I have made some headway in addressing these questions, however, and succeeded in explaining how it is that the category of knowledge might play an important role in empirical theories. To the extent that talk of knowledge can be shown to play an explanatory role in such theories, the analogy I wish to make with paradigm natural kinds such as acids and aluminum starts to make a good deal of sense. This is, of course, connected with the issue of the role of intuitions in philosophy.

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.

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?

I do think that it is legitimate to talk of goals and functions in nature, and that these things can be made sense of in naturalistic terms. There is nothing at all contrary to naturalism in the idea of goal-directed systems.

What I argue is that talk of knowledge plays an important role in theories within cognitive ethology. The idea is this. First, one sees cognitive ethologists arguing that we need to attribute propositional attitudes to some animals in order to explain the sophistication of their cognitive achievements.

Epistemologists should be concerned with knowledge and justification and so on, not our concepts of them; philosophers of mind should be concerned with various features of our mental life and the large-scale structure of the mind, not our concepts of mind, or consciousness, or anything else

It's not just that there is a cooperative spirit of investigation there, where we all recognise that we are engaged in a common project of inquiry. It's also that the philosophers are well-versed in the relevant empirical data, and the scientists are well-versed in the more abstract issues which are typically the central focus of philosophical work.