 Secondly, Prichard is also responsible for an extension of Cook Wilson’s conception of knowledge to moral philosophy, with his paper ‘Does Moral Philosophy Rest on a Mistake?’ (Prichard 1912), whose main argument is analogous to Cook Wilson’s argument for the impossibility of defining knowledge. In a nutshell, duty is sui generis and not definable in terms of anything else. The parallel is explicit in Prichard (1912, 21 &amp; 35–36). That we ought to do certain things, we are told, arises “in our unreflective consciousness, being an activity of moral thinking occasioned by the various situations in which we find ourselves”, and the demand that it is proved that we ought to do these things is “illegitimate” (Prichard 1912, 36). In order to find out our duty, “the only remedy lies in actually getting into a situation which occasions the obligation” and “then letting our moral capacities of thinking do their work” (Prichard 1912, 37). This paper became so influential that Prichard was elected in 1928 to the White’s Chair of Moral Philosophy at Corpus Christi, although his primary domain of competence had been the theory of knowledge. His papers in moral philosophy were edited after his death as Prichard (1949, now 2002). Prichard stands at the origin of the school of ‘moral’ or ‘Oxford intuitionism’, of which another pupil of Cook Wilson, the Aristotle scholar W. D. Ross (Ross 1930, 1939) remains the foremost representative, along with H. W. B. Joseph, E. F. Carritt, and J. Laird. Some of the views they expressed have recently gained new currency within ‘moral particularism’, e.g., in the writings of Jonathan Dancy (Dancy 1993, 2004).