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.

This paper outlines a novel solution to the problem of the many and a conception of ordinary objects that implies it. The solution is that many collections of particles can simultaneously constitute a single object. The proposed conception of ordinary objects maintains that they are fundamentally subjects of change: the changes an object is able to survive explain its constitution.

In arithmetic, if only because many of its methods and concepts originated in India, it has been the tradition to reason less strictly than in geometry, ...

Many of us think that ordinary objects – such as tables and chairs – exist. We also think that ordinary objects have parts: my chair has a seat and some legs as parts, for example. But once we are committed to the thesis that ordinary objects are composed of parts, we then open ourselves up to a whole host of philosophical problems, most of which center on what exactly the composition relation is. Composition as Identity is the view that the (...) composition relation is the identity relation. While such a view has some advantages, there are many arguments against it. In this essay, I will briefly canvass three different varieties of Composition as Identity, and suggest why one of them should be preferred over the others. Then I will outline several versions of the most common objection against CI. I will suggest how a CI theorist can respond to these charges by maintaining that some of the arguments are invalid. (shrink)

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

Although the relationship of part to whole is one of the most fundamental there is, this is the first full-length study of this key concept. Showing that mereology, or the formal theory of part and whole, is essential to ontology, Simons surveys and critiques previous theories--especially the standard extensional view--and proposes a new account that encompasses both temporal and modal considerations. Simons's revised theory not only allows him to offer fresh solutions to long-standing problems, but also has far-reaching consequences for (...) our understanding of a host of classical philosophical concepts. (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)

Objects and Persons presents an original theory about what kinds of things exist. Trenton Merricks argues that there are no non-living inanimate macrophysical objects -- no statues or rocks or chairs or stars -- because they would have no causal role over and above the causal role of their microphysical parts. Humans do exist: we have non-redundant causal powers. Along the way, Merricks has interesting things to say about mental causation, free will, and various philosophical puzzles. Anyone working in metaphysics (...) will enjoy this lucid and provocative book. (shrink)

A short paper proving what the title says.

How do things persist? Are material objects spread out through time just as they are spread out through space? Or is temporal persistence quite different from spatial extension? This key question lies at the heart of any metaphysical exploration of the material world, and it plays a crucial part in debates about personal identity and survival. This book 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, the book concludes by advocating stage theory. Such a basic issue about the nature of the physical world naturally has close ties with other central philosophical problems. This book includes discussions of change and parthood, of how we refer to material objects at different times, of the doctrine of Humean supervenience, and of the modal features of material things. In particular, it contains new accounts of the nature of worldly vagueness, and of what binds material things together over time, distinguishing the career of a natural object from an arbitrary sequence of events. Each chapter concludes with a reflection about the impact of these metaphysical debates upon questions about our personal identity and survival. (shrink)

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.

§ i. After deserting for a time the old Euclidean standards of rigour, mathematics is now returning to them, and even making efforts to go beyond them. ...

Orthodoxy says that the thesis that composition is identity (CAI) entails universalism: the claim that any collection of entities has a sum. If this is true it counts in favour of CAI, since a thesis about the nature of composition that settles the otherwise intractable special composition question (SCQ) is desirable. But I argue that it is false: CAI is compatible with the many forms of restricted composition, and SCQ is no easier to answer given CAI than otherwise. Furthermore, in (...) seeing why this is the case we reveal an objection to CAI: that it allows for the facts concerning what there is to be settled whilst leaving open the question about what is identical to what. (shrink)

Composition as identity, as I understand it, is a theory of the composite structure of reality. The theory’s underlying logic is irreducibly plural; its fundamental primitive is a generalized identity relation that takes either plural or singular arguments. Strong versions of the theory that incorporate a generalized version of the indiscernibility of identicals are incompatible with the framework of plural logic, and should be rejected. Weak versions of the theory that are based on the idea that composition is merely analogous (...) to identity are too weak to be interesting, lacking in metaphysical consequence. I defend a moderate version according to which composition is a kind of identity, and argue that the difference is metaphysically substantial, not merely terminological. I then consider whether the notion of generalized identity, though fundamental, can be elucidated in modal terms by reverse engineering Hume’s Dictum. Unfortunately, for realists about possible worlds, such as myself,... (shrink)

This essay interprets Butler’s distinction between identity in the loose and popular sense and in the strict and philosophical sense. Suppose there are different standards for counting the same things. Then what are two distinct things counting strictly may be one and the same thing counting loosely. Within a given standard identity is one-one. But across standards it is many-one. An alternative interpretation using the parts-whole relation fails, because that relation should be understood as many-one identity. Another alternative making identity (...) relative to sort fails, because whole and parts can be of the same sort. (shrink)

A property, F, is maximal iff, roughly, large parts of an F are not themselves Fs.' Maximality makes trouble for a recent analysis of intrinsicality by Rae Langton and David Lewis.

One of the central questions of material-object metaphysics is which highly visible objects there are right before our eyes. Daniel Z. Korman defends a conservative view, according to which our ordinary, natural judgments about which objects there are are more or less correct. He begins with an overview of the arguments that have led people away from the conservative view, into revisionary views according to which there are far more objects than we ordinarily take there to be or far fewer. (...) Korman criticizes a variety of compatibilist strategies, according to which these revisionary views are actually compatible with our ordinary beliefs. He goes on to respond to debunking arguments; objections that the conservative's verdicts about which objects that are and aren't are objectionably arbitrary; the argument from vagueness; the overdetermination argument; the argument from material constitution; and the problem of the many. (shrink)

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)

This collection of essays is the first of its kind to focus on the relationship between composition and identity. Twelve original articles--written by internationally renowned scholars and rising stars in the field--argue for and against the controversial doctrine that composition is identity.--Provided by publisher.

This bold and original work of philosophy presents an exciting new picture of concrete reality. Peter Unger provocatively breaks with what he terms the conservatism of present-day philosophy, and returns to central themes from Descartes, Locke, Berkeley, Hume and Russell. Wiping the slate clean, Unger works, from the ground up, to formulate a new metaphysic capable of accommodating our distinctly human perspective. He proposes a world with inherently powerful particulars of two basic sorts: one mental but not physical, the other (...) physical but not mental. Whether of one sort or the other, each individual possesses powers for determining his or her own course, as well as powers for interaction with other individuals. It is only a purely mental particular--an immaterial soul, like yourself--that is ever fit for real choosing, or for conscious experiencing. Rigorously reasoning that the only satisfactory metaphysic is one that situates the physical alongside the non-physical, Unger carefully explains the genesis of, and continual interaction of, the two sides of our deeply dualistic world. Written in an accessible and entertaining style, while advancing philosophical scholarship, All the Power in the World takes readers on a philosophical journey into the nature of reality. In this riveting intellectual adventure, Unger reveals the need for an entirely novel approach to the nature of physical reality--and shows how this approach can lead to wholly unexpected possibilities, including disembodied human existence for billions of years. All the Power in the World returns philosophy to its most ambitious roots in its fearless attempt to answer profoundly difficult human questions about ourselves and our world. (shrink)

Peter Unger's puzzle, the problem of the many, is an argument for the conclusion that we are grossly mistaken about what kinds of objects are in our immediate surroundings. But it is not clear what we should make of Unger's argument. There is an epistemic view which says that the argument shows that we don't know which objects are the referents of singular terms in our language. There is a linguistic view which says that Unger's puzzle shows that ordinary singular (...) terms and count nouns are vague. Finally, there is an ontological view which says that the puzzle shows that there are vague objects. ;The epistemic view offers the simplest solution to the problem of the many, but runs foul of a different problem, the problem of vague reference. The problem of vague reference is that given the presuppositions of the epistemic view there are too many too similar objects that might be the reference of a name such as 'Kilimanjaro' for it to be plausible that the name has a determinate reference. The linguistic view, spelled out in terms of semantic indecision and supervaluation, offers the same solution to the problem of the many and to the problem of vague reference. But it leaves no room for de re beliefs about ordinary material object. The ontological view offers a solution to the problem of the many that avoids the problem of vague reference and the problem of de re beliefs. For these reasons it is preferable to the other two. ;However, ontological vagueness has met strong objections. It has been argued that it is a fallacy of verbalism, that it is inconsistent and that once formulated in a consistent way it is not distinguishable from the linguistic view. These objections can be met, but not without cost. To avoid the charge of being inconsistent, friends of the ontological view have to give up the law of excluded middle. ;A positive account of vague parthood has two parts. First, parthood is not primitive but dependent on other primitive facts. The most important of the primitive facts are about to what kinds objects belong and how objects are casually related. Second, sometimes the primitive facts fail do determine of two objects whether one is part of the other. Given a notion of vague parthood, a notion of vague object can be defined roughly in the following way: An object O is vague if there is an object a such that it is indeterminate whether a is part of O. (shrink)

Mereological nihilism says that there do not exist (in the fundamental sense) any objects with proper parts. A reason to accept it is that we can thereby eliminate 'part' from fundamental ideology. Many purported reasons to reject it - based on common sense, perception, and the possibility of gunk, for example - are weak. A more powerful reason is that composite objects seem needed for spacetime physics; but sets suffice instead.

In this work I first develop, motivate, and defend the view that mereological composition, the relation between an object and all its parts collectively, is a relation of identity. I argue that this view implies and hence can explain the logical necessity of classical mereology, the formal study of the part-whole relation. I then critically discuss four contemporary views of the same kind. Finally, I employ my thesis in a recent discussion of whether the world is fundamentally one in number.

In this paper I argue that composition as identity entails unrestricted composition. I also briefly consider a new take on the special composition question.

Some mereologists boast that their view of parts and wholes is ontologically innocent.[Lewis 1991: 72-87] They claim that a fusion is nothing over and above its parts; once you’ve committed to the parts, you get the fusion for free. In other words, fusions are not a further ontological commitment beyond the commitment to the parts. There are various proposals to explain how it is that fusions can come about so cheap. Perhaps the most straightforward of these explanations, and the one (...) I will be concerned with in this paper, is to accept the Strong Composition Thesis:2, 3.. (shrink)

When do several objects compose a further object? The last twenty years have seen a great deal of discussion of this question. According to the most popular view on the market, there is a physical object composed of your brain and Jeremy Bentham’s body. According to the second-most popular view on the market, there are no such objects as human brains or human bodies, and there are also no atoms, rocks, tables, or stars. And according to the third-ranked view, there (...) are human bodies, but still no brains, atoms, rocks, tables, or stars. Although it’s pleasant to have so many crazy-sounding views around, I think it would also be nice to have a commonsense option available. The aim of this paper is to offer such an option. The approach I offer begins by considering a mereological question other than the standard one that has been the focus of most discussions in the literature. I try to show that the road to mereological sanity begins with giving the most straightforward and commonsensical answer to this other question, and then extending that answer to further questions about the mereology of physical objects. On the approach I am recommending, it turns out that all of the mereological properties and relations of physical objects are determined by their spatial properties and relations. (shrink)

Region R Question: How many objects — entities, things — are contained in R? Ignore the empty space. Our question might better be put, 'How many material objects does R contain?' Let's stipulate that A, B and C are metaphysical atoms: absolutely simple entities with no parts whatsoever besides themselves. So you don't have to worry about counting a particle's top half and bottom half as different objects. Perhaps they are 'point-particles', with no length, width or breadth. Perhaps they are (...) extended in space without possessing spatial parts (if that is possible). Never mind. We stipulate that A, B and C are perfectly simple. We also stipulate that they are connected as follows. A and B are stuck together in such a way that when a force is applied to one of them, they move together 'as a unit'. Moreover, the two of them together exhibit behavior that neither would exhibit on its own — Perhaps they emit a certain sound, or glow in the dark — whereas C is.. (shrink)