One of the goals of scientific theorising is to develop concepts which are adequate to the phenomena under study. In my view, things should work the same way in epistemology. We want to know what knowledge actually amounts to, not what our folk concept of knowledge is, since, just as with our pretheoretical concept of acidity, it might contain all sorts of misunderstandings and leave out all manner of important things.

Externalists reject any such view. I think that the idea that we can tell, simply by way of reflection, whether our beliefs are justified, is deeply commonsensical. More than that, the idea that responsible epistemic agents ought to reflect on their beliefs, and hold them only if they somehow pass muster, is utterly natural.

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.

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.

I largely defer to the cognitive ethologists. I believe that the arguments that they make on this score are extremely persuasive. More than this, I do think as well that a priori objections by philosophers to successful research programs in the sciences have a very bad track record.

There is a worry that many have expressed that, on the naturalistic way of approaching philosophical questions, philosophy will somehow be co-opted by science. I'm not much worried about this.