Forthcoming in Oxford Studies in Metaphysics, Vol. 3 For citations, please refer to published version. TIME TRAVEL, COINCIDING OBJECTS, AND PERSISTENCE Cody Gilmore University of Nebraska at Omaha
[email protected] 1. Introduction Endurantism, roughly stated, is the view that material objects lack temporal extent and persist through time by “enduring” – i.e., by being wholly present at each moment of their careers. Perdurantism is the opposing view that material objects persist by “perduring” – i.e., by being temporally extended and having different temporal parts located at different times.1 In this paper I propose an argument against perdurantism based upon the possibility of backward time travel.2 Perdurantists can resist the argument, but not without weakening at least one significant argument against endurantism.3 In one way or another, then, this paper is meant to alter the overall debate between endurantists and perdurantists to the benefit of the former. The heart of the argument is a new type of coincidence puzzle. A coincidence puzzle is an apparent counterexample to the following, widely accepted anti-coincidence principle: It is impossible for numerically distinct material objects to coincide – i.e., to be (i) wholly present in exactly the same location4 and (ii) composed, at some level of decomposition, of all the same parts or all the same matter at the given location.5 To solve such a puzzle, as I shall use the term, is to show that the case in question does not in fact constitute a genuine counterexample to the principle. 6 Existing coincidence puzzles can be divided into two types, corresponding to the manner in which they bear upon the endurantism v.