Eric T. Olson

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

E. J. Lowe’s ‘non-Cartesian dualism’ is the widely held view that we and other thinking things are not organisms, but things materially coinciding with or constituted by them. Lowe added to this the claim that we have no parts. This further claim faces obvious and grave objections. His claim (shared by Baker and others) that we have our physical properties only derivatively may seem to offer an answer to these objections. But it introduces new problems, and appears to reduce Lowe’s view to Cartesian dualism.