Abstract
Having suggested that a salient feature of philosophical naturalism is to deny that there are non‐natural norms, I make a distinction between a moderate naturalism, which admits the existence of natural norms , and a radical naturalism which denies it . On the assumption that intentional facts are irreducibly normative, their existence would thus seem to raise a problem for moderate epistemological naturalism. I argue that no non‐trivial naturalistic explanation of conceptual intentionality is to be possible unless it is denied that norms of rationality are constitutive of intentional content. It follows that the only form of intentional naturalism that is not obviously untenable has to be radical. Other aspects of Quine's doctrine suggest that the introduction of epistemic norms into our “system of the world” is either dubiously coherent, or “merely programmatic”