¹ Of course, this is not the case with identity statements involving descriptions. The statement ‘George W. Bush is the president of the United States’ was once false, is at the time of this writing true, and will at a future time be false.

² ‘Contingent Identity’, Journal of Philosophical Logic 4 (1975), pp. 187-221. I follow Gibbard's definitions of pieces of clay and clay statues, definitions which allow them to be designated with proper names; I also follow his persistence criteria for pieces of clay and statues. See pp. 188-90 for both the definitions and the criteria. While Gibbard utilizes the example to argue for the existence of contingent identities, I wish to put it to a different use.

³ That they are identical is Gibbard's intuition as well: ‘Here, I am tempted to say, the statue and the piece of clay are identical. They began at the same time, and on any usual account, they had the same shape, location, color, and so forth at each instant in their history; everything that happened to one happened to the other; and the act that destroyed the one destroyed the other. If the statue is an entity over and above the piece of clay, then statues seem to take on a ghostly air’ [ibid., p. 191].

⁴ Derek Parfit labels such questions ‘empty questions’. They are questions which we cannot answer though there is no information we lack such that had we that information, we could answer the question.

⁵ See, Lewis, David, On the Plurality of Worlds (Oxford: Blackwell, 1986), pp. 252–63Google Scholar. I am grateful to Dean Zimmerman for pointing out to me Lewis' example of the dishpan and the plastic from which it is made.