The Theory of Sense of Gottlob Frege

Abstract

The notion of meaning plays an essential role in contemporary logic. Bound up with it are the so-called intensional logical calculi, i.e. calculi in which the principle of extensionality does not work. Calculi of this sort aim at clarifying, by formal means, the meaning of expressions of a certain kind of ordinary contentful language (for example, the calculi of strict implication try to explain the meaning of expressions such as “A follows from B”, “from A logically results B”). At the same time the notion of meaning is also required in the exposition of systems of classical two-valued mathematical logic. In this way proceed, e.g., Hermes and Scholz [23] and A. Church [22]. In this case the notion of the meaning of linguistical expressions is used in order to make in a natural way the transition from current languages, with which authors usually begin in the prefaces, to formalized ones. Here it is shown that the idea of meaning, naturally originated in the study of current languages, is superfluous in calculi similar to those which are described by the above authors, in virtue of which these calculi acquire an extensional character (extensional logic).KeywordsEquilateral TriangleOrdinary LanguageSubordinate ClauseContentful ThinkingDirect SpeechThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.