Those who believe that ordinary things have temporal as well as spatial parts must give an account of the truth conditions of temporally modified predications of the form ‘a is F at t ’ in terms of temporal parts. I will argue that the friend of temporal parts is committed to an account of temporal predication that is incompatible with the classical principle of predicate abstraction.

Four-dimensionalists offer a unified picture of various puzzles about identity over time, including the puzzle of fission, the puzzle of constitution and the puzzle of undetached parts. What unifies the four-dimensionalist approaches to these puzzles is the possibility of temporal overlap—the possibility for distinct continuants to share a common temporal part, or stage. I claim that the unified picture is inconsistent, if there are informative criteria of identity over time. I will show that while temporal overlap is compatible with four-dimensionalist (...) criteria of diachronic composition, temporal overlap is incompatible with any four-dimensionalist criteria of diachronic identity. (shrink)

What is the relation between a clay statue andthe lump of clay from which it is made? According to the defender of the standardaccount, the statue and the lump are distinct,enduring objects that share the same spatiallocation whenever they both exist. Suchobjects also seem to share the samemicrophysical structure whenever they bothexist. This leads to the standard objection tothe standard account: if the statue and thelump of clay have the same microphysicalstructure whenever they both exist, how canthey differ in their (...) de re temporalproperties, de re modal properties and soon? In this paper I develop amereological answer to this question – thestatue and the lump differ with respect totheir parts and this explains theirdifference with respect to de re temporalproperties, de re modal properties andthe like. (shrink)

In debate about the nature of persistence over time, the view that material objects endure has played the role of "champion" and the view that they perdure has played the role of the "challenger." It has fallen to the perdurantists rather than the endurantists to motivate their view, to provide reasons for accepting it that override whatever initial presumption there is against it. Perdurantists have sought to discharge their burden in several ways. For example, perdurantism has been recommend on the (...) grounds that: (i) it solves several of the puzzles that raise the problem of material constitution; (ii) it is (at least) suggested by the special theory of relativity (hereafter "SR"); (iii) it is the only view that makes sense out of the possibility of intrinsic change; (iv) it is the only view consistent with the doctrine of Humean supervenience; and (v) it makes better sense than its competitor out of the possibility of fission. There are primary and most powerful claims that have been made on behalf of perdurantism. They are individually persuasive and together they constitute a formidable assault upon the hegemony of endurantism. Endurantists of course, have not been without reply. However, since endurantists typically respond to these claims one at a time and in different ways, it is easy to get the impression that perdurantism offers a single, neat solution to a host of problems whereas endurantism requires a patchwork of different strategies. But this impression is an illusion. In Rea 1995, I argued that though perdurantism does solve some of the puzzles that raise the problem of material constitution, it does not solve the problem of material constitution itself. Thus, the problem of material constitution really has no bearing on the debate between endurantists and perdurantists. In his paper, I will show that the same is true with respect to SR, the problem of intrinsic change, the doctrine of Humean supervenience, and the possibility of fission. In short, I will argue that none of (ii-v) is true and that therefore the doctrine of temporal parts stands unmotivated. (shrink)

Are we the people we were? If we are continuants, then the answer to this question is an affirmative one. But it is a moot point whether anything is a continuant. The debate over this issue—of whether there are such things as continuants—is often conducted in the context of theories concerning the apparent passage of time. Thus it has been argued that the tenseless theory of time, according to which time does not really pass, forces us to tear down part (...) of the basis for the intuitive distinction between ordinary, reidentifiable objects on the one hand, and processes on the other, and to regard such objects as mountains as persisting through time in exactly the way that thunderstorms do: by having distinct temporal parts at different times. I confess that I am a tenseless theorist of time, and take that theory to entail such a conclusion about the persistence of objects. But it is not just a certain stance over time’s passage that motivates sympathy towards temporal parts and suspicion of continuants. Thinking of objects as having temporal parts sits more comfortably than does the rival view with two natural assumptions concerning continuity: that beginning and ceasing to exist, at least for most objects, involves underlying changes which are continuous in nature; and that objects exhibit continuity through time, in the sense of not having gaps in their existence. Or so I shall argue in what follows. (shrink)

The following quotation, from Frank Jackson, is the beginning of a typical exposition of the debate between those metaphysicians who believe in temporal parts, and those who do not: The dispute between three-dimensionalism and four-dimensionalism, or more precisely, that part of the dispute we will be concerned with, concerns what persistence, and correllatively, what change, comes to. Three-dimensionalism holds that an object exists at a time by being wholly present at that time, and, accordingly, that it persists if it is (...) wholly present at more than one time. For short, it persists by enduring. Four-dimensionalism holds that an object exists at a time by having a temporal part at that time, and it persists if it has distinct temporal parts at more than one time. For short, it persists by perduring. In the light of these comments, some readers will perhaps find the question that forms the title of this paper a little puzzling. They may have learned to use the terms ‘fourdimensionalism’ ‘perdurantism’ and ‘belief in temporal parts’ interchangeably; or perhaps even to define one in terms of the other. Such a usage, however, is inapposite. We might imagine a Flatland-like world of two spatial dimensions and one temporal, whose philosophers are divided between a theory of persistence on which they persist by having temporal parts, and a theory on which they persist by being wholly located in each of several times. This is just the same issue we face, but at least the label ‘four-dimensionalism’ seems inapposite: the four-dimensionalist Flatlanders believe in only three dimensions! (shrink)

This paper considers how to put together two popular ideas in the philosophy of time: detenserism and perdurantism (the view that objects persist through time by having temporal parts. On the most obvious way of doing this, certain problems arise. I argue that to deal with these problems we need a tool that is unfamiliar to most detensers and perdurantists - the distinction between sortal and non-sortal predicates.

Paper begins: Chapter 4 of Hud Hudson’s stimulating book The metaphysics of hyperspace contains an discussion of the notion of location in a container spacetime. Hudson uses this idea to define a number of what we might call modes of extension or ways of being extended. A pertended object is what most people think of as a typical extended object — it is made up of spatial parts, one part for each region the object pervades. An entended object is an (...) extended simple (or a complex object made up of extended simples). Elsewhere, I’ve argued that entended objects are conceptually possible; that nothing about the concept of “extended” rules out entention. (More about how this argument works below). Hudson thinks that I did not go far enough. Besides pertended and entended objects, he also sees conceptual room for what he calls spanners and multiply located objects. These last two ways of being extended are even more exotic than extended simples. …. (shrink)

This paper is about the neglected question of what sort of things we are metaphysically speaking. It is different from the mind-body problem and from familiar questions of personal identity. After explaining what the question means and how it differs from others, the paper tries to show how difficult it is to give a satisfying answer.

What is a temporal part? Most accounts explain it in terms of timeless parthood: a thing's having a part without temporal qualification. Some find this hard to understand, and thus find the view that persisting things have temporal parts--fourdimensionalism--unintelligible. T. Sider offers to help by defining temporal parthood in terms of a thing's having a part at a time. I argue that no such account can capture the notion of a temporal part that figures in orthodox four-dimensionalism: temporal parts must (...) be timeless parts. This enables us to state four-dimensionalism more clearly. (shrink)

It seems evident that things sometimes get bigger by acquiring new parts. But there is an ancient argument purporting to show that this is impossible: the paradox of increase or growing argument.i Here is a sketch of the paradox. Suppose we have an object, A, and we want to make it bigger by adding a part, B. That is, we want to bring it about that A first lacks and then has B as a part. Imagine, then, that we conjoin (...) B to A in some appropriate way. Never mind what A and B are, or what this conjoining amounts to: let A be anything that can gain a part if anything can gain a part, and let B be the sort of thing that can become a part of A, and suppose we do whatever it would take to make B come to be a part of A if this is possible at all. Have we thereby made B a part of A? It seems not. We seem only to have brought it about that B is attached to A, like this. (shrink)

Things change. If anything counts as a datum of metaphysics, that does. Change occurs in many ways: it can be accidental or substantial; essential or non-essential; intrinsic or extrinsic; subjective or objective. Changes can be physical, spatial, quantitative, qualitative, natural, artefactual, conceptual, linguistic. Events are arguably best defined as changes in an object or objects. All change is from something and into something, and hence is at least a two-term relation, involving a term from which and a term to which.

In his Ted Sider takes care to define the notion of a temporal part and his doctrine of perdurantism using only the temporally indexed notion of parthood – ‘ x is part of y at t’ – rather than the atemporal notion of classical mereology – ‘ x is a part of y’ – in order to forestall accusations of unintelligibility from his opponents. However, as he notes, endurantists do not necessarily reject the classical mereological notion as unintelligible. They allow (...) that it makes sense and applies to atemporal subject matters and to temporal subject matters when the entities under discussion are not continuants. Thus, they allow that it makes sense to say that metaphysics is a part of philosophy, or that football is a game of two halves. What endurantists deny is only that the classical mereological notion is applicable to continuants: continuants , they say, have no proper parts simpliciter , either because it is false to say that they have or because it is unintelligible.Thus perdurantists do not have to embrace Sider's excessive caution in defining their position. 1 They can safely allow themselves classical mereological notions as long as it is a consequence of their definitions that continuants are perdurers/have temporal proper parts only if they have atemporal proper parts. 2In his Josh Parsons illuminatingly takes on the task he describes as ‘get[tting] the allegedly technical concepts of temporal part, perdurance and so on by ratcheting up from mereological relations, subregion relations among times and the concept of exact temporal location ’. He continues, ‘My definitions provide a good answer to those endurantists who claim …. (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)

I argue that for those who follow Evans in finding indeterminacy of de re identity statements problematic, ontic vagueness within a three-dimensionalist metaphysics will raise some problems that are not faced by the four-dimensionalist. For the types of strategies used to avoid de re indeterminacy within the context of ontic vagueness at-at-time, that is, spatial vagueness, are problematic within a three-dimensionalist framework when put to use within the context of ontic vagueness across-time, that is temporal vagueness.

I argue that two competing accounts of persistence, three and four dimensionalism, are in fact metaphysically equivalent. I begin by clearly defining three and four dimensionalism, and then I show that the two theories are intertranslatable and equally simple. Through consideration of a number of different cases where intuitions about persistence are contradictory, I then go on to show that both theories describe these cases in the same manner. Further consideration of some empirical issues arising from the theory of special (...) relativity lead me to conclude that the two theories are equally explanatory, and thus finally that they are metaphysically equivalent. (shrink)

Endurantism is not inconsistent with the theory of special relativity, or so I shall argue. Endurantism is not committed to presentism, and thus not committed to a metaphysics that is at least prima facie inconsistent with special relativity. Nor is special relativity inconsistent with the idea that objects are wholly present at a time just if all of their parts co-exist at that time. For the endurantist notion of co-existence in terms of which “wholly present” is defined, is not, I (...) will argue, a notion according to which co-existence is transitive. Although an absence of absolute simultaneity presents some problems for the endurantist claim that objects are wholly present whenever they exist, there are a number of ways that the endurantist can respond to this difficulty. Thus, I conclude, considerations pertaining to the theory of special relativity certainly do not rule out endurantism as a metaphysics of persistence. (shrink)

There is a general form of an argument which I call the ‘argument from vagueness’ which attempts to show that objects persist by perduring, via the claim that vagueness is never ontological in nature and thus that composition is unrestricted. I argue that even if we grant that vagueness is always the result of semantic indeterminacy rather than ontological vagueness, and thus also grant that composition is unrestricted, it does not follow that objects persist by perduring. Unrestricted mereological composition lacks (...) the power to ensure that there exist instantaneous objects that wholly overlap persisting objects at times, and thus lacks the power to ensure that there exists anything that could be called a temporal part. Even if we grant that such instantaneous objects exist, however, I argue that it does not follow that objects perdure. To show this I briefly outline a coherent version of three dimensionalism that grants just such an assumption. Thus considerations pertaining to the nature of vagueness need not lead us inevitably to accept perdurantism. (shrink)

In this paper I present a new definition of endurance. I argue that the three-dimensionalist ought to adopt a different understanding from the four-dimensionalist, of what it is to have a part simpliciter. With this new understanding it becomes possible to define endurance in a manner that both preserves the central endurantist intuitions, whilst avoiding commitment to any controversial metaphysical theses. Furthermore, since this endurantist definition is a mereological one, there is an elegant symmetry between the definitions of endurance and (...) perdurance in that the theories of three- and four-dimensionalism are both expressed in the language of mereology. Nevertheless, though both definitions are expressed within the same broad language, some of the terms of that language have subtly different meanings within the context of each theory. It is in understanding on the one hand that each theory is essentially a mereological theory and that therefore each shares some underlying theoretical similarities, and yet also that there are some subtle differences in the way each theory understands some of the terms of mereology, that allows us to see clearly what lies at the heart of the debate between these two accounts of persistence. (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.

This article discusses recent work in metaphysics on temporal parts. After a short introduction introducing the notion of a temporal part, we examine several well‐known arguments for the view that ordinary material objects such as tables, trees, and persons have temporal parts: (1) positing temporal parts makes it possible to solve puzzles of coincidence (e.g., the statue/lump puzzle); (2) positing temporal parts makes it possible to solve the problem of intrinsic change over time; and (3) the existence of temporal parts (...) can be demonstrated based on considerations about vagueness in composition. We conclude by examining briefly a recent argument that the dispute over whether there are temporal parts is merely verbal. (shrink)

This is a defense of endurantism against an alleged paradox.

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.

The thesis of 3D/4D equivalence states that every three-dimensional description of the world is translatable without remainder into a four-dimensional description, and vice versa. In representing an object in 3D or in 4D terms we are giving alternative descriptions of one and the same thing, and debates over whether the ontology of the physical world is "really" 3D or 4D are pointless. The twins paradox is shown to rest, in relativistic 4D geometry, on a reversed law of triangle inequality. But (...) considering the twins as 3D beings who age through time, the paradox implies that time passes at different rates in different reference frames, and therefore that the concept of a single global or Absolute time is unsustainable. (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)

This is the second volume of philosophical essays by one of the most innovative and influential philosophers now writing in English. Containing thirteen papers in all, the book includes both new essays and previously published papers, some of them with extensive new postscripts reflecting Lewis's current thinking. The papers in Volume II focus on causation and several other closely related topics, including counterfactual and indicative conditionals, the direction of time, subjective and objective probability, causation, explanation, perception, free will, and rational (...) decision. Throughout, Lewis analyzes global features of the world in such a way as to show that they might turn out to supervene on the spatiotemporal arrangement of local qualities. (shrink)

Are we the people we were? If we are continuants, then the answer to this question is an affirmative one. But it is a moot point whether anything is a continuant. The debate over this issue—of whether there are such things as continuants—is often conducted in the context of theories concerning the apparent passage of time. Thus it has been argued that the tenseless theory of time, according to which time does not really pass, forces us to tear down part (...) of the basis for the intuitive distinction between ordinary, reidentifiable objects on the one hand, and processes on the other, and to regard such objects as mountains as persisting through time in exactly the way that thunderstorms do: by having distinct temporal parts at different times. I confess that I am a tenseless theorist of time, and take that theory to entail such a conclusion about the persistence of objects. But it is not just a certain stance over time’s passage that motivates sympathy towards temporal parts and suspicion of continuants. Thinking of objects as having temporal parts sits more comfortably than does the rival view with two natural assumptions concerning continuity: that beginning and ceasing to exist, at least for most objects, involves underlying changes which are continuous in nature; and that objects exhibit continuity through time, in the sense of not having gaps in their existence. Or so I shall argue in what follows. (shrink)

This paper begins with a puzzle about certain temporal expressions: phrases like ‘Jones as he was ten years ago’ and ‘the Jones of ten years ago’. There are reasons to take these as substantival, to be interpreted as terms for temporal parts. But it seems that the same reifying strategy would also force us to countenance a host of less attractive posits, among them fictional counterparts of real things (to correspond to such phrases as ‘Garrison as he was in the (...) movie JFK') and much more. I argue that there is a better way: we need only the idea of pretense or make‐believe to make sense of claims embedding such phrases, leaving us with no reason, so far, to accept an ontology of temporal parts. (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.

Problems about the accidental properties of properties motivate us--force us, I think--not to identify properties with the sets of their instances. If we identify them instead with functions from worlds to extensions, we get a theory of properties that is neutral with respect to disputes over counterpart theory, and we avoid a problem for Lewis's theory of events. Similar problems about the temporary properties of properties motivate us--though this time they probably don't force us--to give up this theory as well, (...) and to identify properties with functions from world, time pairs to extensions. Again, the replacement theory is neutral with respect to a metaphysical dispute that the old theory (arguably) forces us to take a stand on--the dispute over whether objects have temporal parts. It also allows us to give a smoother semantics for predication, to better accommodate our intuitions about which objects temporary properties are properties of, and to make temporally self-locating beliefs genuinely self -locating. (shrink)

Sider has argued that four‐dimensionalism can be given a clear and coherent formulation, and has attempted to provide one. He has also argued that three‐dimensionalism resists adequate formulation. I argue that Sider's worries about whether there is an adequate formulation of three‐dimensionalism are misplaced, and suggest a formulation of three‐dimensionalism different from the ones considered and rejected by Sider. I then give a ‘matching’ formulation of four‐dimensionalism, and argue that it captures four‐dimensionalism better than Sider's own formulation of that doctrine.

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. (shrink)

The problem of change plays a central role in the metaphysics of time and material objects, and whoever does best in solving this problem has a leg up when it comes to choosing a metaphysics of time and material objects. But whether this central role of the problem of change in metaphysics is legitimate is not at all clear. This is so in part since it is not clear what the problem of change is, and why it is a problem (...) in metaphysics. We will investigate what metaphysical problem the problem of change might be, and how it relates to various other problems related to change that are studied in the empirical sciences. The problem of change can thus be a case study of what makes a problem a metaphysical one and how metaphysics relates to other parts of inquiry. We conclude that the central role the problem of change is given in the contemporary metaphysics of time is not justified. (shrink)

There has been much recent debate about Presentism among those who believe the doctrine to be nontrivial and true, those who believe it to be nontrivial and false, and those who believe it to be trivial — either trivially true or trivially false. Formulating Presentism precisely is problematic, which accounts for some of the controversy.