I am certainly open to the idea that this might be used to explain other philosophical categories besides knowledge. I have some real sympathy with the work of those moral realists who have tried to give naturalistic accounts of human flourishing, and who offer accounts of right action in such terms. (I suppose this is more evidence that I really do have deep affinities with Aristotle!)

If one's interest is not in some global question about the possibility of knowledge, but about some particular mechanism or inferential tendency, this fact about our evolutionary origin is of no use at all in addressing questions about reliability.

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.

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.

I was often asked how one could even make sense of this. Isn't the category of knowledge something that we project upon the world, rather than something that we discover in it?

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.

No one would suggest that we can adequately investigate what makes something an acid, or what makes something aluminum, by bringing our pretheoretical intuitions about these things into reflective equilibrium by way of armchair theorising.