, eds., Mereology and the Sciences (volume under review at Springer, Synthese Library) Cody Gilmore Endurantism, the view that material objects are wholly present at each moment of their careers, is under threat from supersubstantivalism, the view that material objects are identical to spacetime regions. I discuss three compromise positions. They are alike in that they all take material objects to be composed of spacetime points or regions without being identical to any such point or region. They differ in whether they permit multilocation and in whether they generate cases of mereologically coincident entities.
IntroductionLet me start with a rough characterization of two main views about persistence:Endurantism: At least some material objects persist through time; and every material object is temporally unextended and wholly present at each instant at which it exists at all. Moreover, it is not the case that every material object has a different instantaneous temporal part 1 at each different instant at which it exists.Perdurantism: At least some material objects persist through time; any every material object has a different instantaneous temporal part at each different instant at which it exists. Material objects that do persist are temporally extended and are at most partially present (not wholly present) at any one instant.I will introduce more carefully formulated views later on (from Gilmore 2006), but these are adequate for present purposes. Endurantism fits comfortably with presentism and certain other A-theorist of time.2 It also fits together fairly well with a certain brand of B-theoretic eternalism. What I have in mind here is a view like Newton's, according to which substantival space and substantival time are two separate and fundamental entities, and spacetime, if there is such a thing at all, is merely a construct of some sort. (Perhaps spacetime points are identified with ordered pairs.) Call this view about space and time 'separatist substantivalism'; it should be understood as incorporating eternalism and the B-theory. 1 The standard definition of 'instantaneous temporal part' runs as follows: 'x is an instantaneous temporal part of y at t' means '(i) t is an instant, (ii) x is a part of y at t, (iii) x overlaps-at-t every part-at-t of y, (iii) x is present at t, and (iv) x is not present at any other instant'. (This is based on Sider (2001: 59).) For other definitions, see Gibson and Pooley (2006: 163), Parsons (2007), and Balashov (2010: 73). The key point is that, in order for a thing y to count as a temporal part of a thing x, y must be a part of x and y must be spatially co-located with x at any moment at which y is present. 2 A-theories of time all say that there is a time that is present in some absolute, not-merely-indexical sense. That is, they say that there is a 'metaphysically privileged' present time. The B-theory of time denies this. Presentism is an A-theory of time according to which there are no non-present entities (such as, presumably, p...