Parfit on Personal Identity and What Matters

Derek Parfit set out his reductionist theory of personal identity first in the 1971 article "Personal Identity" (The Philosophical Review) and then at far greater length in Part III of Reasons and Persons (1984, Oxford: Clarendon Press), one of the most discussed works of late-twentieth-century analytic philosophy. Reductionism, in Parfit's sense, holds that a person's existence over time consists in nothing more than the holding of certain physical and psychological facts and relations between temporally distinct person-stages — there is no further, separately existing fact of personal identity over and above these more basic facts, and no persisting Cartesian ego or simple substance is required to unite a life's stages.