Abstract

The paper deals with the connection of "mathesis", intuition and imagination in Descartes' "Regulae ad directionem ingenii" - young Descartes' first writing about methodology, intended to set the foundation of a "mathesis generalis" - and in some of his followers/critics, in particular Leibniz, on the background of the so-called psychology of faculties. Two are the main points at stake: the presence of mental images in thought processes, and the cognitive functions of the imagination. A thorough analysis of Descartes' examples of intuitive, not-imaginative cognition shows the difficulties in his approach. Different solutions will be proposed by Descartes himself and by most cartesians, on one hand, and by Tschirnhaus on the other hand. Leibniz's peculiar solution is finally considered.