There is not really any courage at all in attacking hoary or antiquated things, any more than in offering to fight one's grandmother. The really courageous man is he who defies tyrannies young as the morning and superstitions fresh as the first flowers. The only true free-thinker is he whose intellect is as much free from the future as from the past.
Enlightenment is man's emergence from his self-imposed nonage. Nonage is the inability to use one's own understanding without another's guidance. This nonage is self-imposed if its cause lies not in lack of understanding but in indecision and lack of courage to use one's own mind without another's guidance. Dare to know!
Let no one charge me with ever having abused or encouraged weakness or surrendered on matters of principle. But I have said, as I say again, that every trifle must not be dignified into a principle.