An overview of probability,expectations, uncertainty and rationality in Keynes's conceptual framework 1

Keynes's writings on the cognate topics of probability, expectations, uncertainty and rationality exhibit considerable complexity. This paper seeks to provide a clarifying overview of his position on these topics, both in his main philosophical workThe treatise on probability, and his main economic workThe general theory. It is argued that the most useful approach for understanding the deeper structure of Keynes's thought in each work is by means of a two-dimensional, two-domain analysis.Such an analysis helps demonstrate some of the ways in which the conceptual framework of The treatise on probability provides an essential part of the philosophical foundations of The general theory, while at the same time recognizing some of the key differences between the two works. It also illuminates Keynes's non-neoclassical theorization of rationality, and his path-breaking attempt to develop a theory of rationality under irreducible uncertainty.