Abstract

Beginning with Locke, most philosophers writing on personal identity have claimed that some sort of psychological continuity is necessary for a person to persist from one time to another. I argue that this "psychological approach" to personal identity faces ontological difficulties that many of its proponents have not appreciated. In its place I advocate a "biological approach" to personal identity: you and I are human organisms, and our persistence, like that of other organisms, consists in narrowly biological facts alone. ;Since its biological functions are distinct from its psychology, a human organism can survive without psychological continuity. Thus the psychological approach apparently entails that you and I are not human organisms. But what are we, if not organisms? And how are we related to "our" human organisms? I consider a number of possible answers: perhaps we are not material objects at all; perhaps each of us is a material object coincident with though numerically distinct from a human organism; perhaps identity is not "absolute" but "relative," and a human organism may be different persons at different times; perhaps you and I do not really exist; perhaps we are temporally extended, "four-dimensional" objects and typically share most of our temporal parts with a human organism. The last option is the most popular, and rightly so. However, I argue that it faces technical problems and that it is wildly at odds with our ordinary beliefs about ourselves. ;After considering a wide range of arguments for the psychological approach, I conclude that most are grounded in confusion and have no force whatever. The best arguments appeal to our intuitive convictions about whether we would survive in various science-fiction stories in which the psychological and biological approaches diverge . Without dismissing these intuitions, I argue that they do not unequivocally support the psychological approach