Lehrer’s Dynamic Theory of Knowledge

Abstract

This paper argues that problems of epistemology and problems of belief change are tightly interwoven and that a successful analysis of knowledge depends on a proper solution of the problems of belief change. Following Keith Lehrer, we assume that what an agent knows at a certain instant is dependent u p o n h o w h e i s inclined to change his beliefs in time. However, two of Lehrer's fundamental concepts, personal justiication and undefeated justiication, turn out be problematic. I argue that systematic solutions to the problems must have recourse to a well-developed theory of belief change. While this argument tries to establish that the theory of (the static concept of) knowledge needs help from the theory of the dynamics of belief, it is argued that the reverse strategy should be followed in studies of belief change where the crucial epistemological distinction between foundationalism and coherentism proves useful for the analysis of belief representation and revision.