The topic of my thesis is the epistemic role of perception. I attempt first to explain how perceptual experience can provide an immediate justification for beliefs about the external world in response to Sellars’ and BonJour’s attacks. I thereby also try to see if the possibility of such a perceptual justification depends on a particular metaphysical view of experience. I then pursue on those lines by investigating McDowell’s claim that the very possibility of perceptual knowledge depends on a disjunctive account of perception ; I hope to show that his argument proves to be unconvincing. Finally, I address the debated issue of the conceptual vs nonconceptual content of perception ; I am tempted to agree that the content of perception has to be conceptual if perception is to be able to justify a belief.