What makes philosophy an autonomous discipline regarding sciences? Central in the oeuvre of Granger, this question will lead us to examine the opposition between two procedures: the scientific structuration and the philosophical interpretation. The first builds the experience in structures of objects, whereas the second comments it in systems of significations.We will demonstrate how these two procedures extend a more fundamental distinction that lies in the very level of reality: the virtual and the actual. Acknowledging that the course of knowledge is a constant back and forth between the crude actuality of experience and its built virtuality, the way from science to philosophy can be drawn as follows: at the starting point - formal sciences - birthplace of virtual; to an intermediate stage - the empirical sciences - moment of confrontation between the virtual and the actual; and ultimately - the philosophy - unification field of the reality in the totality of its aspects.