Why do your self-attributions of beliefs and intentions ordinarily constitute authoritative self-knowledge? You can self-attribute a belief or an intention transparently. For instance, you can transparently self-attribute a belief that p by judging that p. You can transparently self-attribute an intention to Φ by deciding to Φ. However, recognizing just this much does not completely explain the epistemology of transparent self-attributions.
Self-attributions of this kind count as authoritative knowledge because they involve a form of practical knowledge. You can intentionally control the kind of attitude you take up in conscious thought, and when you do that, you know what kind of attitude you are taking up in conscious thought. Then, in the context of transparent self-attribution of belief or intention, a judgment that p or a decision to Φ can have a complex identity. A judgment that p can also be a self-attribution of a belief that p, and a decision to Φ can also be a self-attribution of an intention to Φ. To explain how this can be the case I introduce the linked notions of embedded mental action and content plurality.
The view of self-knowledge that emerges also explains why there are contents involving belief attributions that are absurd to assert or to judge even though they can be true. These contents are Moorean absurdities for belief. I argue that there are no corresponding Moorean absurdities for intention, even though you also have transparent self-knowledge of what you intend to do. This points to an important attitudinal distinction between belief and intention: intentions are not beliefs.
The difference between first-personal and third-personal methods of attributing attitudes is subtle. The specialness of the first-personal perspective cannot be explained in terms of epistemic groundlessness, as many have tried to do. You must also make third- personal groundless attributions of belief to understand others’ intentional behavior.
Despite philosophical skepticism on this point, transparent self-knowledge really is valuable, in a special sense. Having complete diachronic transparent self-knowledge involves having no hidden attitudes and having a diachronically unified self of the kind that is required for evaluation in terms of authenticity.
The epistemology of self-knowledge relies crucially on the fact that you can do things in thought. Knowing yourself is something you do because intentional action is indispensable to authoritative, knowledgeable self-attribution of beliefs and intentions.