We do not know our personality traits or our moral character. We do not know many of our most morally and personally important beliefs and desires. We do not know many of the most basic things about our own stream of conscious experience. Further reflection is as likely to deepen our illusions and self-deceptions as it is to yield a more realistic view. For all the vast increases in our knowledge of the physical, biological, and even psychological world over the last two and a half millennia, we have made very little progress in developing the tools for self-knowledge. Is this a good thing or bad?