Possible Worlds, Misc

The problem of communication in de se thoughts is the problem of communication of first-person or self-locating thoughts across the speakers of a conversation. The problem mainly stems from the lack of a proper account of attitude and content — an account that is supposed to explain whether or how the context of linguistic utterances is related to the semantic content of a sentence, assertion and belief. In this paper, after introducing two new semantic items, namely, almost-impossible and almost-necessary propositions, (...) that could be taken as theoretically primitive entities in the semantic framework I wish to draw, I propose an account of modified Lewisian-centered content and attitude based on the metaphysical framework of the Lewisian counterpart-theoretic semantics for quantified modal logic to the extent that the modification relies on those new semantic items. I then show that we can solve the problem by using our modified account. (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)

Essentialism about natural kinds involves talking about kinds across possible worlds. I argue that there is a non-trivial transworld identity problem here, which cannot be (dis)solved in the same way that Kripke treats the corresponding transworld identity problem for individuals. -/- I will briefly discuss some ideas for a solution. The upshot is scepticism concerning natural-kind essentialism.

There is a profound, but frequently ignored relationship between logical consequence (formal implication) and material implication. The first repeats the patterns of the latter, but with a wider modal reach. It is argued that this kinship between formal and material implication simply means that they express the same kind of implication, but differ in scope. Formal implication is unrestricted material implication. This apparently innocuous observation has some significant corollaries: (1) conditionals are not connectives, but arguments; (2) the traditional examples of (...) valid argumentative forms are metalogical principles that express the properties of logical consequence; (3) formal logic is not a useful guide to detect valid arguments in the real world; (4) it is incoherent to propose alternatives to the material implication while accepting the classical properties of formal implication; (5) some of the counter-examples to classical argumentative forms and known conditional puzzles are unsound. (shrink)

Despite the notions of possible worlds and substances are very important subjects of contemporary metaphysics, there are relatively few attempts to combine these in a united framework. This paper considers the metaphysical model of the origins and the evolution of possible worlds that occurs from an interaction between substances. I involve Leibniz’s doctrine of the striving possibles that every possibility of substance has its own essence and tendency towards existence. It is supposed that the activities of substances are constantly aimed (...) at using this tendency in all possible ways. Only the consistent and stable interactions between the substances give birth to stable objects in one of many worlds. Thus activity of substances changes from the possible modality of being to the actual modality of being in form of existence of the worlds. I divide substance’s possibility into two aspects—dynamic (possible or virtual history) and static (possible or potential mutual state). Thanks to the summation of virtual histories, in the possible modality of being, the maximal number of virtual histories is combined into the actual history in the actual modality. (shrink)

If possible worlds are conjunctions of states of affairs, as in David Armstrong’s combinatorial theory, then is the empty world to be thought of as the null conjunction of states of affairs? The proposal seems plausible, and has received support from David Efird, Tom Stoneham, and Armstrong himself. However, in this paper, it is argued that the proposal faces a trilemma: either it leads to the absurd conclusion that the actual world is empty; or it reduces to a familiar representation (...) of the empty world in which the concept of a null conjunction plays no role; or it needs to make room for the null individual of certain non-classical mereologies. (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)

This is a review of Peter Fritz's _Foundations of Modality: From Propositions to Possible Worlds_.

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)

Serious actualism is the view that it is metaphysically impossible for an entity to have a property, or stand in a relation, and not exist. Fine (1985) and Pollock (1985) influentially argue that this view is false. In short, there are properties like the property of nonexistence, and it is metaphysically possible that some entity both exemplifies such a property and does not exist. I argue that such arguments are indeed successful against the standard formulation of serious actualism. However, I (...) also argue that we should distinguish a weaker formulation of serious actualism using the actualist distinction between truth in, and truth at, a possible world. This weaker formulation is then shown to be consistent with the existence and possible exemplification of properties like the property of nonexistence. I end with a novel argument for the truth of the weaker formulation. (shrink)

Brauer (2022) has recently argued that if it is possible that there is nothing, then the correct modal logic for metaphysical modality cannot include D. Here, I argue that Brauer’s argument is unsuccessful; or at the very least significantly weaker than presented. First, I outline a simple argument for why it is not possible that there is nothing. I note that this argument has a well-known solution involving the distinction between truth in and truth at a possible world. However, I (...) then argue that once the semantics presupposed by Brauer’s argument is reformulated in terms of truth at a world, we have good reasons to think that a crucial semantic premise in Brauer’s argument should be rejected in favour of an alternative. Brauer’s argument is, however, no longer valid with this alternative premise. Thus, plausibly Brauer’s argument against D is only valid, if it is not sound. (shrink)

Possible world semantics has been gradually fine-grained over the years. First, simple extensional semantics was fine-grained by relativizing it to worlds considered as counterfactual, thus generating standard possible-world semantics, which was later further fine-grained by relativizing it to worlds considered as actual, thus generating two-dimensional semantics. However, worlds considered as actual were only considered with respect to the empirical facts obtaining in such worlds. This paper shows that no less of an important role is played by another feature of actual (...) worlds, namely, the criteria of identity that obtain in such worlds. (shrink)

My aim is to propose a better way to understand moral demandingness: a counterfactual view that requires us to consider the demands that moral theories make across other possible worlds. Seemingly, the demandingness of any moral theory or principle should be evaluated in terms of that theory’s general demandingness. This, in turn, implies that we ought to be concerned about the possible demandingness of moral theories and not just about how demanding they actually are. This counterfactual view might also have (...) some surprising implications about how demanding commonsense morality really is. After all, commonsense morality might be extremely demanding in many possible worlds. This consideration, in turn, risks undermining the commonsense moral theorist's ability to make purely cost-based demandingness objections against consequentialism, giving us strong reasons to worry about the purely cost-based demandingness objection’s viability in general. (shrink)

Leibniz thinks that every created substance is causally active, and yet causally independent of every other: none can cause changes in any but itself. This is not controversial. But Leibniz also thinks that every created substance is existentially independent of every other: it is metaphysically possible for any to exist with or without any other. This is controversial. I argue that, given a mainstream reading of Leibniz’s essentialism, if one accepts the former, uncontroversial interpretation concerning causal independence, then one ought (...) also to accept the latter, controversial one concerning existential independence. This is a new way to defend the ‘existential independence’ interpretation. Moreover, this defense provides a new approach for defending the broadly ‘non-logical’ interpretive camp in the longstanding debate over Leibniz’s views on incompossibility, against perhaps the strongest objection leveled by advocates of the opposing broadly ‘logical’ interpretation. (shrink)

According to the Principle of Sufficient Reason (‘PSR’), every fact has an explanation for why it obtains. If the PSR is true, there must be a sufficient reason for why God chose to create our world. But a sufficient reason for God’s choice plausibly necessitates that choice. It thus seems that God could not have done otherwise, and that our world exists necessarily. We therefore appear forced to pick between the PSR, and the contingency of creation and divine choice. I (...) show that a third option remains open, and thus that it is possible to preserve the contingency of creation and divine choice even while endorsing the PSR. My solution depends on the coherence of a restricted modal realism. On this modal realism, there is more than one possible morally optimal created world, and for each such world there is an existing possibility in which God creates that world. (shrink)

Paradoxes of nested modality, like Chisholm’s paradox, rely on S4 or something stronger as the propositional logic of metaphysical modality. Sarah-Jane Leslie’s objection to the resolution of Chisholm’s paradox by means of rejection of S4 modal logic is investigated. A modal notion of essence congenial to Leslie’s objection is clarified. An argument is presented in support of Leslie’s crucial but unsupported assertion that, on pain of inconsistency, an object’s essence is the same in every possible world. A fallacy in the (...) argument is exposed. Alternative interpretations of Leslie’s objection are provided and are found to involve equivocation between different notions of “essence.” A material artifact’s modal essence, as distinct from its quiddity essence, could have been different than it is. (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)

Agents' Abilities ist ein Geschenk von einem Buch, das man nicht genug loben kann. Und deswegen versuche ich es erst gar nicht. Stattdessen beschränke ich mich auf einige konstruktiv-kritische Bemerkungen, die in zwei miteinander verbundenen Bereichen Perspektiven der Weiterentwicklung und Verfeinerung aufzeigen sollen.

This paper aspires to meet a philosophical challenge posed to the author to give treatment to what was seen as a particularly nice Meinongian case1; namely the case of Galician Meigas. However, through the playful footpaths of enchanted Galician Meigas, I rehabilitate some relevant discussion on the justification of belief formation and come to some poignant philosophical insights regarding the understanding of possibilities. I hope both the leading promoter of the challenge and, of course, other philosophical readers are satisfied with (...) the outcome. (shrink)

It is widely alleged that metaphysical possibility is “absolute” possibility Conceivability and possibility, Clarendon, Oxford, 2002, p 16; Stalnaker, in: Stalnaker Ways a world might be: metaphysical and anti-metaphysical essays, Oxford University Press, Oxford, 2003, pp 201–215; Williamson in Can J Philos 46:453–492, 2016). Kripke calls metaphysical necessity “necessity in the highest degree”. Van Inwagen claims that if P is metaphysically possible, then it is possible “tout court. Possible simpliciter. Possible period…. possib without qualification.” And Stalnaker writes, “we can agree (...) with Frank Jackson, David Chalmers, Saul Kripke, David Lewis, and most others who allow themselves to talk about possible worlds at all, that metaphysical necessity is necessity in the widest sense.” What exactly does the thesis that metaphysical possibility is absolute amount to? Is it true? In this article, I argue that, assuming that the thesis is not merely terminological, and lacking in any metaphysical interest, it is an article of faith. I conclude with the suggestion that metaphysical possibility may lack the metaphysical significance that is widely attributed to it. (shrink)

A standard contemporary formulation of essentialism defines essential properties with a help of a concept of possible worlds. It is often argued that in order to use possible worlds effectively, facts about transworld identity of individuals need to be determined. In this paper I discuss how essentialist might attempt the issue of transworld identity of individuals. Specifically, I analyze a connection between essentialism and the two theories that explain the transworld identity issue, that is, haecceitism and antihaecceitism. I provide a (...) detailed analysis of different variants of antihaecceitism and argue, that all of them are incompatible with basic intuitions that stay behind essentialism. In contrast to that, I defend a position that essentialism ought to be combined with some form of haecceitism. In the remainder of this paper I provide the two ways through which essentialist might be a haecceitist. (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)

A common argument for atheism runs as follows: God would not create a world worse than other worlds he could have created instead. However, if God exists, he could have created a better world than this one. Therefore, God does not exist. In this paper I challenge the second premise of this argument. I argue that if God exists, our world will continue without end, with God continuing to create value-bearers, and sustaining and perfecting the value-bearers he has already created. (...) Given this, if God exists, our world—considered on the whole—is infinitely valuable. I further contend that this theistic picture makes our world's value unsurpassable. In support of this contention, I consider proposals for how infinitely valuable worlds might be improved upon, focusing on two main ways—adding value-bearers and increasing the value in present value-bearers. I argue that neither of these can improve our world. Depending on how each method is understood, either it would not improve our world, or our world is unsurpassable with respect to it. I conclude by considering the implications of my argument for the problem of evil more generally conceived. (shrink)

Rather than answering the question "What are possible worlds?", I wish to discuss what I think is a more tractable question, namely, "What what theoretical roles are possible worlds supposed to play, and are they cut out to play those roles?" The question is tractable because we can simply look and see to what purposes possible worlds have been put and whether possible worlds analyses have survived the test of time, or whether they have been succeeded by superior analyses which (...) either do away with worlds altogether or else demote them to a lesser role. In giving a partial answer to the question, we will begin by looking at traditional possible worlds analyses of intensional and modal concepts (§2). We will then look at three possible worlds analyses that have played an important role in their perceived success, viz. the analyses of (i) modality and possibilities in counterpart theory (§3), (ii) belief contents (§4), and (iii) conditionals (§5). (shrink)

A counterpossible conditional is a counterfactual with an impossible antecedent. Common sense delivers the view that some such conditionals are true, and some are false. In recent publications, Timothy Williamson has defended the view that all are true. In this paper we defend the common sense view against Williamson’s objections.

“There are no gaps in logical space,” David Lewis writes, giving voice to sentiment shared by many philosophers. But different natural ways of trying to make this sentiment precise turn out to conflict with one another. One is a *pattern* idea: “Any pattern of instantiation is metaphysically possible.” Another is a *cut and paste* idea: “For any objects in any worlds, there exists a world that contains any number of duplicates of all of those objects.” We use resources from model (...) theory to show the inconsistency of certain packages of combinatorial principles and the consistency of others. (shrink)

According to possibilism, or non-actualism, fictional characters are possible individuals. Possibilist accounts of fiction do not only assign the intuitively correct truth-conditions to sentences in a fiction, but has the potential to provide powerful explanatory models for a wide range of phenomena associated with fiction (though these two aspects of possibilism are, I argue, crucially distinct). Apart from the classic defense by David Lewis the idea of modeling fiction in terms of possible worlds have been widely criticized. In this article, (...) I provide a defense of a possibilist account against some lines of criticism. To do so, I assume that names for fictional characters are directly referential and a possible-worlds model that accommodates transworld identity. On this background, I argue, it is possible to construct an elegant model of fictional discourse using familiar models of information exchange in ordinary discourse, and I sketch how this model can be used to i) make a natural distinction between fictional and counterfactual discourse, ii) account for creativity, and iii) sustain a natural definition of truth-in-fiction that avoids certain familiar objections to possibilism. Though I set aside questions about the metaphysical commitments of a possible-world interpretation here, there is accordingly reason to think that the battle over possibilist treatments of fiction will have to be fought over metaphysical foundations rather than technical shortcomings. (shrink)

A new puzzle of modal recombination is presented which relies purely on resources of first-order modal logic. It shows that naive recombinatorial reasoning, which has previously been shown to be inconsistent with various assumptions concerning propositions, sets and classes, leads to inconsistency by itself. The context sensitivity of modal expressions is suggested as the source of the puzzle, and it is argued that it gives us reason to reconsider the assumption that the notion of metaphysical necessity is in good standing.

La logica modale è nata per studiare i ragionamenti su ciò che è possibile e ciò che è necessario. Negli ultimi decenni, a partire dal lavoro di logici e filosofi quali Rudolf Carnap, Saul Kripke e David Lewis, la sua applicazione è stata progressivamente estesa ad altri ambiti, quali il ragionamento sul tempo, sulla conoscenza e sui sistemi di norme. Queste ricerche hanno condotto a un complesso e intrigante dialogo con alcune fondamentali branche della filosofia: la metafisica, l’epistemologia, la filosofia (...) del linguaggio. Lo scopo del volume è offrire una panoramica di questo dialogo al contempo accessibile e rigorosa, pensata sia per gli studenti di un corso universitario, sia per il lettore non specialista. Se da un lato tutte le necessarie nozioni tecniche sono rese accessibili ai non addetti ai lavori, dall'altro si restituisce un'immagine fedele delle sfide concettuali che la ricerca in questi settori è oggi chiamata ad affrontare. (shrink)

The subject of this paper is the notion of similarity between the actual and impossible worlds. Many believe that this notion is governed by two rules. Ac-cording to the first rule, every non-trivial world is more similar to the actual world than the trivial world is. The second rule states that every possible world is more similar to the actual world than any impossible world is. The aim of this paper is to challenge both of these rules. We argue that (...) acceptance of the first rule leads to the claim that the rule ex contradictione sequitur quodlibet is invalid in classical logic. The second rule does not recognize the fact that objects might be similar to one an-other due to various features. (shrink)

La noción de mundos posibles, sostiene que nuestro mundo es un mundo entre otros, un subconjunto de todas las cosas que existen. Esto implica aceptar que existen mundos estructuralmente equivalentes con sus propios lenguajes [formales], que entre sí no tienen ningún estatuto privilegiado, p.e., el mundo y lenguaje del arte o el mundo y lenguaje de la física; no obstante, la idea de aceptar otros mundos equivalentes como mundos posibles epistémica y ontológicamente legítimos para acceder y expresar lo cognoscible del (...) mundo no goza de gran aceptación. En este sentido, de entre las múltiples dimensiones de la noción de mundos posibles anotada, su dimensión lógica, es una de las más extendidas, ésta se entiende como un posible estado de cosas o un posible curso de eventos. Empero, esta concepción es la más restrictiva de la noción de mundos posibles, no sólo porque dicha noción transmuta en una especie de «técnica predictiva» que nos permite analizar y visualizar posibles escenarios de un estado de cosas o un curso de eventos, sino porque fundamentalmente, la noción de mundos posibles pierde gran parte de su potencia conceptual. Hablar de proposiciones como conjuntos de mundos posibles, no es un error, pero es limitar innecesariamente el alcance y campo de acción de la noción de mundos posibles. Si entendemos dicha noción en la versión primaría de Lewis [«Nuestro mundo actual es sólo un mundo entre otros»], sería plausible recuperar, entre otras, las dimensiones ontológica y epistémica de la noción de mundos posibles, y por ende la posibilidad objetiva de indagar en formas alternativas y legitimas de acceder y expresar lo cognoscible del mundo; en este sentido, en este trabajo me propongo: (1) retomar la noción primaria de mundos posibles de Lewis, para analizar y explicitar brevemente sus limitaciones, virtudes y requerimientos; (2) examinar las condiciones de posibilidad de un mundo; y, (3) sugerir los lineamientos epistémicos que deberían considerarse y explicitarse cuando se habla de y desde un mundo posible a la hora de expresar un enunciado. (shrink)

This chapter is concerned with the coextension difficulty for nominalist theories of properties that reject tropes alongside universals. After carefully explaining the coextension difficulty and describing the theories it targets, the chapter describes different solutions to the difficulty. These solutions differ with respect to how much involved they are into a dualist approach to coextension. A dualist approach to a case of coextension consists in agreeing with the realist that the relevant ascriptions of properties are numerically distinct. A monist approach (...) to a case of coextension consists in contending that the relevant ascriptions of properties are identical. In this chapter, I defend a monist approach to cases of coextension that appeals to a counterpart theory for propositions. (shrink)

In a pair of recent essays, William Lane Craig has argued that certain open theist understandings of the nature of the future are both semantically and modally confused. I argue that this is not the case and show that, if consistently observed, the customary semantics for counterfactuals Craig relies on not only undermine the validity of his complaint against the open theist, they actually support an argument for the openness position.

Review of Bob Hale's "Necessary Beings: An Essay on Ontology, Modality, and the Relations Between Them". Oxford: Oxford University Press 2013, ISBN 9780199669578.

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)

This article compares David Lewis’s understanding of counterfactuals with a Platonic theory of counterfactual truthmakers. By pointing to some weaknesses in Lewis’s theory, it will highlight some of the strengths of the Platonic theory. The article will progress in the following way. First, I present David Lewis’s understanding of counterfactuals, and discuss some problems the theory has. Next, I discuss Platonic truthmakers, in general, and then show how this applies to counterfactuals. Finally, I discuss the strengths and weaknesses of the (...) Platonic theory, and how it is superior to Lewis’s theory. (shrink)

David Lewis holds that a single possible world can provide more than one way things could be. But what are possible worlds good for if they come apart from ways things could be? We can make sense of this if we go in for a metaphysical understanding of what the world is. The world does not include everything that is the case—only the genuine facts. Understood this way, Lewis's “cheap haecceitism” amounts to a kind of metaphysical anti-haecceitism: it says there (...) aren't any genuine facts about individuals over and above their qualitative roles. (shrink)

This paper establishes that the occasional identity relation and the contingent identity relation are both non-transitive and as such are not properly classified as identity relations. This is achieved by appealing to cases where multiple fissions and fusions occur simultaneously. These cases show that the contingent and occasional identity relations do not even satisfy the time-indexed and world-indexed versions of the transitivity requirement and hence are non-transitive relations.

A fairly simple theory of the semantics of tense is obtained by combining three claims: (i) for any time t, a present-tense sentence `p' is either true or false at t; (ii) for any time t0 earlier than t, the future-tense sentence `It will be the case that p at t' is true at t0 if `p' is true at t, false otherwise; (iii) for any time t0 later than t, the past-tense sentence `It was the case that p at (...) t' is true at t0 if `p' is true at t, false otherwise. This theory, which has been called the theory of timeless truth, is often dismissed on the basis of its alleged incapacity to comply with indeterminism. Here, instead, it will be suggested that there is no reason to be dismissive. Section 1 provides some elucidations about the theory. Sections 2 and 3 explain how a foregone objection to it can be resisted. Sections 4 and 5 show that there is a plausible sense in which (i)-(iii) are compatible with indeterminism. Sections 6 and 7 dispel some misunderstandings that may lead to think that indeterminism is not vindicated in some important sense other than that outlined. (shrink)

David Lewis argues that centered worlds give us a way to capture de se, or self-locating, contents in philosophy of language and philosophy of mind. In recent years, centered worlds have also gained other uses in areas ranging widely from metaphysics to ethics. In this paper, I raise a problem for centered worlds and discuss the costs and benefits of different solutions. My investigation into the nature of centered worlds brings out potentially problematic implicit commitments of the theories that employ (...) them. In addition, my investigation shows that the conception of centered worlds widely attributed to David Lewis is not only problematic, but in fact not his. (shrink)

This chapter provides an introduction to possible worlds semantics in both logic and the philosophy of language, including a discussion of some of the advantages and challenges for possible worlds semantics.

Accounts of propositions as sets of possible worlds have been criticized for conflating distinct impossible propositions. In response to this problem, some have proposed to introduce impossible worlds to represent distinct impossibilities, endorsing the thesis that impossible worlds must be of the same kind; this has been called the parity thesis. I show that this thesis faces problems, and propose a hybrid account which rejects it: possible worlds are taken as concrete Lewisian worlds, and impossibilities are represented as set-theoretic constructions (...) out of them. This hybrid account (1) distinguishes many intuitively distinct impossible propositions; (2) identifies impossible propositions with extensional constructions; (3) avoids resorting to primitive modality, at least so far as Lewisian modal realism does. (shrink)

In this paper I explore the relationship between the idea of possible worlds and the notion of the beauty of God. I argue that there is a clear contradiction between the idea that God is utterly and completely beautiful on the one hand and the notion that He contains within himself all possible worlds on the other. Since some of the possible worlds residing in the mind of the deity are ugly, their presence seems to compromise God's complete and utter (...) beauty. (shrink)

Metaphysically possible worlds have many uses. Epistemically possible worlds promise to be similarly useful, especially in connection with propositions and propositional attitudes. However, I argue that there is a serious threat to the natural accounts of epistemically possible worlds, from a version of Russell’s paradox. I contrast this threat with David Kaplan’s problem for metaphysical possible world semantics: Kaplan’s problem can be straightforwardly rebutted, the problems I raise cannot. I argue that although there may be coherent accounts of epistemically possible (...) worlds with fruitful applications, any such an account must fundamentally compromise the basic idea behind epistemic possibility. (shrink)

Various writers have proposed that the notion of a possible world is a functional concept, yet very little has been done to develop that proposal. This paper explores a particular functionalist account of possible worlds, according to which pluralities of possible worlds are the bases for structures which provide occupants for the roles which analyse our ordinary modal concepts. It argues that the resulting position meets some of the stringent constraints which philosophers have placed upon accounts of possible worlds, while (...) also trivializing the question what possible worlds are. The paper then discusses a range of problems facing the functionalist position. (shrink)

There are numerous contexts in which philosophers and others use model-theoretic methods in assessing the validity of ordinary arguments; consider, for example, the use of models built upon 'possible worlds' in examinations of modal arguments. But the relevant uses of model-theoretic techniques may seem to assume controversial semantic or metaphysical accounts of ordinary concepts. So, numerous philosophers have suggested that standard uses of model-theoretic methods in assessing the validity of modal arguments commit one to accepting that modal claims are to (...) be analysed in terms of possible worlds. The paper provides a very general account of how uses of model-theoretic methods in demonstrating facts about validity and invalidity may in fact often be uncoupled from controversial semantic or metaphysical theses, applying the resulting techniques to some modal cases in particular. (shrink)

The question of what truths are necessary in the broadest possible sense is a difficult one to answer, as is the question of what the limits are to what is possible. (Most people would see these two questions as different sides of the same coin, of course, since many think the question of what is possible is just the question of what is not necessarily ruled out). We have three general sorts of strategies for determining whether something is necessary (or (...) possible). We can identify it in a class that we were previously sure was a class of things that are necessary – we might show it is a theorem of a logical system that we have confidence in, or that the sentence appears to be true simply in virtue of the meanings of the words, or that it is a true statement involving names or about natural kinds of the “necessary a posteriori” sort discussed by Kripke and Putnam, and there are perhaps other classes of claims which we are prepared to accept are necessary if true.1 Likewise, we might establish the possibility of something occurring by reference to a class of well-established or uncontroversial possibilities: e.g. we are inclined to think that it is possible (in the broadest sense) for an event to occur in the future if one of the same kind has occurred in the past. (shrink)