The emotional qualities are antagonistic to clear reasoning.
Whatsoever is contrary to nature is also contrary to reason, and whatsoever is contrary to reason is absurd.
The sleep of reason breeds monsters.[Goya]
Strong reasons make strong actions.
So man’s insanity is heaven’s sense; and wandering from all mortal reason, man comes at last to that celestial thought, which, to reason, is absurd and frantic; and weal or woe, feels then uncompromised, indifferent as his God.
You can prove anything you want by coldly logical reason – if you pick the proper postulates.
Where youth and diffidence are united, it requires uncommon steadiness of reason to resist the attraction of being called the most charming girl in the world.
True virtue is nothing else but living in accordance with reason.
There is one thing no man can do, and that is to get a woman to listen to reason. Somehow or other, they don’t seem to have any kind of sense.
There is more reason in your body than in your best wisdom.[Es ist mehr Vernunft in deinem Leibe, als in deiner besten Weisheit.]
There cannot any one moral rule be proposed whereof a man may not justly demand a reason.
The world of reason is to be regarded as a great and immortal being, who ceaselessly works out what is necessary, and so makes himself lord also over what is accidental.