Possible World Semantics

In diesem Aufsatz argumentiere ich für eine teleologische Fähigkeitstheorie, derzufolge Fähigkeiten Dispositionen zu zweckmäßigem Handeln sind.

The paper deals with the main contribution of the Finnish logician Jaakko Hintikka: epistemic logic, in particular the 'static' version of the system based on the formal analysis of the concepts of knowledge and belief. I propose to take a different look at this philosophical logic and to consider it from the opposite point of view of the philosophy of logic. At first, two theories of meaning are described and associated with two competing theories of linguistic competence. In a second (...) step, I draw the conclusion that Hintikka's epistemic logic constitutes a sort of internalisation of meaning, by the introduction of epistemic modal operators into an object language. In this respect, to view meaning as the result of a linguistic competence makes epistemic logic nothing less than a logic of unified meaning and understanding. (shrink)

David Lewis [1973] offers a possible worlds approach to a theory of counterfactuals. He attempts to specify necessary and sufficient conditions according to which a given counterfactual is true or false. This MA Thesis surveys Lewis's theory of counterfactuals in detail. Although for the most part I defend Lewis's account from several objections, in the final chapter I reason that his theory is susceptible to skepticism, which threatens any philosophical theory that relies on Lewis's theory to distinguish between non-paradigmatically true (...) and false counterfactuals. As for the more sympathetic portion of my project, while I show how Lewis's canonical account cannot handle some paradigmatically false counterfactuals--viz., those containing true components--I try to repair his analysis in the spirit of Alan Penczek [1997]. I then discuss Lewis's extension or enhancement to his original theory, which he gives in order to foil an objection advanced by Kit Fine [1975] and Jonathan Bennett [1984]. Finally, I outline and raise several worries inherent in Bennett's rival theory. As for the less then sympathetic section of this paper, I exploit arguments put forward by G. Lee Bowie [1979] as well as by Daniel Krasner and Mark Heller [1994], which are designed to undermine any systematic procedure to circumscribe Lewis's crucial three-place comparative similarity relation between possible worlds. (shrink)

I compare Stalnaker’s early take on assertoric content with the one expressed in his recent book (2014). I discern in the latter some striking implications about the semantics of proper names and assertoric content’s relation to semantics.

Against the background of standard possible-worlds semantics, this paper outlines a truthmaker approach to the semantics of attitude reports and modal sentences. This approach is based on an ontology of attitudinal and modal objects, which are considered the primary bearers of conditions truthmaking or satisfaction.

This paper contains an argument to the effect that possible worlds semantics renders semantic knowledge impossible, no matter what ontological interpretation is given to possible worlds. The essential contention made is that possible worlds semantic knowledge is unsafe and this is shown by a parallel with the preface paradox.

In this paper, I present a categorial theory of meaning which asserts that the meaning of a sentence is the function from the actualization of some potentiality or the potentiality of some actuality to the truth of the sentence. I argue that it builds on the virtues of David Lewis’s Possible World Semantics but advances beyond problems that Lewis’s theory faces with its distinctly Aristotelian turn toward actuality and potentiality.

We present and defend the Australian Plan semantics for negation. This is a comprehensive account, suitable for a variety of different logics. It is based on two ideas. The first is that negation is an exclusion-expressing device: we utter negations to express incompatibilities. The second is that, because incompatibility is modal, negation is a modal operator as well. It can, then, be modelled as a quantifier over points in frames, restricted by accessibility relations representing compatibilities and incompatibilities between such points. (...) We defuse a number of objections to this Plan, raised by supporters of the American Plan for negation, in which negation is handled via a many-valued semantics. We show that the Australian Plan has substantial advantages over the American Plan. (shrink)

My modest aim in this paper is to prove certain relations between some type of hyper-intensional operators, namely context shifting operators, and compositionality in natural languages. Various authors (e.g. von Fintel & Matthewson 2008; Stalnaker 2014) have argued that context-shifting operators are incompatible with compositionality. In fact, some of them understand Kaplan’s (1989) famous ban on context-shifting operators as a constraint on compositionality. Others, (e.g. Rabern 2013) take contextshifting operators to be compatible with compositionality but, unfortunately, do not provide a (...) proof, or an argument in favor of their position. The aim of this paper is to do precisely that. Additionally, I provide a new proof that compositionality for propositional content (intension) is a proper generalization of compositionality for character (hyper-intensions). (shrink)

When the Necessity of Identity (NI) is combined with Composition as Identity (CAI), the contingency of composition (CC) is at risk. In the extant literature, either NI is seen as the basis for a refutation of CAI or CAI is associated with a theory of modality, such that: either NI is renounced (if counterpart theory is adopted); or CC is renounced (if the theory of modal parts is adopted). In this paper, we investigate the prospects of a new variety of (...) CAI, which aims to preserve both NI and CC. This new variety of CAI (CCAI, Contingent Composition as identity) is the quite natural product of the attempt to make sense of CAI on the background of a broadly Kripkean view of modality, such that one and the same entity is allowed to exist at more than one possible world. CCAI introduces a world-relative kind of identity, which is different from standard identity, and claims that composition is this kind of world-relative identity. CCAI manages to preserve NI and CC. We compare CCAI with Gibbard’s and Gallois’ doctrines of contingent identity and we show that CCAI can be sensibly interpreted as a form of Weak CAI, that is of the thesis that composition is not standard identity, yet is significantly similar to it. (shrink)

I propose a comprehensive account of negation as a modal operator, vindicating a moderate logical pluralism. Negation is taken as a quantifier on worlds, restricted by an accessibility relation encoding the basic concept of compatibility. This latter captures the core meaning of the operator. While some candidate negations are then ruled out as violating plausible constraints on compatibility, different specifications of the notion of world support different logical conducts for negations. The approach unifies in a philosophically motivated picture the following (...) results: nothing can be called a negation properly if it does not satisfy Contraposition and Double Negation Introduction; the pair consisting of two split or Galois negations encodes a distinction without a difference; some paraconsistent negations also fail to count as real negations, but others may; intuitionistic negation qualifies as real negation, and classical Boolean negation does as well, to the extent that constructivist and paraconsistent doubts on it do not turn on the basic concept of compatibility but rather on the interpretation of worlds. (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.

Possible worlds semantics faces a range of difficulties for at least certain types of modals, especially deontic modals with their distinction between heavy and light permissions and obligations. This paper outlines a new semantics of modals that aims to overcome some of those difficulties. The semantics is based on an a novel ontology of modal objects, entities like obligations, permissions, needs, as well as epistemic states, abilities, and essences. Moreover, it is based on truthmaking, in the sense of Fine’s recent (...) truthmaker semantics. (shrink)

Singular propositions are structured entities which sometimes include macroscopic concrete things as their elements. That leads to numerous difficulties, also those concerning modalities, good example of which is the famous argument developed by Plantinga, who concludes that accepting a theory of singular propositions leads to necessary existence of (apparently contingent) objects — elements of such propos¬itions. In the paper I present a possible way to avoid such harmful consequences and to undermine Plantinga’s reasoning. My approach involves the idea of two (...) modes of evaluating propositions: “in a possible world” and “with regard to a possible world”, which I try to defend by introducing some solutions from the Hybrid Theory of proper names. I also argue that disposing of singular propositions and accepting Descriptivism does not allow to deal with the modal difficulties. (shrink)

O discurso a respeito dos Mundos Possíveis pode ser uma ferramenta bastante útil para a filosofia. Pode ser útil, por exemplo, para a compreensão das modalidades, da necessidade e da possibilidade. No entanto, para utilizar o discurso dos Mundos Possíveis devemos ter uma explicação satisfatória do caráter ontológico da Semântica dos Mundos Possíveis. Para isso, precisamos responder a questões do tipo: O que é um Mundo Possível? De que forma eles existem? Em quantos Mundos Possíveis podemos falar? Há diversas formas (...) de responder a estas perguntas. Neste trabalho pretendemos apresentar duas teorias que possuem uma abordagem realista para a noção de Mundo Possível. Cada uma dessas teorias atribuiu um caráter ontológico diferente para a noção de Mundo Possível e, portanto, uma metafísica diferente. A primeira delas é o Realismo Modal Extremo, teoria atribuída a David Lewis que defende a existência genuína de uma pluralidade de Mundos Possíveis. A segunda teoria é a teoria combinatória da possibilidade de David Armstrong. Essa teoria é uma versão das teorias do atualismo modal que também são teorias realista em relação à existência de mundos possíveis, mas que dão prioridade ao mundo atual. Por fim, pretendemos comparar as duas teorias e avaliar qual é mais vantajosa levando em consideração o custo ontológico de cada uma delas, (i.e., em relação ao número de entidades postuladas) para termos uma metafísica mais econômica. (shrink)

It is sometimes argued that Leibniz’s metaphysical commitments lead to Spinozist Necessitarianism, i.e., the view, in Spinoza’s words, that “Things could not have been produced by God in any way or in any order other than that in which they have been produced”. Leibniz comments on this passage as follows: “This proposition may be true or false, depending on how it is explained”. I suggest in this paper that what Leibniz means by this comment can be fleshed out by making (...) a distinction between what could have been actual and what is possible. I also address some potential objections to this distinction and attempt to elaborate it by means of comparing Leibniz’s and Alvin Plantinga’s approaches to modality. (shrink)

This paper starts out from the idea that semantics is a “special science” whose aim, like that of chemistry or ecology, is to identify systematic, high-level patterns in a fundamentally physical world. I defend an approach to this task on which sentences are associated with with sets of possible worlds (of some kind). These sets of worlds, however, are not postulated for the compositional treatment of intensional contexts; they are not meant to capture what is intuitively asserted or communicated by (...) an utterance; nor are they supposed to shed light on the cognitive processes that underlie out linguistic competence. Instead, their job description is to capture certain regularities in the interactions between subjects using the relevant language. I also raise some questions about how the relevant worlds might be construed. (shrink)

We offer an analysis of future morphemes as epistemic operators. The main empirical motivation comes from the fact that future morphemes have systematic purely epistemic readings—not only in Greek and Italian, but also in Dutch, German, and English will. The existence of epistemic readings suggests that the future expressions quantify over epistemic, not metaphysical alternatives. We provide a unified analysis for epistemic and predictive readings as epistemic necessity, and the shift between the two is determined compositionally by the lower tense. (...) Our account thus acknowledges a systematic interaction between modality and tense—but the future itself is a pure modal, not a mixed temporal/modal operator. We show that the modal base of the future is nonveridical, i.e. it includes p and ¬p worlds, parallel to epistemic modals such as must, and present arguments that future morphemes are a category that stands in between epistemic modals and predicates of personal taste. We identify, finally, a subclass of epistemic futures which are ratificational, and argue that will is a member of this class. (shrink)

We show that actuality entailments arise with goal-oriented modality only and endorse Belnap’s view of that goal-oriented modals use historical accessibility with a fixed past and an open future. This modal-theoretic assumption allows us to spell out the precise modal-temporal configuration in which the actuality entailment arises and our predictions are borne out by the data, cross-linguistically. We also show that, when any assumption about the identity of worlds at branching point is leveled - which appears to be the case (...) with generic deontic and opportunity modals, the actuality entailments disappear. We also predict that the entailment disappears with prospectivity. Finally, we argue that modal sentences giving rise to actuality entailments are informative, insofar as the contribution of the modality survives as a presupposition that the modal base is non-homogeneous. (shrink)

We investigate and compare two major approaches to enhancing the expressive capacities of modal languages, namely the addition of subjunctive markers on the one hand, and the addition of scope-bearing actuality operators, on the other. It turns out that the subjunctive marker approach is not only every bit as versatile as the actuality operator approach, but that it in fact outperforms its rival in the context of cross-world predication.

The purpose of the present paper is to challenge some received assumptions about the logical analysis of modal English, and to show that these assumptions are crucial to certain debates in current philosophy of language. Specifically, I will argue that the standard analysis in terms of quantified modal logic mistakenly fudges important grammatical distinctions, and that the validity of Kripke's modal argument against description theories of proper names crucially depends on ensuing equivocations.

The logic of 'elsewhere,' i.e., of a sentence operator interpretable as attaching to a formula to yield a formula true at a point in a Kripke model just in case the first formula is true at all other points in the model, has been applied in settings in which the points in question represent spatial positions, as well as in the case in which they represent moments of time. This logic is applied here to the alethic modal case, in which (...) the points are thought of as possible worlds, with the suggestion that its deployment clarifies aspects of a position explored by John Divers under the name 'modal agnosticism.' In particular, it makes available a logic whose Halldén incompleteness explicitly registers the agnostic element of the position - its neutrality as between modal realism and modal anti-realism. (shrink)

In the fourteenth century, Duns Scotus suggested that the proper analysis of modality required not just moments of time but also “moments of nature”. In making this suggestion, he broke with an influential view first presented by Diodorus in the early Hellenistic period, and might even be said to have been the inventor of “possible worlds”. In this essay we take Scotus’ suggestion seriously devising first a double-index logic and then introducing the temporal order. Finally, using the temporal order, we (...) define a modal order. This allows us to present modal logic without the usual interpretive questions arising concerning the relation called variously ‘accessibility’, ‘alternativeness’, and, ‘relative possibility.’ The system in which this analysis is done is one of those which have come to be called a hybrid logic. (shrink)

This book discusses a range of important issues in current philosophical work on the nature of possible worlds. Areas investigated include the theories of the nature of possible worlds, general questions about metaphysical analysis and questions about the direction of dependence between what is necessary or possible and what could be.

Pietroski (1993) offers a semantics for belief sentences that is supposed to address the problem of equivalence. This paper argues that his proposal fails to solve the problem.

The topic of this special issue of Synthese is hyperintensionality. This introduction offers a brief survey of the very notion of hyperintensionality followed by a summary of each of the papers in this collection. The papers are foundational studies of hyperintensionality accompanied by ample philosophical applications.Hyperintensionality concerns the individuation of non-extensional entities such as propositions and properties, relations-in-intension and individual roles, as well as, for instance, proofs and judgments and computational procedures, in case these do not reduce to any of (...) the former. Hyperintensional individuation is frequently also referred to as ‘fine-grained’ or sometimes simply ‘intensional’ individuation, when ‘intensional’ is not understood in the specific sense of possible-world semantics or in the pejorative sense of flouting various logical rules of extensional logic. A principle of individuation qualifies as hyperintensional as soon as it is finer than necessary .. (shrink)

I attempt to argue that if statements of permission are to serve as a guide to action then no possible worlds account of their truth-conditions can be correct.

Kit Fine and Robert Adams have independently introduced a distinction between two ways in which a proposition might be true with respect to a world. A proposition is true at a world if it correctly represents the world. A proposition is true in a world, if it exists in that world and correctly represents it. In this paper, I clarify this distinction between outer and inner truth, defend it against recent charges of unintelligibly and argue that outer truth tracks counterfactual (...) possibility while inner truth tracks counter-actual possibility. This connection allows us to clarify the relationship between possibility, possible actuality and the thesis of serious actualism, which is the thesis that nothing could have had a property without existing. I show that this undermines serious actualists' scruples against reading sentences like `Even if Socrates had not existed, he might have' as expressing true and genuinely de re propositions about Socrates. More generally, the connection I draw provides the serious actualist with a justification for treating actually existing but contingent objects differently from how he treats merely possible objects. (shrink)

This introduction to modality places the emphasis on the metaphysics of modality rather than on the formal semetics of quantified modal logic. The text begins by introducing students to the "de re/de dicto" distinction, conventionalist and conceptualist theories of modality and some of the key problems in modality, particularly Quine's criticisms. It then moves on to explain how possible worlds provide a solution to many of the problems in modality and how possible worlds themselves have been used to analyse notions (...) outside modality such as properties and propositions. Possible worlds introduce problems of their own and the book argues that to make progress with these problems a theory of possible worlds is required. The pros and cons of various theories of possible worlds are then examined in turn, including those of Lewis, Kripke, Adams, Stalnaker and Plantinga. (shrink)

_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.

Several theists, including Linda Zagzebski, have claimed that theism is somehow committed to nonvacuism about counterpossibles. Even though Zagzebski herself has rejected vacuism, she has offered an argument in favour of it, which Edward Wierenga has defended as providing strong support for vacuism that is independent of the orthodox semantics for counterfactuals, mainly developed by David Lewis and Robert Stalnaker. In this paper I show that argument to be sound only relative to the orthodox semantics, which entails vacuism, and give (...) an example of a semantics for counterfactuals countenancing impossible worlds for which it fails. (shrink)

Philosophical debate about the meaning of normative terms has long been pulled in two directions by the apparently competing ideas: (i) ‘ought’s do not describe what is actually the case but rather prescribe possible action, thought, or feeling, (ii) all declarative sentences deserve the same general semantic treatment, e.g. in terms of compositionally specified truth conditions. In this paper, I pursue resolution of this tension by rehearsing the case for a relatively standard truth-conditionalist semantics for ‘ought’ conceived as a necessity (...) modal and proposing a revision to it motivated by the distinctively prescriptive character of some deontic modals. In my view, this puts pressure on a popular conception of one of the core debates of metanormative theory between realists and antirealists. To make good on this claim, I go on to explore two very general ways we might interpret the results of compositional semantics—“representationalism” and “inferentialism”—in order to argue that, contrary to what is generally assumed, both can capture the special prescriptivity of ‘ought’ and both can countenance compositionally specified and informative truth-conditions for ought-sentences. Hence, my main thesis is that the deciding factor between them should not be which of ideas (i) and (ii) we are more impressed by but rather what we think of the relative merits of how representationalism and inferentialism respect these ideas. I’m inclined to favor an antirealist form of inferentialism, but the task I’ve set myself here is mainly to articulate the view in the context of metanormative theory and the semantics of deontic modals rather than try to defend it fully. To this purpose, towards the end I also briefly compare and contrast inferentialism with a third “ideationalist” metasemantic view, which may be an attractive home for some sophisticated versions of metanormative expressivism. Depending on how expressivism is worked out, it may be completely compatible with and so perhaps usefully combined with inferentialism or it may offer a competing way to respect ideas (i) and (ii). (shrink)

We defend the view that defines the rigidity of general terms as sameness of designated universal across possible worlds from the objection that such a characterization is incapable of distinguishing rigid from non-rigid readings of general terms and, thus, that it trivializes the notion of rigidity. We also argue that previous attempts to offer a solution to the trivialization problem do no succeed.

We argue that the view that kind terms designate universals does not fall prey to the trivialization problem. We also argue that the view can respond to other challenges, specifically, the claims that an adequate notion of rigidity for kind terms must: (a) classify natural kind terms as rigid and classify many other general terms as non-rigid and (b) account for the necessity of true theoretical identifications involving rigid terms.