Arguments for scepticism about perceptual knowledge are often said to have intuitively plausible premises. In this discussion I question this view in relation to an argument from ignorance and argue that the supposed persuasiveness of the argument depends on debatable background assumptions about knowledge or justification. A reasonable response to scepticism has to show there is a plausible epistemological perspective that can make sense of our having perceptual knowledge. I present such a perspective. In order give a more satisfying response to scepticism, we need also to consider the standing of background beliefs. This is required since the recognitional abilities that enable us to have perceptual knowledge are informed by, or presuppose, a picture or conception of the world the correctness of which we have not ascertained. The question is how, in the face of this, to make sense of responsible belief-formation. In addressing this problem I make a suggestion about the standing of certain crucial beliefs linking appearances with membership of kinds.