A Challenge to Psychological and Biological Theories of Personal Identity

Abstract

Traditionally, reductive accounts of personal identity within a three-dimensionalist framework face notorious problems. I focus mainly on the problem of graduality. This problem arises out of the apparent tension that exists between the nature of identity as a degreeless relation and standard accounts that seem to admit of degrees. An assessment concerning the nature of these relations is given in order to make the apparent tension explicit. It is then argued that the philosophical implications of such a problem entail a rejection of reductive theories that admit of degrees; paradigmatically, those that analyze personal identity either as psychological continuity or as biological continuity. Finally, it is proposed how this conclusion motivates the thesis that there are no criteria of identity over time.