The ArgumentAlexandre Koyré is one of the most important historians of philosophic and scientific though since the thirties. Research on the Scientific Revolution, on Galileo, Descartes, Newton, as well as on Paracelsus and Boehme has deeply changed under his influential method: it has been a model for Kuhn's methodology of paradigms and revolutions in the histroy of science. Whereas Koyré used to be considered opposed in his ideology and method to sociological approaches, he has recently been characterized by Yehuda Elkana (...) as a sociologist of knowledge. In fact, until now one of the main sources of his method had not been identified: it is only by acknowledging the influence of Lucien Lévy-Bruhl on Koyré that it is possible to explain how the latter wrote his thesis on Boehme's mystical thought just before his Etudes galiléennes. Lucien Lévy-Bruhl was teaching history of philosophy at the Sorbonne, and Koyré was strongly influenced by his idea of “prelogical thinking” as a universel phenomenon and in a general way by the sociological school of Durkheim. Conceptual analysis deriving from Husserl, collective representations and attitude mentale, came together in Alexandre Koyrè's method. (shrink)