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Universalism, Vagueness and Supersubstantivalism

2008; Routledge; Volume: 87; Issue: 1 Linguagem: Inglês

10.1080/00048400802215422

1471-6828

Nikk Effingham,

Philosophy and History of Science

Abstract Sider has a favourable view of supersubstantivalism (the thesis that all material objects are identical to the regions of spacetime that they occupy). This paper argues that given supersubstantivalism, Sider's argument from vagueness for (mereological) universalism fails. I present Sider's vagueness argument (§§II–III), and explain why – given supersubstantivalism – some but not all regions must be concrete in order for the argument to work (§IV). Given this restriction on what regions can be concrete, I give a reductio of Sider's argument (§V). I conclude with some brief comments on why this is not simply an ad hominem against Sider, and why this incompatibility of supersubstantivalism with the argument from vagueness is of broader interest (§VI). Notes 1Actually, this isn't quite true. For instance, Lewis says that, given genuine modal realism, objects in different worlds compose [1983: 39]. Sider's argument cannot capture that conclusion, for there are no cases where some ys at different worlds compose for every case must be at a world, and no world contains further worlds. Whilst this omission may be forgivable, it is worth noting that Lewis (universalism's arch-advocate!) would not be able to accept the argument in this form. (With thanks to Joseph Melia for pointing this out.) 2Or, to put it another way, if it were vague as to how many objects there were, it must be vaguely one number and vaguely another, but the only candidate number is ‘infinity’. 3Note that, given SS, occupation is identity. So if the object occupies a region, it is identical to it. 4If you accept the necessity of identity then we do have a problem. Given that y is identical to the fusion of r 3 and r 4 at ω1 it would be identical to that fusion at all worlds, i.e. could never be identical to R at ω n . This is not a problem for me, for if you accept SS you must reject the necessity of identity (which most perdurantists do anyway as they accept counterpart theory to solve lump/statue and person/body problems to which this situation is analogous [Sider Citation2001: 205–6; Lewis Citation1983: 47–54]). This is why: given SS, an object is identical to a region iff the object occupies that region; given the necessity of identity, an object is necessarily identical to the region it is actually identical to; it follows that all objects necessarily occupy the region they actually occupy. This conclusion is reprehensible, so those who accept SS should give up on the necessity of identity. 5It should also be noted that, if you wish, the slight change from world to world can be infinitesimally small (unlike my diagram, where the shift is clearly discrete) so we end up with an infinite series of cases connecting the two cases. 6You might note that in the diagram I present the difference between any two exceedingly similar cases as consisting in more than a single point, but as a single line of points (hence infinitely many points). This was solely for the ease of presentation. If this does unduly concern you, then imagine instead the world line of a point-sized material object as opposed to an extended object as depicted in my diagram. That will make the difference between any two cases a difference in a single point (as opposed to a line of infinite points). 7The endurantists will have to fend for themselves, for I am convinced by Sider's arguments that SS entails perdurantism. Also note that Sider was relying on the vagueness argument for universalism mainly so he could mount his vagueness argument for perdurantism. Given SS he will no longer need this latter argument, so Sider may well rest easy with the conclusion of this paper. 8I would like to thank Joseph Melia for his invaluable help, as well as Neil Clarke, Chris Gifford, Sean Power, Jon Robson, Gina Tsang, the interviewing panel of the University of Manchester (particularly David Liggins) and the referees of the AJP.