Timothy Williamson gives an original and provocative treatment of deep metaphysical questions about existence, contingency, and change, using the latest resources of quantified modal logic. Contrary to the widespread assumption that logic and metaphysics are disjoint, he argues that modal logic provides a structural core for metaphysics.

What are the requirements on an adequate genuine modal realist analysis of modal discourse? One is material adequacy: the modal realist must provide for each candidate analysandum an analysans in the language of counterpart theory which by his lights has the same truth value as the candidate analysandum. Must the material biconditional joining these be necessarily true? This is the requirement of strict adequacy. It is not satisfied if Lewis’s 1968 scheme provides the analysis. John Divers puts forward a modification, (...) which identifies cases of ‘advanced modalizing’ in which the modal operator is semantically redundant. Even with this modification modal realist analyses of statements of modal discourse will be strictly inadequate. Strict adequacy can be achieved by extending the redundancy interpretation to all de dicto modal statements. The price is the denial of de dicto contingency. But perhaps material adequacy is enough. If the modal realist has a systematic means of replacing every sentence of quantified modal logic which he considers true by a sentence of counterpart theory that he considers true, perhaps he need do no more. Still, traditionally philosophical analysis aims at strict adequacy so it is as well to know that this is a test the modal realist analysis fails unless he abandons de dicto contingency. (shrink)

Is what could have happened but never did as real as what did happen? What did happen, but isn't happening now, happened at another time. Analogously, one can say that what could have happened happens in another possible world. Whatever their views about the reality of such things as possible worlds, philosophers need to take this analogy seriously. Adriane Rini and Max Cresswell exhibit, in an easy step-by-step manner, the logical structure of temporal and modal discourse, and show that every (...) temporal construction has an exact parallel that requires a language that can refer to worlds, and vice versa. They make precise, in a way which can be articulated and tested, the claim that the parallel is at work behind even ordinary talk about time and modality. The book gives metaphysicians a sturdy framework for the investigation of time and modality - one that does not presuppose any particular metaphysical view. (shrink)

In this paper I argue in favour of a new definition of presentism that I call ‘existence presentism’ (EP). Typically, presentism is defined as the thesis that ‘only present objects exist’, or ‘nothing exists that is non-present’.1 I assume these statements to be equivalent. I call these statements of presentism ‘conventional presentism’ (CP). First, in §2, I rehearse arguments due to Ulrich Meyer that purport to show that presentism is not adequately defined as CP. In §§2.1–2.4 I show that considerations (...) of the sort raised by Meyer infect attempts to define presentism, due to Thomas Crisp, Tom Stoneham, and Theodore Sider. Thus the first half of the paper is constituted by a negative project that looks to show how extant definitions of presentism fail. In the second half of the paper, I continue in the negative theme in §3, before laying out EP and demonstrating that it solves the problems faced by CP and offering explanations of how to make sense of certain key notions that lie at the heart of EP. I conclude that EP is preferable to CP. (shrink)

It is a common assumption in the metaphysics of time that a commitment to presentism entails a commitment to serious presentism, the view that objects can exemplify properties or stand in relations only at times at which they exist. As a result, non-serious presentism is widely thought to be beyond the bounds for the card-carrying presentist in response to the problem of cross-temporal relations. In this paper, I challenge this general consensus by examining one common argument in favor of the (...) thesis that presentism entails serious presentism. The argument, I claim, begs the question against non-serious defenders in failing to account for their wider metaontological views concerning non-committal quantification. (shrink)

Four- Dimensionalism defends the thesis that the material world is composed of temporal as well as spatial parts. This defense includes a novel account of persistence over time, new arguments in favour of the four-dimensional ontology, and responses to the challenges four- dimensionalism faces." "Theodore Sider pays particular attention to the philosophy of time, including a strong series of arguments against presentism, the thesis that only the present is real. Arguments offered in favour of four- dimensionalism include novel arguments based (...) on time travel, the debate between spacetime substantivalists and relationalists, and vagueness. Also included is a comprehensive discussion of the paradoxes of coinciding material objects, and a novel resolution of those paradoxes based on temporal counterpart theory. In conclusion Sider replies to prominent objections to four- dimensionalism, including discussion of the problem of the rotating homogenous disk. (shrink)

Precis of my book by this title, for a symposium.

It seems obvious that I could have failed to exist. My parents could easily never have met, in which case I should never have been conceived and born. The like applies to everyone. More generally, it seems plausible that whatever exists in space and time could have failed to exist. Events could have taken an utterly different course. Our existence, like most other aspects of our lives, appears frighteningly contingent. It is therefore surprising that there is a proof of my (...) necessary existence, a proof that generalizes to everything whatsoever. I will explain the proof and discuss what to make of it. A first reaction is that a ‘proof’ of such an outrageous conclusion must contain some dreadful fallacy. Yet the proof does not collapse under scrutiny. Further reflection suggests that, suitably interpreted, it may be sound. So interpreted, the conclusion is not outrageous, although it may not be the view you first thought of. (shrink)

∗ Apologies to Mark Hinchliff for stealing the title of his dissertation. (See Hinchliff, A Defense of Presentism. As it turns out, however, the version of Presentism defended here is different from the version defended by Hinchliff. See Section 3.1 below.).

Eternalists say that non-present entities (for instance dinosaurs) exist; presentists say that they do not. But some sceptics deny that this debate is genuine, claiming that presentists simply represent eternalists' quantifiers over non-present entities in different notation. This scepticism may be refuted on purely logical grounds: one of the leading candidate ‘presentist quantifiers’ over non-present things has the inferential role of a quantifier. The dispute over whether non-present objects exist is as genuine and non-verbal as the dispute over whether there (...) is life on other planets. (shrink)

Actualism is the thesis that necessarily, everything that there is exists. Serious actualism is the thesis that necessarily, no object has a property in a world in which it does not exist. Let's call the claim that actualism entails serious actualism the Entailment Thesis (ET). In this paper I will improve upon a previous argument of mine for (ET). I will then consider the prospects for defending a similar thesis in the temporal realm—the thesis that presentism entails serious presentism.

The paper has two parts: First, I describe a relatively popular thesis in the philosophy of propositional attitudes, worthy of the name ‘taking tense seriously’; and I distinguish it from a family of views in the metaphysics of time, namely, the A-theories (or what are sometimes called ‘tensed theories of time’). Once the distinction is in focus, a skeptical worry arises. Some A-theorists maintain that the difference between past, present, and future, is to be drawn in terms of what exists: (...) growing-block theorists eschew ontological commitment to future entities; presentists, to future and past entities. Others think of themselves as A-theorists but exclude no past or future things from their ontology. The metaphysical skeptic suspects that their attempt to articulate an ‘eternalist’ version of the A-theory collapses into merely ‘taking tense seriously’– a thesis that does not imply the A-theory. The second half of the paper is the search for a stable eternalist A-theory. It includes discussion of temporary intrinsics, temporal parts, and truth. (shrink)

Modal realists face a puzzle. For modal realism to be justified, modal realists need to be able to give a successful reduction of modality. A simple argument, however, appears to show that the reduction they propose fails. In order to defend the claim that modal realism is justified, modal realists therefore need to either show that this argument fails, or show that modal realists can give another reduction of modality that is successful. I argue that modal realists cannot do either (...) of these things and that, as a result, modal realism is unjustified and should be rejected. (shrink)

This paper defends three theses: that presentism is either trivial or untenable; that the debate between tensed and tenseless theories of time is not about the status of presentism; and that there is no temporal analogue of the modal thesis of actualism.

Presentism is usually understood as the thesis that only the present exists whereas the rival theory of eternalism is usually understood as the thesis that past, present, and future things are all equally real. The significance of this debate has been threatened by the so-called triviality objection, which allegedly shows that the presentist thesis is either trivially true or obviously false: Presentism is trivially true if it is read as saying that everything that exists now is present, and it is (...) obviously false if read as saying that everything that has existed, exits or will exist is present. If eternalism is taken as the negation of presentism, it is also either trivially false or obviously true. In this paper, I try to respond to the triviality objection on behalf of presentism. In second section, I will examine how the argument proceeds. In third section, I will reflect on three possible ways to respond but will argue that none of them succeeds in giving a satisfactory solution. I will then try to clarify the core idea of presentism and to suggest that if we characterise presentism accurately, the problem will disappear. In fourth section, I will offer a plausible definition of presentism and will show how it can avoid the triviality objection and demonstrate why it is advantageous to accept the version of presentism I offer. (shrink)

There are many questions we can ask about time, but perhaps the most fundamental is whether there are metaphysically interesting differences between past, present and future events. An eternalist believes in a block universe: past, present and future events are all on an equal footing. A gradualist believes in a growing block: he agress with the eternalist about the past and the present but not about the future. A presentist believes that what is present has a special status. My first (...) claim is that the familiar ways of articulating these views result in there being no substantive disagreement at all between the three parties. I then show that if we accept the controversial truthmaking principle, we can articulate a substantive disagreenment. Finally, I apply this way of formulating the debate to related questions such as the open future and determinism, showing that these do not always line up in quite the way one would expect. (shrink)

Ross P. Cameron argues that the flow of time is a genuine feature of reality. He suggests that the best version of the A-Theory is a version of the Moving Spotlight view, according to which past and future beings are real, but there is nonetheless an objectively privileged present. Cameron argues that the Moving Spotlight theory should be viewed as having more in common with Presentism than with the B-Theory. Furthermore, it provides the best account of truthmakers for claims about (...) what was or will be the case. Cameron goes on to defend an account of the open future, and argues that this is a better account than that available to the Growing Block theory. (shrink)

What does the passage of time consist in? There are some suggestive metaphors. âEvents approach us, pass us, and recede from us, like sticks and leaves floating on the river of time.â âWe are moving from the past into the future, like ships sailing into an unknown ocean.â There is surely something right and deep about these metaphors. But how close are they to the literal truth? In this book Bradford Skow argues that they are far from the literal truth. (...) Skowâs argument takes the form of a defense of the block universe theory of time, a theory that, in many ways, treats time as a dimension of reality that closely resembles the three dimensions of space. Opposed to the block universe theory of time are theories that take the metaphors more seriously: presentism, the moving spotlight theory, the growing block theory, and the branching time theory. These are theories of ârobustâ passage of time, or âobjective becoming.â Skow argues that the best of these theories, the block universe theoryâs most worthy opponent, is the moving spotlight theory, the theory that says that âpresentnessâ moves along the series of times from the past into the future. Skow defends the moving spotlight theory against the objection that it is inconsistent, and the objection that it cannot answer the question of how fast time passes. He also defends it against the objection that it is incompatible with Einsteinâs theory of relativity. Skow proposes several ways in which the moving spotlight theory may be made compatible with the theory of relativity. Still, this book is ultimately a defense of the block universe theory, not of the moving spotlight theory. Skow holds that the best arguments against the block universe theory, and for the moving spotlight theory, start from the idea that, somehow, the passage of time is given to us in experience. Skow discusses several different arguments that start from this idea, and argues that they all fail. (shrink)

It follows from Humean principles of plenitude, I argue, that island universes are possible: physical reality might have 'absolutely isolated' parts. This makes trouble for Lewis's modal realism; but the realist has a way out. First, accept absolute actuality, which is defensible, I argue, on independent grounds. Second, revise the standard analysis of modality: modal operators are 'plural', not 'individual', quantifiers over possible worlds. This solves the problem of island universes and confers three additional benefits: an 'unqualified' principle of compossibility (...) can be accepted; the possibility of nothing can be accommodated; and the identity of indiscernible worlds can be decisively refuted. (shrink)

The aim of this paper is to describe and defend the moving spotlight theory of time. I characterise the moving spotlight theory as the conjunction of two theses: permanentism, the thesis that everything exists forever, and the A-theory, the thesis that there is an absolute, objective present time. I begin in Sect. 2 by clearing up some common misconceptions about the moving spotlight theory, focusing on the discussion of the theory in Sider. In doing so, I also fill-out the barebones (...) picture of the moving spotlight theory as the conjunction of permanentism and the A-theory. In Sect. 3 I show how moving spotlighters can avoid the two common objections to their view, the McTaggartian argument that the view is contradictory, and the epistemic argument that the view implies that we should believe we are not located at the present moment. I conclude that the moving spotlight theory does not deserve its current relative unpopularity. (shrink)

_Possible Worlds_ presents the first up-to-date and comprehensive examination of one of the most important topics in metaphysics. John Divers considers the prevalent philosophical positions, including realism, antirealism and the work of important writers on possible worlds such as David Lewis, evaluating them in detail.

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

Different versions of the A-theory of time are traditionally defined in terms of whether everything is present, or whether there are also past and future things. In this paper I argue that the traditional way of defining A-theories should be abandoned. I focus on the traditional definition of presentism, according to which always, everything is present. First, I argue that there are good reasons to reject all the most plausible interpretations of the predicate ‘is present’ as it appears in the (...) traditional definition of presentism. It follows that there are also good reasons to reject the most plausible interpretations of the traditional definitions of the other A-theories. I then argue that there is a better way of defining the A-theories, in terms of the question of whether existence has a beginning and an end. Finally, I argue that what goes for the traditional definition of presentism goes for the traditional definition of its modal analogue actualism, according to which necessarily, everything is actual : there are good reasons to reject the traditional definition of actualism in favour of a definition in terms of contingent existence. (shrink)

According to the A-theory of time some instant of time is absolutely present. Many reject the A-theory on the grounds that it is inconsistent with current spacetime physics, which appears to leave no room for absolute presentness. However, some reject the A-theory on purely philosophical grounds. In this article I describe three purely philosophical arguments against the A-theory and show that there are plausible A-theoretic responses to each of them. I conclude that, whatever else is wrong with the A-theory, it (...) is not obviously a philosophically suspect theory. (shrink)

Is what could have happened but never did as real as what did happen? What did happen, but isn't happening now, happened at another time. Analogously, one can say that what could have happened happens in another possible world. Whatever their views about the reality of such things as possible worlds, philosophers need to take this analogy seriously. Adriane Rini and Max Cresswell exhibit, in an easy step-by-step manner, the logical structure of temporal and modal discourse, and show that every (...) temporal construction has an exact parallel that requires a language that can refer to worlds, and vice versa. They make precise, in a way which can be articulated and tested, the claim that the parallel is at work behind even ordinary talk about time and modality. The book gives metaphysicians a sturdy framework for the investigation of time and modality - one that does not presuppose any particular metaphysical view. (shrink)

I discuss a problem for modal realism raised by John Divers and others. I argue that the problem is real enough but that Divers’ “advanced modalising” solution is inadquate. The problem can only be solved by 1) holding that modal realism is only contingently true, 2) embracing a kind of Meinongianism about ontological commitment, or 3) abandoning the project of “analysing modality”.