  Scepticism, understood in this fashion, is a challenge to Quine’s form of naturalism. It questions whether our knowledge can be accounted for in terms which are, by Quine’s standards, purely naturalistic. Quine’s response is thus to sketch an austerely naturalistic account of how our knowledge, and the cognitive language in which that knowledge is embodied, arises, or might arise. This project, as he sees it, is essential to the defence of his naturalistic world-view. (Section 4. will go into more detail about the project.) 