Dividing without Reducing: Bodily Fission and Personal Identity

Abstract

Prudence requires persistence, and not just because the rational pursuit of selfinterest often strains our abilities. If I show prudential concern for someone who will exist next year, I must at least believe that I am that person and hence that I will persist until then.' Morality, too, seems to require persistence. We think that, with some explicable exceptions, people bear no moral responsibility for past actions they did not commit; so at the least they bear none for actions committed when they did not exist. Our judgments about prudence and responsibility presuppose verdicts on questions of personal persistence or, as it is usually called, personal identity. Derek Parfit (1989) has argued influentially that our pre-theoretical conceptions of personal identity and its connection with prudence and morality are incoherent, and that cherished moral and prudential intuitions must be revised. We believe, he says, both that personal identity is matters for prudential and moral purposes, and also that a certain relation of psychological connectedness and continuity-relation R-is what matters. But, he argues, these two relations can diverge. I take this to be the central thesis of what Parfit calls Reductionism.2 Since reductionism is true, says Parfit, our pre-theoretical view of personal identity-which includes the denial of reductionism is incoherent.