Abstract: There are two traditionally rival views about the nature of time: substantivalism that takes time to be a substance that exists independently of events located in it, and relationism that takes time to be constructed out of events. In this paper, first, I want to make some progress with respect to the debate between these two views, and I do this mainly by examining the strategies they use to face the possibilities of ‘empty time’ and ‘time without change’. As (...) we shall see, the two allegedly very different rival views are much less different than has been thought: their structure is extremely similar, their strategies are extremely similar, and they can both face the possibilities of ‘empty time’ and ‘time without change’ in the same way. Thus, I argue in favour of a certain kind of equivalence between the two views; I discuss a Strong and a Weak version of this claim; and I provide reasons for endorsing the former. I also discuss the parallel between this pair of views about the nature of time and another analogous pair of views: the bundle theory and the substratum theory about the nature of material objects, with respect to the problem with Identity of Indiscernibles. (shrink)

It is standardly assumed that there are three — and only three — ways to solve problem of temporary intrinsics: (a) embrace presentism, (b) relativize property possession to times, or (c) accept the doctrine of temporal parts. The first two solutions are favoured by endurantists, whereas the third is the perdurantist solution of choice. In this paper, I argue that there is a further type of solution available to endurantists, one that not only avoids the usual costs, but is structurally (...) identical to the temporal-parts solution preferred by perdurantists. In addition to providing a general characterization of this new type of solution, I discuss certain of its anticipations in the literature on bundle theory, as well as provide a detailed development of it in terms of my own preferred metaphysics of ordinary objects — namely, a distinctive form of substratum theory tracing to Aristotle. (shrink)

Can we directly experience change? Although some philosophers have denied it, the phenomenological evidence is unambiguous: we can, and do. But how is this possible? What structures or features of consciousness render such experience possible? A variety of very different answers to this question have been proposed, answers which have very different implications for the nature of consciousness itself. In this brief survey no attempt is made to engage with the often complex (and sometimes obscure) literature on this topic. Instead, (...) a largely schematic examination of the main options is conducted, with a view to determining the most promising avenues for further investigation. (shrink)

The Argument from Temporary Intrinsics is one of the canonical arguments against endurantism. I show that the two standard ways of presenting the argument have limited force. I then present a new version of the argument, which provides a more promising articulation of the underlying objection to endurantism. However, the premises of this argument conflict with the gauge theories of particle physics, and so this version of the argument is no more successful than its predecessors. I conclude that no version (...) of the Argument from Temporary Intrinsics gives us a compelling reason to favor one theory of persistence over another. (shrink)

Here I develop the idea, which I have presented elsewhere, that time instants are abstract entities existing tenselessly and therefore that events and changes likewise may be said to exist tenselessly in virtue of their place at a certain space-time point.

Some have concluded that the only appropriate response to the problem of temporary intrinsics is the view that familiar, concrete objects persist through time by perduring, that is, by having temporal parts. Many, including myself, believe this view of persistence is false, and so reject this conclusion. However, the most common attempts to resolve the problem and yet defend the view that familiar, concrete objects endure are self-defeating. This has heretofore gone unnoticed. I consider the most familiar such attempts, based (...) on a strategy called tensing the copula , and present a general argument to demonstrate why this strategy – and any strategy based on relativization – fails. I then show how the considerations raised in this general argument undermine other attempts to resolve the problem while denying perdurance. All these attempts are undermined by an assumption essential to the problem of temporary intrinsics, to wit, that there are many moments of time and all have the same ontological status. As long as this assumption is maintained, the only solution to the problem is that familiar, concrete objects perdure. Thus, in order to defend the view that objects persist through time by enduring, one must adopt a different metaphysics of time (viz., presentism). I conclude that it is neither unreasonable nor impracticable to do so. (shrink)

How can an object remain the same, numerically identical, while undergoing change? This is a worry for endurantists, who hold that for any stages, x and y, of a persisting object, x is numerically identical with y. Endurantists might try to avoid the problem of change by insisting that all properties are temporally anchored. It is argued here that while this strategy helps in many cases, it does not help in all. A type of case is presented in which a (...) property is time-indexed but the property is one that an object exemplifies at only one time in its career. The choice between the A theory and the B theory of time (in particular, presentism versus eternalism), and how that bears on the problem presented here, is also considered. It is argued that regardless of our views about the nature of time, so long as objects persist through time while undergoing change, the risk of violating the Indiscernibility of Identicals remains a serious threat to endurantism. (shrink)

This is a copy of my DPhil thesis, the abstract for which is as follows: The first third of this thesis argues for a B-theoretic conception of time according to which all times exist equally and the present is in no way privileged. I distinguish "ontological" A-theories from "non-ontological" ones, arguing that the latter are experientially unmotivated and barely coherent. With regard to the former, I focus mainly on presentism. After some remarks on how to formulate this (and eternalism) non-trivially, (...) I review the non-relativistic case against presentism. I then consider the impact of Special Relativity on the debate, and attempt to deepen this impact by supplying a modal variation on the standard arguments. The middle third of the thesis investigates persistence, contending that both endurance and perdurance are consonant with the eternalism already endorsed. After introducing these theories of persistence, and discussing in particular how best to formulate an eternalist endurance, I proceed to defend the coherence of this combination. The Problem of Change is addressed here. I then respond in some detail to recent allegations of relativistic threats to endurance. The final third of the thesis questions the validity of the endurantist-perdurantist dispute. I criticize two recently proposed translation schemes that aim to show this dispute to be non-substantive. However, the second scheme suggests a doctrine of "Ontological Equivalence" which I develop and consider. I then address the Rotating Discs Argument, using this to launch a discussion of identity, genidentity, and the relationship between them. (shrink)

The aim of this paper is to explain how the Heraclitean doctrine of universal flux must be rejected, while the notion of flux should and can be preserved. Against the reductionist account of subjectless change, a modern version of the Heraclitean doctrine advocated by revisionist metaphysics, I argue that (1) the idea of subjectless change is one that can and should be formulated in the established conceptual framework, and (2) subjectlessness is a feature that most aptly characterizes material changes. In (...) essence, I seek to provide a proper accommodation for the notion of flux in a conceptual framework that is traditionally understood (or rather misunderstood) as decidedly excluding it. (shrink)

Take this banana. It is now yellow, and when I bought it yesterday it was green. How can a single object be both green all over and yellow all over without contradiction? It is, of course, the passage of time which dissolves the contradiction, but how is this possible? How can a banana ripen? These questions raise the problem of change. The problem is sometimes called the problem of temporary intrinsics, but, as I shall explain below, this emphasis on intrinsic (...) properties is misleading. (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)

A solution to the problem of intrinsic change for enduring things should meet three conditions. It should not replace monadic intrinsic properties by relations. It should not replace the having simpliciter of properties by standing in some relation to them (unless having them simpliciter always means standing in some relation to them, which is refuted by Bradley's regress). It should not rely on an unexplained notion of having an intrinsic property at a time. Johnston's solution satisfies the first condition at (...) the expense of the second. Haslanger's solution satisfies the first and second at the expense of the third. (shrink)

There is a strong intuition that for a change to occur, there must be a moment at which the change is taking place. It will be demonstrated that there are no such moments of change, since no state the changing thing could be in at any moment would suffice to make that moment a moment of change. A moment in which the changing thing is simply in the state changed from or the state changed to cannot be the moment of (...) change, since these states are respectively before and after the change; moreover, to select one of these moments over the other as the moment of change would be arbitrary. A moment in which the changing thing is neither in the state changed from nor in the state changed to cannot be the moment of change, since there are changes for which it is impossible for something to be in neither state. Finally, the moment of change cannot be a moment in which the changing thing is in both the state changed from and the state changed to, as suggested by Graham Priest and others. Even if, like proponents of this view, we are willing to accept the contradictions that the account entails, it is demonstrated that on such a model, every change would require an infinite number of other changes, every change would take an infinite amount of time, and some changes would occur without occurring at any time. Further, the model is grossly counterintuitive, with the exact nature of the counterintuitive element depending on what model of time and space one endorses. Finally, it is demonstrated that this model is incompatible with the Leibniz Continuity Condition. (shrink)

It has been argued that there is a problem oftemporary intrinsics, the problem of explaininghow it is possible for things to possesssuccessively contrary properties, if a certaintheory about time, ``eternalism'', is true. Inthis paper, I consider whether there really issuch a problem and survey some standardsolutions to it. I argue for one of them, onewhich has been offered by Mark Johnston andPeter van Inwagen, and which I call the``exemplification-solution''''. I consider avariant on that solution offered by E.J. Lowe(and Sally Haslanger), (...) and I argue that thisvariant should be rejected. (shrink)

Worlds, Lewis says this: Let us say that something persists iff, somehow or other, it exists at various times; this is the neutral word. Something perdures iff it persists by having different temporal parts, or stages, at different times, though no one part of it is wholly present at more than one time; whereas it endures iff it persists by being wholly present at more than one time. Perdurance corresponds to the way a road persists through space; part of it (...) is here, and part of it is there, and no part is wholly present at two different places. Endurance corresponds to the way a universal, if there are such things, would be wholly present wherever and whenever it is instantiated. Endurance involves overlap: the content of two different times has the enduring thing as a common part. Perdurance does not.1 Lewis's remarks suggest the following formulations of the two views in the 3D/4D controversy.2.. (shrink)

Memory seems intuitively to consist in the preservation of some proposition (in the case of semantic memory) or sensory image (in the case of episodic memory). However, this intuition faces fatal difficulties. Semantic memory has to be updated to reflect the passage of time: it is not just preservation. And episodic memory can occur in a format (the observer perspective) in which the remembered image is different from the original sensory image. These difficulties indicate that memory cannot be preserved content. (...) It is proposed that what is preserved in memory isan underlying "trace", and that in every act of remembering, memorial content is reconstructed from the preserved trace. (shrink)

Some authors have recently arguedthat an objects velocity is logicallyindependent of its locations throughout time.Their aim is to deny the Russellianview that motion is merely a change oflocation, and to promote a rival account onwhich the connection between velocities andtrajectories is provided by the laws ofnature. I defend the Russellian view of motionagainst these attacks.

In what follows, I suggest that, against most theories of time, there really is an actual present, a now, but that such an eternal moment cannot be found before or after time. It may even be semantically incoherent to say that such an eternal present exists since “it” is changeless and formless (presumably a dynamic chaos without location or duration) yet with creative potential. Such a field of near-infinite potential energy could have had no beginning and will have no end, (...) yet within it stirs the desire to experience that brings forth singularities, like the one that exploded into the Big Bang (experiencing itself through relative and relational spacetime). From the perspective of the eternal now of near-infinite possibilities (if such a sentence can be semantically parsed at all), there is only the timeless creative present, so the Big Bang did not happen some 13 billion years ago. Inasmuch as there is neither time past nor time future nor any time at all at the null point of forever, we must understand the Big Bang (and all other events) as taking place right here and now. In terms of the eternal now, the beginning is happening now and we just appeared (and are always just appearing) to witness it. The rest is all conscious construction; time and experience are so entangled, they need each other to exist. (shrink)

We are no less directly acquainted with the temporal structure of the world than with its spatial structure. We hear one word succeeding another; feel two taps as simultaneous; or see the glow of a firework persisting, before it finally fizzles and fades. However, time is special, for we not only experience temporal properties; experience itself is structured in time. -/- Part One articulates a natural framework for thinking about experience in time. I claim (i) that experience in its experiential (...) aspect has a realistically conceived temporal structure; (ii) that our judgements about that structure always go via judgements about the temporal structure of the apparent objects of perception; and (iii) that a subject undergoing perceptual experience of a given experiential kind is always in a position to know that they are undergoing experience of that kind simply in virtue of so undergoing. On this basis, I argue that the temporal structure of experience cannot systematically come apart from the temporal structure of its objects. -/- Part Two treats four puzzles relating to our experience of time. The first is Dennett’s notorious discussion of masking and apparent motion phenomena. The second is the traditional debate regarding the very possibility of perceiving temporal properties. The third is Fara’s recent contention that standard explanations of our experience of slow changes preclude us from perceiving constant motion. A common reaction to these three puzzles is to reject some element of the naïve picture of temporal experience developed in Part One. I resolve them instead by showing how each arises from mistakenly thinking that experience is homoeomerous down to very short durations or instants. That is, thinking that we can analyse experience into a series of independent short slices, and explain the nature of the stream of consciousness in terms of those slices. The final chapter discusses a fourth puzzle about visual motion perception which I diagnose as driven by a rather different, but equally misguided way of thinking about vision. (shrink)

Impostors are pseudo-problems masquerading as genuine problems. Impostors should be exposed. The problem of change appears genuine. But some, such as Hofweber ( 2009 ) and Rychter ( 2009 ), have recently denounced it as an impostor. They allege that it is mysterious how to answer the meta - problem of saying what problem it is: for even if any problem is genuinely about change per se, they argue, it is either empirical or trivially dissolved by conceptual analysis. There is (...) indeed an impostor in our midst. But it is the meta-problem of change. I defend the appearance that the problem of change is a genuine metaphysical problem about change. This vindicates philosophers’ lasting interest in it. It also illuminates what makes a problem metaphysical, how metaphysics relates to other inquiries, and how best to respond to attempts to undermine metaphysical problems. (shrink)

If reality is temporary, then reality changes, and if reality changes, the past has explanatory work to do, and it cannot do that work unless it is no longer real. This tells against the Moving Now Theory, the Growing Block Theory, and any form of Presentism that attempts to understand the past in terms of the present, including Tensed Properties Presentism and Tensed Facts Presentism. It tells in favor of a form Presentism that allows us to appeal to unreal past (...) facts. I suggest that Priorian Presentism, conjoined with a certain way of understanding the role played by tense operators, is one such view. (shrink)

Four-dimensionalism, as I’ll use the term, is the doctrine that reality is spread out in time as well as space.1 Just as objects that are located at multiple regions of space contain parts confined to those regions of space, so objects that are located at multiple regions of time contain parts — temporal parts — that are confined to those regions of time. (Or better: an object that occupies an extended spatiotemporal region R has parts confined to the various subregions (...) of R; but I’ll ignore this complication henceforth.) Most who accept this ontology of perduring objects, as they are often called, identify the continuants of our everyday ontology with “space-time worms” — mereological sums of stages from different times. Elsewhere (1996) I have proposed a different version of four-dimensionalism, which identifies continuants with the stages themselves, and which analyses de re temporal predication with a temporal version of modal counterpart theory (Lewis, 1968, 1971). On this view, a current assertion of ‘Clinton was indiscreet’ is true iff the (current) referent of ‘Clinton’ — a stage — has an indiscreet temporal counterpart in the past. The temporal counterpart relation is the same “genidentity” or “unity” relation used by the worm theorist to unify the successive stages of continuing space-time worms. In my 1996 I supported this view by appeal to its ability to resolve various philosophical puzzles, including the paradoxes of material constitution and Derek Parfit’s (1971) puzzle about identity and what matters; the purpose of the present note is to mention one other line of argument. A widely discussed contemporary argument for temporal parts is David Lewis’s argument from temporary intrinsics, according to which only the fourdimensionalist can explain the phenomenon of intrinsic change.2 I am now straight-shaped, but will fail to be straight-shaped in the future. There is an.. (shrink)

Four-dimensionalism, as I’ll use the term, is the doctrine that reality is spread out in time as well as space.1 Just as objects that are located at multiple regions of space contain parts con ned to those regions of space, so objects that are located at multiple regions of time contain parts — temporal parts — that are con ned to those regions of time. (Or better: an object that occupies an extended spatiotemporal region R has parts con ned to (...) the various subregions of R; but I’ll ignore this complication henceforth.) Most who accept this ontology of perduring objects, as they are often called, identify the continuants of our everyday ontology with “space-time worms” — mereological sums of stages from different times. Elsewhere ( ) I have proposed a different version of four-dimensionalism, which identi es continuants with the stages themselves, and which analyses de re temporal predication with a temporal version of modal counterpart theory (Lewis, , ). On this view, a current assertion of ‘Clinton was indiscreet’ is true iff the (current) referent of ‘Clinton’ — a stage — has an indiscreet temporal counterpart in the past. The temporal counterpart relation is the same “genidentity” or “unity” relation used by the worm theorist to unify the successive stages of continuing space-time worms. In my I supported this view by appeal to its ability to resolve various philosophical puzzles, including the paradoxes of material constitution and Derek Par t’s ( ) puzzle about identity and what matters; the purpose of the present note is to mention one other line of argument. A widely discussed contemporary argument for temporal parts is David Lewis’s argument from temporary intrinsics, according to which only the fourdimensionalist can explain the phenomenon of intrinsic change.2 I am now straight-shaped, but will fail to be straight-shaped in the future. There is an.. (shrink)

Time, Change and Freedom is the first introduction to metaphysics that uses the idea of time as a unifying principle. Time is used to relate the many issues involved in the complex study of metaphysics. Sections of the book are written in dialogue form which allows the reader to question the theories while they read and have those queries answered in the text. In addition, the authors provide glossaries of key terms as well as recommendations for further reading at the (...) conclusion of each chapter. Quentin Smith and L. Nathan Oaklander examine the tensions between determinism and freedom, temporality and historical change as well as an array of other issues fundamental to introductory metaphysics. (shrink)

The problem of temporary intrinsics is the problem of how persisting objects can have different intrinsic properties at different times. The relativizer responds to this problem by replacing ordinary intrinsic properties with relations to times. In this note, I identify and respond to three different objections to the relativizer's proposal, each of which can be traced to the work of David Lewis.

Our world is a world of change. Children are born and grow into adults. Material possessions rust and decay with age and ultimately perish. Yet scepticism about change is as old as philosophy itself. Heraclitus, for example, argued that nothing could survive the replacement of parts, so that it is impossible to step into the same river twice. Zeno argued that motion is paradoxical, so that nothing can alter its location. Parmenides and his followers went even further, arguing that the (...) very concept of qualitative change is inconsistent. Change in any respect is impossible, they argued, as change requires difference and nothing differs from itself. Few today would accept the Eleatic conclusion that change is impossible. But the topic of change continues to be a source of much debate, as it brings together various issues that are central to metaphysics, language, and logic – including identity, persistence, time, tense, and temporal logic. Author Recommends Wasserman, Ryan. 'The Problem of Change.' Philosophy Compass 1 (2006): 1–10. This article presents the problem of change and provides a brief survey of potential solutions. Haslanger, Sally. 'Persistence Through Time.' The Oxford Handbook of Metaphysics . Eds. M. Loux and D. Zimmerman. Oxford: Oxford University Press, 2003. This article presents the problem of change and provides a detailed survey of potential solutions. Heller, Mark. 'Things Change.' Philosophy and Phenomenological Research 52 (1992): 695–704. This article presents, explains, and defends the temporal parts solution to the problem of change. Hinchliff, Mark. 'The Puzzle of Change.' Philosophical Perspectives 10 (1996): 119–36. This article presents, explains, and defends the presentist solution to the problem of change. Wasserman, Ryan. 'The Argument from Temporary Intrinsics.' Australasian Journal of Philosophy 81 (2003): 413–19. This article presents, explains, and defends the relationist solution to the problem of change. Sider, Theodore. Four-Dimensionalism . Oxford: Oxford University Press, 2001. This book provides an introduction to various issues related to the problem of change, including the nature of time, tense, and persistence. Chapter 5 presents, explains, and defends the stage-view solution to the problem of change. Online Materials Change. URL: http://plato.stanford.edu/entries/change/ The Stanford Encyclopedia of Philosophy entry on change, by Chris Mortensen. Time. URL: http://plato.stanford.edu/entries/time/ The Stanford Encyclopedia of Philosophy entry on time, by Ned Markosian. Temporal Parts. URL: http://plato.stanford.edu/entries/temporal-parts/ The Stanford Encyclopedia of Philosophy entry on temporal parts, by Katherine Hawley. Material Constitution. URL: http://plato.stanford.edu/entries/material-constitution/ The Stanford Encyclopedia of Philosophy entry on material constitution, by Ryan Wasserman. Persistence Bibliography. URL: http://tedsider.org/teaching/pp_bibliography.pdf A bibliography on change and related issues, by Theodore Sider. Sample Syllabus Books on Syllabus Rea, Michael. Material Constitution: A Reader . Lanham: Rowman & Littlefield, 1997. Sider, Theodore. Four-Dimensionalism . Oxford: Oxford University Press, 2001. van Inwagen, P. and Zimmerman, D. 2008. Metaphysics: The Big Questions . 2nd ed. Oxford: Blackwell, 2008. Week 1: Time and Tense Four-Dimensionalism , chapters 1 and 2. Markosian, Ned. 'A Defence of Presentism.' Oxford Studies in Metaphysics, Volume 1. Ed. D. Zimmerman. Oxford: Oxford University Press, 2004: 47–82. In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 116-123. In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 124-129. Week 2: Time and Persistence Four-Dimensionalism , chapter 3. McGrath, Matthew. 'Temporal Parts.' Philosophy Compass 2 (2007): 730–48. In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 265-267. Hawthorne, J, Scala, M., and Wasserman, R. 'Recombination, Humean Supervenience, and Causal Constraints: An Argument for Temporal Parts?' Oxford Studies in Metaphysics , Volume 1. Ed. D. Zimmerman, Oxford: Oxford University Press, 2004: 301-318. Week 3: Change and Presentism In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 141-149. In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 267-269. In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 269-281. Week 4: Change and Temporal Parts Four-Dimensionalism , pp. 92–8. Heller, Mark. 'Things Change.' Philosophy and Phenomenological Research 52 (1992): 695–704. Lombard, Lawrence. 'The Doctrine of Temporal Parts and the "No Change" Objection.' Philosophy and Phenomenological Research 54 (1994): 365–72. Week 5: Change, Relationism, and Adverbialism Hawley, Katherine. 'Why Temporary Properties are not Relations between Physical Objects and Times.' Proceedings of the Aristotelian Society 98 (1998): 211–16. Wasserman, Ryan. 'The Argument from Temporary Intrinsics.' Australasian Journal of Philosophy 81 (2003): 413–19. Lewis, David. 'Tensing the Copula.' Mind 111 (2002): 1–13. Caplan, Ben. 'Why so Tense about the Copula?' Mind 114 (2007): 703–8. Week 6: Change and Tropes Ehring, Douglas. 'Lewis, Temporary Intrinsics and Momentary Tropes.' Analysis 57 (1997): 254–8. MacBride, Fraser. 'Four New Ways to Change Your Shape.' Australasian Journal of Philosophy 79 (2001): 81–9. Simons, Peter. 'On Being Spread Out in Time: Temporal Parts and the Problem of Change.' Existence and Explanation . Eds. W. Spohn, B.C. van Fraassen, and B. Skyrms. Dordrecht: Kluwer, 1991: 131-147. Weeks 7 and 8: Special Topic – Material Change Four-Dimensionalism , chapter 5. Selections from Material Constitution: A Reader. Week 9: Special Topic – Change of Position In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 186-195. In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 195-215. Week 10: Special topic – Changing the Past In van Inwagen, P. and Zimmerman, D. Metaphysics: The Big Questions. 2nd ed. Oxford: Blackwell, 2008: 224-235. van Iwagen, Peter. 'Changing the Past.' Oxford Studies in Metaphysics , Volume 5 . Ed. D. Zimmerman. Oxford: Oxford University Press, 2009: 1-22. Hudson, H. and Wasserman, R. 'Van Inwagen on Time Travel and Changing the Past.' Oxford Studies in Metaphysics , Volume 5. Ed. D. Zimmerman. Oxford: Oxford University Press, 2009: 41-49. (shrink)

Our world is a world of change. Children are born and grow into adults. Material possessions rust and decay with age and ultimately perish. Yet scepticism about change is as old as philosophy itself. Heraclitus, for example, argued that nothing could survive the replacement of parts, so that it is impossible to step into the same river twice. Zeno argued that motion is paradoxical, so that nothing can alter its location. Parmenides and his followers went even further, arguing that the (...) very concept of qualitative change is inconsistent. Change in any respect is impossible, they argued, since change requires difference and nothing differs from itself.1 Few today would accept the Eleatic conclusion that change is impossible. But the topic of change continues to be a source of much debate, as it brings together various issues that are central to metaphysics, language and logic – including identity, persistence, time, tense, and temporal logic. As we consider various approaches to our topic, it will become clear that one’s perspective on change is often determined by one’s position in the broader philosophical landscape. (shrink)

I argue that ordinary objects are fusions of past and present, but not future, temporal parts. This theory provides the neatest solution to some puzzles concerning intrinsic properties, and is supported by some surprising linguistic data. (This paper is probably inconsistent with some other papers I've written, but the line it runs is at least amusing and original.).

The ‘friends of temporal parts’ and their opponents disagree about how things persist through time. The former, who hold what is sometimes called a ‘4D’ theory of persistence, typically claim that all objects that last for any period of time are spread out through time in the same way that spatially extended objects are spread out through space — a different part for each region that the object fills. David Lewis calls this manner of persisting ‘perdurance’. The opposing, ‘3D’ theory (...) has it that at least some objects do not persist in this manner; they ‘endure’ through time by ‘being wholly present at more than one time’.1 A related dispute pits ‘presentists’ against ‘non-presentists’. Presentists hold that the only things that really exist are those that exist now, at the present moment; and nonpresentists believe in something like a ‘block-universe’ in which non-simultaneous objects and events nevertheless co-exist (in a tenseless or non-temporal sense). Of late, the relations between these four positions have come under considerable scrutiny.2 As Ned Markosian has pointed out, it would be surprising if commitment to a perdurance or endurance theory of persistence automatically foreclosed one’s options in the presentism—non-presentism debate. But, says Markosian, that is just what the standard formulations of the perdurance and endurance theories imply.3 David Lewis has set the terms of the debate; in his usage, someone who thinks that all persisting objects endure would be said to hold the following. (shrink)