This paper argues that Kepler considered his work in optics as part of natural philosophy and that, consequently, he aimed at change within natural philosophy. Back-to-back with John Schuster’s claim that Descartes’ optics should be considered as a natural philosophical appropriation of innovative results in the tradition of practical and mixed mathematics the central claim of my paper is that Kepler’s theory of optical imagery, developed in his Paralipomena ad Vitellionem (1604), was the result of a move similar to Descartes’ (...) by Kepler. My argument consists of three parts. First, Kepler borrowed a geometrical model and experiment of optical imagery from the mélange of mixed and practical mathematics provided in the works of the sixteenth-century mathematicians Ettore Ausonio and Giovanni Battista Della Porta. Second, Kepler criticized the Aristotelian theory of light and he developed his own alternative metaphysics. Third, Kepler used his natural philosophical assumptions about the nature of light to re-interpret the model of image formation taken from Della Porta’s work. Taken together, I portray Kepler’s theory of optical imagery as a natural philosophical appropriation of an innovative model of image formation developed in a sixteenth-century practical and mixed mathematical tradition which was not interested in questioning philosophical assumptions on the nature of light. (shrink)

Cet article a pour objet la réinterprétation, dans le sillage de la rénovation keplérienne de l’optique, de la fonction de l’image rétinienne pour la vision par Gassendi et Descartes. Une comparaison de leurs approches montre qu’elles reposent sur une interprétation différente du modèle iconique de la perception. S’ils attribuent un rôle crucial à l’imagination pour la perception visuelle, leurs positions philosophiques font jouer un rôle différent à l’image dans la perception visuelle et les amènent à concevoir de façon divergente l’imagination (...) et son rapport aux autres pouvoirs de l’esprit. (shrink)