includes the theory of reference, the theory of truth, philosophical pragmatics, and the philosophy of linguistics. The main question addressed by the theory of meaning is: In virtue of what are certain physical marks or noises meaningful linguistic expressions, and in virtue of what does any particular set of marks or noises have the distinctive meaning it does? A theory of meaning should also give a comprehensive account of the ‘meaning phenomena,’ or general semantic properties of sentences: synonymy, ambiguity, entailment, and the like. Some theorists have thought to express these questions and issues in terms of languageneutral items called propositions: ‘In virtue of what does a particular set of marks or noises express the proposition it does?’; cf. ‘ ‘La neige est blanche’ expresses the proposition that snow is white’, and ‘Synonymous sentences express the same proposition’. On this view, to understand a sentence is to ‘grasp’ the proposition expressed by that sentence. But the explanatory role and even the existence of such entities are disputed. It has often been maintained that certain special sentences are true solely in virtue of their meanings and/or the meanings of their component expressions, without regard to what the nonlinguistic world is like (‘No bachelor is married’; ‘If a thing is blue it is colored’). Such vacuously true sentences are called analytic. However, Quine and others have disputed whether there really is such a thing as analyticity. Philosophers have offered a number of sharply competing hypotheses as to the nature of meaning, including: (1) the referential view that words mean by standing for things, and that a sentence means what it does because its parts correspond referentially to the elements of an actual or possible state of affairs in the world; (2) ideational or mentalist theories, according to which meanings are ideas or other psychological phenomena in people’s minds; (3) ‘use’ theories, inspired by Wittgenstein and to a lesser extent by J. L. Austin: a linguistic expression’s ‘meaning’ is its conventionally assigned role as a game-piece-like token used in one or more existing social practices; (4) Grice’s hypothesis that a sentence’s or word’s meaning is a function of what audience response a typical speaker would intend to elicit in uttering it; (5) inferential role theories, as developed by Wilfrid Sellars out of Carnap’s and Wittgenstein’s views: a sentence’s meaning is specified by the set of sentences from which it can correctly be inferred and the set of those which can be inferred from it (Sellars himself provided for ‘language-entry’ and ‘language-exit’ moves as partly constitutive of meaning, in addition to inferences); (6) verificationism, the view that a sentence’s meaning is the set of possible experiences that would confirm it or provide evidence for its truth; (7) the truth-conditional theory: a sentence’s meaning is the distinctive condition under which it is true, the situation or state of affairs that, if it obtained, would make the sentence true; (8) the null hypothesis, or eliminativist view, that ‘meaning’ is a myth and there is no such thing – a radical claim that can stem either from Quine’s doctrine of the indeterminacy of translation or from eliminative materialism in the philosophy of mind.
Following the original work of Carnap, Alonzo Church, Hintikka, and Richard Montague in the 1950s, the theory of meaning has made increasing use of ‘possible worlds’–based intensional logic as an analytical apparatus. Propositions (sentence meanings considered as entities), and truth conditions as in (7) above, are now commonly taken to be structured sets of possible worlds – e.g., the set of worlds in which Aristotle’s maternal grandmother hates broccoli. And the structure imposed on such a set, corresponding to the intuitive constituent structure of a proposition (as the concepts ‘grandmother’ and ‘hate’ are constituents of the foregoing proposition), accounts for the meaning-properties of sentences that express the proposition.
Theories of meaning can also be called semantics, as in ‘Gricean semantics’ or ‘Verificationist semantics,’ though the term is sometimes restricted to referential and/or truth-conditional theories, which posit meaning-constitutive relations between words and the nonlinguistic world. Semantics is often contrasted with syntax, the structure of grammatically permissible ordering relations between words and other words in well-formed sentences, and with pragmatics, the rules governing the use of meaningful expressions in particular speech contexts; but linguists have found that semantic phenomena cannot be kept purely separate either from syntactic or from pragmatic phenomena. In a still more specialized usage, linguistic semantics is the detailed study (typically within the truth-conditional format) of particular types of construction in particular natural languages, e.g., belief-clauses in English or adverbial phrases in Kwakiutl. Linguistic semantics in that sense is practiced by some philosophers of language, by some linguists, and occasionally by both working together. Montague grammar and situation semantics are common formats for such work, both based on intensional logic. The theory of reference is pursued whether or not one accepts either the referential or the truthconditional theory of meaning. Its main question is: In virtue of what does a linguistic expression designate one or more things in the world? (Prior to theorizing and defining of technical uses, ‘designate’, ‘denote’, and ‘refer’ are used interchangeably.) Denoting expressions are divided into singular terms, which purport to designate particular individual things, and general terms, which can apply to more than one thing at once. Singular terms include proper names (‘Cindy’, ‘Bangladesh’), definite descriptions (‘my brother’, ‘the first baby born in the New World’), and singular pronouns of various types (‘this’, ‘you’, ‘she’). General terms include common nouns (‘horse’, ‘trash can’), mass terms (‘water’, ‘graphite’), and plural pronouns (‘they’, ‘those’). The twentieth century’s dominant theory of reference has been the description theory, the view that linguistic terms refer by expressing descriptive features or properties, the referent being the item or items that in fact possess those properties. For example, a definite description does that directly: ‘My brother’ denotes whatever person does have the property of being my brother. According to the description theory of proper names, defended most articulately by Russell, such names express identifying properties indirectly by abbreviating definite descriptions. A general term such as ‘horse’ was thought of as expressing a cluster of properties distinctive of horses; and so forth. But the description theory came under heavy attack in the late 1960s, from Keith Donnellan, Kripke, and Putnam, and was generally abandoned on each of several grounds, in favor of the causal-historical theory of reference. The causal-historical idea is that a particular use of a linguistic expression denotes by being etiologically grounded in the thing or group that is its referent; a historical causal chain of a certain shape leads backward in time from the act of referring to the referent(s). More recently, problems with the causal-historical theory as originally formulated have led researchers to backpedal somewhat and incorporate some features of the description theory. Other views of reference have been advocated as well, particularly analogues of some of the theories of meaning listed above – chiefly (2)–(6) and (8).
Modal and propositional-attitude contexts create special problems in the theory of reference, for referring expressions seem to alter their normal semantic behavior when they occur within such contexts. Much ink has been spilled over the question of why and how the substitution of a term for another term having exactly the same referent can change the truth-value of a containing modal or propositional-attitude sentence.
Interestingly, the theory of truth historically predates articulate study of meaning or of reference, for philosophers have always sought the nature of truth. It has often been thought that a sentence is true in virtue of expressing a true belief, truth being primarily a property of beliefs rather than of linguistic entities; but the main theories of truth have also been applied to sentences directly. The correspondence theory maintains that a sentence is true in virtue of its elements’ mirroring a fact or actual state of affairs. The coherence theory instead identifies truth as a relation of the true sentence to other sentences, usually an epistemic relation. Pragmatic theories have it that truth is a matter either of practical utility or of idealized epistemic warrant. Deflationary views, such as the traditional redundancy theory and D. Grover, J. Camp, and N. D. Belnap’s prosentential theory, deny that truth comes to anything more important or substantive than what is already codified in a recursive Tarskian truth-definition for a language.
Pragmatics studies the use of language in context, and the context-dependence of various aspects of linguistic interpretation. First, one and the same sentence can express different meanings or propositions from context to context, owing to ambiguity or to indexicality or both. An ambiguous sentence has more than one meaning, either because one of its component words has more than one meaning (as ‘bank’ has) or because the sentence admits of more than one possible syntactic analysis (‘Visiting doctors can be tedious’, ‘The mouse tore up the street’). An indexical sentence can change in truth-value from context to context owing to the presence of an element whose reference fluctuates, such as a demonstrative pronoun (‘She told him off yesterday’, ‘It’s time for that meeting now’). One branch of pragmatics investigates how context determines a single propositional meaning for a sentence on a particular occasion of that sentence’s use. Speech act theory is a second branch of pragmatics that presumes the propositional or ‘locutionary’ meanings of utterances and studies what J. L. Austin called the illocutionary forces of those utterances, the distinctive types of linguistic act that are performed by the speaker in making them. (E.g., in uttering ‘I will be there tonight’, a speaker might be issuing a warning, uttering a threat, making a