Theo Todman's Web Page - Paper Abstracts

Author’s introduction

• A plausible principle governing identity is that whether a later individual, y, is identical with an earlier individual, x, cannot ever merely depend on whether there are, at the later time, any better candidates¹ than y around for identity with x. I shall call this principle 'the only x and y principle²'. It has been a bone of contention amongst philosophers interested in identity for many years. In "Wiggins (David) - Sameness and Substance" (1980) David Wiggins, who has always been one of the stoutest defenders of the only x and y principle³, includes a formulation of it among his D theses as thesis D(x) and presents what he believes to be 'the most fundamental objection' to the opposing 'best candidate⁴' approach to identity, i.e. the approach involving rejection of the only x and y principle⁵. In what follows I argue that Wiggins' objection fails, but that there is another objection to the 'best candidate⁶' approach which succeeds.
• An example which makes rejection of the only x and y principle⁷ seem plausible, and also brings out exactly what that involves, is that of the Ship of Theseus⁸, as described by Thomas Hobbes (De Corpore, 11 (Molesworth, p. 136)). And it is in connection with this example, also, that Wiggins presents his fundamental objection to the 'best candidate' approach to identity.
• In this case it does seem plausible to say that the continuously repaired ship is the Ship of Theseus⁹ but that the plank-hoarder's ship is a candidate too, and would have been the Ship of Theseus¹⁰ if its rival, the continuously repaired ship, had not existed. To insist that the plank-hoarder's ship is not the Ship of Theseus even when its rival does not exist seems absurd - for ships can certainly undergo dismantling and reconstruction; while to insist that it is still the Ship of Theseus¹¹ when its rival does exist seems implausible. But even if a case could be made out for saying the latter (e.g. by reference to the antiquarian interest in the Ship of Theseus), it is clear that any considerations in favour of the plank-hoarder's ship can lend it plausibility at best, so that even if it is not definitely true that the continuously repaired ship is the Ship of Theseus¹² in the situation Hobbes describes, it is not definitely false either. The identity statement in question is at worst indeterminate in truth value.