Say someone regularly plays devil's advocate, arguing against whatever belief is currently espoused, even if he believes in it. In particular the individual believes in doing this with his own beliefs as well, and regularly mentally argues against a belief he holds to ensure they are reasonable and not skewed by bias.
Is there a word to describe a person who does this, or the belief in the importance of doing this with one's own beliefs?
Is there a word to refer to the act of arguing against your personal beliefs, particularly in situations where the argument is done internally, purely to verify the validity of the belief, rather then externally as part of a debate or discussion with others?
Edit:
to clarify I'm trying to avoid negative connotations, looking for either value neutral or positive word. The focus should be on questioning ideas as a path towards checking biases, flawed logic, or simply finding missed arguments against that may change one's judgement; with the ultimate goal of ensuring a more informed final decision. Or in short, a way to avoid personal dogma clouding reason.