The main topic of this study is to discuss the idea according to which perceptual experiences sould be conceive as ways of being in contact with the world and perceptual experiences can give reasons for believing some propositions about the world and can give rise to knowledge. Lots of philosophers countervail this intuitive and naive conception of perception. This rejection is linked to the fact that they adopt an internalist conception of perception and/or justication and/or perceptual knowledge. Perceiving sould be conceive as an purely internal event of subjects which possess perceptual capacities. And so, one may doubt that they can have justifications for their beliefs or that they can know anything. Is it possible to avoid this concl...