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.

As is well known, Aristotelian natural philosophy, and many other systems of natural philosophy since, have relied heavily on teleology and teleological causation. Somehow, the purpose or end of an obj ect can be used to predict and explain what that object does: once you know that the end of an acorn is to become an oak, and a few things about what sorts of circumstances are conducive to the attainment of this end, you can predict a lot about the (...) sprouting of the acorn and the subsequent behaviour of the piece of vegetation that results. Once you know that a rock seeks to move towards the centre of the Earth, you gain some insight into why it falls when released, and why it deforms the carpet or foot that it lands on. Once you know that the rabbit seeks to preserve itself, you can predict it will run from the fox. And so on. There are at least three features of Aristotle’s teleology, and more generally of an Aristotelian frame of mind about teleology, that may induce suspicion. One is that an end can serve as a "cause": as well as the sort of causation we all recognize, efficient causation, there are other forms, one of which is teleological causation. However, this can look less odd if we think of causes as things that figure in "because" answers to "why" questions. Whether or not self-preservation, or the rabbit’s continued existence, or something similar, causes the rabbit to run, the reply "because it seeks to continue in existence" certainly makes sense as an answer, or part of an answer, to a question about why it ran from the fox. (At present we are only. (shrink)

According to Peter van Inwagen, visible inanimate objects do not, strictly speaking, exist. In defending this controversial thesis, he offers fresh insights on such topics as personal identity, commonsense belief, existence over time, the phenomenon of vagueness, and the relation between metaphysics and ordinary language.

Vagueness provides the first comprehensive examination of a topic of increasing importance in metaphysics and the philosophy of logic and language. Timothy Williamson traces the history of this philosophical problem from discussions of the heap paradox in classical Greece to modern formal approaches such as fuzzy logic. He illustrates the problems with views which have taken the position that standard logic and formal semantics do not apply to vague language, and defends the controversial realistic view that vagueness is a kind (...) of ignorance--that there really is a grain of sand whose removal turns a heap into a non-heap, but we cannot know which one it is. (shrink)

According to standard, pre-philosophical intuitions, there are many composite objects in the physical universe. There is, for example, my bicycle, which is composed of various parts - wheels, handlebars, molecules, atoms, etc. Recently, a growing body of philosophical literature has concerned itself with questions about the nature of composition.1 The main question that has been raised about composition is, roughly, this: Under what circumstances do some things compose, or add up to, or form, a single object? It turns out that (...) it is surprisingly difficult to give a satisfactory answer to this question that accords with standard, pre-philosophical intuitions about the universe's composite objects. In fact, the three rival views in response to this question that have received the most support in the literature are (i) that there are no objects composed of two or more parts (which means that there are no stars, chairs, humans, or bicycles);2 (ii) that the only objects composed of two or more parts are living organisms (which still means no stars. (shrink)

The topic of this book is material objects. Like most interesting concepts, the concept of a material object is one without precise boundaries.

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.

There will be a few themes. One to get us going: expansion versus contraction. About an object, o, and the region, R, of space(time) in which o is exactly located,1 we may ask: i) must there exist expansions of o: objects in filled superregions2 of R? ii) must there exist contractions of o: objects in filled subregions of..

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)

I give reasons to suggest that the various ‘homogeneous substance’ objections to perdurance theory should not be regarded as raising serious difficulties. The main strategy is to show that there are equally exotic possibilities involving extended mereological simples that may turn the tables on the endurance theorist, insofar as she will have difficulties with these cases analogous to those she raises for the perdurantist. I conclude that such exotic cases are less useful that we might suppose in adjudicating between these (...) competing doctrines of persistence. (shrink)

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. (shrink)

‘Restricted composition’ says that there are some composite objects. And it says that some objects jointly compose nothing at all. The main threat to restricted composition is the influential and widely defended Vagueness Argument. We shall see that the Vagueness Argument fails. In seeing how this argument fails, we shall discover a new focus for the debate over composition's extent.

I argue that extended simples are possible. The argument given here parallels an argument given elsewhere for the claim that the shape properties of material objects are extrinsic, not intrinsic as is commonly supposed. In the final section of the paper, I show that if the shape properties of material objects are extrinsic, the most popular argument against extended simples fails.

Theodore Sider’s Four-Dimensionalism is a well-organized and clearly written book that is chock-full of important arguments. Both friends and foes of the views defended by Sider will benefit enormously from careful study of the book. I am going to focus on just two of Sider’s many arguments for Four-Dimensionalism: his argument from vagueness, which I take to be the most important and powerful argument in the book, and his argument from time travel, which I find to be the funnest to (...) think about. (shrink)

In this essay for a PPR book symposium on Theodore Sider's _Four-Dimensionalism<D>, I focus on two of Sider's arguments for four-dimensionalism: (i) his argument from vagueness, and (ii) his argument from time travel. Concerning (i), I first show that Sider's argument commits him to certain strange consequences that many four-dimensionalists may not endorse, and then I discuss an objection that involves appealing to 'brutal composition', the view that there is no informative answer to Peter van Inwagen's 'special composition question'. Concerning (...) (ii), I argue that the three-dimensionalist can account for time travel scenarios in a way that is analogous to Sider's four-dimensionalist account of such scenarios. (shrink)

Since the publication of Peter van Inwagen's book, Material Beings,1 there has been a growing body of philosophical literature on the topic of composition. The main question addressed in both van Inwagen's book and subsequent discussions of the topic is a question that van Inwagen calls "the Special Composition Question." The Special Composition Question is, roughly, the question Under what circumstances do several things compose, or add up to, or form, a single object? For the purposes of formulating a more (...) precise version of the Special Composition Question, we can adopt the following technical terms. (shrink)

In his excellent book, Four-Dimensionalism: An Ontology of Persistence and Time (Sider, 2001), Theodore Sider defends a version of four-dimensionalism which he calls the ‘stage-theory’. This paper focuses on Sider's argument from vagueness and argues that, due to the problematic nature of the argument from vagueness, Sider’s case in favor of four-dimensionalism is in the end not successful.

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

Debunking arguments—also known as etiological arguments, genealogical arguments, access problems, isolation objec- tions, and reliability challenges—arise in philosophical debates about a diverse range of topics, including causation, chance, color, consciousness, epistemic reasons, free will, grounding, laws of nature, logic, mathematics, modality, morality, natural kinds, ordinary objects, religion, and time. What unifies the arguments is the transition from a premise about what does or doesn't explain why we have certain mental states to a negative assessment of their epistemic status. I examine (...) the common, underlying structure of the arguments and the different strategies for motivating and resisting the premises of debunking arguments. (shrink)

Vague existence can seem like the worst kind of vagueness in the world, or seem to be an entirely unintelligible notion. This bad reputation is based upon the rumour that if there is vague existence then there are non-existent objects. But the rumour is false: the modest brand of vague existence entailed by certain metaphysical theories of composition does not deserve its bad reputation.

Vague existence can seem like the worst kind of vagueness in the world, or seem to be an entirely unintelligible notion. This bad reputation is based upon the rumour that if there is vague existence then there are non-existent objects. But the rumour is false: the modest brand of vague existence entailed by certain metaphysical theories of composition does not deserve its bad reputation.

John Hawthorne is widely regarded as one of the finest philosophers working today. He is perhaps best known for his contributions to metaphysics, and this volume collects his most notable papers in this field. Hawthorne offers original treatments of fundamental topics in philosophy, including identity, ontology, vagueness, and causation. Six of the essays appear here for the first time, and there is a valuable introduction to guide the reader through the selection.

I argue that there are is no informative statement of necessary and sufficient conditions for being a mereological simple.

Four- Dimensionalism defends the thesis that the material world is composed of temporal as well as spatial parts. This defense includes a novel account of persistence over time, new arguments in favour of the four-dimensional ontology, and responses to the challenges four- dimensionalism faces." "Theodore Sider pays particular attention to the philosophy of time, including a strong series of arguments against presentism, the thesis that only the present is real. Arguments offered in favour of four- dimensionalism include novel arguments based (...) on time travel, the debate between spacetime substantivalists and relationalists, and vagueness. Also included is a comprehensive discussion of the paradoxes of coinciding material objects, and a novel resolution of those paradoxes based on temporal counterpart theory. In conclusion Sider replies to prominent objections to four- dimensionalism, including discussion of the problem of the rotating homogenous disk. (shrink)