Abstract

La Logique ou L'Art de Penser (LAP), also known as the Port-Royal Logic, is generally presented as a "logic of ideas" in which the idea, the central epistemological entity, is the starting point of this logic based on Cartesian ontology. Structured around the four main operations of the mind - conceiving, judging, reasoning and ordering - the first part of the LAP contains "reflections on ideas". The idea, "the form by which we represent things [objects]", thus takes the place of the concept in Aristotelian-inspired logic. Some of the chapters in this first part deal with the problems raised in scholasticism by the theory of _proprietates terminorum_, which means that it is also a semantics of terms. The word 'term' itself must be understood in its logical and grammatical dimensions. The analyses of the 'Messieurs' of Port-Royal often have a logico-grammatical character, because, according to the anthropology of the authors, men need to make their thoughts heard by one another through language (institutional signs) and, therefore, "it is necessary in logic to consider ideas joined to words, and words joined to ideas". In this text, we shall endeavour to show the importance and innovative character of the semantics of terms in this logic of ideas which makes LAP a pivotal moment in the evolution of the language sciences, reviving the tradition and allowing dialogue with future developments (extension vs. comprehension, explanation, determination of terms, etc.). We will pay particular attention to the chapters on definition, "a remedy for the confusion that arises in our thoughts and speech from the confusion of words".