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.

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.

There has certainly been a great deal of work addressing the relationship between naturalism and the first-person perspective. Quite a number of philosophers have suggested that there are features of the first-person perspective that naturalism just cannot accommodate, whether it be qualitative character, or consciousness, or simply the ability we have to think of ourselves in a distinctively first-person manner.

When reflection is thereby demystified, I believe that the temptation to view human knowledge as different in kind from animal knowledge is undermined.

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.

What we need to do, however, is figure out what our best available theories of the mind suggest about epistemological issues, while we recognise that we may need to change our views on these questions as new evidence comes in.

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.