Ramsey and Keynes revisited

Abstract This paper re-assesses Ramsey’s influence on Keynes. It is argued that the Standard View has restricted attention to the implications for probability theory of Ramsey’s criticisms of Keynes’s concepts of logical probability-relations and non-numerical probabilities. Building on the work of both Coates (1996) and Misak (2016), an Alternative View is proposed in which Ramsey’s influence on Keynes is seen as principally philosophical. Specifically, the Alternative View recognises Ramsey’s adoption of the logical pragmatist philosophy of C. S. Peirce from 1924 onwards with a dispositional theory of belief in which beliefs are treated not only as useful mental habits that can successfully guide future actions but also as able to provide true explanations of observed empirical facts. The textual evidence is examined, particularly Keynes’s biographical essay on Ramsey, which, it is argued, supports the contention that Keynes fully appreciated and was sympathetic to Ramsey’s pragmatism especially the importance of vague knowledge and the need for the development of human logic as the study of reasonable human behaviour.