Precis of my book by this title, for a symposium.

This anthology introduces advanced undergraduates and beginning graduate students to today's debates in metaphysics. The book consists of essays by contemporary metaphysicians, and all but one appear here for the first time. For each of nine topics, there are two essays, one "pro-" and one "con-".

Katherine Hawley explores and compares three theories of persistence -- endurance, perdurance, and stage theories - investigating the ways in which they attempt to account for the world around us. Having provided valuable clarification of its two main rivals, she concludes by advocating stage theory.

∗ Apologies to Mark Hinchliff for stealing the title of his dissertation. (See Hinchliff, A Defense of Presentism. As it turns out, however, the version of Presentism defended here is different from the version defended by Hinchliff. See Section 3.1 below.).

A radical metaphysical theory typically comes packaged with a semantic theory that reconciles those radical claims with common sense. The metaphysical theory says what things exist and what their natures are, while the semantic theory specifies, in terms of these things, how we are to interpret everyday language. Thus may we “think with the learned, and speak with the vulgar.” This semantic accommodation of common sense, however, can end up undermining the very theory it is designed to protect. This paper (...) is a case study, showing in detail how one popular version of temporal parts theory is self-undermining. This raises the specter that the problem generalizes to other metaphysical theories. (shrink)

In this paper, we provide a comprehensive survey of the space of possible analyses of the phenomenon of quantifier domain restriction, together with a set of considerations which militate against all but our own proposal. Among the many accounts we consider and reject are the ‘explicit’ approach to quantifier domain restric‐tion discussed, for example, by Stephen Neale, and the pragmatic approach to quantifier domain restriction proposed by Kent Bach. Our hope is that the exhaustive discussion of this special case of (...) context‐dependence will provide guidelines for how to decide, for an arbitrary case of context‐dependent discourse, whether it should be treated syntactically, semantically, or pragmatically. (shrink)

Some philosophers believe that everyday objects are 4-dimensional spacetime worms, that a person (for example) persists through time by having temporal parts, or stages, at each moment of her existence. None of these stages is identical to the person herself; rather, she is the aggregate of all her temporal parts.1 Others accept “three dimensionalism”, rejecting stages in favor of the notion that persons “endure”, or are “wholly present” throughout their lives.2 I aim to defend an apparently radical third view: not (...) only do I accept person stages; I claim that we are stages.3 Likewise for other objects of our everyday ontology: statues are statue-stages, coins are coin-stages, etc. At one level, I accept the ontology of the worm view. I believe in spacetime worms, since I believe in temporal parts and aggregates of things I believe in. I.. (shrink)

Persistence through time is like extension through space. A road has spatial parts in the subregions of the region of space it occupies; likewise, an object that exists in time has temporal parts in the various subregions of the total region of time it occupies. This view — known variously as four dimensionalism, the doctrine of temporal parts, and the theory that objects “perdure” — is opposed to “three dimensionalism”, the doctrine that things “endure”, or are “wholly present”.1 I will (...) attempt to resolve this dispute in favor of four dimensionalism by means of a novel argument based on considerations of vagueness. But before argument in this area can be productive, I believe we must become much clearer than is customary about exactly what the dispute is, for the usual ways of formulating the dispute are flawed, especially where three dimensionalism is concerned. (shrink)

This book is a defense of modal realism; the thesis that our world is but one of a plurality of worlds, and that the individuals that inhabit our world are only a few out of all the inhabitants of all the worlds. Lewis argues that the philosophical utility of modal realism is a good reason for believing that it is true.

An introduction to temporal parts theory. Most of us believe in spatial parts: hands are spatial parts of people, an electron is a spatial part of a hydrogen atom, the earth is a spatial part of the solar system. Why are these parts "spatial" parts? Because they are spatially smaller: the hand is spatially smaller than the person, the electron is spatially smaller than the atom, the earth is spatially smaller than the solar system. Temporal parts, then, are parts that (...) are temporally smaller. My current temporal part, "me-today", we might call it, is temporally smaller than me, since it exists today and only today. Temporal parts theory says that objects are made up of temporal as well as spatial parts. (shrink)

I demonstrate that the theory of persistence defended in Sider [2001] does not accommodate our intuitions about counting sentences. I develop two theories that improve on Sider's: a contextualist theory and an error theory. I argue that the latter is stronger, simpler, and better fitted to some important ordinary language judgments than rival four-dimensionalist theories of persistence.

It seems obvious that I could have failed to exist. My parents could easily never have met, in which case I should never have been conceived and born. The like applies to everyone. More generally, it seems plausible that whatever exists in space and time could have failed to exist. Events could have taken an utterly different course. Our existence, like most other aspects of our lives, appears frighteningly contingent. It is therefore surprising that there is a proof of my (...) necessary existence, a proof that generalizes to everything whatsoever. I will explain the proof and discuss what to make of it. A first reaction is that a ‘proof’ of such an outrageous conclusion must contain some dreadful fallacy. Yet the proof does not collapse under scrutiny. Further reflection suggests that, suitably interpreted, it may be sound. So interpreted, the conclusion is not outrageous, although it may not be the view you first thought of. (shrink)

I defend counterpart theory against post-Kripkean objections. Trenton Merricks objects that no construction of ersatz counterparts is uniquely and intrinsically suitable; I reply that metaphysical constructions need not have these features. Sarah Moss refutes my solution (from "All the world's a stage") to the problem of timeless counting for temporal counterpart theory; I offer a new solution. Hazen, Fara, Williamson, and others have objected that counterpart theory generates an unacceptable logic for an actuality operator; I attempt to give a better (...) semantics. (shrink)

Two fundamental rules of reasoning are Universal Generalisation and Existential Instantiation. Applications of these rules involve stipulations such as ‘Let n be an arbitrary number’ or ‘Let John be an arbitrary Frenchman’. Yet the semantics underlying such stipulations are far from clear. What, for example, does ‘n’ refer to following the stipulation that n be an arbitrary number? In this paper, we argue that ‘n’ refers to a number—an ordinary, particular number such as 58 or 2,345,043. Which one? We do (...) not and cannot know, because the reference of ‘n’ is fixed arbitrarily. Underlying this proposal is a more general thesis: Arbitrary Reference : It is possible to fix the reference of an expression arbitrarily. When we do so, the expression receives its ordinary kind of semantic-value, though we do not and cannot know which value in particular it receives. Our aim in this paper is defend AR. In particular, we argue that AR can be used to provide an account of instantial reasoning, and we suggest that AR can also figure in offering new solutions to a range of difficult philosophical puzzles. (shrink)