  The provocative words ‘building a brain’ from the outset announced the relationship of Turing's technical computer engineering to a philosophy of Mind. Even in 1936, Turing had given an interpretation of computability in terms of ‘states of mind’. His war work had shown the astounding power of the computable in mechanising expert human procedures and judgments. From 1941 onwards, Turing had also discussed the mechanisation of chess-playing and other ‘intelligent’ activities with his colleagues at Bletchley Park (Hodges 1983, p. 213). But more profoundly, it appears that Turing emerged in 1945 with a conviction that computable operations were sufficient to embrace all mental functions performed by the brain. As will become clear from the ensuing discussion, the uncomputable ‘intuition’ of 1938 disappeared from Turing's thought, and was replaced by new ideas all lying within the realm of the computable. This change shows even in the technical prospectus of (Turing 1946), where Turing referred to the possibility of making a machine calculate chess moves, and then continued: 