This article includes a basic overview of possible world semantics and a relatively comprehensive overview of three central philosophical conceptions of possible worlds: Concretism (represented chiefly by Lewis), Abstractionism (represented chiefly by Plantinga), and Combinatorialism (represented chiefly by Armstrong).

Possible world semantics considers not only what an expression actually refers to but also what it might have referred to in counterfactual circumstances. This has proven exceptionally useful both inside and outside philosophy. The way this is achieved is by using intensions. An intension of an expression is a function that assigns to each possible world the reference of the expression in that world. However, the specific intension of terms has been subject to frequent disputes. (...) How is one to determine the intension of a term? Carnap has shown how the intension of a term depends on the type of that term. Two-dimensional semantics has shown how intensions also depend on the actual state of affairs. I will show how, in addition, intensions are no less dependent on metaphysical criteria of identity. Furthermore, I will reveal how these three factors interact to fix the exact intension of a term. In other words, I propose an outline of the overall mechanism by which intensions are being fixed. (shrink)

This paper is about possible worlds semantics for propositional attitude sentences. In particular I shall focus on belief reports in English such as "Lusina believes that tofu is nutritious." It is well-known that possible worlds semantics for such reports suffers from the so-called _problem of equivalence_ . In this paper I shall examine some attempts to deal with this problem and argue that they are unsatisfactory.

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

The canonical version of possible worlds semantics for story prefixes is due to David Lewis. This paper reassesses Lewis's theory and draws attention to some novel problems for his account.

If □ is conceived as an operator, i.e., an expression that gives applied to a formula another formula, the expressive power of the language is severely restricted when compared to a language where □ is conceived as a predicate, i.e., an expression that yields a formula if it is applied to a term. This consideration favours the predicate approach. The predicate view, however, is threatened mainly by two problems: Some obvious predicate systems are inconsistent, and possible-worlds semantics for predicates (...) of sentences has not been developed very far. By introducing possible-worlds semantics for the language of arithmetic plus the unary predicate □, we tackle both problems. Given a frame (W, R) consisting of a set W of worlds and a binary relation R on W, we investigate whether we can interpret □ at every world in such a way that □ $\ulcorner A \ulcorner$ holds at a world ᵆ ∊ W if and only if A holds at every world $\upsilon$ ∊ W such that ᵆR $\upsilon$ . The arithmetical vocabulary is interpreted by the standard model at every world. Several 'paradoxes' (like Montague's Theorem, Gödel's Second Incompleteness Theorem, McGee's Theorem on the ω-inconsistency of certain truth theories, etc.) show that many frames, e.g., reflexive frames, do not allow for such an interpretation. We present sufficient and necessary conditions for the existence of a suitable interpretation of □ at any world. Sound and complete semi-formal systems, corresponding to the modal systems K and K4, for the class of all possible-worlds models for predicates and all transitive possible-worlds models are presented. We apply our account also to nonstandard models of arithmetic and other languages than the language of arithmetic. (shrink)

In the paper we will study the notions of possible-worlds semantics, fiction, and creativity. The intention is to show how the notion of possible-worlds semantics allows us to generate a fresh interpretation of the notions of fiction and creativity. To do this, we have to consider the philosophy of logic. Possible-worlds semantics can be used in interpreting modal notions. The intention is to interpret the notions of fiction and creativity as modal notions. However, the analysis shows that (...) the notions of fiction and creativity are multimodal notions. (shrink)

In the tech report Artemov and Yavorskaya [4] an elegant formulation of the first-order logic of proofs was given, FOLP. This logic plays a fundamental role in providing an arithmetic semantics for first-order intuitionistic logic, as was shown. In particular, the tech report proved an arithmetic completeness theorem, and a realization theorem for FOLP. In this paper we provide a possible-world semantics for FOLP, based on the propositional semantics of Fitting [5]. We also give an Mkrtychev semantics. Motivation (...) and intuition for FOLP can be found in Artemov and Yavorskaya [4], and are not fully discussed here.This paper is dedicated to Sergei Artemov, an honored colleague and friend, who has made wonderful things for the rest of us to play with. (shrink)

I outline a neo-Fregean strategy in the debate on the existence of possible worlds. The criterion of identity and the criterion of application are formulated. Special attention is paid to the fact that speakers do not possess proper names for worlds. A broadly Quinean solution is proposed in response to this difficulty.

If a possible-worlds semantic theory for modal logics is pure, then the assertion of the theory, taken at face-value, can bring no commitment to the existence of a plurality of possible worlds (genuine or ersatz). But if we consider an applied theory (an application of the pure theory) in which the elements of the models are required to be possible worlds, then assertion of such a theory, taken at face-value, does appear to bring commitment to the existence (...) of a plurality of possible worlds. Or at least that is so if the applied theory is adequate. For an applied possible-worlds semantic theory that is constrained to contain only one-world models is bound to deliver results on validity, soundness and completeness that are apt to seem disastrous. I attempt to steer a course between commitment to the existence of a plurality of possible worlds and commitment to such a disastrous applied possible-worlds semantics by noting, and developing, the position of one who asserts such a theory at face-value but who remains agnostic about the existence of other (non-actualized) possible worlds. Thus, a novel interpretation of applied possible-worlds semantics is offered on which we may lay claim to whatever benefits such a theory offers while avoiding realism about (other) possible worlds. Thereby, the contention that applied possible-worlds semantics gives us reason to be realists about possible worlds is (further) undermined. (shrink)

As part of an ongoing study of causal models in the history of science, a counterfactual scenario in the history of modern astronomy is explored with the aid of computer simulations. After the definition of “linking advance”, a possible world involving technological antecedence is described, branching out in 1510, in which the telescope is invented 70 years before its actual construction, at the time in which Fracastoro actually built the first prototelescope. By using the principle of the closest (...) possible world, we estimate that in this scenario the discovery of the elliptical orbit of Mars would by anticipated by only 28 years. The second part of the paper involves an estimate of the probability of the previous scenario, guided by the principle that the actual world is the mean and using computer simulations to create possible worlds in which the time spans between advances is varied according to a gamma distribution function. Taking into account the importance of the use of the diaphragm for the invention of the telescope, the probability that the telescope were built by 1538 for a branching time at 1510 is found to be smaller than 1%. The work shows that one of the important features of computational simulations in philosophy of science is to serve as a consistency check for the intuitions and speculations of the philosopher. (shrink)

_ Source: _Page Count 19 The theory of possible worlds has been minimally employed in the field of theory and philosophy of history, even though it has found a place as a tool in other areas of philosophy. Discussion has mostly focused on arguments concerning counterfactual history’s status as either useful or harmful. The theory of possible worlds can, however be used also to analyze historical writing. The concept of textual possible worlds offers an interesting framework to (...) work with for analyzing a historical text’s characteristics and features. However, one of the challenges is that the literary theory’s notion of possible worlds is that they are metaphorical in nature. This in itself is not problematic but while discussing about history, which arguably deals with the real world, the terminology can become muddled. The latest attempt to combine the literary and philosophical notions of possible worlds and apply it to historiography came from Lubomír Doležel in his _Possible Worlds of Fiction and History: The Postmodern Stage_. I offer some criticism to his usage of possible worlds to separate history and fiction, and argue that when historiography is under discussion a more philosophical notion of possible worlds should be prioritized over the metaphorical interpretation of possible worlds. (shrink)

It is difficult to wander far in contemporary metaphysics without bumping into talk of possible worlds. And reference to possible worlds is not confined to metaphysics. It can be found in contemporary epistemology and ethics, and has even made its way into linguistics and decision theory. What are those possible worlds, the entities to which theorists in these disciplines all appeal? This paper sets out and evaluates a leading contemporary theory of possible worlds, David Lewis's Modal (...) Realism. I note two competing ambitions for a theory of possible worlds: that it be reductive and user-friendly. I then outline Modal Realism and consider objections to the effect that it cannot satisfy these ambitions. I conclude that there is some reason to believe that Modal Realism is not reductive and overwhelming reason to believe that it is not user-friendly. (shrink)

... 112 ROBERT STALNAKER example Alvin Plantinga and Robert Adams) define possible worlds in terms of states of affairs or propositions ; others (for example Max Cresswell) use a strategy quite similar to that of situation semantics, defining possible worlds as constructs out of ..

Those who object to David Lewis' modal realism express qualms about philosophical respectability of the Lewisian notion of a possible world and its correlate notion of an inhabitant of a possible world. The resulting impression is that these two notions either stand together or fall together. I argue that the Lewisian notion of a possible world is otiose even for a good Lewisian modal realist, and that one can carry out a good Lewisian semantics (...) for modal discourse without Lewisian possible worls. I do so by generalizing Lewis' own idea that restrictions on quantification come and go with the pragmatic wind and relativizing possible worlds as shifting domains of discourse. I then suggest a way to soften the infamous incredulous stare. (shrink)

With the development of technology, video games have become more and more realistic and indistinguishable from the real world. In this regard, this article takes a semiotic approach to create a better understanding of how possible worlds are created in video games, placing them on a continuum, which shows that the development of possible worlds is based on the reality we face in the real world. A video game called Player Unknown’s Battle Grounds is used to (...) demonstrate a new approach to analysis, which shows that each video game is created within its own possible world that is created through the selection and combination of entities from the real world. (shrink)

Providing a possible worlds semantics for a logic involves choosing a class of possible worlds models, and setting up a truth definition connecting formulas of the logic with statements about these models. This scheme is so flexible that a danger arises: perhaps, any (reasonable) logic whatsoever can be modelled in this way. Thus, the enterprise would lose its essential tension. Fortunately, it may be shown that the so-called incompleteness-examples from modal logic resist possible worlds modelling, even in (...) the above wider sense. More systematically, we investigate the interplay of truth definitions and model conditions, proving a preservation theorem characterizing those types of truth definition which generate the minimal modal logic. (shrink)

The issue of reduction of propositions to sets of possible worlds is addressed. It is shown that, under some natural assumptions, there always exist recursive propositions, i.e. decidable sets of possible worlds, which are not assigned to any sentence of a language. Some consequences of this result are discussed.

Providing a possible worlds semantics for a logic involves choosing a class of possible worlds models, and setting up a truth definition connecting formulas of the logic with statements about these models. This scheme is so flexible that a danger arises: perhaps, any logic whatsoever can be modelled in this way. Thus, the enterprise would lose its essential 'tension'. Fortunately, it may be shown that the so-called 'incompleteness-examples' from modal logic resist possible worlds modelling, even in the (...) above wider sense. More systematically, we investigate the interplay of truth definitions and model conditions, proving a preservation theorem characterizing those types of truth definition which generate the minimal modal logic. (shrink)

The article investigates the sceptical challenge from an informationtheoretic perspective. Its main goal is to articulate and defend the view that either informational scepticism is radical, but then it is epistemologically innocuous because redundant; or it is moderate, but then epistemologically beneficial because useful. In order to pursue this cooptation strategy, the article is divided into seven sections. Section 1 sets up the problem. Section 2 introduces Borei numbers as a convenient way to refer uniformly to (the data that individuate) (...) different possible worlds. Section 3 adopts the Hamming distance between Borei numbers as a metric to calculate the distance between possible worlds. In Sects. 4 and 5, radical and moderate informational scepticism are analysed using Borei numbers and Hamming distances, and shown to be either harmless (extreme form) or actually fruitful (moderate form). Section 6 further clarifies the approach by replying to some potential objections. In the conclusion, the Peircean nature of the overall approach is briefly discussed. (shrink)

In the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb Log 50:510–530, 1985 ). This paper focuses on the extension of AGM that accounts for contractions of a theory by a set of sentences instead of only by a single sentence. Hansson (Theoria 55:114–132, 1989 ), Fuhrmann and Hansson (J Logic Lang Inf 3:39–74, 1994 ) generalized Partial Meet Contraction to the case of contractions by (possibly non-singleton) sets of sentences. In this (...) paper we present the possible worlds semantics for partial meet multiple contractions. (shrink)

In this paper we discuss the notion of “possible worlds” contrasting a philosophical idea due to Malebranche with a mathematical concept of modern logic due to Kripke from which many pseudo-philosophical discussions have arisen.

This entry provides a brief exposition and formal reconstruction of the argument for possible worlds in David Lewis's _Counterfactuals_.

Saul Kripke did more than anyone else to bring possible worlds into the contemporary philosophical discourse, first with his more formal work on the model theory for modal logic in the 1960s, and then with his more philosophical lectures on reference and modality, delivered in January 1970, that used the possible worlds apparatus informally to clarify the relations between semantic issues about names and metaphysical issues about individuals and kinds. Possible worlds semantics have been widely applied since (...) then, both in philosophy and in other fields such as linguistic semantics and pragmatics, theoretical computer science, and game theory. Kripke’s work, along with that of David Lewis, stimulated an ongoing debate about the nature and metaphysical status of possible worlds. Kripke himself has had little to say about the issues raised in this debate, in print, beyond what he said in Naming and Necessity and in brief remarks in a preface to a later edition of the lectures, published in 1980. But there is a clear view of the nature of possible worlds, and of the status of an explanation of modality in terms of possible worlds, implicit in the lectures and the preface. -/- The central focus of the post–Naming and Necessity debate about possible worlds has been a contrast between David Lewis’s modal realism and various versions of actualism. On this general issue, it is clear enough where Kripke stands: His criticisms of what he describes as the “other countries” picture of possible worlds are an explicit rejection of Lewis’s realism about possible worlds. But the rejection of modal realism raises a range of further questions: What exactly are possible worlds (or possible states of the world, which Kripke suggests would be less misleading terminology)? What contribution do they make to the explanation of modal discourse, and of the distinctive facts that modal discourse is used to state? Does the slogan “necessity is truth in all possible worlds” provide, or point to, a reductive analysis of necessity? Are possible worlds, in some sense, prior to modal operators and modal auxiliaries? If not, in what sense are they explanatory? How are possible worlds, or counterfactual situations, specified? How do they contribute to our understanding of specific meta- physical questions about the relations between particular individuals and their qualitative characteristics, the kinds to which they belong, and the matter of which they are constituted? How are we to understand the possible existence of individuals that do not actually exist? What is the status of the domains of individuals in merely possible worlds? -/- My aim in this chapter is to spell out the views about some of these foundational questions that are expressed or at least implicit in Kripke’s lectures. In Section 2, I discuss the general contrast between modal realism and actualism and questions about the kind of explanation that possible worlds provide for modal discourse and modal facts. In Section 3, I look at Kripke’s views about how possible worlds are specified, in particular at the role of individuals in specifying possible worlds. In Section 4, I consider the problems about merely possible individuals. (shrink)

David Lewis' modal counterpart theory falls prey to the famous Saul Kripke's objection, and this is mostly due to his 'static' ontology (divergence) of possible worlds. This paper examines a genuinely realist but different, branching ontology of possible worlds and a new definition of the counterpart relation, which attempts to provide us with a better account of de re modality, and to meet satisfactorily Kripke's claim, while being also ontologically more 'parsimonious'.

It is sometimes argued that if God were to exist, then the actual world would be the best possible world. However, given that the actual world is clearly not the best possible world, then God doesn’t exist. In response, some have argued that the world could always be improved with the creation of new people and that there is thus no best possible world. I argue that this reasoning gives rise to (...) an instance of Parfit’s mere addition paradox and should thus be rejected. Others (Robert Adams, in particular) have argued that the actual world may, in fact, be the best possible world, at least for all actual people. I argue that this reasoning gives rise to Parfit’s non-identity problem and should thus be rejected. (shrink)

The role of possible worlds in philosophy is hard to overestimate. Nevertheless, their nature and existence is very controversial. This is particularly serious, since their standard applications depend on there being sufficiently many of them. The paper develops an account of possible worlds on which it is particularly easy to believe in their existence: an account of possible worlds as pleonastic entities. Pleonastic entities are entities whose existence can be validly inferred from statements that neither refer to (...) nor quantify over them as a matter of conceptual necessity. Definitions are proposed that ensure that this is the case for possible worlds. (shrink)

Ever since Saul Kripke and others developed a semantic interpretation for modal logic, 'possible worlds' has been a much debated issue in contemporary metaphysics. To propose the idea of a possible world that differs in some way from our actual world - for example a world where the grass is red or where no people exist - can help us to analyse and understand a wide range of philosophical concepts, such as counterfactuals, properties, modality, and (...) of course, the notions of possibility and necessity. This book examines the ways in which possible worlds have been used as a framework for considering problems in logic and argument analysis. The book begins with a non-technical introduction to the basic ideas of modal logic in terms of Kripke's possible worlds and then moves on to a discussion of 'possible for' and 'possible that'. The central chapters examine questions of meaning, epistemic possibility, temporal logic, metaphysics, and impossibility. Girle also investigates how the idea of a possible world can be put to use in different areas of philosophy, the problems it may raise, and the benefits that can be gained. (shrink)

This thesis examines the alethic modal concepts of possibility and necessity. It is argued that one cannot do justice to all our modal talk without possible worlds, i.e., complete ways that a cosmos might have been. I argue that not all of the proposed applications of possible worlds succeed but enough remain to give one good theoretical reason to posit them. The two central problems now are: What feature of reality makes correct alethic modal claims true and What (...) are possible worlds? ;David Lewis makes possible worlds be concretely existing universes. Unfortunately, I show Lewis's account involves set-theoretic, ethical, inductive and probabilistic paradoxes, and commits Lewis to an objectionable form of primitive modality that governs the choice of the counterpart relation. The most promising contemporary alternatives to Lewis's theory have been the worlds of Adams and Plantinga constructed out of Platonic entities such as maximal collections of consistent propositions. However, these approaches fail to provide a satisfactory answer to the question of what makes true modal claims true. I also criticize some alternative accounts. ;Finally, I discuss and combine two historical approaches. The first is an Aristotelian approach that says a non-actual event is possible is to say that some actual substances could have initiated a causal chain that could lead up to the event in question. However, it can be shown that some plausible global possibility claims can be made true on this account only if there is a necessarily existent first cause capable of initiating very different universes. On the other hand, Leibniz made possible worlds be ideas in the mind of an omniscient necessarily existent deity. Leibniz fails to explain what it is that makes these possible worlds possible, but if we were willing to combine his story with the conclusion drawn from the Aristotelian one, we could get the following story: Possible worlds are ideas in the mind of an omniscient deity and what makes them possible is that this deity has the Aristotelian capability of initiating causal chains that can lead to them being actualized. (shrink)

An outline for a modal interpretation in terms of possible worlds is presented. The so-called Schmidt histories are taken to correspond to the physically possible worlds. The decoherence function defined in the histories formulation of quantum theory is taken to prescribe a non-classical probability measure over the set of the possible worlds. This is shown to yield dynamics in the form of transition probabilities for occurrent events in each world. The role of the consistency condition is (...) discussed. (shrink)

In this chapter, I survey what I call Lewisian approaches to modality: approaches that analyze modality in terms of concrete possible worlds and their parts. I take the following four theses to be characteristic of Lewisian approaches to modality. (1) There is no primitive modality. (2) There exists a plurality of concrete possible worlds. (3) Actuality is an indexical concept. (4) Modality de re is to be analyzed in terms of counterparts, not transworld identity. After an introductory section (...) in which I motivate analyzing modality in terms of possible worlds, I devote one section to each of these four theses. For each thesis, I take Lewis’s interpretation and defense as my starting point. I then consider and endorse alternative ways of accepting the thesis, some of which disagree substantially with Lewis’s interpretation or defense. There is more than one way to be a Lewisian about modality. (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)

“The Craft of Formal Logic” is Arthur Prior’s unpublished textbook, written in 1950–51, in which he developed a theory of modality as quantification over possible worlds-like objects. This theory predates most of the prominent pioneering texts in possible worlds semantics and anticipates the significance of its basic concept in modal logic. Prior explicitly defines modal operators as quantifiers of ‘entities’ with modal character. Although he talks about these ‘entities’ only informally, and hesitates how to name them, using alternately (...) the phrases ‘possible states of affairs’, ‘chances’, ‘cases’ or ‘peculiar objects’, he is nevertheless very clear that they should be the fundamental concept of any theory of modality as a form of quantity. Without the assumption that modal operators quantify over such modal objects, the modal system will be incapable of distinguishing an actually true proposition from a necessarily true one. Due to the fact that Prior never made any direct reference to this theory in his subsequently published papers, it remained largely unknown. The comparison of “The Craft” with some of his papers on tense logic suggests that this early theory of modality underlies his later work on temporality. (shrink)

Alvin Plantinga’s solution to J. L. Mackie’s logical problem of evil invokes possible-worlds metaphysics. There are reasons for thinking that the solution is, at least, problematic. Difficulties emerge in the attempts to answer four related questions. (1) Can God’s necessary existence, understood in terms of possible-world metaphysics, make God’s actual existence impossible to explain? (2) Can an omniscient being with knowledge of the contents of every possible world (a being endowed with “middle knowledge”) prove ignorant (...) of the consequences of his creative acts? (3) Can an immoral action performed by an agent suffering from “transworld depravity” also be free in the libertarian sense? (4) Does the possible-worlds interpretation of libertarian freedom generate a vicious infinite regress? Special focus is on the possibility, advanced by Plantinga, that there are possible worlds that even an omnipotent being cannot create. Plantinga’s views are contrasted with those of Thomas Aquinas. (shrink)

In his paper "Are There Set Theoretic Possible Worlds?", Selmer Bringsjord argued that the set theoretic definition of possible worlds proffered by, among others, Robert Adams and Alvin Plantinga is incoherent. It is the purpose of this note to evaluate that argument. The upshot: these set theoretic accounts can be preserved, but only by abandoning the power set axiom.

Istanbul Feminist Night Marches are a long-lasting branch of feminist activism for Women’s Day in Turkey. Each year, thousands of women get together around Istiklal Street and sing and chant together; drum beats emanate from percussion groups; whistles accompany slogans, slogans accompany songs. In the end, the acoustic experience becomes one of the most memorable aspects of the demonstration. Following this premise, this article investigates the political significance of the Istanbul Feminist Night Marches through its acoustic atmosphere and asks the (...) question: How is the soundscape of the march related to its political power? What does this soundscape do? And what might we discover from trying to listen to the soundscape of the march with a theoretical ear? Combining personal experiences of individuals who participated in these protests with theories and historical discussions about the gendered acoustic sensory order of the social fabric, this article sets out to reveal the political and transformative power of the Istanbul Feminist Night Marches by investigating the voices and sounds within. The article argues that the composition of Feminist Night Marches, where women gather to stand side by side with their differences, is represented by the acoustic atmosphere of the march that women describe as a cacophony. This acoustic atmosphere enables a different type of relationality and politics that privilege who is speaking rather than what is spoken. When women tune in to this atmosphere they get materially affected by it and leave the scene with an increased capacity to act. The combination of protest against patriarchy and celebration of life within this soundscape creates affective solidarities among women and new potentialities regarding how we relate to each other by sounding possible worlds. (shrink)

This paper is predicated on the idea that some modal operators are better understood as quantificational expressions over worlds that determine not only first-order facts but modal facts also. In what follows, we will present a framework in which these two types of facts are brought closer together. Structural features will be located in the worlds themselves. This result will be achieved by decomposing worlds into parts, where some of these parts will have “modal import” in the sense that they (...) will determine structure on other worldly parts. The main upshot of this will be a clearer grasp of the interaction between modal notions. (shrink)

We analyze a recent trend in epistemic logic which consists in studying construction of knowledge from the agents’ observational abilities. It is based on the intuition that an agent’s knowledge comes from three possible sources: her observations, communication with other agents, and inference. The approaches mainly focus on the former two and suppose that the object of observations are propositional variables and that agents learn from public announcements. This allows to model knowledge in a more compact and intuitive way (...) than with Hintikka’s semantics. However, the semantics that one can find in the literature come with some counter-intuitive validities such as common knowledge of visibilities or the knowledge operator distributing over disjunctions. We propose a solution of each of these two issues and illustrate them with well-known toy examples of epistemic logic. (shrink)

Formalized physical theories are not, as a rule, stated in intensional languages. Yet in talking about them we often treat them as if they were. We say for instance: 'Consider what would happen if instead of p's being true q were. In such a case r would be likely.' If we say this sort of thing, p, q and r appear to stand for the meanings of sentences of the theory, but meanings in some intensional sense. Now it is very (...) easy to extend the syntax of the formal theory by adding all sorts of intensional operators, e.g. a modal operator; and it is possible to extend the semantics by adding a set of possible worlds and evaluating the modal formulae in the usual way. But this procedure is open to the criticism that we are extending the theory by adding something which is not already there. In particular the criticism will be that the possible worlds required by the semantics seem to have no connection with the intended interpretations of the original physical theory. The aim of this paper is to shew how a set of possible worlds is already implicit in the intended interpretations of a formally presented physical theory and that these interpretations induce, in a comparatively direct way, an intensional semantics which corresponds to the original one. (shrink)

When we watch movies, or are tricked by a trompe-l'oeil painting, we seem to be visually representing possible worlds; often non-actual possible worlds. This suggests that we really can visually represent possible worlds. The suggested claim is refined and developed here into a theory of visual experience that holds that all visual experiences, both veridical and non-veridical, represent possible worlds, many of which are non-actual.

Arthur Prior was one of the logicians who participated in the invention of the possible worlds’ semantics. The ontology, which is connected with his systems of modal logic, is unique. Prior tried to reduce the number of abstract entities as much as possible. Hence he did not elect to introduce possible worlds and possibilia into his ontology. In addition, he held a reductionist view, which is called modal actualism by Fine or modalism by Melia. Prior was inspired (...) by various authors but this paper mainly discusses the influence of two prominent sources, Wittgenstein and logicians from Warsaw School. Prior acknowledged Wittgenstein’s influence, when he discuss the view that possible worlds consist of propositions. The second important feature of Prior’s concept is the denial of the real existence of possible worlds and the denial of the existence of entities which are in them. It was probably enabled by Prior’s adoption of some systems of logic invented by logicians from the Warsaw school, especially Lesniewski’s and Łukasiewicz’s systems. (shrink)

The most commonly heard proposals for reducing possible worlds to language succumb to a simple cardinality argument: it can be shown that there are more possible worlds than there are linguistic entities provided by the proposal. In this paper, I show how the standard proposals can be generalized in a natural way so as to make better use of the resources available to them, and thereby circumvent the cardinality argument. Once it is seen just what the limitations are (...) on these more general proposals, it can be clearly seen where the real difficulty lies with any attempt to reduce possible worlds to language. Roughly, the difficulty is this: no actual language could have the descriptive resources needed to represent all the ways things might have been. I conclude by arguing that this same difficulty spells doom for any nominalist or conceptualist proposal for reducing possible worlds. (shrink)

I rest this unusual claim on the ground of a metaphysics that is at odds with the metaphysical viewpoint implied in the theories of possible worlds. I suggest a different and, I think, superior way of conceiving the world, experience, and what we mean by possibility.

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)

Possible-worlds talk obscures, rather than clarifies, the debate about haecceitism. In this paper I distinguish haecceitism and anti-haecceitism from other doctrines that sometimes go under those names. Then I defend the claim that there are no non-tendentious definitions of ‘haecceitism’ and ‘anti-haecceitism’ using possible-worlds talk. That is, any definition of ‘haecceitism’ using possible-worlds talk depends, for its correctness, on a substantive theory of the nature of possible worlds. This explains why using possible-worlds talk when discussing (...) haecceitism causes confusion: if the parties to the discussion presuppose different theories of the nature of possible worlds, then they will mean different things by ‘haecceitism’. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Possible Worlds in the Tahâfut al-tahâfut:Averroes on Plenitude and PossibilityTaneli Kukkonen1.It has become customary to credit John Duns Scotus with having first systematically laid out the basis for treating the modal terms as referring to synchronic alternative states of affairs. This has been viewed as constituting a genuine shift in modal paradigms, as no former model had included the idea of genuine synchronic alternative possibilities. Historians of modal (...) logic and contemporary logicians alike have found it interesting that certain key features of Duns Scotus's theory and subsequent late medieval work markedly resemble the so-called possible worlds semantics approach of modern modal theory.1Duns Scotus' innovations were not completely without precedent. Several key elements in Scotus' theory were foreshadowed by twelfth-century developments. Perhaps somewhat amusingly, one of the most important forerunners to the Latin discussion was one in whose context the expression "possible worlds" would have made sense in a very special way.2 This is the medieval Arabic debate on the eternity of the world and its modal status. In this paper I propose to take stock of the positions the Arabs reached, and to do so by way of [End Page 329] consulting one of the documents central to the debate, the Tahâfut al-tahâfut or the "Incoherence of the Incoherence," by Abû al-Walîd Ibn Rushd (the Latin "Averroes," 1126-1198). In the first part I examine Averroes' exposition of the received Aristotelian tradition; in the second I assess the revisions to modal theory suggested by al-Ghazâlî (1058-1111), in the latter's comprehensive critique of philosophical doctrine. Though the two inquiries are obviously complementary, they can be accomplished independently of each other.It will be seen that Averroes' and his formidable adversary's views on the interpretation of the modal concepts differ quite fundamentally. What makes the ensuing debate, often fraught with misunderstandings and misrepresentation, so engaging is that both parties, in spite of their differences, refer to a common Aristotelian backdrop in questions of terminology and mode of argumentation. Both Averroes and al-Ghazâlî are well-placed to present a considered and balanced account of what they take to be crucial in the issues involved. It is on account of this that the complex interplay between the old and the new comes to the fore with exceptional force and clarity in the Tahâfut debates.2.The Tahâfut al-tahâfut, first published in 1180, is a philosophical rejoinder to an attack on philosophy, Abû Hâmid al-Ghazâlî's Tahâfut al-falâsifa or "The Incoherence of the Philosophers" (1095). In that celebrated work al-Ghazâlî had claimed to expose certain philosophical doctrines as not only contrary to orthodox Muslim belief, but also internally incoherent.3 Averroes' reply in turn was written in order "to show the different degrees of assent and conviction attained by the assertions in The Incoherence of the Philosophers, and to prove that the greater part has not reached the degree of evidence and of truth."4 The work is thus of a doubly dialectical nature. Whereas al-Ghazâlî tries to show the philosophers' reasoning to be defective, Averroes has to show both that al-Ghazâlî is likewise lacking in intellectual rigor and that philosophy, properly understood, is innocent of the charges leveled at it. If the Islamic philosophers (al-Fârâbî and, above all, Avicenna) have in fact erred, this is only to the extent that they have misrepresented correct Aristotelian doctrine. [End Page 330]Averroes' presentation is appropriately delicate considering the complexity of the task at hand. Averroes quotes al-Ghazâlî exclusively in full, lengthy passages, with the result of incorporating almost all of the Tahâfut al-falâsifa in his own work. In so doing he gives us an adequate and comparably fair representation of al-Ghazâlî's views. Averroes then goes on to discuss what al-Ghazâlî says both in the philosophers' name and in his own, and points out their respective deviations from Aristotelian doctrine. The text thus comes laid out in three successive layers, with Averroes' own... (shrink)

It is difficult to wander far in contemporary metaphysics without bumping into talk of possible worlds. And, reference to possible worlds is not confined to metaphysics. It can be found in contemporary epistemology and ethics, and has even made its way into linguistics and decision theory. What are those possible worlds, the entities to which theorists in these disciplines all appeal? Some have hoped that a theory of possible worlds can be used to reduce modality to (...) non-modal terms. This paper sets reductive theories aside, and articulates and applies a framework for evaluating non-reductive theories of possible worlds. I argue that, if we abjure reduction, we should aim for a theory of possible worlds that is user-friendly. I then outline four leading contemporary theories and consider objections to each. My conclusions are negative: every theory we discuss fails to be user-friendly in some significant respect. (shrink)

At the outset of his instructive and thought-provoking paper, ‘The Nature of Possibility,’ Professor David Armstrong gives a succinct description, in itself almost complete, of his ‘combinatorial theory’ of possibility. He says: ‘Such a view traces the very idea of possibility to the idea of the combinations - allthe combinations which respect certain simple form- of given, actual elements’. We can perhaps start a bit further back than this. In explaining the idea of a ‘possible world,’ some philosophers (...) begin with the idea of ‘things being a certain way’ or ‘the way things are.’ From this idea a leap is made to ‘things might have been a certain other way’ or ‘ways things could have been.’ And here we already have possible worlds, or so some philosophers assure us: David Lewis, for example, says his talk of possible worlds is nothing but a ‘permissible paraphrase’ of this familiar and innocent-sounding locution, ‘ways things could have been.'. (shrink)