The fact that we have been able to develop a successful science, which issues in ever more accurate predictions and broader explanations, is the real ground for confidence that we are in a position to gain knowledge of the world around us. At the same time, one might ask how it is that the cognitive equipment we have came about, and here, no doubt, our evolutionary origins are relevant.

So I do, of course, reject much that is central not only to the psychology of Descartes and Kant, but to their epistemology as well. No doubt, the best available theories of today will look primitive in comparison with what we are in a position to understand hundreds of years from now.

The kinds of claims I make about knowledge are thus meant to be illustrative of a general argumentative strategy which might well bear fruit in areas of philosophy which I have not thus far explored.

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.

Chemists in earlier centuries were quite interested in the nature of acids. They had no interest in analysing their concept of acid. After all, they knew that their understanding of acids was at a fairly primitive level, and what they wanted to do was understand something about the world better - the nature of acidity - not something about their own concepts.

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.

The kind of approach I take is different from much of experimental philosophy. Although the experimental philosophers and I are certainly in agreement about the relevance of empirical work to philosophy, a good deal of their work is devoted to understanding features of our folk concepts, and in this respect, at least, I see them as making the same mistake as those armchair philosophers who are interested in conceptual analysis.