Philosophy of language

Philosophy of language is the philosophical study of the nature of language. It investigates the relationship between language, language users, and the world. Investigations may include inquiry into the nature of meaning, intentionality, reference, the constitution of sentences, concepts, learning, and thought.

Gottlob Frege and Bertrand Russell were pivotal figures in analytic philosophy's "linguistic turn". These writers were followed by Ludwig Wittgenstein (Tractatus Logico-Philosophicus), the Vienna Circle, logical positivists, and Willard Van Orman Quine.

In the West, inquiry into language stretches back to the 5th century BC with philosophers such as Socrates, Plato, Aristotle, and the Stoics. Linguistic speculation predated systematic descriptions of grammar which emerged c. the 5th century BC in India and c. the 3rd century BC in Greece.

In the dialogue Cratylus, Plato considers the question of whether the names of things are determined by convention or by nature. He criticizes conventionalism as leading to the bizarre consequence that, as anything can be conventionally denominated by any name, there can hence be neither fitting, or correct, names, nor unfitting or incorrect ones—yet it seems, intuitively, that such "incorrect" names are indeed possible: e.g., if Theophilus means "god-beloved", it seems inappropriate for anyone who is not, in fact, very pious at all. Plato argues, further, that primitive (as opposed to derived) names have a natural correctness, because each phoneme represents basic ideas or sentiments; for example, the letter λ and its sound represent—for Plato—the idea of smoothness or softness. However, by the end of Cratylus, he seems to admit that some social conventions are also involved, and that the idea that phonemes have individual meanings is not without flaw. Plato is often considered a proponent of extreme realism.

Aristotle interested himself with issues of logic, categories, and the creation of meaning. He separated all things into categories of species and genus. He thought that the meaning of a predicate was established through an abstraction of the similarities between various individual things. This theory later came to be called nominalism. However, since Aristotle took these similarities to be constituted by a real commonality of form, he is more often considered a proponent of moderate realism.

The Stoics made important contributions to the analysis of grammar, distinguishing five parts of speech: nouns, verbs, appellatives (names or epithets), conjunctions and articles. They also developed a sophisticated doctrine of the lektón associated with each sign of a language, but distinct from both the sign itself and the thing to which it refers. This lektón was the meaning or sense of every term. The complete lektón of a sentence is what we would now call its proposition. Only propositions were considered truth-bearing—meaning they could be considered true or false—while sentences were simply their vehicles of expression. Different lektá could also express things besides propositions, such as commands, questions and exclamations.

Medieval philosophers were greatly interested in the subtleties of language and its usage. For many scholastics, this interest was provoked by the necessity of translating Greek texts into Latin. There were several noteworthy philosophers of language in the medieval period. According to Peter J. King (though this has been disputed), Peter Abelard anticipated the modern theories of reference. Also, William of Ockham's Summa Logicae brought forward one of the first serious proposals for codifying a mental language.

The scholastics of the high medieval period, such as Ockham and John Duns Scotus, considered logic to be a scientia sermocinalis (science of language). The result of their studies was the elaboration of linguistic-philosophical notions whose complexity and subtlety has only recently come to be appreciated. Many of the most interesting problems of modern philosophy of language were anticipated by medieval thinkers. The phenomena of vagueness and ambiguity were analyzed intensely, and this led to an increasing interest in problems related to the use of syncategorematic words, such as and, or, not, if, and every. The study of categorematic words (or terms) and their properties was also developed greatly. One of the major developments of the scholastics in this area was the doctrine of the suppositio. The suppositio of a term is the interpretation that is given of it in a specific context. It can be proper or improper (as when it is used in metaphor, metonym, and other figures of speech). A proper suppositio, in turn, can be either formal or material according to whether it refers to its usual non-linguistic referent (as in "Charles is a man"), or to itself as a linguistic entity (as in "'Charles' has seven letters"). Such a classification scheme is the precursor of modern distinctions between use and mention, and between language and metalanguage.