I am quite wedded to the view that epistemologists should concern themselves with knowledge rather than our concept of knowledge. The analogy I like to draw here is with our understanding of (other) natural kinds.

Epistemologists should be concerned with knowledge and justification and so on, not our concepts of them; philosophers of mind should be concerned with various features of our mental life and the large-scale structure of the mind, not our concepts of mind, or consciousness, or anything else

No one worries terribly much about who the questions belong to, or whether a given contribution is really philosophy or, instead, properly nothing but science. Perhaps another way to put this is that, although I think that knowledge is a natural kind, I don't think that philosophy is.

I think that when I first suggested the idea that knowledge should be viewed as a natural kind, many people thought this was just crazy.

The experimentalists think that we can only get at our concepts by way of empirical investigation, while the armchair philosophers think that we can skip the experiments and figure things out from our armchairs. What they have in common, however, is regarding our concepts as the targets of philosophical theorising, and I just don't think that, in the vast majority of cases, the subject matter of philosophy has our concepts as its target.

The fact that these scientific theories have a fine track record of successful prediction and explanation speaks for itself. (Which is not to say that I don't directly discuss the work of those philosophers who would disagree.) But even if we grant this, many will argue that scientific knowledge in humans, and, indeed, reflective knowledge in general, is quite different in kind from the knowledge we see in other animals.

17th century philosophers were not in a position to understand the mind as well as we can today, since the advent of experimental methods in psychology. It shows no disrespect for the brilliance of Descartes or Kant to acknowledge that the psychology which they worked with was primitive by comparison with what is available today in the cognitive sciences, any more than it shows disrespect for the brilliance of Aristotle to acknowledge that the physics he worked with does not compare with that of Newton or Einstein.