This article discusses the notion of transparency condition proposed by Richard Moran in Authority and Estrangement (2001). According to this notion the question in the first-person present tense about our own belief ("Do I believe in p?") is answered in reference with the same reasons that justify the answer to a corresponding question about the world (about the truth of p). Transparency, in this sense, is the fundamental characteristic of self-knowledge in the context of common experience. Understanding this idea helps (...) us to understand the notions which are normally associated to self-knowledge, such as immediacy (we do not need to turn to observation or inference) first-person authority (I have different access to my attitudes than other people do) and the relationship between self-knowledge, rationality and psychic health of a person. Through the presentation of the transparency condition and some objections to this notion, I aim to offer an interpretation of the notion of transparency which favors a modest conception of self-knowledge and rationality. (shrink)