This text investigates some difficulties that Semantic Externalism presents for the idea of “self-knowledge” and “first person authority”. I would like to defend that those difficulties originate mainly from the fact that externalist arguments often fall back on mental experiments construed in the perspective of an omniscient narrator. I believe that “self-knowledge” and “first person authority” should be thought of not from the viewpoint of epistemology, but our normal practical capacities to evaluate, ponder, criticize, judge our thoughts, attitudes and actions, (...) especially when we want to give proof, plan something, talk with other people, justify, explain, in short, when we want to offer reasons. (shrink)