Philosophy/science about consciousness?

I know that at some point some fairly notable scientist/philosopher has said that the mind has awareness of itself by knowing and othering what is "not it." That is, the human mind knows itself by knowing what it isn't.

I've totally forgotten where these ideas come from. Please help point me towards the right thinker!
Asked Nov 14, 2013

TIP: If it's not your answer to this question, please click "Leave a Comment" button under the question to communicate with the question owner.