, but I don't believe it is raining" — a sentence that is not contradictory yet absurdly assertable, an anomaly Wittgenstein later mined for what it shows about belief. Moore received the Order of Merit in 1951. Russell once wrote that Moore "fulfilled my ideal of genius," and Wittgenstein took the title of his Tractatus on Moore's suggestion.