Jean-Pierre Descles: Is the «lntensional Logic» Truly Intensional? Starting from an analysis of a concept as «course-of-values» in Grundgsetze (the Basic Laws of Arithmetic) of Frege, the A. proposes a new characterization of intensionaI equality vs extensional equality. This opposition belongs to a project for defining clearly the duaiity intensioniextension by means oÏ mathematical anà logic tools (combinatory logic and topology -theories of topoi and sheaves -). This approach is closely connected with an adequate formalization of traditional and classic viewpoints in logic, for instance with Leibnitz's views. It is not clear that the actual «intensionallogic» constructed from the works of Karnap, Church and Montague is connected with th...