Philosophy of language is the branch of philosophy that studies language in its most general and fundamental aspects, such as the nature of meaning and reference, the relationship between language, thought and the world, language use (or pragmatics), interpretation, translation and the limits of speech.
Philosophy of language differs from linguistics in that it uses non-empirical methods (such as mental experiments) to reach its inferences. Moreover, philosophy of language generally does not distinguish between spoken, written language or any other of its manifestations, but focuses on what is common to all of them. Finally, linguists generally study language for descriptive means, analysing its forms, levels and functions. In turn, the approach of philosophers of language is more abstract and detached from the practical description of particular languages.
Semantics is the part of the philosophy of language (and of linguistics) that focuses on the relationship between language and the world. Some problems that fall under this field are the problem of reference, the nature of predicates, representation and truth. In the Cratylus, Plato pointed out that if the connection between words and the world is arbitrary or conventional, then it is difficult to understand how language can enable knowledge about the world. For example, it is evident that the name “Venus” could have designated anything apart from the planet Venus, and that the planet Venus could have been called anything else. Then, when it is said that “Venus is bigger than Mercury”, the truth of this sentence is conventional, because it depends on our conventions about what “Venus”, “Mercury” and the rest of the words involved mean. In another language, those same words might, by some coincidence, mean something quite different and express something false. However, although the meaning of words is conventional, once their meaning is fixed, it seems that truth and falsehood do not depend on conventions, but on how the world is. This “fixing of meaning” is often called interpretation, and is one of the central themes of semantics.
A subsequent dilemma in this sense is that if an interpretation is given in linguistic terms (e.g. “Venus is the name of the second planet from the Sun”), then the question remains as to how the words of the interpretation are to be interpreted. If they are interpreted by means of new words, then the problem re-emerges, and a threat of regress to infinity, of circularity, or of arbitrary cut-off in reasoning (perhaps in words whose meaning is supposedly self-evident) becomes visible. But for others, this problem encourages one to think of a non-linguistic form of interpretation, such as behaviourism or ostensive definition.
Pragmatics, on the other hand, is the part of the philosophy of language that deals with the relationship between language users and speech. Some of the central questions of pragmatics are the elucidation of the process of language learning, of the rules and conventions that make communication possible, and the description of the many and varied uses to which language is put, including: describing states of affairs, asking, ordering, joking, translating, pleading, thanking, cursing, greeting, praying, and so on.
