Online research in philosophy

There are certain metaphysically interesting arguments ‘from vagueness’, for unrestricted mereological composition and for four-dimensionalism, which involve a claim to the effect that idioms for unrestricted quantification are precise. An elaboration of Lewis’ argument for this claim, which assumes the view of vagueness as semantic indecision, is presented. It is argued that the argument also works according to other views on the nature of vagueness, which also require for an expression to be vague that there are different admissible alternatives of the relevant sort, such as epistemicism, as defended by Williamson. Recent attempts to resist the argument are discussed and rejected.

Unrestricted Composition (UC) is, roughly, the claim that given any objects at all, there is something which those objects compose. (UC) conflicts in an obvious way with common sense. It has as a consequence, for instance, that there is something which has as parts my nose and the moon. One of the more influential arguments for (UC) is Theodore Sider’s version of the Argument from Vagueness. (A version of the Argument from Vagueness was first presented by David Lewis (1986), pp. 212–213). That argument purports to show that some plausible claims concerning the nature of vagueness entail (UC). In this paper I will suggest a response to this argument. I will show that the proponent of Supersubstantivalism (SS)—the view that material objects are identical to regions of spacetime—can reject a premise of Sider’s argument without denying the plausible claims concerning vagueness. Doing so requires only rejecting a certain view concerning the relationship between the proper sub-region relation and the proper parthood relation. So, proponents of (SS) are in a better position than many of us to side with common sense regarding composition. In the first section of the paper, I will present Sider’s argument. In the second section, I will introduce (SS) and briefly discuss some reasons one might have to believe that it is true. In the third section, I will show how the proponent of (SS) can avoid commitment to (UC) and reject a premise of Sider’s argument. Last, I’ll briefly consider and respond to some objections.

I attempt to block the Lewis-Sider argument from vagueness by defending the possibility of borderline composition. After presenting Sider’s argument against borderline composition, and explaining why many universalists have reason to resist the argument, I examine a suppressed premise of Sider’s argument that has been entirely overlooked in the literature and show that one who denies this premise can block the argument without incurring commitment to the vagueness of any logical vocabulary. I then examine the charge that proponents of borderline composition incur commitment to “ontic vagueness,” distinguish ten things that might be meant by this charge, and explain why the form of “ontic vagueness” to which they are committed is largely superficial and does not compromise the determinacy of the world as a whole.

David Lewis (1986) criticizes moderate views of composition on the grounds that a restriction on composition must be vague, and vague composition leads, via a precisificational theory of vagueness, to an absurd vagueness of existence. I show how to resist this argument. Unlike the usual resistance, however, I do not jettison precisificational views of vagueness. Instead, I blur the connection between composition and existence that Lewis assumes. On the resulting view, in troublesome cases of vague composition, there is an object, which definitely exists, about which it is vague whether the relevant borderline parts compose it.

The Vagueness Argument for universalism only works if you think there is a good reason not to endorse nihilism. Sider’s argument from the possibility of gunk is one of the more popular reasons. Further, Hawley has given an argument for the necessity of everything being either gunky or composed of mereological simples. I argue that Hawley’s argument rests on the same premise as Sider’s argument for the possibility of gunk. Further, I argue that that premise can be used to demonstrate the possibility of simples. Once you stick it all together, you get an absurd consequence. I then survey the possible lessons we could draw from this, arguing that whichever one you take yields an interesting result.

There’s an argument around from so-called “linguistic theories of vagueness”, plus some relatively uncontroversial considerations, to powerful metaphysical conclusions. David Lewis employs this argument to support the mereological principle of unrestricted composition, and Theodore Sider employs a similar argument not just for unrestricted composition but also for the doctrine of temporal parts. This sort of argument could be generalised, to produce a lot of other less palatable metaphysical conclusions. However, arguments to Lewis’s and Sider’s conclusions on the basis of considerations about vagueness are uncompelling, even if we accept the crucial premises about vagueness. And a good thing too, since the generalised form of the argument would prove far too much.

A presentation of the Lewis-Sider argument from vagueness for unrestricted composition and possible responses.

In this paper, I critically discuss one of the more influential arguments for mereological universalism, what I will call ‘the Vagueness Argument’. I argue that a premise of the Vagueness Argument is not well supported and that there are at least two good reasons for thinking that the premise in question is false.

Anyone who endorses Universalism and Four Dimensionalism owes us an argument for those controversial mereological theses. One may put forth David Lewis's and Ted Sider's arguments from vagueness. However, the success of those arguments depends on the rejection of the epistemic view of vagueness, and thus opens the door to a fatal confrontation with one particularly troubling version of The Problem of the Many. The alternative for friends of Universalism and Four Dimensionalism is to abandon those currently fashionable arguments in favor of others which are consistent with the epistemic view of vagueness and with the elegant solution it furnishes to that problem.

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).