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.

I do realise that talk of natural kinds dates back to Aristotle, but I'd better not say too much about ancient philosophers lest I be convicted of practicing history of philosophy without a license.

In my view, since the case can be made that knowledge too is a natural kind, the role of pretheoretical intuitions is similarly diminished in epistemology.

What I hankered for was an account of knowledge which would do far more than get our intuitions about cases right; I wanted a kind of account which would somehow be explanatory.

Bealer argues that the kind of naturalistic view which Quine holds will rob him of the ability to make the normative claims which (many) naturalists wish to make in epistemology. I don't think this is right about Quine, but I'm certain it's not right about my own view. To the extent that I can show that talk of knowledge is firmly rooted within empirical theories where it plays an important explanatory role, I thereby demonstrate its naturalistic credentials.

For one thing, I think that there are questions which philosophers raise which, although science bears on them, are not typically the central focus of those who work in the sciences. At the same time, I don't have a view of philosophy which marks it out as different in kind from scientific work

My own reasons for favouring talk of natural kinds is just that I believe the best accounts of the success of scientific theories presupposes the existence of natural kinds.