A man should always have these two rules in readiness: the one, to do only whatever the reason of the ruling and legislating faculty may suggest… the other, to change his opinion, if some other person sets him right, and moves him from an opinion. But this change of opinion must proceed only from a certain persuasion, as of what is just or of common advantage, and the like, not because it appears pleasant or brings reputation.

Marcus Aurelius (121 – 180)