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)

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)

According to David Lewis, a realist about possible worlds must hold that actuality is relative: the worlds are ontologically all on a par; the actual and the merely possible differ, not absolutely, but in how they relate to us. Call this 'Lewisian realism'. The alternative, 'Leibnizian realism', holds that actuality is an absolute property that marks a distinction in ontological status. Lewis presents two arguments against Leibnizian realism. First, he argues that the Leibnizian realist cannot account for the contingency of (...) actuality. Second, he argues that the Leibnizian realist cannot explain why skepticism about one's own actuality is absurd. In this paper, I mount a defense of Leibnizian realism. (shrink)

Actualists routinely characterize their view by means of the slogan, “Everything is actual.” They say that there aren’t any things that exist but do not actually exist—there aren’t any “mere possibilia.” If there are any things that deserve the label ‘possible world’, they are just actually existing entities of some kind—maximally consistent sets of sentences, or maximal uninstantiated properties, or maximal possible states of affairs, or something along those lines. Possibilists, in contrast, do think that there are mere possibilia, that (...) there are things that are not actual. They think that more exists than what actually exists. All I have done so far, though, is rephrase the slogan in various ways. To say that everything is actual is precisely to say that there are no things that do not actually exist, which is precisely to say that there are no mere possibilia, and which is also precisely to say that we cannot sep- arately quantify over what exists and what is actual. These claims all amount to the same thing. But what is that, exactly? What on earth does it mean to say that everything is actual, that there are no mere possibilia, and so on? What does the actualist slogan really come to? I think the literature is far from clear on this point, and that people work themselves into unnecessary muddles because of it. Indeed, certain confusions that I shall discuss in the first half of this article seem to be on the rise. It is high time to lay out the issues and the choice points as clearly as possible. There are two primary choices to be made; there are two axes along which versions of actualism can vary. One choice has to do with how to treat claims about things that merely could exist. The other choice has to do with the modal status of the view and of how we should think about the “actual” in actualism. I make no claim that the positions I will eventually endorse are star- tlingly new. I think that most people will agree with the decisions I make at both choice points and will in fact find some bits of this essay obvious. But not everyone agrees with my decisions, and it has been my experience that people differ remarkably about which bits they find obvious—a fact I find rather telling. My goal, then, is to show that the two axes are there and to clarify the consequences of the choices. (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 ‘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)

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)

The theorems of the simplest and strongest sensible quantified modal logic include the Barcan Formula and its converse. Both formulas face strong intuitive objections. This paper develops a theory of possibilia to meet those objections.

Timothy Williamson thinks that every object is a necessary, eternal existent. In defense of his view, Williamson appeals primarily to considerations from modal and tense logic. While I am uncertain about his modal claims, I think there are good metaphysical reasons to believe permanentism: the principle that everything always exists. B-theorists of time and change have long denied that objects change with respect to unqualified existence. But aside from Williamson, nearly all A-theorists defend temporaryism: the principle that there are temporary (...) existents. I think A-theorists are better off without this added commitment, but I will not argue for that in any great detail here. Instead, I will contend that a very tempting A-theoretic argument for temporaryism is unsound. In the first half of the paper, I will develop the Moorean “common sense” argument for temporaryism and dispute its central premise, namely that temporaryism is a valid generalization from highly plausible beliefs about change. I will argue that given the pervasive vagueness in our ordinary beliefs about change and the background commitments of all A-theories, no party can claim to be the common sense view because no party can accommodate most of our common sense beliefs about change in existence. In the second half of the paper, I will propose a permanentist A-theory that explains all change over time as a species of property change. I call it the minimal A-theory, since it dispenses with the change in existence assumption. As we'll see, the permanentist alternative performs well enough in explaining our ordinary beliefs about change, and it has better prospects for answering some objections commonly levied against A-theories. (shrink)

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

The paper is a detailed reconstruction of Bernard Bolzano’s account of merely possible objects. According to Bolzano, there are some objects which are merely possible. They are neither denizens of space and time nor members of the causal order, but they could have been so. Examples are merely possible persons, mountains etc., objects which are neither actual nor persons or mountains, but which could have been both. Bolzano’s views are contrasted with the theory of Alexius Meinong, and it is shown (...) that they have a modern counterpart in the accounts of merely possible objects that were developed by Bernard Linsky & Ed Zalta, and by Timothy Williamson. (shrink)

Possibilism—the view that there are non-actual, merely possible entities—is a surprisingly resilient doctrine.1 One particularly hardy strand of possibilism—the modal realism championed by David Lewis—continues to attract both foes who seek to demonstrate its falsity (or at least stare its advocates into apostasy) and friends who hope to defend modal realism (or, when necessary, modify modal realism so as to avoid problematic objections).2 Although I am neither a foe nor friend of modal realism (but some of my best friends are!), (...) like many I continue to be fascinated by the doctrine. (shrink)

The simplest quantified modal logic combines classical quantification theory with the propositional modal logic K. The models of simple QML relativize predication to possible worlds and treat the quantifier as ranging over a single fixed domain of objects. But this simple QML has features that are objectionable to actualists. By contrast, Kripke-models, with their varying domains and restricted quantifiers, seem to eliminate these features. But in fact, Kripke-models also have features to which actualists object. Though these philosophers have introduced variations (...) on Kripke-models to eliminate their objectionable features, the most well-known variations all have difficulties of their own. The present authors reexamine simple QML and discover that, in addition to having a possibilist interpretation, it has an actualist interpretation as well. By introducing a new sort of existing abstract entity, the contingently nonconcrete, they show that the seeming drawbacks of the simplest QML are not drawbacks at all. Thus, simple QML is independent of certain metaphysical questions. (shrink)

In "Actualism or Possibilism?" (Philosophical Studies, 84 (2-3), December 1996), James Tomberlin develops two challenges for actualism. The challenges are to account for the truth of certain sentences without appealing to merely possible objects. After canvassing the main actualist attempts to account for these phenomena, he then criticizes the new conception of actualism that we described in our paper "In Defense of the Simplest Quantified Modal Logic" (Philosophical Perspectives 8: Philosophy of Logic and Language, Atascadero, CA: Ridgeview, 1994). We respond (...) to Tomberlin's criticism by showing that we wouldn't analyze the problematic claim (e.g., "Ponce de Leon searched for the fountain of youth") in the way he suggests. (shrink)

In this paper, I formulate, elucidate, and defend a version of modal realism with overlap, the view that objects are literally present at more than one possible world. The version that I defend has several interesting features: (i) it is committed to an ontological distinction between regions of spacetime and material objects; (ii) it is committed to compositional pluralism, which is the doctrine that there is more than one fundamental part-whole relation; and (iii) it is the modal analogue of endurantism, (...) which is the doctrine that objects persist through time by being wholly present at each moment they are located. (shrink)

In "How Do We Know It Is Now Now?" David Braddon-Mitchell (Analysis 2004) develops an objection to the thesis that the past is real but the future is not. He notes my response to this, namely that the past, although real, is lifeless and (a fortiori?) lacking in sentience. He argues, however, that this response, which I call 'the past is dead hypothesis', is not tenable if combined with 'special relativity'. My purpose in this reply is to argue that, on (...) the contrary, 'special relativity' supports the thesis that the future is unreal. (shrink)

The principle of modal ubiquity - that every truth is necessary or contingent - and the validity of possibility introduction, are principles that any modal theory suffers for failing to accommodate. Advanced modal claims are modal claims about entities other than spatiotemporally unified individuals (perhaps, then, spatiotemporally disunified individuals, sets, numbers, properties, propositions and events). I show that genuine modal realism, as it has thus far been explicitly developed, and in so far as it deals with advanced modal claims, cannot (...) accommodate the principles in question. On behalf of the genuine modal realist I motivate and propose a redundancy interpretation of advanced possibility claims and extend that interpretation to the cognate cases of necessity, impossibility and contingency. I then show that the problematic principles as they apply to advanced modal claims can be derived from these interpretations. I show further how the proposed interpretation enables the genuine modal realist to deal with a number of objections that centre on the alleged inadequacy of the genuine modal realist's expressive resources. I conclude that genuine modal realism emerges the stronger for having been shown capable of dealing with advanced modal claims on the basis of no conceptual and ontological resources beyond those it requires to deal with ordinary modal claims. (shrink)

How can we talk meaningfully about the past if it does not exist to be talked about? What gives time its direction? Is time travel possible? This defence of presentism - the view that only the present exists - makes an original contribution to a fast growing and exciting debate.

There are different ways to be. This paper explicates and defends this controversial thesis. Special attention is given to the meta-ontology of Martin Heidegger. -/- .

Some argue that Lewisian realism fails as a reduction of modality because in order to meet some criterion of success the account needs to invoke primitive modality. I defend Lewisian realism against this charge; in the process, I hope to shed some light on the conditions of success for a reduction. In §1 I detail the resources the Lewisian modal realist needs. In §2 I argue against Lycan and Shalkowski’s charge that Lewis needs a modal notion of ‘world’ to ensure (...) that worlds correspond to possibilities. In §3 I respond to Divers and Melia’s objection that Lewis needs to invoke primitive modality to give a complete account of what worlds there are. In §4 I ask what it is for a notion to ‘involve’ modality. I conclude that the question is either in bad standing or at best offers little traction on the debate, and propose a different way of assessing when materials are appropriately included in a reductive base. (shrink)