Whatever it is that makes what would otherwise be mere sounds and inscriptions into instruments of communication and understanding. The philosophical problem is to demystify this power, and to relate it to what we know of ourselves and the world. Contributions to this study include the theory of speech acts and the investigation of communication and the relationship between words and ideas, and words and the world. For particular problems see content, ideas, indeterminacy of translation, inscrutability of reference, language, predication, reference, rule-following, semantics, translation, and the topics referred to under headings associated with logic. The loss of confidence in determinate meaning (‘every decoding is another encoding’) is an element common both to postmodernist uncertainties in the theory of criticism, and to the analytic tradition that follows writers such as Quine.