I do agree with Stich that a quick move from our evolutionary origins to the reliability of our cognitive mechanisms is not legitimate. As I see it, the case for the reliability or unreliability of various cognitive mechanisms lies elsewhere.

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.

By putting the first-person point of view in a naturalistic perspective, I believe that we may genuinely come to understand it for the first time.

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 think that an understanding of contemporary work in the cognitive sciences has a profound effect on how one views the workings of the mind. It doesn't work the way we pretheoretically think it does. Such an understanding, of course, should have a large effect on one's views in philosophy of mind, but also in epistemology.

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.

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.