Tobias Hansson Wahlberg argues in a recent article (2009) that the truth of “Hesperus is Phosphorus” depends on the assumption that the endurance theory of persistence is true. The statement is not true (or at least can reasonably be doubted), he argues, if one assumes (a) the theory of persistence according to which objects are four-dimensional entities, persisting through perdurance, i.e. by having temporal parts that are numerically distinct, and (b) the thesis of unrestricted mereological composition (UMC), that is, that (...) any two things, however scattered in space or time, compose a sum. (shrink)

Lynne Rudder Baker presents and defends a unique account of the material world: the Constitution View. In contrast to leading metaphysical views that take everyday things to be either non-existent or reducible to micro-objects, the Constitution View construes familiar things as irreducible parts of reality. Although they are ultimately constituted by microphysical particles, everyday objects are neither identical to, nor reducible to, the aggregates of microphysical particles that constitute them. The result is genuine ontological diversity: people, bacteria, donkeys, mountains and (...) microscopes are fundamentally different kinds of things - all constituted by, but not identical to, aggregates of particles. Baker supports her account with discussions of non-reductive causation, vagueness, mereology, artifacts, three-dimensionalism, ontological novelty, ontological levels and emergence. The upshot is a unified ontological theory of the entire material world that irreducibly contains people, as well as non-human living things and inanimate objects. (shrink)

On the B-theory of time, the experiences we have throughout our conscious lives have the same ontological status: they all tenselessly occur at their respective dates. But we do not seem to experience all of them on the same footing. In fact, we tend to believe that only our present experiences are real, to the exclusion of the past and future ones. The B-theorist has to maintain that this belief is an illusion and explain the origin of the illusion. The (...) paper argues that this cannot be properly done unless one rejects endurantism in favor of the stage view of persistence. (shrink)

Hud Hudson has recently suggested a scenario intended to show that, assuming the doctrine of temporal parts and a sufficiently liberal view of composition, there are material objects that move faster than light. I accept Hudson's conditional but contend that his modus ponens is less plausible that the corresponding modus tollens. Reversed in this way, the argument stemming from the scenario raises the cost of mereological liberalism and advances the case for a principled restriction on diachronic composition.

I offer an argument in defense of four-dimensionalism, the view that objects are temporally, as well as spatially extended. The argument is of the inference-to-the-best-explanation variety and is based on relativistic considerations. It deals with the situation in which one and the same object has different three-dimensional shapes at the same time and proceeds by asking what sort of thing it must be in order to present itself in such different ways in various “perspectives” (associated with moving reference frames) without (...) being different from itself. I argue that the best answer is that the object must be four-dimensional. It will then have differing 3D shapes in different perspectives because such shapes are intrinsic properties of its 3D parts. (shrink)

Four-dimensionalism, or perdurantism, the view that temporally extended objects persist through time by having (spatio-)temporal parts or stages, includes two varieties, the worm theory and the stage theory. According to the worm theory, perduring objects are four-dimensional wholes occupying determinate regions of spacetime and having temporal parts, or stages, each of them confined to a particular time. The stage theorist, however, claims, not that perduring objects have stages, but that the fundamental entities of the perdurantist ontology are stages. I argue (...) that considerations of special relativity favor the worm theory over the stage theory. (shrink)

Although considerations based on contemporary space-time theories, such as special and general relativity, seem highly relevant to the debate about persistence, their significance has not been duly appreciated. My goal in the paper is twofold: (1) to reformulate the rival positions in the debate (i.e., endurantism (three-dimensionalism) and perdurantism (four-dimensionalism, the doctrine of temporal parts)) in the framework of special relativistic space-time; and (2) to argue that, when so reformulated, perdurantism exhibits explanatory advantages over endurantism. The argument builds on the (...) fact that four-dimensional entities extended in space as well as time are relativistically invariant in a way three-dimensional entities are not. (shrink)

In an earlier work I developed an argument favoring one view of persistence (viz., perdurance) over its rivals, based on considerations of the relativity of three-dimensional spatial shapes of physical objects in Minkowski spacetime. The argument has since come under criticism (in the works of Theodore Sider, Kristie Miller, Ian Gibson, Oliver Pooley, and Thomas Sattig). Two related topics, explanatory virtues and explanatory relevance, are central to these critical discussions. In this paper I deal with these topics directly and respond (...) to my critics by offering a new perspective on the issue. (shrink)

On stage theory, ordinary continuants are instantaneous stages which persist by exduring—by bearing temporal counterpart relations to other such stages. Exduring objects lack temporal extension and there is a sense in which they are wholly present at multiple instants. How then is exdurance different from endurance? I offer a definition of ‚exdurance’ that clearly sets it apart from other modes of persistence.

In two earlier works (Balashov, 2000a: Philosophical Studies 99, 129–166; 2000b: Philosophy of Science 67 (Suppl), S549–S562), I have argued that considerations based on special relativity and the notion of coexistence favor the perdurance view of persistence over its endurance rival. Cody Gilmore (2002: Philosophical Studies 109, 241–263) has subjected my argument to an insightful three fold critique. In the first part of this paper I respond briefly to Gilmore’s first two objections. I then grant his observation that anyone who (...) can resist the first objection is liable to succumb to the third one. This, however, opens a way to other closely related relativistic arguments against endurantism that are immune to all three objections and, in addition, throw new light on a number of important issues in the ontology of persistence. I develop two such novel arguments in the second half of the paper. (shrink)

I offer a new criticism of the argument from vagueness to four-dimensionalism [Sider 2001. The argument is modelled after an older argument for mereological universalism [Lewis 1986 and may be looked upon as a tightened-up and extended version of the latter. While I agree with other critics [Koslicki 2003; Markosian 2004 that the argument from vagueness fails precisely because of this affinity, my recipe for dealing with it is different. I reject the assumption, shared by Sider with his opponents, that (...) synchronic composition and 'minimal diachronic fusion' are sufficiently similar to use considerations inspired by the analysis of the former to bear on the latter. My objection to a crucial premise of the argument from vagueness turns on the relevant aspect of dissimilarity between these two cases. (shrink)

The nature of persistence of physical objects over time has been intensely debated in contemporary metaphysics. The two opposite views are widely known as "endurantism" (or "three-dimensionalism") and "perdurantism" ("four-dimensionalism"). According to the former, objects are extended in three spatial dimensions and persist through time by being wholly present at any moment at which they exist. On the rival account, objects are extended both in space and time and persist by having "temporal parts," no part being present at more than (...) one time. Relativistic considerations seem highly relevant to this debate. But they have played little role in it so far. This paper seeks to remedy that situation. I argue that considerations based on the special theory of relativity and the notion of coexistence favor perdurantism over endurantism. (shrink)

I examine the issue of persistence over time in thecontext of the special theory of relativity (SR). Thefour-dimensional ontology of perduring objects isclearly favored by SR. But it is a different questionif and to what extent this ontology is required, andthe rival endurantist ontology ruled out, by thistheory. In addressing this question, I take theessential idea of endurantism, that objects are whollypresent at single moments of time, and argue that itcommits one to unacceptable conclusions regardingcoexistence, in the context of SR. (...) I then propose anddiscuss a plausible account of coexistence forperduring objects, which is free of these defects. This leaves the endurantist room for some maneuvers. I consider them and show that they do not really helpthe endurantist out. She can accommodate the notionof coexistence in the relativistic framework only atthe cost of renouncing central endurantist intuitions. (shrink)

I offer an argument in defense of four-dimensionalism, the view that objects are temporally, as well as spatially extended. The argument is of the inference-to-the-best-explanation variety and is based on relativistic considerations. It deals with the situation in which one and the same object has different three-dimensional shapes at the same time and proceeds by asking what sort of thing it must be in order to present itself in such different ways in various "perspectives" (associated with moving reference frames) without (...) being different from itself. I argue that the best answer is that the object must be four-dimensional. It will then have differing 3D shapes in different perspectives because such shapes are intrinsic properties of its 3D parts. (shrink)

The eternalist endurantist and perdurantist theories of persistence through time come in various versions, namely the two versions of perdurantism: the worm view and the stage view , and the two versions of endurantism: indexicalism and adverbialism . Using as a starting point the instructive case of what is depicted by photographs, I will examine these four views, and compare them, with some interesting results. Notably, we will see that two traditional enemies—the perdurantist worm view and the endurantist theories—are more (...) like allies : they are much less different than what is usually thought, and some alleged points of central disagreement fall prey to closer scrutiny. The aim of this paper is to examine carefully all those points, and to call attention to the places where the real differences between these views lie. I will then turn to the perdurantist stage view, and claim that with respect to some central issues it is the view that is the most different from the other three, but that in some places the reason why it different is also the reason why it is less satisfactory. (shrink)

The paper defends a combination of perdurantism with mereological universalism by developing semantics of temporary predications of the sort ’some P is/was/will be (a) Q’. We argue that, in addition to the usual application of causal and other restrictions on sortals, the grammatical form of such statements allows for rather different regimentations along three separate dimensions, according to: (a) whether ‘P’ and ‘Q’ are being used as phase or substance sortal terms, (b) whether ‘is’, ‘was’, and ‘will be’ are the (...) ‘is’, ‘was’, ‘will be’ of identity or of constitution, and (c) whether ‘Q’ is being used as a subject or predicate term. We conclude that this latitude is beneficial, as it conforms with linguistic reality (i.e., the multiple uses actually in place) and also enables one to turn what is ordinarily perceived as a problem for universalist perdurantism viz., a commitment to all sorts of weird and gerrymandered temporally extended entities, into an advantage, for the richness in questions allows us to make sense of the many different readings of sentences of the same grammatical form. (shrink)

This paper considers the question whether a psychological approach to personal identity can be formulated within an endurantist, as opposed to four-dimensionalist, framework. Trenton Merricks has argued that this cannot be done. I argue to the contrary: a perfectly coherent endurantist version of the psychological approach can indeed be formulated.

The rotating discs argument (RDA) against perdurantism has been mostly discussed by metaphysicians, though the argument of course appeals to ideas from classical mechanics, especially about rotation. In contrast, I assess the RDA from the perspective of the philosophy of physics. I argue for three main conclusions. The first conclusion is that the RDA can be formulated more strongly than is usually recognized: it is not necessary to ‘imagine away’ the dynamical effects of rotation. The second is that in general (...) relativity, the RDA fails because of frame-dragging. The third conclusion is that even setting aside general relativity, the strong formulation of the RDA can after all be defeated, namely, by the perdurantist taking objects in classical mechanics (whether point-particles or continuous bodies) to have only temporally extended (i.e. non-instantaneous) temporal parts, which immediately blocks the RDA. Admittedly, this version of perdurantism defines persistence in a weaker sense of ‘definition’ than pointilliste versions that aim to define persistence assuming only instantaneous temporal parts. But I argue that temporally extended temporal parts (i) can do the jobs within the endurantism–perdurantism debate that the perdurantist wants temporal parts to do and (ii) are supported by both classical and quantum mechanics. Introduction The story so far 2.1 The RDA 2.2 Intrinsic properties and the idea of velocity 2.2.1 The intrinsic–extrinsic distinction 2.2.2 Velocity to the rescue? 2.3 ‘Naturalism’ 2.4 The accompaniments of rotation 2.5 Two kinds of reply: against the consensus Describing rotation 3.1 Rotation is kinematic 3.2 Beware of rigidity 3.3 An improved RDA: allowing the actual accompaniments 3.4 The RDA fails in general relativity Perdurantism without tears: the classical case 4.1 Rejecting instantaneous temporal parts 4.2 Replying to the RDA 4.2.1 ‘Kinematics’ 4.2.2 ‘Dynamics’ 4.2.3 An ‘anti-pointilliste’ objection and reply 4.3 Intrinsic properties of non-instantaneous temporal parts 4.3.1 Can the perdurantist appeal to them? 4.3.2 Temporal intrinsicality at an instant is rare 4.3.3 A better reason for temporal intrinsicality 4.4 Non-instantaneous parts can do the jobs 4.4.1 Humean supervenience revisited 4.4.2 The problem of change 4.4.3 Puzzles of coincidence 4.5 Instantaneous velocity is hardly extrinsic Support from decoherence in quantum theory 5.1 Classical and quantum: relativizing the intrinsic–extrinsic distinction 5.1.1 Unitarity: momentum as temporally intrinsic 5.2 Position and existence as nomically extrinsic. (shrink)

This paper forms part of a wider campaign: to deny pointillisme, the doctrine that a physical theory's fundamental quantities are defined at points of space or of spacetime, and represent intrinsic properties of such points or point-sized objects located there; so that properties of spatial or spatiotemporal regions and their material contents are determined by the point-by-point facts. More specifically, this paper argues against pointillisme about the concept of velocity in classical mechanics; especially against proposals by Tooley, Robinson and Lewis. (...) A companion paper argues against pointillisme about (chrono)-geometry, as proposed by Bricker. To avoid technicalities, I conduct the argument almost entirely in the context of "Newtonian" ideas about space and time, and the classical mechanics of point-particles, i.e. extensionless particles moving in a void. But both the debate and my arguments carry over to relativistic physics. Introduction The wider campaign 2.1 Connecting physics and metaphysics         2.1.1 Avoiding controversy about the intrinsic–extrinsic distinction         2.1.2 Distinction from three mathematical distinctions 2.2 Classical mechanics is not pointilliste, and can be perdurantist         2.2.1 Two versions of pointillisme         2.2.2 Two common claims         2.2.3 My contrary claims 2.3 In more detail...         2.3.1 Four violations of pointillisme         2.3.2 For perdurantism Velocity as intrinsic? 3.1 Can properties represented by vectors be intrinsic to a point? 3.2 Orthodox velocity is extrinsic but local         3.2.1 A question and a debate         3.2.2 The verdict 3.3 Against intrinsic velocity         3.3.1 A common view—and a common problem         3.3.2 Tooley's proposal and his arguments         3.3.3 Tooley's further discussion "Shadow velocities": Lewis and Robinson 4.1 The proposal 4.2 Criticism: the vector field remains unspecified 4.3 Avoiding the presupposition of persistence, using Hilbert's symbol 4.4 Comparison with Robinson and Lewis. (shrink)

The rotating discs argument (RDA) against perdurantism has been mostly discussed by metaphysicians, though the argument of course appeals to ideas from classical mechanics, especially about rotation. In contrast, I assess the RDA from the perspective of the philosophy of physics. I argue for three main conclusions. The first conclusion is that the RDA can be formulated more strongly than is usually recognized: it is not necessary to imagine away the dynamical effects of rotation. The second is that in general (...) relativity, the RDA fails because of frame-dragging. The third conclusion is that even setting aside general relativity, the strong formulation of the RDA can after all be defeated. Namely, by the perdurantist taking objects in classical mechanics (whether point-particles or continuous bodies) to have only temporally extended, i.e. non-instantaneous, temporal parts: which immediately blocks the RDA. Admittedly, this version of perdurantism defines persistence in a weaker sense of `definition' than pointilliste versions that aim to define persistence assuming only instantaneous temporal parts. But I argue that temporally extended temporal parts: (i) can do the jobs within the endurantism-perdurantism debate that the perdurantist wants temporal parts to do; and (ii) are supported by both classical and quantum mechanics. This is an extract from a much longer paper, which is available at: http://philsci-archive.pitt.edu/archive/00001760. The main differences are that the longer paper: (i) gives much more detail about the form and scope of the RDA, the interpretative subtleties of classical mechanics, and the physics of rotation; and (ii) reports and assesses several other replies to the RDA, especially those by Callender, Lewis, Robinson and Sider. (shrink)

This paper is about the metaphysical debate whether objects persist over time by the selfsame object existing at different times (nowadays called `endurance' by metaphysicians), or by different temporal parts, or stages, existing at different times (called ` perdurance'). I aim to illuminate the debate by using some elementary kinematics and real analysis: resources which metaphysicians have, surprisingly, not availed themselves of. There are two main results, which are of interest to both endurantists and perdurantists. (1): I describe a precise (...) formal equivalence between the way that the two metaphysical positions represent the motion of the objects of classical mechanics (both point-particles and continua). (2): I make precise, and prove a result about, the idea that the persistence of objects moving in a void is to be analysed in terms of tracking the continuous curves in spacetime that connect points occupied by matter. The result is entirely elementary: it is a corollary of the Heine-Borel theorem. (shrink)

Some recent philosophical debate about persistence has focussed on an argument against perdurantism that discusses rotating perfectly homogeneous discs (the `rotating discs argument'; RDA). The argument has been mostly discussed by metaphysicians, though it appeals to ideas from classical mechanics, especially about rotation. In contrast, I assess the RDA from the perspective of the philosophy of physics. After introducing the argument and emphasizing the relevance of physics (Sections 1 to 3), I review some metaphysicians' replies to the argument, especially those (...) by Callender, Lewis, Robinson and Sider (Section 4). Thereafter, I argue for three main conclusions. They all arise from the fact, emphasized in Section 2, that classical mechanics (non-relativistic as well as relativistic) is both more subtle, and more problematic, than philosophers generally realize. The first conclusion is that the RDA can be formulated more strongly than is usually recognized: it is not necessary to ``imagine away'' the dynamical effects of rotation (Section 5.5). The second is that in general relativity, the RDA fails because of frame-dragging (Section 5.6). The third is that even setting aside general relativity, the strong formulation of the RDA can after all be defeated (Section 6 onwards). Namely, by the perdurantist taking objects in classical mechanics (whether point-particles or continuous bodies) to have only temporally extended, i.e. non-instantaneous, temporal parts: which immediately blocks the RDA. Admittedly, this version of perdurantism defines persistence in a weaker sense of `definition' than pointilliste versions that aim to define persistence assuming only instantaneous temporal parts. But I argue that temporally extended temporal parts: (i) can do the jobs within the endurantism-perdurantism debate that the perdurantist wants temporal parts to do; and (ii) are supported by both classical and quantum mechanics. (shrink)

In “Tropes and Ordinary Physical Objects”, Kris McDaniel argues that ordinary physical objects are fusions of monadic and polyadic tropes. McDaniel calls his view “TOPO”—for “Theory of Ordinary Physical Objects”. He argues that we should accept TOPO because of the philosophical work that it allows us to do. Among other things, TOPO is supposed to allow endurantists to reply to Mark Heller’s argument for perdurantism. But, we argue in this paper, TOPO does not help endurantists do that; indeed, we argue (...) that anyone who accepts TOPO should reject endurantism. (shrink)

If musical works are abstract objects, which cannot enter into causal relations, then how can we refer to musical works or know anything about them? Worse, how can any of our musical experiences be experiences of musical works? It would be nice to be able to sidestep these questions altogether. One way to do that would be to take musical works to be concrete objects. In this paper, we defend a theory according to which musical works are concrete objects. In (...) particular, the theory that we defend takes musical works to be fusions of performances. We defend this view from a series of objections, the first two of which are raised by Julian Dodd in a recent paper and the last of which is suggested by some comments of his in an earlier paper. (shrink)

This is a critical notice of Theodore Sider's book, _Four-Dimensionalism_.

In 'Four-Dimensional Objects' Peter van Inwagen gives two arguments for the claim that proponents of four-dimensionalism have to be counterpart theorists. Recently Jack Copeland, Heather Dyke, and Diane Proudfoot, echoing in part points made by Mark Heller in this journal in 1993, have sought to rebut one of van Inwagen's arguments. In this paper I shall criticize their discussion and by implication certain points made by Heller. In so doing I shall also rebut a possible objection to van Inwagen's second (...) argument. While I shall conclude that Copeland et al . fail to make their case, I nevertheless argue that van Inwagen's argument can be resisted, provided that the four-dimensionalist is willing to adopt a certain conception of transworld identity. Moreover, I shall argue that to the extent that van Inwagen's paper highlights something problematic for four-dimensionalism in this particular conception of transworld identity, the paper highlights something equally problematic for three-dimensionalism. (shrink)

Recently, Cody Gilmore has deployed an ingenious case involving backwards time travel to highlight an apparent conflict between the theory that objects persist by perduring, and the thesis that wholly coincident objects are impossible. However, careful attention to the concepts of location and parthood that Gilmore’s cases involve shows that the perdurantist faces no genuine objection from these cases, and that the perdurantist has a number of plausible and dialectically appropriate ways to avoid the supposed conflict.

Recently, Jim Stone has argued that counterpart theory is incompatible with the existence of temporal parts. I demonstrate that there is no such incompatibility.

There is a consensus that we need an informative definition of what a temporal part is. I argue that the most popular definition does not work given both the standard perdurantist treatment of temporary intrinsics and the possibility of time travel (§1). I consider Sider’s attempts to remedy this problem (§2), a prima facie plausible alternative (§3) and then all extant alternatives to the popular definition (§4). Each approach is flawed. I then argue that we can give up on the (...) standard treatment of temporary intrinsics. Whilst it is costly to perdurantism to do so, it is not prohibitively costly, and is the best option perdurantists have available to them (§5). (shrink)

In this paper, we argue that time travel is problematic for the endurantist. For it appears to be possible, given time travel, to construct a wall out of a single time travelling brick. This commits the endurantist to one of the following: (a) the wall is composed of the time travelling brick many times over; (b) the wall does not in fact exist at all; (c) the wall is identical to the brick. We argue that each of these options is (...) unsatisfactory. (shrink)

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)

In this paper, I try to make a bundle theory of objects consistentwith a temporal parts theory of object persistence. To that end,I propose that such bundles are made up of tropes includingthe co-instantiation relation.

This is an essay for undergraduates. I set out the statue/clay problem in rich detail.

Those who endorse the Psychological Continuity Approach (PCA) to analyzing personal identity need to impose a non-branching constraint to get the intuitively correct result that in the case of fission, one person becomes two. With the help of Brueckner's (2005) discussion, it is shown here that the sort of non-branching clause that allows proponents of PCA to provide sufficient conditions for being the same person actually runs contrary to the very spirit of their theory. The problem is first presented in (...) connection with perdurantist versions of PCA. The difficulty is then shown to apply to endurantist versions as well. (shrink)

Under the eternalist hypothesis that objects or events exist independently of being present two different views of persistence are on the market: Persisting objects endure if they are multiply located in (space-)time, and persisting objects perdure if they are singly located by having numerically different temporal parts. Recently, several authors (Balashov, Hales/Johnson, Gilmore, Gibson/Pooley) have argued that special relativity (SR) favours perdurantism over its endurantist rival. In my talk, I want to show that in fact the purported arguments are only (...) those against endurantism, and that with similar ones we should argue against perdurantism, as well: Enduring and perduring entities are both in conflict with SR which undermines the eternalist hypothesis. For arguing in favour of perdurantism Yuri Balashov (2000b; 2005), on the one hand, considers spatially unextended (persisting) objects in Minkowski space-time and claims that for the endurantists there are unwelcome consequences from an adequate concept of their coexistence. On the other hand, spacelike extended (persisting) objects are under investigation. Concerning point-like objects, Cody Gilmore (2002) has convincingly shown that Balashov’s arguments fail and, therefore, I will confine me to extended object. My paper has two parts following the two different strategies – namely, concerning the problem of the endurantist “explanatory deficiency” according to Balashov (2000a; 2008), and the problem of criss-crossing hyperplanes according to Gilmore (2006). (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)

We have two aims in this paper. The first is to provide the reader with a critical guide to recent work on relativity and persistence by Balashov, Gilmore and others. Much of this work investigates whether endurantism can be sustained in the context of relativity. Several arguments have been advanced that aim to show that it cannot. We find these unpersuasive, and will add our own criticisms to those we review. Our second aim, which complements the first, is to demarcate (...) the most defensible form of relativistic endurantism (and similarly, of perdurantism). A recurring theme of this paper is that even those philosophers who do worry about relativity have not taken it seriously enough. (shrink)