The concept of possible worlds is common in contemporary philosophical discourse but has been disputed. These species are defined by their internal structure, determined by genetics in the case of living things and by chemical or physical properties in the case of others. Although possible world has been part of the philosophical lexicon at least since leibniz, the notion became firmly entrenched in contemporary philosophy with the development of possible world semantics for the languages of propositional and firstorder modal logic. When possible worlds are seen as finite and furnished human constructs, the concept is brought. As for the semantics, the central idea is that both regular modal statements as well as aas involve quantification over possible worlds, i. Possible world semantics definition of possible world. Possible worlds semantics is a general approach to theories of meaning, on which meanings or, more precisely, semantic values are assigned to sentences in terms of the truthvalues they take across all possible worlds. Gibbards contents are sets, and the content of a conjunction is the. Jxkw the intension of x the intension of a sentence is a function from worlds to truth values, called proposition. We develop a compositional framework for intensional semantics.
Ohearn hongseok yang november 29, 2002 abstract the logic of bunched implications, bi, is a substructural system which freely combines an additive intuitionistic and a multiplicative linear implication via bunches contexts with two combining oper. For instance, in possible worlds semantics, the proposition matt has a dog would be thought of as the set of worlds in which matt has a dog. Possible worlds semantics and linguistic theory the monist. Keywords possible worlds realism context principle possibility semantics wright dummett stalnaker i 1. Possible worlds semantics is a general approach to theories of meaning, on which meanings or, more precisely, semantic values are assigned to sentences in. The debate over the nature of possible worlds has been driven largely by david lewis modal realism. Indeed, one of the nice features of kratzers framework is that it accounts for the polysemous nahlre of modal verbs in a very elegant way while maintaining the. I characterize the semantics of the modal would in terms of quantification over worlds that contain counterparts of the actual. The notion of the possible world is connected to logic and science, and the notions of fiction and creativity are connected to art. English, and presumably any natural language, contains a small group of expressions referring to species of things found in nature. By introducing possibleworlds semantics for the language of arithmetic plus the unary predicate. So the physical accessibility relation should be compatibility with the laws of physics. The intension of an expression xis a function which i takes a possible world as an argument, and ii returns the extension of xin that world. The concept of possible worlds henceforth pw, loosely inspired by leibniz.
Possible world, conception of a total way the universe might have been. The first part takes the reader through a stepbystep guide to the main. Rather, it is the semantic theory itself more exactly, the logic in which the theory is expressed that is extensional. To read these files, you will need adobe acrobat reader installed on your computer. In effect, possible worlds semantics takes the meanings of. Other possible worlds are just as real as the actual world. A statement in modal logic that is possible is said to be true in at least one possible world. We assume a dynamic possible worlds semantics, with a stalnaker 1978style context. The basic idea of the development is to consider, instead of a set of worlds that are possible outright. In philosophy and logic, the concept of a possible world is used to express modal claims. Claims, or what philosophers like to call propositions, can be thought of as sets of possible worlds.
They may not actually exist, since to actually exist is to exist in the actual world, but they do, nevertheless, exist. Indeed possible worlds are called reference pints in mo2 and indices in sc. Attitudes are represented as separate compartments that can be referentially. On lewis view, possible worlds are spatiotemporally and causally isolated universes. I do not aim to refute possibleworlds semantics, or any other candidate.
Questions about modal logic, possible worlds, probability. We will then look at the various debates on the existence and nature of possible worlds and their inhabitants. Ti, where xis a set, and tis a collection of subsets of xthat is closed under. Intensional approaches to semantics model the meaning of a language or a fragment using more than extensionsthey acknowledge that with. But most possibleworlds sentences contain no modal language, in the sense introduced in the previous section. Attitudes and mental files in discourse representation theory. Pdf on oct 1, 1995, joe y f lau and others published possible worlds semantics for belief sentences find, read and cite all the research. It is often contrasted with the way things actually are. In addition to the usual sentence operators of classical logic such as and. Stalnakers that possible worlds are properties that the only actual world might have. Thus, the enterprise would lose its essential tension.
Possible worlds semantics and linguistic theory, the monist, volume 60, issue 3, 1 july. C is true in a possible world w if the closest aworld of w is also a cworld. Consider the development of possible worlds semantics for modal logic. The notions of possibleworlds semantics, fiction, and creativity are all of great importance. For our purposes, the important member of the context is the contextset. 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. In the formal literature on evidentiality it is often assumed that evidentials.
This gives rise to possible worlds semantics, which received its first systematic application to natural language in the work of montague 1970. Understanding semantics, second edition, provides an engaging and accessible introduction to linguistic semantics. I present a concrete drtbased syntax and semantics for the representation of mental states in the style of kamp. So lets see first how the transformed apparatus works in the same contexts. A semantics for modal logic was first introduced in the late1950s work of saul kripke and his colleagues. Computing most probable worlds for action probabilistic. Recall that the intuitive idea behind the possibleworlds model is that.
Jxkw the extension of x in w the intension of an expression x is a function which i takes a possible world as an argument, and. If we use extension as a label for the reference of an expression so that the extensions of names are objects, and the extensions of simple predicates are functions from objects to truthvalues we can introduce intension as a label for an expressions reference across possible worlds. This is the guiding idea of possible worlds semantics. Roughly, they are the kinds of things of which it is a. Possible worlds semantics university of notre dame. Possible worlds semantics have been widely applied both in philosophy and in other fields such as linguistic semantics and pragmatics, theoretical computer.
Intensionality and context change harvard university. Intuitively, for every sentence a, the proposition ia is the set of possible worlds at which a is true. This paper reassesses lewiss theory and draws attention to some novel problems for his account. Specifically, in possible world semantics, the modal operators are interpreted as quantifiers over possible worlds, as expressed informally in the following two general principles.
Similarly, logical, mathematical, metaphysical, biological, etc. Possible worlds semantics, i 485 language, l o, and the corresponding formulas in the first or higherorder language l x of the possible worlds models for l o. A sentences meaning is the set of possible worlds in which the sentence is true. A theory of properties and propositions that meets these desiderata is developed and several applications to the semantic analysis of natural languages are explored. In possible worlds semantics, p is physically possible if there is an accessible world at which p is true. In such a case, the normal semantic rules are overridden.
This system is closely related to recanatis mental files framework, but adds a crucial distinction between anchors, the analogues of mental files, and attitudes like belief, desire and imagination. Theories of meaning stanford encyclopedia of philosophy. Possible worlds semantics philosophy 431 february 5, 20. The reader is therefore left in the dark about how asserting all instances of mf gives the fictionalist the right to go on using possible worlds sentences like z. The canonical version of possible worlds semantics for story prefixes is due to david lewis. Similarly, a meaning for a name is something that determines what thing, if any, the name names in various possible states of affairs, at various times, and so on. As noted, possible world semantics does not make modal logic itself extensional. General semantics 23 to nondeclarative sentences, but postpone consideration of them.
Hintikkas insight was to see that an agents beliefs could be characterized as a set of possible worlds, in the following way. The possible worlds model for logics of knowledge and belief was originally proposed by hintikka hintikka, 1962, and is now most commonly formulated in a normal modal logic using the techniques developed by kripke kripke, 1963. From this groundwork, the theory of possible worlds became a central part of. Possible worlds stanford encyclopedia of philosophy. This works well in applications where it is intuitively clear what a possible world is.
Possibleworlds semantics for modal notions conceived as. Leibniz used the concept of a possible world in his proposed solution to the theological problem of the existence of evil, arguing that an allperfect god would actualize the best of all possible worlds. What is known in the possible worlds of w and the real situations in the possible worlds of w are given below as 2. Roughly speaking, the idea is that the counterfactual from a to c should. Truthmaker semantics chapter for the blackwell philosophy.
Possible worlds is being made available, free of charge, for personal i. Pdf on jan 1, 1997, john perry and others published u039 semantics, possibleworlds find, read and cite all the research you. Represent the set of all possible worlds as a rectangle and the propositions denoted by p, q, and r as overlapping circles within this rectangle. The context set is the set of possible worlds that describe what the actual world could be like as. Recent relativism contemporary relativists claim that the truth of some propositions varies with a novel parameter, for example, with a standard of taste, with a state of information, with interests or with a moral code. They claim that a sentence should be evaluated not only with respect to a single index or possible world, but to a pair thereof, fabio lampert. Possible world semantics synonyms, possible world semantics pronunciation, possible world semantics translation, english dictionary definition of possible world semantics. Analyticity an unfinished business in possible world. For example, m dmic bgic a possible world is just a program state prall, i.
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