Relativity theory is often said to support something called ‘the four-dimensional view of reality’. But there are at least three different views that sometimes go by this name. One is ‘spacetime unitism’, according to which there is a spacetime manifold, and if there are such things as points of space or instants of time, these are just spacetime regions of different sorts: thus space and time are not separate manifolds. A second is the B-theory of time, according to which the (...) past, present, and future are all equally real and there is nothing metaphysically special about the present. A third is perdurantism, according to which persisting material objects are made up of different temporal parts located at different times. We sketch routes from relativity to unitism and to the B-theory. We then discuss some routes to perdurantism, via the B-theory and via unitism. (shrink)

How should we account for the extraordinary regularity in the world? Humeans and Non-Humeans sharply disagree. According to Non-Humeans, the world behaves in an extraordinarily regular way because of certain necessary connections in nature. However, Humeans have thought that Non-Humean views are metaphysically objectionable. In particular, there are two general metaphysical principles that Humeans have found attractive that are incompatible with all existing versions of Non-Humeanism. My goal in this paper is to develop a novel version of Non-Humeanism that is (...) consistent with (and even entails) both of these general metaphysical principles. By endorsing such a view, one can have the explanatory benefits of Non-Humeanism while at the same time avoiding two of the major metaphysical objections towards Non-Humeanism. (shrink)

The notion of multiple location plays an important role in the characterization of endurantism. Several authors have recently offered cases intended to demonstrate the incoherence of multiple location. I argue that these cases do not succeed in making multiple location problematic. Along the way, several crucial issues about multiple location and its use by endurantists are clarified.

According to one of the more popular endurantist packages on the market, a package I will call multilocational endurantism, enduring objects are exactly located at multiple instantaneous regions of spacetime. However, for all we know, the world might turn out to be spatiotemporally gunky and spatiotemporal gunk entails that this package is false. The goal of this paper is to sketch a view which retains the spirit of multilocational endurantism while also recognizing the possibility of certain types of objects which (...) endure through gunk. (shrink)

John Bell proposed an ontology for the GRW modification of quantum mechanics in terms of flashes occurring at space- time points. This article spells out the motivation for this ontology, inquires into the status of the wave function in it, critically examines the claim of its being Lorentz invariant, and considers whether it is a parsimonious but nevertheless physically adequate ontology.

Endurantists have recently faced a mereological puzzle in various forms. Here I argue that, instead of presenting a genuine worry, the puzzle actually reveals a common misunderstanding about the endurantist ontology. Furthermore, through this discussion of the alleged problem and the misunderstanding which motivates it, I reveal metaphysical commitments the endurantist has that may not be widely recognized. For instance, she is committed to interesting and perhaps controversial views about shape and location. I highlight these commitments and what they mean (...) for the endurantist. (shrink)

Endurantism, the view that material objects are wholly present at each moment of their careers, is under threat from supersubstantivalism, the view that material objects are identical to spacetime regions. I discuss three compromise positions. They are alike in that they all take material objects to be composed of spacetime points or regions without being identical to any such point or region. They differ in whether they permit multilocation and in whether they generate cases of mereologically coincident entities.

This book defends a relational theory of the passage of time. The realist view of passage developed in this book differs from the robust, substantivalist position. According to relationism, passage is nothing over and above the succession of events, one thing coming after another. Causally related events are temporally arranged as they happen one after another along observers’ worldlines. There is no unique global passage but a multiplicity of local passages of time. After setting out this positive argument for relationism, (...) the author deals with five common objections to it: (a) triviality of deflationary passage, (b) a-directionality of passage, (c) the impossibility of experiencing passage, (d) fictionalism about passage, and (e) the incompatibility of passage with perduring objects. (shrink)

The paper provides a new and detailed critique of Barker and Dowe’s argument against multi-location. This critique is not only novel but also less committal than previous ones in the literature in that it does not require hefty metaphysical assumptions. The paper also provides an analysis of some metaphysical relations between mereological and locational principles.

Ned Markosian has recently defended a new theory of composition, which he calls regionalism : some material objects xx compose something if and only if there is a material object located at the fusion of the locations of xx. Markosian argues that regionalism follows from what he calls the subregion theory of parthood. Korman and Carmichael agree. We provide countermodels to show that regionalism does not follow from, even together with fourteen potentially implicit background principles. We then show that regionalism (...) does follow from five of those background principles together with and two additional principles connecting parthood and location, which we call and. While the additional principles are not uncontroversial, our conjecture is that many will find them attractive. We conclude by mentioning that fills a previously unnoticed gap in the formal theory of location presented in Parsons. (shrink)

I argue that four-dimensionalism and the desire satisfaction account of well-being are incompatible. For every person whose desires are satisfied, there will be many shorter-lived individuals (‘person-stages’ or ‘subpersons’) who share the person’s desires but who do not exist long enough to see those desires satisfied; not only this, but in many cases their desires are frustrated so that the desires of the beings in whom they are embedded as proper temporal parts may be fulfilled. I call this the frustrating (...) problem for four-dimensionalism. In the first half of the paper I lay the groundwork for understanding the frustrating problem, and then in the second half, I will examine six possible responses to the frustrating problem on behalf of the four-dimensionalist, (i) the Parfit (1984) inspired claim that identity is not what matters, (ii) the personal pronoun revisionism of Noonan (2010), (iii) the indirect concern account of Hudson (2001), (iv) the sensible stages account of Lewis (1986), (v) a multiple-concepts account of desire satisfaction, and (vi) a No Desire View according to which subpersons have no mental states and thus no desires to frustrate. I argue that none of these solutions will help the four-dimensionalist; she does better to reject the desire satisfaction theory, while the defender of the desire satisfaction theory does better to reject four-dimensionalism. (shrink)

I argue for a four dimensional, non-dynamical view of space-time, where becoming is not an intrinsic property of reality. This view has many features in common with the Parmenidean conception of the universe. I discuss some recent objections to this position and I offer a comparison of the Parmenidean space-time with an interpretation of Heraclitus’ thought that presents no major antagonism.

This article provides a new context for an established metaphysical debate regarding the problem of persistence. I contend that perdurance, a popular view about persistence which maintains that objects persist by having temporal parts, can be formulated in quantum mechanics due to the existence of a formal analogy between temporal and spatial location. However, this analogy fails due to a ‘no-go’ result which demonstrates that quantum systems cannot be said to have temporal parts in the same way that they have (...) spatial parts. Therefore, if quantum mechanics describes persisting physical objects then those objects cannot be said to perdure. (shrink)

Eternalism is the view that the past, the present and the future exist simpliciter. A typical argument in favor of this view leans on the relativity of simultaneity. The ‘equally real with’ relation is assumed to be transitive between spacelike separated events connected by hyperplanes of simultaneity. This reasoning is in tension with the conventionality of simultaneity. Conventionality indicates that, even within a specific frame, simultaneity is based on the choice of the synchronization parameter. Hence the argument for eternalism is (...) compromised. This paper lays out alternative eternalist strategies which do not hinge on hyperplanes. While we lack a rigorous proof for eternalism, there are still cogent reasons to prefer eternalism over presentism. (shrink)

In a number of papers, Kit Fine introduced a theory of embodiment which distinguishes between rigid and variable embodiments, and has been successfully applied to clarify the ontological nature of entities whose parts may or may not vary in time. In particular, he has applied this theory to describe a process such as the erosion of a cliff, which would be a variable embodiment whose manifestations are the different states of erosion of the cliff. We find this theory very powerful, (...) and especially appropriate to capture the intuition that the same process may go on at different times. However, its formal principles have been subject to some criticisms, mainly concerning the mereological structure of a variable embodiment. Moreover, since the notion of variable embodiment is very general, simply saying that processes are variable embodiments is not enough to understand their ontological nature. To address these concerns, in this paper we proceed in two phases: first, we propose a revised version of Fine’s original theory adapted to the case of processes, which adopts a classical mereology instead of Fine’s hylomorphic mereology, and a temporalized constitution relation in place of Fine’s function of variable embodiment; second, we go deeper into the ontological nature of processes by revisiting the notions of homogeneity, intentionality, and telicity discussed in the literature, and propose an account based on ontological principles and not on semantic properties of predicates. This allows us to organize processes into a novel taxonomy based exclusively on their unity and individuation principles. (shrink)

The paper presents a thorough exploration of the problem of persistence in a relativistic context. Using formal methods such as mereology, formal theories of location and the so called intrinsic formulation of special relativity we provide a new, more rigorous and more comprehensive taxonomy of persisting entities. This new taxonomy differs significantly from the ones that are present in the recent literature.

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)

When do objects at different times compose a further object? This is the question of diachronic composition. The universalist answers, ‘under any conditions whatsoever’. Others argue for restrictions on diachronic composition: composition occurs only when certain conditions are met. Recently, some philosophers have argued that restrictions on diachronic compositions are motivated by our best physical theories. In Persistence and Spacetime and elsewhere, Yuri Balashov argues that diachronic compositions are restricted in terms of causal connections between object stages. In a recent (...) article, Nikk Effingham argues that the standard objections to views that endorse restrictions on composition do not apply to a view that restricts composition according to compliance with the laws of nature. On the face of it, such restrictions on diachronic composition preserve our common-sense ontology while eliminating from it scientifically revisionary objects that travel faster than the speed of light. I argue that these attempts to restrict diachronic composition by appealing to either causal or nomological constraints face insurmountable difficulties within the context of special relativity. I discuss how the universalist should best respond to Hudson’s argument for superluminal objects, and in doing so, I present and defend a new sufficient condition for motion that does not entail that such objects are in superluminal motion. 1 Introduction2 Diachronic Composition3 Diachronic Composition and Superluminal Objects4 Restricting Diachronic Composition5 Causal and Nomological Restrictions on Composition in a Relativistic Context6 Superluminal Objects and Motion7 Conclusion. (shrink)

Traynor identifies a tension between armchair reasoning telling us about the mereological structure of objects and empirical investigation telling us about the structure of spacetime. Section 1 explains, and bolsters, that tension. Section 2 discusses Traynor's resolution, and suggests some possible problems with it, whilst Section 3 discusses an alternative.

In this paper we describe a novel approach to defining an ontologically fundamental notion of co-presentness that does not go against the tenets of relativity theory. We survey the possible reactions to the problem of the present in relativity theory, introducing a terminological distinction between a static role of the present, which is served by the relation of simultaneity, and a dynamic role of the present, with the corresponding relation of co-presentness. We argue that both of these relations need to (...) be equivalence relations, but they need not coincide. Simultaneity, the sharing of a temporal coordinate, need not have fundamental ontological import, so that a relativizing strategy with respect to simultaneity seems promising. The notion of co-presentness, on the other hand, does have ontological import, and can therefore not be relativized to an observer or to an arbitrarily chosen frame. We argue that a formal representation of indeterminism can provide the structure needed to anchor the relation of co-presentness, and that this addition is in fact congenial to the notion of dynamic time as requiring real change. The resulting picture is one of an extended dynamic present, implying a formal distinction between static simultaneity and dynamic co-presentness. After working out the basics of our approach in the simpler framework of branching time, we provide our full analysis in the framework of branching space-times, which allows for a formal definition of modal correlations. The spatial extension of the dynamic present can reach as far as the modal correlations do. In the limit, the dynamic present could extend across a maximal space-like hypersurface. (shrink)

I argue against the claim -- advocated by Albert Einstein, Bernard Williams, and Ted Sider, among others -- that a description is objective only if it says how the world is in itself. Instead, I argue for the claim -- inspired by comments of Niels Bohr -- that a family of descriptions is objective only if they co-vary with their respective descriptive contexts. Moreover, I claim that "there is a shared objective reality" simply means that it is possible to satisfy (...) this kind of covariance requirement. (shrink)

The arrow paradox is an argument purported to show that objects do not really move. The two main metaphysics of motion, the At–At theory of motion and velocity primitivism, solve the paradox differently. It is argued that neither solution is completely satisfactory. In particular it is contended that there are no decisive arguments in favor of the claim that velocity as it is constructed in the At–At theory is a truly instantaneous property, which is a crucial assumption to solve the (...) paradox. If so the At–At theory faces the threat that most of our physical theories turn out to be non-Markovian. Finally it is considered whether all those threats and paradoxes are dispelled if only a new metaphysics of persistence is taken into account, namely four-dimensionalism. (shrink)

In this paper, we address an infamous argument against divisibility that dates back to Zeno. There has been an incredible amount of discussion on how to understand the critical notions of divisibility, extension, and infinite divisibility that are crucial for the very formulation of the argument. The paper provides new and rigorous definitions of those notions using the formal theories of parthood and location. Also, it provides a new solution to the paradox of divisibility which does not face some threats (...) that can possibly undermine the standard Lebesgue measure solution to such a paradox. (shrink)

It is notoriously difficult to define Metaphysics1, its content, its method, its language, its scope. Thus I will not even try an attempt here. I will rest content to point out some widely held characterizations. A long and highly influential tradition maintains that Metaphysics is the study of being qua being. It is concerned with what there is, what kind of things are the things that there are, what properties do they have, how they are related. In this sense Metaphysics (...) deals with the more general features of reality, the most fundamental categories of being. Call this tradition General Metaphysics. (shrink)

G. F. Stout is famous as an early twentieth century proselyte for abstract particulars, or tropes as they are now often called. He advanced his version of trope theory to avoid the excesses of nominalism on the one hand and realism on the other. But his arguments for tropes have been widely misconceived as metaphysical, e.g. by Armstrong. In this paper, I argue that Stout’s fundamental arguments for tropes were ideological and epistemological rather than metaphysical. He moulded his scheme to (...) fit what is actually given to us in perception, arguing that our epistemic practices would break down in an environment where only universals were given to us. (shrink)

Nel nostro universo, qualunque cosa, dalla più piccola particella alla più smisurata galassia, esiste in un qualche tempo e in un qualche luogo. Ma cosa significa esistere in un qualche tempo? Il fenomeno dell’esistenza temporale gioca un ruolo fondamentale nella comprensione dell’universo e di noi stessi quali creature temporali. Eppure è un fenomeno profondamente misterioso. L’esistenza temporale è da intendersi come una relazione? Che legami ha con l’esistenza dell’ontologia? L’esistenza temporale e la localizzazione spaziale sono due fenomeni essenzialmente differenti o (...) due istanze di un’unica relazione? Tutto ciò che esiste nel tempo esiste nel tempo nello stesso modo? Tutto ciò che è nel tempo è anche nello spazio? (shrink)

Space and time are two obvious candidates as dimensions of reality. Yet, are they the only two dimensions of reality? Famously, David Lewis maintained the doctrine of ―modal realism‖, the thesis that possible worlds exist and are entities as concrete as the actual world that we live in. In this paper, I will explore the idea that modality can be construed as a dimension along with space and time. However, although Lewis‘ modal realism is the main source of inspiration for (...) this construal of modality, I will argue that something else is required for having a modal dimension. (shrink)

Thing ontologies are ontologies that consider the universe to be made up of a plurality of discrete objects. Non-thing ontologies can take the form of ontologies of discrete objects, too, but not necessarily so: they can also be conceived as ontologies of one continuous object. The paper considers the central versions of ontologies of discrete objects first, starting with thing ontologies, moving from there to non-thing ontologies of discrete objects and finally ontologies of one continuous object.