... possess and exercise in order to know something by perceptual means. capacity ability propositional thought perceptual knowledge perceptual experience restrictive conception of perception In speaking of perceptual knowledge I will speak exclusively of visual perception: seeing. Perceptual knowledge...

..., not that the overly restrictive conception of perception is false, but that it cannot be consistently embraced by anyone who also believes that we have knowledge of the world through perception. For you cannot consistently claim to believe something while also accepting something that implies that the thing you say...