I don't think it's anyone who doesn't know who he is, it's just that many people hide who they are, maybe because they are proud and ashamed to admit they are, sometimes we are ashamed to admit that we are unemployed and want to show ourselves worthy so that many people respect it.
As a human with complete sence know who he really his or her. This question is straight forward, for someone to say he don't knows him/herself is not true statement. There are two types of talking through mouth and mind.