"The Great Man's sincerity is of the kind he cannot speak of, is not conscious of: nay, I suppose, he is conscious rather of insincerity; for what man can walk accurately by the law of truth for one day? No, the Great Man does not boast himself sincere, far from that; perhaps does not ask himself if he is so: I would say rather, his sincerity does not depend on himself; he cannot help being sincere!"

Source: Thomas Carlyle (1871). “The Collected Works of Thomas Carlyle”, p.218