Online research in philosophy

Locke’s account of personal identity has been highly influential because of its emphasis on a psychological criterion. The same consciousness is required for being the same person. It is not so clear, however, exactly what Locke meant by ‘consciousness’ or by ‘having the same consciousness’. Interpretations vary: consciousness is seen as identical to memory, as identical to a first personal appropriation of mental states, and as identical to a first personal distinctive experience of the qualitative features of one’s own thinking. There is wide agreement, however, that Locke’s theory of personal identity is meant to complement his moral and theological commitments to a system of divine punishment and reward in an afterlife. But these commitments seem to require also a metaphysical criterion, and Locke is insistent that it cannot be substance. The difficulty reconciling the psychological and metaphysical requirements of the theory has led, at worst, to charges of incoherence and, at best, to a slew of interpretations, none of which is widely accepted.

Parfit’s well known book, Reasons and Persons, argues, among other things, that ‘what matters’ in regard to ‘survival’ is not personal identity but something he calls ‘relation R.’ On this basis, plus other considerations, he rejects the ‘Self-interest’ theory as to what should be our aim in life. Here I show, or try to show, that his over-all argument is seriously defective. In particular, he fails to prove that personal identity is not what matters for survival.

Sydney Shoemaker argues that the functionalist theory of mind entails a psychological-continuity view of personal identity, as well as providing a defense of that view against a crucial objection. I show that his view has surprising consequences, e.g. that no organism could have mental properties and that a thing's mental properties fail to supervene even weakly on its microstructure and surroundings. I then argue that the view founders on "fission" cases and rules out our being material things. Functionalism tells us little if anything about personal identity.

Self-interest is widely regarded as an important, if not as the only, source of reasons for action, and hence it is widely held that one can rationally give special weight to one’s self-interest in deciding how to act. In what follows, I will argue against this view. I will do so by following the lead of Derek Parfit, and considering cases in which personal identity appears to break down. My argument will differ from Parfit’s, however, in that it will have a stronger conclusion, it will involve fewer assumptions, and it will be compatible with a wider range of theories of personal identity.

In this paper, I compare John Locke’s “memory theory” of personal identity and Memento (directed by Christopher Nolan). I argue that the plot of Memento is ambiguous, in that the main character (Leonard Shelby, played by Guy Pearce) seems to have two histories. As such, Memento is but a series of puzzle cases that intend to illustrate that, although our memories may not be chronologically related to one another, and may even be fused with the memories of other persons, those memories still constitute personal identity. Just as Derek Parfit argues, perhaps there is no personal identity as such, since only survival (in some degree) matters to us. In Memento, Leonard Shelby is not identity to his former self, but survives to some extent.

Abstract In Reasons and Persons, Derek Parfit argues that personal identity is indeterminate and that identity is not what matters in personal survival. Parfit argues that traditional views of personal identity have counterintuitive consequences and that they violate a plausible requirement, suggested by Bernard Williams, that must be met by any acceptable criterion of identity. Parfit argues that, unlike traditional determinate views of personal identity, his view succeeds in accommodating intuitions and in meeting (an analogue to) Williams' requirement. I argue that Parfit's view has more counterintuitive consequences than do the traditional views of identity. Though the traditional views do seem to violate Williams' requirement, Parfit's view fares no better. In fact, it seems that any theory of personal survival that appeals to connections that may hold to a greater or lesser extent will fail to meet the relevant requirement. This is an important general point, since the requirement is a plausible one.

Does intention presuppose personal identity, and what relevance does the issue have for the contemporary personal identity debate? I distinguish three ways in which intention might be said to presuppose personal identity, focusing mainly on causal presupposition and content presupposition. I argue that intention often causally presupposes personal identity. I argue that intention does not content-presuppose personal identity. The former result is a potential basis for a Butlerian circularity objection to Lockean theories of personal identity. The latter result undercuts a prominent Lockean reply to ‘the thinking animal’ objection which has recently supplanted traditional Butlerian circularity objections in the personal identity debate.

One of the main problems of personal identity is supposed to be how we relate to our bodies. A few philosophers endorse what is called a 'bodily criterion of personal identity': they say that we are our bodies, or at any rate that our identity over time consists in the identity of our bodies. Many more deny this--typically on the grounds that we can imagine ourselves coming apart from our bodies. But both sides agree that the bodily criterion is an important view which anyone thinking about personal identity must consider.