In this paper I outline and defend an introspectionist account of authoritative self-knowledge for a certain class of cases, ones in which a subject is both thinking and thinking about a current, conscious thought. My account is distinctive in a number of ways, one of which is that it is compatible with the truth of externalism—the view that the contents of subjects’ intentional states are individuation-dependent on factors external to their minds. It is thus decidedly anti-Cartesian, despite being introspectionist. My argument proceeds in three stages. A virtue of the position I develop is that the epistemic features on which it is based also apply to sensations and to non-episodic intentional states, to the extent that one has authoritative knowledge of them. However, despite the appeal to analogies with observable properties of objects of perception, the account is not a ‘perceptual’ model of such knowledge in the sense that those such as Shoemaker, Burge and others have in mind. Because the features on which the analogy is based are abstract and general, they are not tied to cases of observation alone. Those who appeal to such phenomena as ‘intellectual experience’ (Burge, Proceedings of the Aristotelian Society, 96, 91–116, 1996) or ‘intellectual intuition’ (Bealer, Philosophical perspectives, Cambridge, MA: Basil Blackwell, 29–55, 1999) in their accounts of authoritative self-knowledge may well appeal to such features. This, amongst other factors, distinguishes the position from other introspectionist ones in a way that makes it immune to standard objections to perceptual models of self-knowledge.