Pragmatics is the study of how meanings are determined in a context. It studies a variety of phenomena, including the ways that the meanings of words can change as they are used and how utterances are interpreted. In its broadest sense, it also addresses the question of how the underlying social, cultural and psychological assumptions are expressed in language. It is often contrasted with semantics, which is concerned with the conventional meanings that are attached to expressions and sentences and the way that these may change in different contexts.

The philosophers who studied the nature of language in the classical period typically emphasized near-side pragmatics and left far-side issues largely to other disciplines, especially the social sciences, psychology and philosophy. This amounted to a sort of partitioning of pragmatics, with semantics taking the form of the Gricean model of what is said and what is not; what is conveyed in an utterance and how it does so; and, ultimately, the significance that the linguistic contribution takes on by way of the context.

This was the first major split in the discipline, and it is still the case that many neo-Griceans retain much of the classical picture and tend to regard semantics as the core of language study, with the Gricean maxims serving as a sort of shock absorber that prevents pragmatic considerations from undermining or overwhelming semantic interpretation. This is often done by mistaking pragmatic presuppositions for semantic content.

In the broadest sense, this is a mistake. Pragmatic presuppositions entail that the speaker and hearer take certain things for granted. These include the fact that, for example, a word such as ‘elwood’ has the usual meaning in the context, and the convention that if the utterance refers to a person or thing it is assumed that the person or thing exists in reality. But that is quite a different thing from stating that the word ‘elwood’ has an idiomatic meaning in the context, or that if the utterance refers in some other manner, that implication has a particular sense that will not be obvious to everyone who listens.

The distinction between semantics and pragmatics reflects the fact that different phenomena require a somewhat different approach. It is important to distinguish them because, for most of the history of language study, it was thought that a person communicates by encoding thoughts into words and decoding words into those thoughts, and the best way to understand communication was to try to determine what was being encoded, what was being transmitted, how it was transmitted and so on. It is not clear that this has been the most fruitful method for understanding how people communicate. This is because it is now believed that much of what we actually communicate is not expressible in terms of the logical forms that a person might express them. This is why there has been a move to see pragmatics as the more fruitful approach to the problem of communication.