In this paper I take issue with the doctrine that organisms belong of their very essence to the natural kinds (or biological taxa, if these are not kinds) to which they belong. This view holds that any human essentially belongs to the species Homo sapiens, any feline essentially belongs to the cat family, and so on. I survey the various competing views in biological systematics. These offer different explanations for what it is that makes a member of one species, family, (...) etc. a member of that taxon. Unfortunately, none of them offers an explanation that is compatible with the essentialism in question. (shrink)

This paper is a defence of a psychological view of personal identity against the attack Peter Unger launches against it in his Identity, Consciousness and Value. Unger attempts to undermine the traditional support which a psychological criterion of identity has drawn from thought-experiments, and to show that such a criterion has totally unacceptable implications -- in particular, that it allows that persons can go out of and come back into existence. I respond to both aspects of this criticism, arguing that (...) the relevant thought-experiments (and the support they appear to offer) survive Unger's attack intact, and that he does not establish his case against intermittent existence. (shrink)

Thought-experiments in which one person divides into two have been important in the literature on personal identity. I consider three influential arguments which aim to undermine the force of these thought-experiments – arguments from David Wiggins, Patricia Kitcher and Kathleen Wilkes. I argue that all three fail, leaving us to face the consequences of splitting, whatever those may be.

In this paper, I attempt to map out the 'logical geography' of the territory in which issues of mental content and of personal identity meet. In particular, I investigate the possibility of combining a psychological criterion of personal identity with an externalist theory of content. I argue that this can be done, but only by accepting an assumption that has been widely accepted but barely argued for, namely that when someone switches linguistic communities, the contents of their thoughts do not (...) change immediately, but only after the person becomes integrated within the new linguistic community. I also suggest that recent work on personal identity, notably by Derek Parfit, has tacitly assumed internalism regarding mental content. I do not intend to argue for either externalism or a psychological criterion. My aim is merely to explicate the issues involved in making them compatible. (shrink)