In this dissertation I provide a tenseless account of tensed sentences and tensed belief. I begin by distinguishing tensed theories of time from tenseless theories of time. Tensed theories of time hold that there is a time that is objectively present, and that the moment that is objectively present changes from one moment to the next. I reject tensed theories of time. I deny that there is a time that is objectively present that changes from one moment to the next. (...) Instead, time is in many ways analogous to space and 'now' is in many ways analogous to 'here'. Just as there is no one location that is objectively here, there is no one moment that is objectively now. Nothing metaphysically distinguishes the present moment from past and future moments. ^ There are two major challenges facing the tenseless theory of time. The first challenge is: can a tenseless theory of time provide a plausible account of the truth-conditions for tensed sentences? Tensed sentences such as 'The meeting is now!' provide a prima facie reason in favor of irreducibly tensed properties: the sentence is true if and only if the meeting has the tensed property of being now. I examine existing attempts by tenseless theorists for providing tenseless truth-conditions for tensed sentences. I argue that they are unable to provide a complete account of what makes tensed sentences true. I formulate and defend a new tenseless account of the truth-conditions for tensed sentences, the type-context theory, which makes use of David Kaplan's theory of indexicals. ^ The second challenge facing the tenseless theory of time is: can a tenseless theory of time provide a plausible account of our tensed psychological attitudes? Most of our psychological attitudes such as belief, desire, relief, regret and anticipation are irreducibly tensed: we cannot adequate describe such attitudes without appealing to tensed language. I do not take relief in the tenseless fact that I got my wisdom teeth out in 1998. I take relief in the tensed fact that my wisdom teeth were extracted in the past. I do not run to the bus stop merely because I believe that the bus arrives at 8:45. I run to the bus stop because I believe that the bus is arriving now. How can the tenseless theory of time explain the central role that tense plays in our psychological attitudes? I claim that the objects of tensed beliefs are properties. The account I defend is a version of the self-ascription accounts defended by Roderick Chisholm and David Lewis. I argue that such a view can provide a plausible tenseless account of tensed belief. ^. (shrink)

The article concerns two axiom systems of Słupecki for the functionally complete three-valued propositional logic: W1–W6 and A1–A9. The article proves that both of them are inadequate—W1–W6 is semantically incomplete, on the other hand, A1–A9 governs a functionally incomplete calculus, and thus, it cannot be a semantically complete axiom system for the functionally complete three-valued logic.

In this book, Alston articulates and argues for a use-based and normative account of sentence meaning. He proposes that sentence meaning consists in illocutionary act potential, the usability of a sentence for the performance of a certain illocutionary act type. This potential is itself explained in terms of illocutionary rules, normative rules governing the acceptable use of sentences.

A-theorists think there is a fundamental difference between the present and other times. This concern shows up in what kinds of properties they take to be instantiated, what objects they think exist and how they formalize their views. Nearly every contemporary A-theorist assumes that her metaphysics requires a tense logic – a logic with operators like and. In this paper, I show that there is at least one viable A-theory that does not require a logic with tense operators. And I (...) will argue that three common indispensability arguments for tense operators are unsound. (shrink)

Analytic metaphysics is in resurgence; there is renewed and vigorous interest in topics such as time, causation, persistence, parthood and possible worlds. We who share this interest often pay lip-service to the idea that metaphysics should be informed by modern science; some take this duty very seriously.2 But there is also a widespread suspicion that science cannot really contribute to metaphysics, and that scientific findings grossly underdetermine metaphysical claims. For some, this prompts the thought ‘so much the worse for metaphysics’; (...) others mutter ‘so much the worse for science’. (shrink)

Since J. McTaggart’s paper on “The Unreality of Time” the opposition of “A-theorists” and “B-theorists” establishes a focal point in the modern debate on the metaphysics of time: While “A-theorists” claim the existence of an objective present, moving along time positions, “B-theorists” maintain that time is just a set of ontologically equivalent coordinates, “now” being merely the indexical of the speaker’s position. Contemporary attempts to resolve the issue by resorting to the analysis of language or to the theory of science (...) seem to deliver no definite results. By contrast, practical and existential aspects of the two models promise to be more univocal guides in deciding between them. Particularly, C. D. Broad’s hybrid conception of a “growing block theory” attains special attractiveness in this regard. (shrink)

This paper motivates and develops a new theory of time: priority presentism. Priority presentism is the view according to which (i) only present entities exist fundamentally and (ii) past and future entities exist, but they are grounded in the present. The articulation of priority presentism is an exercise in applied grounding: it draws on concepts from the recent literature on ontological dependence and applies those concepts in a new way, to the philosophy of time. The result, as I will argue, (...) is an attractive position that can do much of the same work in satisfying our intuitions about time as presentism, but without the ontological cost. (shrink)

A‐theorists of time postulate a deep distinction between the present, past and future. Settling on an appropriate logic for such a view is no easy matter. This Philosophy Compass article describes one of the most vexing formal problems facing A‐theorists. It is commonly thought that A‐theories can only be formally expressed in a tense logic: a logic with operators like P and F . And it seems natural to think that we live in a world where objects come to exist (...) and cease to exist as time passes. Indeed, this is typically a key component of the most prominent kind of A‐theory, presentism. But the temporary existence assumption cannot be upheld in any tense logic with a standard quantification theory. I will explain the problem and outline the philosophical and logical considerations that generate it. I will then consider two possible solutions to the problem – one that targets our logic of quantification and one that targets our assumptions about change. I survey the costs of each solution. (shrink)

In his review of The Ontology of Time, Thomas Crisp (Notre Dame Philosophical Reviews, 2005a ) argues that Oaklander's version of McTaggart's paradox does not make any trouble for his version of presentism. The aim of this paper is to refute that claim by demonstrating that Crisp's version of presentism does indeed succumb to a version of McTaggart's argument. I shall proceed as follows. In Part I I shall explain Crisp's view and then argue in Part II that his analysis (...) of temporal becoming, temporal properties and temporal relations is inadequate. Finally, in Part III, I shall demonstrate that his presentist ontology of time is susceptible to the paradox he so assiduously sought to avoid. (shrink)

We use a new, distinctly “geometrical” interpretation of non-relativistic quantum mechanics (NRQM) to argue for the fundamentality of the 4D blockworld ontology. We argue for a geometrical interpretation whose fundamental ontology is one of spacetime relations as opposed to constructive entities whose time-dependent behavior is governed by dynamical laws. Our view rests on two formal results: Kaiser (1981 & 1990), Bohr & Ulfbeck (1995) and Anandan, (2003) showed independently that the Heisenberg commutation relations of NRQM follow from the relativity of (...) simultaneity (RoS) per the Poincaré Lie algebra. And, Bohr, Ulfbeck & Mottelson (2004a & 2004b) showed that the density matrix for a particular NRQM experimental outcome may be obtained from the spacetime symmetry group of the experimental configuration. This shows how the blockworld view is not only consistent with NRQM, not only an implication of our geometrical interpretation of NRQM, but it is necessary in a non-trivial way for explaining quantum interference and “non-locality” from the spacetime perspective. Together the formal results imply that contrary to accepted wisdom, NRQM, the measurement problem and so-called quantum non-locality do not provide reasons to abandon the 4D blockworld implication of RoS. But rather, the deep non-commutative structure of the quantum and the deep structure of spacetime as given by the Minkowski interpretation of special relativity (STR) are deeply unified in a 4D spacetime regime that lies between Galilean spacetime (G4) and Minkowski spacetime (M4). Taken together the aforementioned formal results allow us to model NRQM phenomena such as interference without the need for realism about 3N Hilbert space, establishing that the world is really 4D and that configuration space is nothing more than a calculational device. Our new geometrical interpretation of NRQM provides a geometric account of quantum entanglement and so-called non-locality free of conflict with STR and free of interpretative mystery. In section 2 we discuss the various tensions between STR and NRQM with respect to the dimensionality of the world. Section 3 is devoted to an explication of the Kaiser et al. results and their philosophical implications. Likewise, the Bohr et al. results and their implications are the subject of section 4. In section 5, we present our geometric interpretation of quantum entanglement and “non-locality.”. (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 -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)

There is an eminent tradition of thought that sees in the phenomenon of time something contradictory. This tradition has been recently revived by some contemporary proponents of dialethism – the view that there are true contradictions. In this paper, I will contribute to this line of thinking by tracing the first steps of a dialethic account of time-consciousness. In particular, I will argue that the experiential flow of time can be accounted for in the framework of an intentionalist approach to (...) temporal perception if we conceive of time-consciousness as a quasi-multiplicity, i.e., a multiplicity of non-self-identical parts, hence the embrace of dialethism. Section 1 introduces dialethism, discusses Priest's dialethic theory of motion and time, and motivates the project of a dialethic account of time-consciousness. Section 2 introduces the intentionalist approach to time-consciousness and distinguishes pure intentionalism from sense-data intentionalism; both subscribes to a certain Principle of Simultaneous Awareness but interprets it differently. In Sect. 3, I offer an in-depth analysis of this principle and identify its core as the requirement of self-unification, i.e., the requirement that time-consciousness unifies itself in flowing without any higher-order act of unification. Section 4 then argues that pure intentionalism can satisfy this requirement by embracing dialethism. I conclude by noting how the dialethic account of time-consciousness incorporates a central extensionalist insight within an intentionalist outlook. (shrink)

In this paper I argue that the growing block theory of time has rather surprising, and hitherto unexplored, explanatory benefits when it comes to certain enduring philosophical puzzles concerning death. In particular, I claim the growing block theorist has readily available and convincing answers to the following questions: Why is it an evil to be dead but not an evil to be not yet born? How can death be an evil for the dead if they no longer exist to suffer (...) it? When is death an evil for the one who dies? The ability to give such answers is a significant, but by no means decisive, advantage for the growing block view of time. (shrink)

A temporal levels structure for temporal metaphysics is outlined and employed to convey a dilemma threatening the temporal collapse of Growing-Block Theories to their meta-temporal level. The outline further explains how Presentism occupies a privileged position in that temporal levels structure. Moreover, that dilemma relies crucially on the acceptance of productive causation as explaining additions to the growing block, for which it is argued any reasonable growing-block theory should incorporate. The dilemma’s first horn considers growing-block theories where productive causes are (...) only so when present; the second, growing-block theories where productive causes continue being so when past. Either way, growing-block theory collapses into Accruing-Present Theory: whereby all entities survive into succeeding present “blocks” of existents. It is argued, the presentness of surviving entities undermines their intended theoretical role, undercutting motivations for believing accruing-present theses. Ultimately, I recommend rejection of both growing-block and accruing-present theses based on these explanatory inadequacies. (shrink)

This essay offers a reading of a difficult passage in the first book of Lucretius' "De Rerum Natura" in which the poet first explains the Epicurean account of time and then responds to a worry about the status of the past (1.459-82). It identifies two possible readings of the passage, one of which is compatible with the claim that the Epicureans were presentists about the past. Other evidence, particularly from Cicero "De Fato", suggests that the Epicureans maintained that all true (...) assertions must have a contemporaneous truth-maker and that no contingent future-tensed assertions are true. It appears, however, that they did not assert a symmetrical view of past-tensed assertions. There is no compelling reason, therefore, to think that the Epicureans were presentists about the past. (shrink)

Presentism is held by most to be the intuitive theory of time, due in large part to the view's supposed preservation of time's passage. In this paper, I strike a blow against presentism's intuitive pull by showing how the presentist, contrary to overwhelming popular belief, is unable to establish temporal change upon which the passage of time is based. I begin by arguing that the presentist's two central ontological commitments, the Present Thesis and the Change Thesis, are incompatible. The main (...) problem is that satisfying the Change Thesis to establish passage requires the existence of more than one moment. This conflicts with the Present Thesis that only the present moment exists. The presentist's response is to appeal to surrogates to stand proxy for the past, so as to account for the difference between what does exist and what did exist. I argue that, for this surrogate strategy to be successful, the proposed surrogates must track what actually happened. I demonstrate that there is no guarantee that t.. (shrink)

There is an old but powerful argument for the claim that exhaustive divine foreknowledge is incompatible with the freedom to do otherwise. A crucial ingredient in this argument is the principle of the “Fixity of the Past”. A seemingly new response to this argument has emerged, the so-called “dependence response,” which involves, among other things, abandoning FP for an alternative principle, the principle of the “Fixity of the Independent”. This paper presents three arguments for the claim that FI ought to (...) be preferred to FP. (shrink)

Investigation into the reality of time can be pursued within the ontological domain or it can also span human thought and natural language. I propose to approach time by correlating three domains of inquiry: metaphysical time, the human concept of time, and temporal reference in natural language, entertaining the possibility of what I call a ‘horizontal reduction’ and ‘vertical reduction’. I present a view of temporalityL/E as epistemic modality, drawing on evidence from the L domain and its correlates in the (...) E and M domains. On this view, the human concept of time is a complex, ‘molecular’ concept and can be broken down into primitive concepts that are modal in nature, featuring as degrees of epistemic commitment to representations of states of affairs. I present evidence from tensed and tenseless languages and point out its compatibility with the view of real time as metaphysical modality. (shrink)

Argument for fatalism attempts to prove that free choice is a logical or conceptual impossibility. The paper argues that the first two premises of the argument are sound: propositions are either true or false and they have their truth-value eternally. But the claim that from the fatalistic premises with the introduction of some innocent further premise dire consequences follow as regards to the possibility of free choice is false. The introduced premise, which establishes the connection between the first two premises (...) (which are about the nature of propositions) and the concept of free choice is not innocent. It creates the impression that the truth of certain propositions can somehow determine the occurrence of certain events. But no proposition can have such an effect since the counterfactuals If proposition P were true, event E would happen does not say anything about determination. The argument for fatalism is, however, not a boring sophism. It does reveal something about the nature of propositional representation. It shows that each proposition represents necessarily the fact what it represents, i.e. it shows that propositions have their truth conditions non-contingently. But from this nothing follows as regards to the contingent nature of the facts represented. On the bases of the first two premises of the argument for fatalism we cannot infer to the impossibility of free choice. The argument for fatalism should not be interpreted as an attempt to prove on purely logical or conceptual grounds that we do not have the ability to influence future events by our choices. But it could be used to show something about the nature of propositional representation. (shrink)

La relación entre el problema de la temporalidad del valor y el de nuestra persistencia diacrónica prácticamente no ha sido explorada hasta ahora. Sin embargo, el análisis de cada una de estas cuestiones puede arrojar luz sobre la otra de manera interesante. Este artículo argumentará que las conexiones entre la asimetría de nuestras actitudes hacia el futuro y el pasado, y la cuestión de nuestra persistencia diacrónica pueden defenderse sin incurrir en modo alguno a una petición de principio. The relation (...) between the problem of the temporality of value and the problem of our diachronic persistence has virtually not been explored so far. However, the analysis of these questions can shed light on each other in an interesting way. This paper argues that an explanation of the connections between the asymmetry of our attitudes towards the future and the past and the question of our diachronic persistence is possible without begging the question in any way. (shrink)

In this paper, I defend a theory of local temporality, sometimes referred to as a point-present theory. This theory has the great advantage that it allows for the possibility of an open future without requiring any alterations to our standard understanding of special relativity. Such theories, however, have regularly been rejected out of hand as metaphysically incoherent. After surveying the debate, I argue that such a transformation of temporal concepts (i) is suggested by the indexical semantics of tense in a (...) relativistic universe, (ii) when properly understood easily withstands the usual accusations of metaphysical incoherence and (iii) leads naturally to a meta-philosophical position from which we can understand and escape the increasing sterility of debates between radical Parmenideans and radical Heracliteans in the philosophy of time. (shrink)

I argue that Mumford and Anjum’s recent theory of simultaneous causation among powerful meso-level objects is problematic in several respects: it is based on a false dichotomy, it is incompatible with standard meso-level physics, it is explanatory deficient, and it threatens to render the powers metaphysics incoherent. Powers theorists are advised, therefore, to adopt a purely sequential conception of causation.

Relativity allegedly contradicts presentism, the dynamic view of time and reality, according to which temporal passage is conceived of as an existentially distinguished ‘moving’ now. Against this common belief, the paper motivates a presentist interpretation of spacetime: It is argued that the fundamental concept of time—proper time—cannot be characterized by the earlier-later relation, i.e., not in the B-theoretical sense. Only the presentist can provide a temporal understanding of the twins’ paradox and of universes with closed timelike curves.

It is plausible that every true representation is made true by something in the world beyond itself. I believe that a simple fact is the truthmaker of each true proposition. Simple facts are not familiar entities. This lack of familiarity might lead many to regard them with suspicion, to think that including them in one’s ontology is an ad hoc maneuver. Although such suspicion is warranted initially, it is, I believe, ultimately unfounded. In this paper, I first present what I (...) take to be the simplest argument for simple facts. I then clarify what a simple fact is supposed to be by elucidating the way in which such entities are simple and elaborating an account of their nature. The simplest argument for simple facts relies on a premise that is deeply plausible and yet not uncontroversial, so I present a second argument that forgoes this premise. The second argument is more subtle—and shows the relevance to this discussion of unity from complexity, a metaphysical notion of profound importance—and yet leads to the same conclusion: simple facts exist. I end by considering some concerns one might have regarding the existence of simple facts or the fundamental role that I maintain they have in making true our thoughts and claims about the world. (shrink)

There are two extant versions of the new tenseless theory of time: the date versionand the token-reflexive version. I ask whether they are equivalent, and if not, whichof them is to be preferred. I argue that they are not equivalent, that the date version isunsatisfactory, and that the token-reflexive version is correct. I defend the token-reflexive version against a string of objections from Quentin Smith. My defence involves a discussion of the ontological and semantic significance of truth conditions, and of (...) the connection between truth and reality on the one hand, and that between truth and meaning on the other. I argue that Smith's objections to the token-reflexive theory stem from his confusing these two aspects of the notion of truth. (shrink)

My goal in this paper is to address what I call the ‘Incoherence’ objection to the growing universe theory of time. At the root of the objection is the thought that one cannot wed objective temporal becoming with the existence of a tenseless past—which is apparently what the growing universe theorist tries to do. To do so, however, is to attribute both dynamic and static aspects to time, and, given the mutual exclusivity of these two aspects—so the thought goes—incoherence results. (...) My solution to the problem is to offer an alternative account of past existence that is compatible with a dynamic conception of time. I take as my starting point Adams’ suggestion that the past exists in virtue of the existence of thisnesses of past individuals. I first seek to defend this suggestion, before amending it in order to provide a satisfactory response to the Incoherence objection. The result is a new growing universe theory which avoids the Incoherence objection but which has some surprising features of its own. Chief among these is the rejection of present events. I argue, however, that such a rejection is a necessary consequence of endorsing the growing universe theory, and that it is not as counter-intuitive as it initially sounds. (shrink)

In this paper, I argue that there is an inconsistency between two presentist doctrines: that of ontological symmetry and asymmetry of fixity. The former refers to the presentist belief that the past and future are equally unreal. The latter refers to the A-Theoretic intuition that the past is closed or actual, and the future is open or potential. My position in this paper is that the presentist is unable to account for the temporal asymmetry that is so fundamentally a part (...) of her theory. In Section I, I briefly outline a recent defence of presentism due to Craig, and argue that a flaw in this defence highlights the tension between the presentist's doctrines of ontological symmetry and asymmetry of fixity. In Section II, I undertake an investigation, on the presentist's behalf, in order to determine whether she is capable of reconciling these two doctrines. In the course of the investigation, I consider different asymmetries, other than that of ontology, which might be said fundamentally to constitute temporal asymmetry, and the asymmetry of fixity in particular. In Section III, I also consider whether the presentist is able to avail herself of some of the standard B-Theoretic accounts of the asymmetry of fixity, and argue that she cannot. Finally, I conclude that temporal asymmetry cannot be accounted for (or explained) other than through the postulation of an ontological asymmetry. (shrink)

Time, along with concepts as space and matter, is bound to be a central concept of any physical theory. The chapter first discusses how time is treated similarly in quantum and classical theories. It then provides a few references on time‐reversal. The chapter discusses three chosen authors' (Paul Busch, Jan Hilgevoord and Jos Uffink) clarifications of uncertainty principles in general. Next, the chapter follows Busch in distinguishing three roles for time in quantum physics. They are external time, intrinsic time and (...) observable time. It also provides a brief discussion on time operators, in particular Pauli's influential proof. Finally, the chapter talks about time‐energy uncertainty principles with intrinsic times. (shrink)

It is argued that acceptance of determinism sits badly with the way we use counterfactual conditionals when considering gains and losses in light of how things would have been if such‐and‐such had or had not happened; it is further suggested that one type of indeterminism runs into the same difficulty; also that the difficulty may escape notice through failure to distinguish different uses of counterfactuals.

This dissertation offers new proposals, based on a philosophical appraisal of scientific findings, to address old philosophical problems regarding our immediate acquaintance with time. It focuses on two topics: our capacity to determine the length of intervals and our acquaintance with the present moment. A review of the relevant scientific findings concerning these topics grounds the main contributions of this dissertation. Thus, this study introduces to the philosophical literature an empirically adequate way to talk about how the mind represents time (...) at the most fundamental level. In order to account for our immediate acquaintance with the duration of intervals, a theoretical framework for classifying clocks is used to explain why the representational outputs of the circadian clock and the stopwatch have metric structure. A philosophical analysis of these outputs is proposed to classify them and explain their properties. With respect to our immediate acquaintance with the present, a novel two-phase model of the present is proposed. This model shows that there are two forms of acquaintance with the present, which has consequences for contemporary debates in the philosophy of time. (shrink)

Quantum mechanics portrays the universe as involving non-local influences that are difficult to reconcile with relativity theory. By postulating backward causation, retro-causal interpretations of quantum mechanics could circumvent these influences and accordingly reconcile quantum mechanics with relativity. The postulation of backward causation poses various challenges for the retro-causal interpretations of quantum mechanics and for the existing conceptual frameworks for analyzing counterfactual dependence, causation and causal explanation. In this chapter, we analyze the nature of time, causation and explanation in a local, (...) deterministic retro-causal interpretation of quantum mechanics that is inspired by Bohmian mechanics. This interpretation of quantum mechanics offers a deterministic, local ‘hidden-variables’ model of the Einstein-Podolsky-Rosen experiment that poses a new challenge for Reichenbach’s principle of the common cause. In this model, the common cause – the state of particles at the emission from the source – screens off the correlation between its effects – the distant measurement outcomes – but nevertheless fails to explain the correlation between the effects. (shrink)

When we begin to investigate the persistence of objects through time, we find immediately that the sort of concerns embodied in Leibniz's Law cause philosophers to divide themselves into the two major camps of Purdurantists and Endurantists. What is required according to each for a given object at a given time to be identified with a given object at another time is held to be dramatically different, even while both often look to the same general sort of indicators for their (...) answers to identity questions: identity or similarity of physical properties, including relational properties like spatial location. I believe, however, that logically prior to the problem of the persistence of objects through time will be questions regarding the composition of objects--we must have coherent notions of what an object is, what it means for parts to compose an object, and what is required for an object to be considered to exist at a single time before we can discuss the continued existence of objects at other times. I believe that posing the problem of temporal gaps for both the Perdurantist and Endurantist to solve can help us uncover reasonable answers to these more basic questions, and thereby help us judge the comparative coherence of the parent theories. Towards this goal, we investigate here some of the assumptions of persistence theories--that Perdurantists are four-dimensionalists and Endurantists are Presentists, for example--before moving on to find reasonable explanations of the composition of objects from within each theory. Important at this stage is clarifying such concepts as parthood and the present. When we at length turn our attention to the problem of gaps, it becomes useful to distinguish two sorts of gaps, each with their own difficulties: a 'gap' as a length of time during which the proper parts of an object are scattered through space, and a 'gap' as a length of time during which the proper parts of an object do not exist in space at all. My contention here is that Perdurantism, paired with four-dimensional spacetime, provides the most coherent answers to the challenges presented throughout. (shrink)