In this paper, I support a hybrid view regarding the metaphysics of worlds. I endorse Lewisian Modal Realism for possible worlds (LMR). My aim is to come up with a hybrid account of impossible worlds that provides all the plenitude of impossibilities for all fine-grained intentional contents. I raise several challenges for such a plenitudinous hybrid theory. My version of hybrid modal realism builds impossible worlds as set-theoretic constructions out of genuine individuals and sets of them, (...) that is, as set-theoretic constructions from parts and sets of parts of genuine Lewisian worlds. _Structured worlds_ are defined as sets of tuples: structured entities built out of Lewisian ‘raw material’. These structured worlds are ersatz worlds, some of which are impossible. I claim that propositions must be sets of worlds rather than members of sets. Once the construction is in place, I evaluate the proposal and show that my hybrid account is able to supply a plenitude of impossibilities and thus giving the resources to make all the hyperintensional distinctions we are looking for, whilst remaining Lewisian-conservative. (shrink)

Some arguments against David Lewis’s modal realism seek to exploit apparent inconsistencies between it and anthropic reasoning. A recent argument, in particular, seeks to exploit an inconsistency between modal realism and typicality anthropic premises, premises common in the literature on physical multiverses, to the effect that observers who are like human observers in certain respects must be typical in the relevant multiverse. Here I argue that typicality premises are not applicable to the description of Lewis’s metaphysical (...) multiverse, where the proportions of metaphysically possible observers possessing the pertinent properties can be independently established by metaphysical reasoning. However, other kinds of reasonable anthropic premises can be seen to be consistent with and usable within modal realism. (shrink)

Conceivability is, I say, prima facie evidence for possibility. Hence, we may count the cost of theories about possibility by listing the ways in which, according to the theory in question, something conceivable is said nonetheless to be impossible. More succinctly we may state a principle, Hume's razor to put alongside Ockham's. Hume's razor says that necessities are not to be multiplied more than necessary. In this paper I count the cost of David Lewis's modal realism, showing that (...) many of the objections are replied to by Lewis only at the cost of multiplying necessities. (shrink)

We argue that genuine modal realism can be extended, rather than modified, so as to allow for the possibility of nothing concrete, a possibility we term ‘metaphysical nihilism’. The issue should be important to the genuine modal realist because, not only is metaphysical nihilism itself intuitively plausible, but also it is supported by an argument with pre-theoretically credible premises, namely, the subtraction argument. Given the soundness of the subtraction argument, we show that there are two ways that (...) the genuine modal realist can accommodate metaphysical nihilism: (i) by allowing for worlds containing only spatiotemporal points and (ii) by allowing for a world containing nothing but the null individual. On methodological grounds, we argue that the genuine modal realist should reject the former way but embrace the latter way. (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)

Kriegel described the problem of intentional inexistence as one of the ‘perennial problems of philosophy’, 307–340, 2007: 307). In the same paper, Kriegel alluded to a modal realist solution to the problem of intentional inexistence. However, Kriegel does not state by name who defends the kind of modal realist solution he has in mind. Kriegel also points out that even what he believes to be the strongest version of modal realism does not pass the ‘principle of (...) representation’ and thus modal realism is not an adequate solution to the problem of intentional inexistence. In this paper, I respond to Kriegel by defending a modal realist solution that he did not consider in 2007, called ‘extended modal realism’. EMR is a version of modal realism where possible worlds are not completely isolated as they are under the Lewisian model. Rather, under EMR worlds are, in a way, spatiotemporally related. The fact EMR worlds are related allows EMR to sufficiently pass the principle of representation and thus can be deemed a legitimate solution to the problem of intentional inexistence. I conclude that either EMR can pass the principle of representation in some cases or, and I think the more sensible option, we give up on the principle of representation altogether. (shrink)

In Sections 1–7, I provide a detailed description of some of the advantages of theistic modal realism. The aim is to show specifically how theistic modal realism solves many of the intractable problems of philosophical theology. A detailed description of all of the advantages would require a much longer treatment. The aim is to give a good sense of the theoretical benefits that theistic modal realism affords traditional theists. I offer some concluding remarks in (...) Section 8. (shrink)

The main aim in the forthcoming discussion is to contrast theistic modal realism and theistic actualist realism. Actualist realism is the dominant view among theists and presents the most serious challenge to theistic modal realism. I discuss various prominent forms of theistic actualist realism. I offer reasons for rejecting the view of metaphysical reality that actualist realism affords. I discuss theistic modal realism and show that the traditional conception of God (...) is perfectly consistent with the metaphysics of genuine modal realism. Indeed theistic modal realism is more suited to traditional theism than is any version of actualist realism. (shrink)

It is a commonsense thesis that unactualized possibilities are not parts of actuality. To keep his modal realism in line with this thesis, David Lewis employed his indexical account of the term “actual.” I argue that the addition of counterpart theory to Lewis’s modal realism undermines his strategy for respecting the commonsense thesis. The case made here also reveals a problem for Lewis’s attempt to avoid haecceitism.

This article aims to provide a new ontological argument for the existence of God. A specific ‘modal’ version of the ontological argument—termed the Modal Realist Ontological Argument—is formulated within the modal realist metaphysical framework of David K. Lewis, Kris McDaniel and Philip Bricker. Formulating this argument within this specific framework will enable the plausibility of its central premise (i.e., the ‘Possibility Premise’) to be established, and allow one to affirm the soundness of the argument—whilst warding off two (...) oft-raised objections against this type of natural theological argument. (shrink)

Here I first raise an argument purporting to show that Lewis’ Modal Realism ends up being entirely trivial. But although I reject this line, the argument reveals how difficult it is to interpret Lewis’ thesis that possibilia “exist.” Five natural interpretations are considered, yet upon reflection, none appear entirely adequate. On the three different “concretist” interpretations of ‘exist’, Modal Realism looks insufficient for genuine ontological commitment. Whereas, on the “multiverse” interpretation, Modal Realism acknowledges physical (...) possibilities only--and worse, (assuming either axiom S5 or axiom B) each possibilium ends up as a necessary physical existent. Finally, on the “broadly Actualist” of ‘exist’, Modal Realism is either inconsistent or it mistakenly identifies the unrestricted quantifier with the unrestricted Actualist quantifier. The upshot is that it remains obscure in what non-trivial sense Lewisian possibilia “exist.”. (shrink)

In this paper I argue that Modal Realism, the thesis that there exist non-actual possible individuals and worlds, can be made compatible with Metaphysical Nihilism, the thesis that it is possible that nothing concrete exists. Modal Realism as developed by Lewis rules out the possibility of a world where nothing concrete exists and so conflicts with Metaphysical Nihilism. In the paper I argue that Modal Realism can be modified so as to be compatible with (...) Metaphysical Nihilism. Such a modification makes Modal Realism neither incur further theoretical costs nor lose its theoretical benefits. Thus such a modification constitutes an improvement of Modal Realism. (shrink)

The paper argues that Lewis’ Genuine Modal Realism, in taking the plurality of worlds to be necessarily the way it is, implies the existence of necessary connections of the sort that contradicts the Humean thesis that Lewis endorses. By endorsing, pace Divers, a non-redundancy interpretation of advanced modalizing, we gain the means to exactly state what these connections amount to.

In this article, I defend Lewisian modal realism against objections arising from the possibility of ‘Island Universes’ and other similar cases. The problem comes from Lewis’ claim that possible worlds are spatio-temporally isolated. I suggest a modification of Lewisian modal realism in order to avoid this family of objections. This modification may sound quite radical since it amounts to abandoning the very notion of a possible world, but as radical as it may sound it in fact (...) remains well in the spirit of Lewis’ original view. (shrink)

Modal realists should fashion their theory by postulating and taking seriously the modal equivalent of tense, or modal tense. This will give them a uniform way to respond to five different objections, one each by Skyrms, Quine, and Peacocke, and two by van Inwagen, and suggest a non-Lewisian path to modal realism.

This thesis argues that we should consider extended modal realism as a new player in the debate about non-existence. The primary aim is to show that extended modal realism is a viable theory when it comes to solving problems of non-existence. At times I will argue that extended modal realism has advantages over Lewisian modal realism when it comes to examining the problems of non-existence, not only in the case of problems relating (...) to thought but also problems concerning truth as well. However, I do not intend for the proposed advantages of extended modal realism to be presented as knockdown arguments against other strategies. -/- Not only do I argue that extended modal realism is viable when it comes to solving these problems, but I also make adjustments and additions to the theory that supports the conclusion of this thesis, and I argue that these are improvements to the modal realist theory. I include arguments for a new theory of existence that removes the need for the extended modal realist to rely on set-theoretic notations to understand existence, which I consider problematic. I argue for the revival of the Lewis-Rosen proposal for truth-making and a semantic instrumentalist theory of thought, both of which naturally accompany extended modal realism. Throughout this thesis, I will comment on the proposals and strategies of other authors, and some of these comments will be critical. At this very early stage, I want to clarify that this thesis's success does not rest on showing that all other competitor theories fail. I only include critical comments to situate extended modal realism within the landscape of viable positions that are available for one to occupy. (shrink)

A major criticism of David Lewis’ counterfactual theory of causation is that it allows too many things to count as causes, especially since Lewis allows, in addition to events, absences to be causes as well. Peter Menzies has advanced this concern under the title “the problem of profligate causation.” In this paper, I argue that the problem of profligate causation provides resources for exposing a tension between Lewis’ acceptance of absence causation and his modal realism. The result is (...) a different problem of profligate causation—one that attacks the internal consistency of Lewisian metaphysics rather than employing common sense judgments or intuitions that conflict with Lewis’ extensive list of causes. (shrink)

Divers presents a set of de re modal truths which, he claims, are inconvenient for Lewisean modal realism. We argue that there is no inconvenience for Lewis.

When I profess realism about possible worlds, I mean to be taken literally. Possible worlds are what they are, and not some other thing. If asked what sort of thing they are, I cannot give the kind of reply my questioner probably expects: that is, a proposal to reduce possible worlds to something else. I can only ask him to admit that he knows what sort of thing our actual world is, and then explain that possible worlds are more (...) things of that sort, differing not in kind but only in what goes on at them. (shrink)

This article aims to provide a new ontological argument for the existence of God. A specific ‘modal’ version of the ontological argument—termed the Modal Realist Ontological Argument—is formulated within the modal realist metaphysical framework of David K. Lewis, Kris McDaniel and Philip Bricker. Formulating this argument within this specific framework will enable the plausibility of its central premise (i.e., the ‘Possibility Premise’) to be established, and allow one to affirm the soundness of the argument—whilst warding off two (...) oft-raised objections against this type of natural theological argument. (shrink)

John Divers and Joseph Melia have argued that Lewis's modal realism is extensionally inadequate. This paper explains why their argument does not succeed.

In this reply, we defend our argument for the incompleteness of Genuine Modal Realism against Paseau's criticisms. Paseau claims that isomorphic set of worlds represent the same possibilities, but not only is this implausible, it is inimical to the target of our paper: Lewis's theory of possible worlds. We argue that neither Paseau's model-theoretic results nor his comparison to arithmetic carry over to GMR. We end by distinguishing two notions of incompleteness and urge that, for all that Paseau (...) has said, GMR remains incomplete in the relevant sense. (shrink)

Divers (2014) presents a set of de re modal truths which, he claims, are inconvenient for Lewisean modal realism. We argue that there is no inconvenience for Lewis.

In his book Worlds and Individuals, Possible and Otherwise (2010), Takashi Yagisawa presents and argues for a novel and imaginative version of modal realism. It differs both from Lewis’s modal realism (Lewis 1986) and from actualists’ ersatz accounts (Adams 1974; Sider 2002). In this paper, I’ll present two arguments, each of which shows that Yagisawa’s metaphysics is incoherent. The first argument shows that the combination of Yagisawa’s metaphysics with impossibilia leads to triviality: every sentence whatsoever comes (...) out true. This is so even if Yagisawa accepts a paraconsistent notion of logical consequence, on which contradictions do not entail arbitrary conclusions. The second argument is independent of Yagisawa’s acceptance of impossibilia. It shows that Yagisawa’s metaphysics of possible worlds is incoherent. Using ordinary modal reasoning, I derive a contradiction from Yagisawa’s account of possible worlds. (shrink)

A powerful challenge to some highly influential theories, this book offers a thorough critical exposition of modal realism, the philosophical doctrine that many possible worlds exist of which our own universe is just one. Chihara challenges this claim and offers a new argument for modality without worlds.

Theistic modal realism argues for an extension of Lewis's modal realism capable of accommodating a theistic God. By affording elegant solutions to many atheistic challenges, the view is of great theoretical utility for the theist. However, it has been objected that within a Lewisian framework God cannot be causally efficacious on pain of collapsing intuitively distinct modal notions. In this article I explain why these worries are ill-founded and show how God's existence and causal power (...) over the pluriverse can be consistently understood. If successful, the proposal offers a congenial theistic way to adopt modal realism and address the atheological problems. (shrink)

This book defends a radical new theory of contingency as a physical phenomenon. Drawing on the many-worlds approach to quantum theory and cutting-edge metaphysics and philosophy of science, it argues that quantum theories are best understood as telling us about the space of genuine possibilities, rather than as telling us solely about actuality. When quantum physics is taken seriously in the way first proposed by Hugh Everett III, it provides the resources for a new systematic metaphysical framework encompassing possibility, necessity, (...) actuality, chance, counterfactuals, and a host of related modal notions. -/- Rationalist metaphysicians argue that the metaphysics of modality is strictly prior to any scientific investigation; metaphysics establishes which worlds are possible, and physics merely checks which of these worlds is actual. Naturalistic metaphysicians respond that science may discover new possibilities and new impossibilities. This book's quantum theory of contingency takes naturalistic metaphysics one step further, allowing that science may discover what it is to be possible. As electromagnetism revealed the nature of light, as acoustics revealed the nature of sound, as statistical mechanics revealed the nature of heat, so quantum physics reveals the nature of contingency. (shrink)

The paper outlines and immediately discusses the so-called ‘soft’ impossibility, i.e., non-logical impossibility generated by modal realism. It will be shown that although in a particular case genuine modal realism, straightforwardly applied, deems impossible a proposition that other philosophers have claimed to be (intuitively) possible, there is a variety of methodologically acceptable moves available in order to avoid the problem. The impossibility at issue is the existence of island universes. Given the Lewisian analysis there are three (...) points at which we might try to square genuine modal realism with such a controversial and problematic claim of (im)possibility, namely: a) the contraction of our pre-theoretical opinions about possibility, b) the revision of some Lewisian definitions and/or c) the extension of our ontological commitments. I shall look at each of these approaches applied to the problematic case. (shrink)

Some philosophers worry that if modal realism is true, you have no reason to prevent evils. For if you prevent an evil, you’ll have a counterpart somewhere that allows a similar evil. And if you refrain, your counterpart will end up preventing the relevant evil. Either way one evil is prevented and one is allowed. Your act makes no difference. I argue that this is mistaken. If modal realism is true, you are in a variant of (...) Newcomb’s Problem. And if Lewis’ view about Newcomb’s Problem is true, then your act does make a difference and you should prevent the evil. (shrink)

The standard conception of God is that of a necessary being. On a possible worlds semantics, this entails that God exists at every possible world. According to the modal realist account of David Lewis, possible worlds are understood to be real, concrete worlds—no different in kind from the actual world. Some have argued that Lewis’s view is incompatible with classical theism (e.g., Sheehy, 2006). More recently, Ross Cameron (2009) has defended the thesis that Lewisian modal realism and (...) classical theism are in fact compatible. I argue that this is not the case. Modal realism, I argue, is equipped to accommodate necessary beings in only one of three ways: (1) By way of counterpart theory, or (2) by way of a special case of trans-world identity for causally inert necessary beings (e.g., pure sets), or else (3) causally potent ones which lack accidental intrinsic properties. However, each of these three options entails unacceptable consequences—(1) and (2) are incompatible with theism, and (3) is incompatible with modal realism. I conclude that (at least) one of these views is false. (shrink)

In this paper, I examine the putative incompatibility of three theses: (1) Haecceitism, according to which some maximal possibilities differ solely in terms of the non-qualitative or de re possibilities they include; (2) Modal correspondence, according to which each maximal possibility is identical with a unique possible world; (3) Counterpart theory, according to which de re modality is analyzed in terms of counterpart relations between individuals. After showing how the modal realism defended by David Lewis resolves this (...) incompatibility by rejecting modal correspondence, I defend modal correspondence and develop an alternative strategy for reconciling these theses. Specifically, I examine Lewis’s arguments against non-qualitative counterpart theory and undermine them by developing a novel version of non-qualitative counterpart theory that appeals to a metaphysics of bare particulars. I then indicate how this version of non-qualitative counterpart theory accommodates both haecceitism and modal correspondence. (shrink)

The current conception of the plurality of worlds is founded on a set theoretic understanding of possibilia. This paper provides an alternative category theoretic conception and argues that it is at least as serviceable for our understanding of possibilia. In addition to or instead of the notion of possibilia conceived as possible objects or possible individuals, this alternative to set theoretic modal realism requires the notion of possible morphisms, conceived as possible changes, processes or transformations. To support this (...) alternative conception of the plurality of worlds, I provide two examples where a category theoretic account can do work traditionally done by the set theoretic account: one on modal logic and another on paradoxes of size. I argue that the categorial account works at least as well as the set theoretic account, and moreover suggest that it has something to add in each case: it makes apparent avenues of inquiry that were obscured, if not invisible, on the set theoretic account. I conclude with a plea for epistemological humility about our acceptance of either a category-like or set-like realist ontology of modality. (shrink)

Jim Stone has argued that a multiversal version of Modal Realism together with Counterpart Theory cannot account for a certain intuitive possibility. Roughly, it is the possibility that all free moral choices of a certain sort are the right choices in all cases in the multiverse. The present work offers an explanation of how the metaphysics in question can account for the intuitive possibility in question.

Theories of possible worlds abound. Since the introduction of modal logic, the term of a possible world, and the very nature of an entity denoted by the term, have stood on the top of metaphysical inquiries. A possible world, roughly speaking, is a complete way things could have been. On the face of it, whatever is possible takes place in some possible world, and whatever is not possible, does not. The aim of the present book is to argue that (...) even impossible things happen. By taking David Lewis’s Modal Realism (henceforth as “MR”) seriously, I claim that besides infinitely many concrete ways things could have been, there exist ways things could not have been. I call them concrete impossible worlds. In Chapter I, I outline Lewis’s well-defined conception of philosophical analysis. I present its structure, aims, methodology and criteria for success. Besides the virtues of the Lewisian conception, I point out several limitations the theory has and offer very simple solution: the admission of concrete impossible worlds. In Chapter II, I present a version of an epistemological objection against MR and a positive account in favour of Modal Fictionalism (henceforth as “MF”). I then present the puzzle in this matter and attempt to generalise my point. 9 Introduction Chapter III demonstrates how flexible Lewis’s theory is. I consider a putative impossibility of there being island universes – spatiotemporally disjoint spacetimes – and show what a proponent of modal realism can do in order to account for it. I present three possible moves: a revision of our pre-theoretical opinions, a modification of our definitions and, finally, an ex- tension of our metaphysical commitments. I consider two ersatz theories of impossible worlds in Chapter IV. In particular, I scrutinize Franz Berto’s and Edwin Mares’s (hybrid) theories of MR. Although I admit that the theories radically extend the scope of applications of MR without extending its metaphysical commitments, the approaches do have some limits. Finally, in Chapter V, I present Extended Modal Realism (henceforth EMR), a theory according to which the best way to go in order to account for impossible phenomena is to ex- tend our metaphysical base by genuine impossibilia. I try to (at least) weaken, if not meet, the crucial objections to the proposal. Namely, I challenge the proclaimed universality of classical logic and, subsequently, motivate certain kind of paraconsistent approach to modal reality. Although the consequences are very hard to swallow, I argue that it is because of the fact that we are unsure of our pre-theoretical opinions concerning the impossible. (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)

Modal realism is an ontological position made familiar by David Lewis, according to which there exist possible worlds other than the actual world that we inhabit. It is hard to uphold modal realism, and indeed modal realism has only a few advocates. However, as most contemporary metaphysicians agree, this does not mean that it is easy to refute modal realism. In this paper, I argue against modal realism from a metaontological (...) point of view. First, I provide a precise formulation of modal realism based on Lewis’ discussion of modal realism. Second, I argue that modal realism is undermined unless it incorporates a view of metaontology known as ontological realism. Third, I point out that if modal realism incorporates ontological realism, it comes into conflict with its own formulation. (shrink)

Charles Chihara gives a thorough critical exposition of modal realism, the philosophical doctrine that there exist many possible worlds of which the actual world--the universe in which we live--is just one. The striking success of possible-worlds semantics in modal logic has made this ontological doctrine attractive. Modal realists maintain that philosophers must accept the existence of possible worlds if they wish to have the benefit of using possible-worlds semantics to assess modal arguments and explain (...) class='Hi'>modal principles. Chihara challenges this claim, and argues instead for modality without worlds; he offers a new account of the role of interpretations or structures of the formal languages of logic. (shrink)

The aim of this paper is to provide an analysis of modality by means of the existence of concrete impossible worlds. In particular, I pursue a strategy according to which logical impossibility is analyzed as logical inaccessibility. I then consider whether it makes sense to think of logical models in isolation from the concrete world but without their being divorced from all spatiotemporal totalities. The metaphysics of structure developed in this paper assumes that structural properties of possible and impossible worlds (...) are primitive and objective. However, I provide some characterizations of their logical and metaphysical behavior, as well as guidelines for talking about them. (shrink)