Traditionally, this puzzle has been solved in various ways. Aristotle, for example, distinguished between “accidental” and “essential” changes. Accidental changes are ones that don't result in a change in an objects' identity after the change, such as when a house is painted, or one's hair turns gray, etc. Aristotle thought of these as changes in the accidental properties of a thing. Essential changes, by contrast, are those which don't preserve the identity of the object when it changes, such as when (...) a house burns to the ground and becomes ashes, or when someone dies. Armed with these distinctions, Aristotle would then say that, in the case of accidental changes, (1) and (2) are both false—a changing thing can really change one of its “accidental properties” and yet literally remain one and the same thing before and after the change. (shrink)

This paper draws attention to a proof of the necessity of identity given by Arthur Prior. In its simplicity, it is comparable to a proof of Quine's, popularised by Kripke, but it is slightly different. Prior's Polish notation is transcribed into a more familiar idiom. Prior's proof is followed by a proof of the necessity of difference, possibly the first such proof in the literature, which is also repeated here and transcribed. The paper concludes with a brief discussion of Prior's (...) views on identity and difference over time. (shrink)

In his famous letter to A. N. Prior dated 3 September 1958, Saul Kripke suggested the use of branching time in temporal logic. In this paper, however, it is argued that Prior worked with an idea close to the notion of branching time (‘the big Y’) already the year before he received Kripke’s letter. It is likely that Prior’s findings based on this early study can explain why Prior so quickly accepted the idea of branching time when he received Kripke’s (...) letter. (shrink)

First published Sat Apr 5, 2003; most recent substantive revision Wed Aug 22, 2018. -/- Samuel Clarke (1675–1729) was the most influential British philosopher in the generation between Locke and Berkeley. His philosophical interests were mostly in metaphysics, theology, and ethics.

I defend the claim that bodily continuity is the primary criterion of personal identity by arguing there is an important sense in which it (unlike rival criteria) is a necessary condition of such identity. This claim is shown to be misunderstood in recent discussions because of a confusion of it with the claim that bodily continuity is a sufficient condition of personal identity. In the course of my argument, I criticize williams, Shoemaker, Puccetti, Quinton, Miri, And others.