Modal Realism

This paper investigates the form a modal realist analysis of possibility and necessity should take. It concludes that according to the best version of modal realism, the notion of a world plays no role in the analysis of modal claims. All contingent claims contain some de re element; the effect of modal operators on these elements is described by a counterpart theory which takes the same form whether the de re reference is to a world or to something else. This (...) fully general counterpart theory can validate orthodox modal logic, including the logic of 'actually'. (shrink)

The thesis, typical among dualists, that there are no necessitation relations between events of consciousness and physical events implies that it is prima facie lucky that in our world the apparently existing psychophysical laws usually match events of consciousness and physical events in a “harmonious” way. The lucky psychophysical laws argument concludes that typical dualism amounts to a psychophysical parallelism that is prima facie too improbable to be true. I argue that an anthropic reasoning in the space of possible worlds (...) makes the appearance of a harmonious match situation unsurprising, and that this is all that is needed for the argument to be harmless to a typical dualist. (shrink)

Imagine two objects, a lump of clay called Lumpl and a statue named Goliath, which are created and destroyed simultaneously, sharing all spatiotemporal properties. Despite their complete coincidence throughout existence, they appear to possess different properties, leading to a philosophical debate among metaphysicians. Monists argue for their identity, while pluralists deny it. Pluralists face the challenge of explaining the differences between these coincident objects, while monists must account for the modal differences if they are identical. Monists often turn to Lewisean (...) modal realism to reject pluralism and explain the differences, claiming it offers qualitative parsimony. However, I will argue that Lewisean modal realism is not truly parsimonious and cannot be used to reject pluralism and explain the modal differences between Lumpl and Goliath due to inherent circularity in the theory. (shrink)

Many philosophers have been attracted to a restricted version of the principle of indifference in the case of self-locating belief. Roughly speaking, this principle states that, within any given possible world, one should be indifferent between different hypotheses concerning who one is within that possible world, so long as those hypotheses are compatible with one’s evidence. My first goal is to defend a more precise version of this principle. After responding to several existing criticisms of such a principle, I argue (...) that existing formulations of the principle are crucially ambiguous, and I go on to defend a particular disambiguation of the principle. According to the disambiguation I defend, how we should apply this restricted principle of indifference sensitively depends on our background metaphysical beliefs. My second goal is to apply this disambiguated principle to classical skeptical problems in epistemology. In particular, I argue that Eternalism threatens to lead us to external world skepticism, and Modal Realism threatens to lead us to inductive skepticism. (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)

Time and modality show remarkable similarities. Each of the most discussed theories in philosophy of time finds an analogous counterpart in modal metaphysics, suggesting that the parallel between the two notions is metaphysically deep. This chapter offers a brief overview of their analogies. Section 1 addresses the analogy between presentism and actualism. Section 2 explores the analogy between non-presentist theories and possibilism. Section 3 discusses the analogy between temporal and modal persistence.

Fragmentalism allows incompatible facts to constitute reality in an absolute manner, provided that they fail to obtain together. In recent years, the view has been extensively discussed, with a focus on its formalisation in model-theoretic terms. This paper focuses on three formalisations: Lipman’s approach, the subvaluationist interpretation, and a novel view that has been so far overlooked. The aim of the paper is to explore the application of these formalisations to the alethic modal case. This logical exploration will allow us (...) to study (i) cases of metaphysical incompatibility between modal facts and (ii) cases of modal dialetheias. In turn, this will enrich our understanding of the role of impossibility in the fragmentalist framework. (shrink)

The ontological pictures underpinning David Lewis's Parts of Classes and On the Plurality of Worlds are in some tension. One tension concerns whether the sets and classes of Parts of Classes can be found in Lewis's modal space, since they cannot in general be parts of any possible world. The second is that the atoms that are the mathematical ontology of Parts of Classes seem to meet the criteria for being possible worlds themselves, and so fail to be the material (...) Parts of Classes needs. Two different responses to these tensions are discussed: one is unappealing in several ways but keeps more of Lewis's doctrines, while the other requires some modifications to the system of Parts of Classes. (shrink)

Many things can be other than they are. Many other things cannot. But what are statements like these about? One answer to this question is that we are speaking of possible worlds: if something can be other than it is, then it actually is that way in some possible world. If something cannot be otherwise, it is not otherwise in any world. This answer is presently dominant in analytical philosophy of language and logic. What are these worlds? David Lewis famously (...) claimed that every world exists, just like ours does: there is no difference between the other worlds and ours. In contrast, the medieval thinker John Buridan understands modal logic in terms of objects and causal powers in this world: if something can be other than it is, then there is a causal power that can make it that way. If it cannot, then no causal power—not even God—can alter it, at least without destroying its nature. As we’ll see, the Lewisian plurality is not possible on Buridan’s account; accordingly, a basic tenet of classical theism is untenable on Lewis’s metaphysics. In short, either the Lewisian plurality is incoherent, or a core monotheistic tenet is impossible. (shrink)

I propose an account of possible worlds. According to the account, possible worlds are pluralities of sentences in an extremely large language. This account avoids a problem, relating to the total number of possible worlds, that other accounts face. And it has several additional benefits.

In this review, I specify the metametaphysical background against which Alastair Wilson’s “_The Nature of Contingency_” (Oxford University Press, 2020) should be properly understood. Metaphysics, as a philosophical discipline, is standing on thin ice. The caricature of the situation is polarized, and is often presented as follows: metaphysics is either entirely extracted from science or it is entirely independent of science. There is a recent trend that focuses on the middle ground between these extremes, searching the philosophical literature for metaphysical (...) theories that can fill the gap, i.e., leaving metaphysics as a free discipline to produce spoils for the eventual needs of philosophers of science. We can appreciate it better with the following distinction between the tasks of ontology and metaphysics, as complementary disciplines. If, on the one hand, we understand ontology as dealing with what exists, we can somehow extract the entities that are existentially postulated by scientific theories. Metaphysics, on the other hand, would be located as an extra layer, in charge of investigating questions about the nature of the entities obtained in this “naturalized ontology”. As a tailor, Wilson adjusts a metaphysical theory in order to perfectly dress the physical and ontological nuances of Everettian quantum mechanics, thus creating a metaphysical theory that gives us intelligibility, with the concept of modality, in two areas: in quantum mechanics, and analytic metaphysics. (shrink)

This paper explores the physical and metaphysical implications of time travel, focusing on the possibility of changing the past, through a comparative analysis of David Lewis' modal realism and Everett's many-worlds interpretation of quantum mechanics. The existence of closed timelike curves (CTCs) in certain solutions to Einstein's field equations provides a theoretical basis for the possibility of backwards time travel, but this leads to a range of paradoxes, most notably the grandfather paradox. David Lewis argues that time travel must maintain (...) consistency and that the past cannot be changed, even if time travel were possible. His view is supported by his modal realism, which posits the existence of a plurality of possible worlds. In contrast, Everett's many-worlds interpretation, which holds that quantum mechanics describes a multiverse of branching realities, might seem to allow for the possibility of multiple, inconsistent histories. By examining these two ontological frameworks, this paper aims to shed light on the paradoxes of time travel and to explore whether the many-worlds interpretation provides a more satisfactory resolution to these paradoxes than Lewis' modal realism. It is argued that while Lewis' view provides a coherent model for maintaining consistency in time travel, Everett's interpretation may offer a more physically grounded and philosophically compelling account of the metaphysics of time travel. The paper concludes by suggesting that the many-worlds interpretation, by locating the branching of timelines within the structure of quantum mechanics itself, may provide a more promising framework for understanding the possibility and implications of time travel than Lewis' modal realism. However, significant questions remain about the nature of personal identity and free will in a branching multiverse. This comparative analysis aims to contribute to the ongoing debate about the metaphysical possibility of time travel and to highlight the value of engaging with interpretations of quantum mechanics in this context. Keywords: time travel, closed timelike curves, modal realism, many-worlds interpretation, grandfather paradox, metaphysics of time. (shrink)

This paper sketches a new and somewhat heterodox metaphysical theory of consciousness: the “many-worlds theory”. It drops the assumption that all conscious subjects’ experiences are features of one and the same world and instead associates different subjects with different “first-personally centred worlds”. We can think of these as distinct “first-personal realizers” of a shared “third-personal world”, where the latter is supervenient, in a sense to be explained. This is combined with a form of modal realism, according to which different subjects’ (...) first-personally centred worlds are all real, though only one of them is present for each subject. The theory offers a novel way of capturing the irreducibly subjective nature of conscious experience without lapsing into solipsism. The paper also looks at some scientific theories of consciousness, such as integrated information theory, through the proposed lens and reconsiders the hard problem of consciousness. (shrink)

‘Shallow’ and ‘deep’ versions of scientific realism may be distinguished as follows: the shallow realist is satisfied with belief in the existence of the posits of our best scientific theories; by contrast, deep realists claim that realism can be legitimate only if such entities are described in metaphysical terms. We argue that this methodological discussion can be fruitfully applied in Everettian quantum mechanics, specifically on the debate concerning the existence of worlds and the recent dispute between Everettian actualism and quantum (...) modal realism. After presenting what is involved in such dispute, we point to a dilemma for realists: either we don’t have the available metaphysical tools to answer the deep realist’s demands, and realism is not justified in this case, or such demands of metaphysical dressing are not mandatory for scientific realism, and deep versions of realism are not really required. (shrink)

This paper investigates Ockhamism from a metaphysical point of view. Its main point is that the claim that future contingents are true or false is less demanding than usually expected, as it does not require particularly contentious assumptions about the future. First it will be argued that Ockhamism is consistent with a wide range of metaphysical views. Then it will be shown that each of these views leaves room for the claim that the future is open, at least on some (...) plausible interpretations of that claim. (shrink)

This paper offers an argument in favour of a Lewisian version of concretism that maintains both the principle of material inheritance (according to which, if all the parts of an object x are material, then x is material) and the materiality-modality link (that is, the principle that, for every x, if x is material, then x is possible).

Aim of this paper is to analyse and assess two divergent understandings of metaphysical modality. On one hand, according to the absolutist conception, metaphysical modality is the extreme variety of objective modality and can be characterised in terms of all the varieties of objective modality: for example, p is metaphysically necessary if and only if p is necessary for every variety of objective necessity. The absolutist conception can also be framed in terms of counterfactual inevitability. On the other hand, according (...) to the essentialist conception of metaphysical modality, p is metaphysically necessary if and only if the truth of p is grounded by the essences of some entities. Based on the analysis of these two conceptions, I show that possible worlds are not helpful in characterising metaphysical modality. I finally suggest that in the light of a general principle about philosophical terminology, the essentialist conception has an edge over the absolutist one. (shrink)

Necessitism is the controversial thesis that necessarily everything is necessarily something, namely that everything, everywhere, necessarily exists. What is controversial about necessitism is that, at its core, it claims that things could not have failed to exist, while we have a pre-theoretical intuition that not everything necessarily exists. Contingentism, in accordance with common sense, denies necessitism: it claims that some things could have failed to exist. Timothy Williamson is a necessitist and claims that David Lewis is a necessitist too. The (...) paper argues that, granted the assumptions that lead to interpret the Lewisian as a necessitist, she can preserve contingentist intuitions, by genuinely agreeing with the folk that existence is contingent. This is not just the uncontroversial claim that the Lewisian, as a result of the prevalence of restricted quantification in counterpart theoretic regimentations of natural language, can agree with the folk while disagreeing with them in the metaphysical room. Rather, this is the claim that it is in the metaphysical room that the Lewisian can endorse the intuitions lying behind contingentism. (shrink)

My topic in this paper is the relationships of metaphysical priority which might hold between the different alethic modal statuses—necessity, contingency, possibility and impossibility. In particular, I am interested in exploring the view that the necessity of necessities is ungrounded while the contingency of contingencies is grounded—a scenario I call ‘necessity first’. I will explicate and scrutinize the contrast between necessity first and its ‘contingency first’ contrary, and then compare both views with ‘multimodal’ and ‘amodal’ alternatives, drawing on David Lewis’s (...) modal realism and Barbara Vetter’s potentialism as example cases. I will then defend the necessity-first point of view from a reversed version of Blackburn’s classic dilemma against theories of the source of necessity. (shrink)

In On the Plurality of Worlds (Lewis 1986), David Lewis imposes a condition on realist theories of modality which he calls ‘plenitude’. Lewis apparently assigns this condition considerable importance, and uses it to motivate his Humean principle of recombination, but he never says exactly what plenitude amounts to. This chapter first sets aside some obvious ways of reconstructing the plenitude criterion which do not fit with the textual evidence. An objection to modal realism due to John Divers and Joseph Melia (...) (Divers and Melia 2002) is diagnosed as equivocating between an overly-demanding plenitude constraint and a weaker constraint which fails to establish their conclusion. An alternative deflationary interpretation of the plenitude condition has it following from an application of standard theoretical virtues to a modal realist’s total theory; Lewis’ correspondence provides new evidence in support of this interpretation. The deflationary plenitude criterion also has broader application, beyond Lewisian modal realism. (shrink)

It has been argued recently that classical theism and Lewisian modal realism are incompatible theses. The most substantial argument to this effect takes the form of a trilemma. It argues that no sense can be made of God’s being a necessary being in the modal realistic picture, on pain of, among other things, modal collapse. The question of this essay is: Is that so? My goal here is to detail the reasons that have been offered in support of this contention (...) and then defend the coherence of theistic modal realism from the trilemma. I call my reply to the argument an “Anselmian-Thomistic” defense, since it appeals to resources from classical medieval philosophy, especially from Anselm and Aquinas. (shrink)

As a candidate theory of quantum gravity, the popularity of string theory has waxed and waned over the past four decades. One current source of scepticism is that the theory can be used to derive, depending upon the input geometrical assumptions that one makes, a vast range of different quantum field theories, giving rise to the so-called landscape problem. One apparent way to address the landscape problem is to posit the existence of a multiverse; this, however, has in turn drawn (...) heightened attention to questions regarding the empirical testability and predictivity of string theory. We argue first that the landscape problem relies on dubious assumptions and does not motivate a multiverse hypothesis. Nevertheless, we then show that the multiverse hypothesis is scientifically legitimate and could be coupled to string theory for other empirical reasons. Looking at various cosmological approaches, we offer an empirical criterion to assess the scientific status of multiverse hypotheses. (shrink)

This article aims to provide a metaphysical elucidation of the notion of Theism and a coherent theological synthesis of two extensions of this notion: Classical Theism and Neo-Classical Theism. A model of this notion and its extensions is formulated within the ontological pluralism framework of Kris McDaniel and Jason Turner, and the (modified) modal realism framework of David Lewis, which enables it to be explicated clearly and consistently, and two often raised objections against the elements of this notion can be (...) successfully answered. (shrink)

When a novel scientific theory conflicts with otherwise plausible moral assumptions, we do not treat that as evidence against the theory. We may scrutinize the empirical data more keenly and take extra care over its interpretation, but science is in some core sense immune to moral refutation. Can the same be said of philosophical theories (or the non-ethical, ‘metaphysical’ ones at least)? If a position in the philosophy of mind, for example, is discovered to have eye-widening moral import, does that (...) count against it at all? Actual responses by philosophers to the question of whether unanticipated moral consequences of metaphysical theories have evidential force are scattered, implicit, divergent, under-argued, and sometimes even self-undermining. The present discussion is, most immediately, an attempt to sort out the confusion. Beyond that, it exploits the new perspective this question gives us on a familiar topic: the relation of philosophy to science. (shrink)

The Forrest-Armstrong argument, as reconfigured by David Lewis, is a reductio against an unrestricted principle of recombination. There is a gap in the argument which Lewis thought could be bridged by an appeal to recombination. After presenting the argument, I show that no plausible principle of recombination can bridge the gap. But other plausible principles of plenitude can bridge the gap, both principles of plenitude for world contents and principles of plenitude for world structures. I conclude that the Forrest-Armstrong argument, (...) when fortified in one of these ways, demands that unrestricted recombination be rejected. The appropriate restriction comes from a consideration of what world structures are possible. I argue that, although there are too many worlds to form a set, for any world, the individuals at that world do form a set. To defend it I invoke a principle of Limitation of Size together with an iterative conception of structure. (shrink)

In this paper, I will argue that there is a version of possibilism—inspired by the modal analogue of Kit Fine’s fragmentalism—that can be combined with a weakening of actualism. The reasons for analysing this view, which I call Modal Fragmentalism, are twofold. Firstly, it can enrich our understanding of the actualism/possibilism divide, by showing that, at least in principle, the adoption of possibilia does not correspond to an outright rejection of the actualist intuitions. Secondly, and more specifically, it can enrich (...) our understanding of concretism, by proving that, at least in principle, the idea that objects have properties in an absolute manner is compatible with transworld identity. (shrink)

In this thesis I argue against unrestricted mereological hybridism, the view that there are absolutely no constraints on wholes having parts from many different logical or ontological categories, an exemplar of which I take to be ‘mixed fusions’. These are composite entities which have parts from at least two different categories – the membered (as in classes) and the non-membered (as in individuals). As a result, mixed fusions can also be understood to represent a variety of cross-category summation such as (...) the abstract with the concrete, the physical with the non-physical, and the possible with the impossible, just to name a few. -/- Proposed by David Lewis (1991) alongside his defence of classical mereology (the major theory of parthood which permits such transcategorial composites through its principle of unrestricted composition) it is my contention that mixed fusions are an under-examined consequence of indiscriminate mereological fusion which harbour a multitude of complications. In my attempt to discern their substantive character, throughout this thesis I make a case study of mixed fusions and uncover several problematic consequences which I think follow from their most plausible assessment. -/- These include: (1) that mixed fusions’ probable membership relations may lead to dubious foundational loops in the mereological Universe, or (2) otherwise that mixed fusions oblige an implausible ontological priority of the mereological Universe as a whole; (3) that mixed fusions contradict the reductive account of set theory they are proposed within, by plausibly being seen to have the same members as their class parts, and (4) that mixed fusions therefore confound a mereological thesis of Composition as Identity, which some (including Lewis) use to support classical mereology – a consequence which is potentially self-defeating; (5) that mixed fusions as sums of abstract and concrete entities both subvert Lewis’s (1986) system of modal realism, while (6) also undermining less expansive theories of possible worlds; and finally, (7) that even where some of the foregoing is resisted, it remains implausible that mixed fusions are ontologically innocent, because their supposed distinction from their parts in this case ensures that they need to be counted as additional entities in one’s ontology. -/- To be clear, I do not advance a theory of mereological hybrid nihilism in the sense of denying all cases of transcategorial composition. (I only cover a few select instances of mereological hybridism via mixed fusions after all.) Rather, I deny that mereological hybridism is plausible in full generality, by demonstrating that any cases of it are at least limited by the constraints that I identify. This in turn vindicates a call for a restriction on parthood theories and composition principles which allow certain types of categorially mixed entities – including restricting classical mereology with its principle of unrestricted composition. -/- Although theories of parthood like the standard classical mereology are not ordinarily developed for the sake of mereological hybrids like mixed fusions, these and other transcategorial composites are still among the logical consequences of such parthood systems operating with sufficient generality. The significance of my thesis, then, comes from showcasing how some of these kinds of entities do not conform to the systems in which they are included as required, and hence I argue for the rejection of unrestricted mereological hybridism as well as any mereological principles which support it. (shrink)

I examine what the mathematical theory of random structures can teach us about the probability of Plenitude, a thesis closely related to David Lewis's modal realism. Given some natural assumptions, Plenitude is reasonably probable a priori, but in principle it can be (and plausibly it has been) empirically disconfirmed—not by any general qualitative evidence, but rather by our de re evidence.

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)

Dualism about possible worlds says that merely possible worlds aren’t concrete objects, but the actual world is concrete. This view seems to be the natural one for ersatzers about merely possible worlds to take; yet one is hard-pressed to find any defenders of it in contemporary modal metaphysics. The main reason is that Dualism struggles with the issue of how merely possible worlds could have been actual. I explain that there are two different Dualist strategies that can be taken to (...) address the problem. Furthermore, one or other of these strategies should be plausible to anyone who accepts both Existentialism—which tells us that the existence of singular propositions depends on what they directly refer to—and Serious Actualism—which tells us that things must exist in order to instantiate properties. Though it has long been ignored, Dualism is a live option. (shrink)

A lump theorist claims that ordinary objects are spread out across possible worlds, much like many of us think that tables are spread out across space. We are not wholly located in any one particular world, the lump theorist claims, just as we are not wholly spatially located where one’s hand is. We are modally spread out, a trans-world mereological sum of world-bound parts. We are lump sums of modal parts. And so are all other ordinary objects. In this paper, (...) I explore lump theory and investigate five arguments against it. These arguments may be the primary reasons why lump theory has not been widely accepted––or extensively explored––until now. I maintain that these arguments can be answered, and moreover, that accepting lump theory has distinct advantages, making it a competitive view in its own right. (shrink)

An intuitive objection to modal realism is that merely possible worlds and their inhabitants seem to be irrelevant to an analysis of modality. Kripke originally phrased the objection in terms of being concerned about one’s modal properties without being concerned about the properties one’s other-worldly counterparts have. The author assesses this objection in a variety of forms, and then provides his own formulation that does not beg the question against the modal realist. Finally, the author considers two potential answers to (...) the objection so understood and concludes that only one of them has a chance of succeeding. (shrink)

One’s involvement with the world seems limited merely to things as they are; hence, modal knowledge—knowledge of what could be or must be simpliciter—should be perplexing. Traditionally, the notion of conceivability has been regarded as crucial to an account of modal knowledge. I believe one has a good deal of such knowledge (though perhaps less than others presume one has). I maintain, however, that conceiving is utterly idle in acquiring modal knowledge: the conceivability of a proposition can provide no evidence (...) whatsoever that what it represents is possible. To show this, I first examine the basis of modal knowledge. I consider what conceivability in general is supposed to be and argue, in light of the preceding considerations, that conceivability is not epistemically efficacious, in the sense of providing evidence, on any proposed specific account. I then maintain that there could be no account of conceivability on which it is epistemically efficacious, that the very idea of the conceivability of a proposition being evidential is misguided. I conclude with some brief recommendations for pursuing a satisfactory modal epistemology. (shrink)

David Lewis objected to theories that posit necessary connections between distinct entities and to theories that involve a magical grasping of their primitives. In On the Plurality of Worlds, Lewis objected to nondescript ersatzism on these grounds. The literature contains several reconstructions of Lewis’ critique of nondescript ersatzism but none of these interpretations adequately address his main argument because they fail to see that Lewis’ critique is based on broader methodological considerations. I argue that a closer look at his methodology (...) reveals the broader objection he presented against nondescript ersatzism. This objection, I further argue, remains a challenge for the ersatzer who posits structure-less entities as possible worlds. (shrink)

Divers (2014) argues that a Lewisian theory of modality which includes both counterpart theory and modal realism cannot account for the truth of certain intuitively true modal sentences involving cross-world comparatives. The main purpose of this paper is to defend the Lewisian theory against Divers’s challenge by developing a response strategy based on a degree-theoretic treatment of comparatives and by showing that this treatment is compatible with the theory.

Non-skeptical robust realists about normativity, mathematics, or any other domain of non- causal truths are committed to a correlation between their beliefs and non- causal, mind-independent facts. Hartry Field and others have argued that if realists cannot explain this striking correlation, that is a strong reason to reject their theory. Some consider this argument, known as the Benacerraf–Field argument, as the strongest challenge to robust realism about mathematics, normativity, and even logic. In this article I offer two closely related accounts (...) for the type of explanation needed in order to address Field's challenge. I then argue that both accounts imply that the striking correlation to which robust realists are committed is explainable, thereby discharging Field's challenge. Finally, I respond to some objections and end with a few unresolved worries. (shrink)

This paper argues that scientific realism commits us to a metaphysical determination relation between the mathematical entities that are indispensible to scientific explanation and the modal structure of the empirical phenomena those entities explain. The argument presupposes that scientific realism commits us to the indispensability argument. The viewpresented here is that the indispensability of mathematics commits us not only to the existence of mathematical structures and entities but to a metaphysical determination relation between those entities and the modal structure of (...) the physical world. The no-miracles argument is the primary motivation for scientific realism. It is a presupposition of this argument that unobservable entities are explanatory only when they determine the empirical phenomena they explain. I argue that mathematical entities should also be seen as explanatory only when they determine the empirical facts they explain, namely, the modal structure of the physical world. Thus, scientific realism commits us to a metaphysical determination relation between mathematics and physical modality that has not been previously recognized. The requirement to account for the metaphysical dependence of modal physical structure on mathematics limits the class of acceptable solutions to the applicability problem that are available to the scientific realist. (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)

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.

I argue in this dissertation that natural properties play a central role in David Lewis' modal realism. To argue in favor of this thesis I present: a bottom-up explanation of a top-down possible world metaphysics; a new definition of natural properties and natural fusion, a new mereological operation. To achieve these aims, in the first chapter, I contextualize the discussion, in the second I resume the discussion about universals in contemporary philosophy and argue that, considering the distinct formulations of the (...) problem, class nominalism combined with modal realism might be the best solution. Furthermore, I discuss Devitt's solution in which he defends that the problem about universals is, in fact, a pseudo problem. In the third chapter, I introduce a minimal ontology of properties, regarding natural properties, I discuss the existing definitions, present a new one and discuss some theories of similarity, a notion that is in the core of the definition I propose. Besides, I present how natural properties benefit the definition of terms of nomological package, linked to its fundamentality role. I also present some applications related to the rationality role that encompass some well-known philosophical problems of the second half of 20th century. In the fourth chapter, I present some varieties of philosophical realism, I consider the theoretical advantages of taking scientific realism as background and I discuss one more utility of natural properties, the solution to the problem of eligibility of reference or, the Putnam's paradox. In the fifth chapter, I discuss how mereology is important to link several aspects of Lewis' modal realism. For such, I discuss the relation between composition as identity and ontological innocence of mereology and I present the natural fusion mereology, a new mereological operation that aims to minimize the problems of unrestricted composition. (shrink)

Modal dimensionalism is realism about spaces, times and worlds—metaphysical indices that make objects spatial, temporal and modal, respectively, and that play the role of alethic relativizers, i.e. items to which matters of truth are relativized. This paper examines several arguments against MD and shows that MD offers a feasible way to understand modal discourse.

Book review of 'The Metaphysics of Perfect Beings'.

The integration challenge for modality states that metaphysical theories of modality tend to fail in one of two ways: either they render the meanings of modal sentences mysterious, or they render modal knowledge mysterious. I argue that there are specific semantic and epistemic constraints on metaphysics implied by the integration challenge and that a plausible metaphysical theory of modality will satisfy both of them. I further argue that no popular metaphysical theory of modality simultaneously satisfies both of the constraints. Therefore, (...) a new metaphysical theory of modality is needed, one that can offer a clear response to the integration challenge. I attempt to supply the needed theory and show that it satisfies the constraints of the integration challenge. The overall result is an argument for a new and unique metaphysical theory of modality that I call constructionism. (shrink)

I present an internal problem for David Lewis’s genuine modal realism. My aim is to show that his analysis of modality is inconsistent with his metaphysics. I consider several ways of modifying the Lewisian analysis of modality, but argue that none are successful. I argue that the problem also affects theories related to genuine modal realism, including the stage theory of persistence and modal fictionalism.

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 this article, I am interested in four versions of what is often referred to as "the Humphrey objection". This objection was initially raised by Kripke against Lewis's modal counterpart theory, so this is where I will start the discussion. As we will see, there is a perfectly good answer to the objection. I will then examine other places where a similar objection can be raised: it can arise in the case of temporal counterpart theory (in fact, it can arise (...) in the case of all kinds of counterpart theories, independently on modal realism), and a very similar worry can also arise against modal realism itself or against an ersatzist theory of possible worlds itself. For similar reasons, in similar situations, a similar objection will arise. What is interesting is that it is not the case that a similar response can be given in all of these similar cases. So, in the end, we will see what dissimilarities there are and how and why they are relevant. In particular, we will see the differences there are between alethic modalities and temporal modalities. In the case of alethic modalities (metaphysical necessity and possibility), the objection can be answered by appealing to the notion of representation, while this does not work very well in the case of temporal modalities. (shrink)

The revival of analytic metaphysics in the latter half of the twentieth century is typically understood as a consequence of the critiques of logical positivism, Quine’s naturalization of ontology, Kripke’s Naming and Necessity, clarifications of modal notions in logic, and the theoretical exploitation of possible worlds. However, this explanation overlooks the work of metaphysicians at the height of positivism and linguisticism that affected metaphysics of the late twentieth century. Donald C. Williams is one such philosopher. In this paper I explain (...) how Williams’s fundamental ontology and philosophy of time influenced in part the early formation of David Lewis’s metaphysics. Thus, Williams played an important role in the revival of analytic metaphysics. (shrink)

This thesis is an argument for the view that there are problems for Modal Reductionism, the thesis that modality can satisfactorily be defined in non-modal terms. -/- I proceed via a case study of David Lewis’s theory of concrete possible worlds. This theory is commonly regarded as the best and most influential candidate reductive theory of modality. Based on a detailed examination of its ontology, analysis and justification, I conclude that it does badly with respect to the following four minimal (...) conditions on a satisfactory reductive theory of modality: that it be (a) genuinely reductive, (b) materially adequate, (c) conceptually adequate and (d) that its justification provides good reason to think it true. -/- These problems for Lewis’s theory are not, I suggest, due to his idiosyncratic conception of possible worlds as concrete entities. Rather, because Lewis’s theory can be seen to represent an important class of structurally similar reductive theories of modality, the problems for Lewis’s theory generalise to problems for these other theories. This suggests that Modal Reductionism is unpromising. In the light of this, the alternative approach to understanding modality, Modal Primitivism, appears more attractive. (shrink)

O objetivo geral da pesquisa da qual esse artigo faz parte é investigar o sistema metafísico que emerge dos trabalhos de David Lewis. Esse sistema pode ser decomposto em pelo menos duas teorias. A primeira nomeada como realismo modal genuíno (RMG) e a segunda como mosaico neo-humeano. O RMG é, sem dúvida, mais popular e defende a hipótese metafísica da existência de uma pluralidade de mundos possíveis. A principal razão em favor dessa hipótese é a sua aplicabilidade na discussão de (...) problemas losó cos, esse motivo não será diretamente abordado neste artigo. Pois, o foco está em compreender o mosaico neo-humea- no e como ele relaciona-se com a metafísica de mundos possíveis. Em outras palavras, o meu objetivo é entender as bases losó cas que sus- tentam o realismo modal genuíno. (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.