This paper addresses whether we have transparent accurate access to our own conscious experience. It first sketches the origin and social history of this issue in the seventeenth century, when the trust one can have in self- knowledge was disputed in the religious, social and scientific domains. It then reviews evidence that our conscious experience is disunified in several ways and has two levels, can be opaque to us, and contains much that is non-explicit; and that attending to one's experience (...) not only affects and changes it, but may also bring about specific content and phenomenal experience. Quite apart from trusting other people's introspective reports, we cannot trust ourselves even in knowing our own consciousness. Finally, several ways of coping with the problems produced by these characteristics are suggested. (shrink)