Background and assumptions. Persistence and philosophy of time ; Atomism and composition ; Scope ; Some matters of methodology -- Persistence, location, and multilocation in spacetime. Endurance, perdurance, exdurance : some pictures ; More pictures ; Temporal modification and the "problem of temporary intrinsics" ; Persistence, location and multilocation in generic spacetime ; An alternative classification -- Classical and relativistic spacetime. Newtonian spacetime ; Neo-Newtonian (Galilean) spacetime ; Reference frames and coordinate systems ; Galilean transformations in spacetime ; Special relativistic (...) spacetime ; Length contraction and time dilation ; Invariant properties of special relativistic spacetime -- Persisting objects in classical spacetime. Enduring, perduring, and exduring objects in Galilean spacetime ; The argument from vagueness ; From minimal D-fusions to temporal parts ; Motivating a sharp cutoff ; Some objections and replies ; Implications -- Persisting objects in Minkowski spacetime. Enduring, perduring, and exduring objects in Minkowski spacetime ; Flat and curved achronal regions in Minkowski spacetime ; Early reflections on persisting objects in Minkowski spacetime : Quine and Smart ; "Profligate ontology"? ; Is achronal universalism tenable in Minkowski spacetime? ; "Crisscrossing" and immanent causation -- Coexistence in spacetime. The notion of coexistence ; Desiderata ; Coexistence in Galilean spacetime ; Coexistence in Minkowski spacetime : CASH ; Alexandrov-Stein present and Alexandrov-Stein coexistence ; AS-Coexistence v. CASH : symmetry, multigrade, and objectivity ; As-coexistence v. CASH : relevance ; The mixed past of coexistence ; No need in the extended now -- Strange coexistence? Coexistence and [email protected] ; The asymmetry thesis ; The absurdity thesis ; Collective CASH value of coexistence ; Collective [email protected] and coexistence in classical spacetime ; Collective [email protected] and coexistence in Minkowski spacetime ; Contextuality ; Chronological incoherence ; Some objections -- Shapes and other arrangements in Minkowski spacetime. How rigid is a granite block? ; Perspectives in space ; Perspectives in spacetime ; Are shapes intrinsic to objects? ; The causal objection ; The micro-reductive objection ; Pegs, boards, and shapes ; Perduring objects exist. (shrink)

In this critical notice we argue against William Craig's recent attempt to reconcile presentism (roughly, the view that only the present is real) with relativity theory. Craig's defense of his position boils down to endorsing a ‘neo-Lorentzian interpretation’ of special relativity. We contend that his reconstruction of Lorentz's theory and its historical development is fatally flawed and that his arguments for reviving this theory fail on many counts. 1 Rival theories of time 2 Relativity and the present 3 Special relativity: (...) one theory, three interpretations 4 Theories of principle and constructive theories 5 The relativity interpretation: explanatorily deficient? 6 The relativity interpretation: ontologically fragmented? 7 The space-time interpretation: does God need a preferred frame of reference? 8 The neo-Lorentzian interpretation: at what price? 9 The neo-Lorentzian interpretation: with what payoff? 10 Why we should prefer the space-time interpretation over the neo-Lorentzian interpretation 11 What about general relativity? 12 Squaring the tenseless space-time interpretation with our tensed experience. (shrink)

Material objects persist through time and survive change. How do they manage to do so? What are the underlying facts of persistence? Do objects persist by being "wholly present" at all moments of time at which they exist? Or do they persist by having distinct "temporal segments" confined to the corresponding times? Are objects three-dimensional entities extended in space, but not in time? Or are they four-dimensional spacetime "worms"? These are matters of intense debate, which is now driven by concerns (...) about two major issues in fundamental ontology: parthood and location. It is in this context that broadly empirical considerations are increasingly brought to bear on the debate about persistence. Persistence and Spacetime pursues this empirically based approach to the questions. Yuri Balashov begins by setting out major rival views of persistence -- endurance, perdurance, and exdurance -- in a spacetime framework and proceeds to investigate the implications of Einstein's theory of relativity for the debate about persistence. His overall conclusion -- that relativistic considerations favour four-dimensionalism over three-dimensionalism -- is hardly surprising. It is, however, anything but trivial. Contrary to a common misconception, there is no straightforward argument from relativity to four-dimensionalism. The issues involved are complex, and the debate is closely entangled with a number of other philosophical disputes, including those about the nature and ontology of time, parts and wholes, material constitution, causation and properties, and vagueness. (shrink)

Yuri Balashov sets out major rival views of persistence--endurance, perdurance, and exdurance--in a spacetime framework and proceeds to investigate the implications of Einstein's theory of relativity for the debate about persistence. His overall conclusion--that relativistic considerations favour four-dimensionalism over three-dimensionalism--is hardly surprising. It is, however, anything but trivial. Contrary to a common misconception, there is no straightforward argument from relativity to four-dimensionalism. The issues involved are complex, and the debate is closely entangled with a number of other philosophical disputes, including (...) those about the nature and ontology of time, parts and wholes, material constitution, causation and properties, and vagueness. (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)

To state an important fact about the photon, physicists use such expressions as (1) “the photon has zero (null, vanishing) mass” and (2) “the photon is (a) massless (particle)” interchangeably. Both (1) and (2) express the fact that the photon has no non-zero mass. However, statements (1) and (2) disagree about a further fact: (1) attributes to the photon the property of zero-masshood whereas (2) denies that the photon has any mass at all. But is there really a difference between (...) saying that something has zero mass (charge, spin, etc.) and saying that it has no mass (charge, spin, etc.)? Does the distinction cut any physical or philosophical ice? I argue that the answer to these questions is yes. Put briefly, the claim of this paper is that some zero-value physical quantities are not mere “privations”, “absences” or “holes in being”. They are respectable properties in the same sense in which their non-zero partners are. This, I will show, has implications for the debate between two rival views of the nature of property, dispositionalism and categoricalism. (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)

In this critical notice we argue against William Craig's recent attempt to reconcile presentism (roughly, the view that only the present is real) with relativity theory. Craig's defense of his position boils down to endorsing a 'neo-Lorentzian interpretation' of special relativity. We contend that his reconstruction of Lorentz's theory and its historical development is fatally flawed and that his arguments for reviving this theory fail on many counts.

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 argue that the contemporary interplay of cosmology and particle physics in their joint effort to understand the processes at work during the first moments of the big bang has important implications for understanding the nature of lawhood. I focus on the phenomenon of spontaneous symmetry breaking responsible for generating the masses of certain particles. This phenomenon presents problems for the currently fashionable Dretske-Tooley-Armstrong theory and strongly favors a rival nomic ontology of causal powers.

Philosophical considerations have been essentially involved in the origin and development of the steady-state cosmological theory. These considerations include an explicit uniformitarian methodology and implicit metaphysical views concerning the status of natural laws in a changing universe. I shall examine the foundations of SST by reconstructing its early history. Whereas the strong uniformitarian methodology of SST found no support in the subsequent development of cosmology, the idea of a possible influence the global structure of the universe may have on the (...) laws of physics operative in it has been assimilated by the standard big bang theory as it made its remarkable progress in recent decades. (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)

in D. Dieks (ed.), The Ontology of Spacetime, Vol. 2. Elsevier, forthcoming.

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)

Composition, persistence, vagueness, and more constitute an interconnected network of problems. My criticism of Hud Hudson's provocative claims made in a recent paper (Hudson 2002) was focused almost exclusively on the issue of diachronic composition (Balashov 2003). Hudson's response (2003) has highlighted the dangers of such isolationism. But I want to hold to my strategy to the end. Part of the reason is to evade the appalling responsibility of presenting a full-blown theory of all the above phenomena; I must confess (...) that I do not have such a theory. At the same time, I contend that diachronic composition can be profitably carved out from the medley of the surrounding issues more or less at the joints provided by nature itself. And I do subscribe to some sort of realism about the joints of nature. (shrink)

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)

Most four-dimensionalists, including both worm and stage theorists, endorse mereological universalism, the thesis that any class of objects has a fusion. But the marriage of fourdimensionalism and universalism is unfortunate and unprofitable: it creates a recalcitrant problem for stage theory’s account of lingering properties, such as writing ‘War and Piece’ and traveling across the tennis court, which take time to be instantiated. This makes it necessary to impose a natural restriction on diachronic composition.

The success of deep learning in natural language processing raises intriguing questions about the nature of linguistic meaning and ways in which it can be processed by natural and artificial systems. One such question has to do with subword segmentation algorithms widely employed in language modeling, machine translation, and other tasks since 2016. These algorithms often cut words into semantically opaque pieces, such as ‘period’, ‘on’, ‘t’, and ‘ist’ in ‘period|on|t|ist’. The system then represents the resulting segments in a dense (...) vector space, which is expected to model grammatical relations among them. This representation may in turn be used to map ‘period|on|t|ist’ (English) to ‘par|od|ont|iste’ (French). Thus, instead of being modeled at the lexical level, translation is reformulated more generally as the task of learning the best bilingual mapping between the sequences of subword segments of two languages; and sometimes even between pure character sequences: ‘p|e|r|i|o|d|o|n|t|i|s|t’ → ‘p|a|r|o|d|o|n|t|i|s|t|e’. Such subword segmentations and alignments are at work in highly efficient end-to-end machine translation systems, despite their allegedly opaque nature. The computational value of such processes is unquestionable. But do they have any linguistic or philosophical plausibility? I attempt to cast light on this question by reviewing the relevant details of the subword segmentation algorithms and by relating them to important philosophical and linguistic debates, in the spirit of making artificial intelligence more transparent and explainable. (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)

Are shapes of objects intrinsic to them? The issue has been intensely debated. Special relativity (SR) adds a new dimension to it by relativizing three-dimensional (3D) shapes not just to times, but to times-in-frames. Arguably, however, such relativized spatial shapes are mere perspectival representations of an invariant, hence intrinsic, four-dimensional (4D) shape of an object in Minkowski spacetime. In a recent note, Matthew Davidson questions the intrinsicality of 4D shapes in SR. I show that his conclusion and the reasoning behind (...) it are in error. (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.

This comprehensive anthology draws together writings by leading philosophers on the philosophy of science. Each section is prefaced by an introductory essay from the editors, guiding students gently into the topic. Accessible and wide-ranging, the text draws on both contemporary and twentieth century sources. The readings are designed to complement Alex Rosenberg's textbook, _Philosophy of Science: A Contemporary Introduction_, but can also serve as a stand-alone volume in any philosophy of science course. Includes readings from the following leading philosophers: Achinstein, (...) Anderson, Bloor, Earman, Feyerabend, Gutting, Hanson, Hempel, Kitcher, Kuhn, Laudan, Leplin, Mackie, McMullin, Nagel, Popper, Quine, Rosenberg, Russell, Salmon, Schlick, Shapere, Van Fraassen. (shrink)

Des Jardins (1976) and Dreher (1990) have suggested that Plato's Line should be thought of as divided in the mean and extreme ('golden') ratio. I examine their arguments, as well as other reasons that could be brought up in support of the 'golden division' of the Line, and show that all of them are wanting.

Are the laws of nature real? Do they belong to the world or merely reflect the way we speak about it? And if they are real, what sort of entity are they? These questions have been intensely debated by philosophers. Modern cosmology, however, has given such questions a new twist by introducing a unique perspective on physical reality, the perspective which I shall call the cosmological point of view. In this perspective, the universe as a whole presents itself as a (...) single individual entity that undergoes a radical change with time. Laws of physics, on the other hand, have both local and global significance. They characterize how things behave locally. But they also characterize the entire universe. This suggests an interesting connection between the universe as a whole and what laws of physics hold in this universe. From the cosmological point of view, these two totalities, the laws of physics and the universe, may be related. But how exactly? Are the laws “inscribed” in the fabric of the universe or do they in some sense “precede” it in the order of being? If the latter, what is a “medium,” over and above the physical universe, in which physical laws are “written”? If the former, are they but a consequence of the universe’s very existence? And if so, how could the laws of physics survive the dramatic change the physical state of the universe underwent in the course of time? (shrink)

I had excruciating back pain last night. The next day I went to a spa and the pain disappeared. Psychologically speaking, my pain is gone. Where is it, speaking ontologically? Atheorists have an easy time here. But B-theorists who think that persons persist by enduring are in trouble. Why am I finding myself at this particular time, with this particular set of experiences, rather than at numerous other times, with different experiences, despite the fact that all times are on the (...) same ontological footing and I am wholly present at all of them? I argue that the Puzzle of the Experience of the Present is a real challenge for B-theorists, and the best way to deal with it is to adopt the stage view of persistence. (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)

Duhem's and Quine's holistic theses, when properly understood, allow methodologically responsible ways of resolving a conflict between a theoretical system and experience; they only deny the possibility of doing it in an epistemically persuasive way. By developing a "string" model of scientific tests I argue that the pattern of interaction between the elements of a theoretical system arising in response to multiple adverse data can be helpful in locating a "weak spot" in it. Combining this model with anti-holistic arguments of (...) Popper, Greenwood, and Lakatos significantly reinforces their joint power. (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.

ABSTRACT Many philosophers believe in the Block Universe containing all objects and events - those that we intuitively call past, present, and future. But some of those who endorse this ontology of time also believe that objects persist by enduring - by being present in their entirety at all moments at which they exist. This combination of views, the Block Universe with Endurance, has survived the initial assault of the problem of temporary intrinsics and of several later objections. But I (...) argue that the Block Universe with Endurance fails to account for a striking feature of our temporal experience and must be rejected in favor of the Block Universe with Exdurance. (shrink)

Neural machine translation (NMT) is one of the success stories of deep learning and artificial intelligence. Revolutionary innovations in the computational architectures made in 2015–2017 have led to dramatic improvements in the quality of machine translation (MT) and changed the field forever. Some professional translators welcome these changes with enthusiasm, others less so. But everyone has to deal with them. Historically, the relationship between human translation and MT has been uneasy and complicated, but an increasing number of players in both (...) fields are now coming to view it as synergistic. -/- OPUS-CAT is a collection of machine translation software based on a Windows implementation of Marian NMT—a stable production-ready neural machine translation framework used in many industrial and research applications. It can be installed on your PC, fine-tuned to specialized translation domains, and integrated into CAT tools. (shrink)

Our present experiences are strikingly different from past and future ones. Every philosophy of time must explain this difference. It has long been argued that A-theorists can do it better than B-theorists because their explanation is most natural and straightforward: present experiences appear to be special because they are special. I do not wish to dispute one aspect of this advantage. But I contend that the general perception of this debate is seriously incomplete as it tends to conflate two rather (...) different aspects of the phenomenon behind it, the individual and the common dimensions of the present. When they are carefully distinguished and the emerging costs of the A-theories are balanced against their benefits, the advantage disappears. (shrink)

Debates about material coincidence tend to start with common-sense intuitions but quickly leave them behind and lead to highly problematic conclusions. Reconciling the latter with common sense is the next stage in the process, which often requires revision of some of the initial beliefs and has been used to adjudicate many rather abstract and technical proposals in the metaphysics of composition and persistence, ranging from natural (constitutionalism) to radical (nihilism). -/- I have no disagreement with this overall strategy: theories do (...) need to turn abstract at some point, move beyond common sense, and eventually force upon us interesting, novel, and often counterintuitive revisions in our overall conceptual scheme. This applies to all theoretical areas, and contemporary metaphysics is no exception. But while the latter is widely regarded as being quite extreme in this respect, I want to argue that, in one sense, it is not extreme enough. I do it by developing a new case of material coincidence that is initially motivated not by common sense but by physical considerations, and is not susceptible to any of the standard solutions. -/- One lesson of science is its ability to expand our imagination beyond the limits of common sense. This may have importance for metaphysics too. (shrink)

The author’s studies in the philosophy of science, culminating in this book, were inspired by his previous research in the domains of classical and quantum gravity. In fact it was the need to bring some order in the family of modern classical theories of gravitation and to build up the appropriate conceptual foundations of quantum gravity , that forced the author to create his own methodological model of theory change, which he applies rather successfully to the most controversial case study, (...) the Lorentz-Einstein transition. (shrink)

The rapid development of natural language processing in the last three decades has drastically changed the way professional translators do their work. Nowadays most of them use computer-assisted translation or translation memory tools whose evolution has been overshadowed by the much more sensational development of machine translation systems, with which TM tools are sometimes confused. These two language technologies now interact in mutually enhancing ways, and their increasing role in human translation has become a subject of behavioral studies. Philosophers and (...) linguists, however, have been slow in coming to grips with these important developments. The present paper seeks to fill in this lacuna. I focus on the semantic aspects of the highly distributed human–computer interaction in the CAT process which presents an interesting case of an extended cognitive system involving a human translator, a TM tool, an MT engine, and sometimes other human translators or editors. Considered as a whole, such a system is engaged in representing the linguistic meaning of the source document in the target language. But the roles played by its various components, natural as well as artificial, are far from trivial, and the division of linguistic labor between them throws new light on the familiar notions that were initially inspired by rather different phenomena in the philosophy of language, mind, and cognitive science. (shrink)

Are the laws of nature real? Do they belong to the world or merely reflect the way we speak about it? If they are real, what sort of entity are they? This study contributes to the ongoing discussion of these questions by emphasizing the importance of a cosmological perspective on them. I argue that the evidence coming from modern evolutionary cosmology presents difficulties for certain currently fashionable philosophical accounts of laws, in particular, for the Dretske-Tooley-Armstrong theory. I defend, in light (...) of this evidence, the idea of laws as grounded in irreducible nomic properties of basic objects and examine its cosmological implications and consequences for the philosophy of modality. ;If the laws of nature are real, they must represent an integral aspect of the universe as a whole. From a cosmological point of view, these two totalities, the laws of nature and the universe, may be related. I begin by showing that a concern about the consequences of such possible relationship was an important factor in the historical rivalry between the steady-state and big bang cosmologies . ;The cosmological perspective on laws has still more striking implications in the context of the contemporary interplay between big-bang cosmology and high energy physics in the effort to understand the processes at work during the first moments of cosmic evolution. In a sense, the evolution of the physical state of the universe as a whole may have "carried" with it the evolution of certain nomic properties of matter. I contend that this poses problems for some nomic ontologies, such as the relations-between-universals theory, and favors the view of laws as grounded in causal powers of particulars. I show how the universe of causally powerful basic substances provides a natural framework for an interesting sense of modality characteristic of laws and how this illuminates the notoriously difficult problems of essential properties and natural kinds. (shrink)

Cosmology as Weltanschauung is as old as the world. Cosmology as a physical discipline, however, is a child of this century, born in 1917, when Albert Einstein and Willem de Sitter first applied the theory of general relativity to the space-time of the entire universe. When did the child come of age and become a fully-fledged science? A popular myth shared by many practitioners holds that this did not happen until 1965, when the discovery of the 2.7K cosmic microwave background (...) radiation validated the concept of the hot big bang. Earlier accomplishments culminating in the 1965 event include the derivation of evolving relativistic models by Alexander Friedmann and George Lemaître, Edwin Hubble’s discovery of the redshift-magnitude relationship and George Gamow’s theory of the primordial nucleosynthesis containing the prediction of the microwave background left from the hot and dense past of the universe. This linear development is thrown into sharper relief in textbooks, by referring to an inarticulate.. (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)

I examine the issue of persistence over time in the context of the special theory of relativity (SR). The four-dimensional ontology of perduring objects is clearly favored by SR. But it is a different question if and to what extent this ontology is required, and the rival endurantist ontology ruled out, by this theory. In addressing this question, I take the essential idea of endurantism, that objects are wholly present at single moments of time, and argue that it commits one (...) to unacceptable conclusions regarding coexistence, in the context of SR. I then propose and discuss a plausible account of coexistence for perduring 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 help the endurantist out. She can accommodate the notion of coexistence in the relativistic framework only at the cost of renouncing central endurantist intuitions. (shrink)