In this paper I address the question whether self-knowledge is compatible with an externalist individuation of mental content. Against some approaches, I consider self-knowledge as a genuine cognitive achievement. Though it is neither incorrigible nor infallible, self-knowledge is direct, a priori (no based on empirical investigation), presumptively true and authoritative. The problem is whether self-knowledge, so understood, is compatible with externalism. My answer will be affirmative. I will defend this species of compatibilism against several objections, in particular those based on (...) the possibility of an individual’s being unwittingly switched between worlds. (shrink)