Ethologists thus have an interest in looking at these capacities for the reliable acquisition of belief, and it is not surprising that they have a name for the true beliefs which are the typical product of these reliable capacities. They call them items of knowledge. So I argue that talk of knowledge may thereby be seen to be embedded within a successful empirical theory.

I believe, that empirically informed approaches to the question have issued in more illuminating answers than the old armchair approaches. But I think that it would be a terrible mistake to give up on addressing normative questions in epistemology.

Internalist approaches to epistemology, I believe, have a great deal of intuitive appeal. Internalists believe that the features in virtue of which a belief is justified must somehow be internal to the agent. On some views, this amounts to the claim that these features must be accessible to introspection and armchair reflection. On others, it amounts only to the claim that they must be mental features.

But there is no doubt that my own views on this are, in quite a number of ways, very different from those of Quine.

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.

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.

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.