This project focuses on the French philosopher and physicist Pierre Gassendi (1592-1655). Itexplores Gassendi’s optics and its relation to his commitment to empiricism. My aim is to propose,through Gassendi, a new interpretation of the genesis of early modern empiricisms and of thearticulation between empiricism understood as a theory of knowledge based on the senses on onehand, and new optical theories and experimental practices on the other hand. In so doing I intendto overcome the divide between “Continental rationalist” and “British empiricist” philosophies.Since few of Gassendi’s writings have been translated or even edited, the method I propose aimsto bring a contribution to filling this lacuna: my approach is precisely based on the study and theedition and translation of some unpublished manuscripts, especially from Gassendi’scorrespondence. I thus plan to reconstruct the genesis of Gassendi’s theories on the basis of thewhole of his writings and correspondence. I also want to take into account the whole scientificcontext to which his approach belongs and connect the physical, physiological, psychological, andepistemological dimensions of the topic. For that purpose, I will explore three main topics andshow their connection to one another and to Gassendi’s epistemology, namely: (1) the physics oflight, (2) the physiology of vision, (3) the psychology of vision.