The mother of useful arts is necessity; that of the fine arts is luxury. For father the former has intellect; the latter genius, which itself is a kind of luxury.

Education perverts the mind since we are directly opposing the natural development of our mind by obtaining ideas first and observations last. This is why so few men of learning have such sound common sense as is quite common among the illiterate.

Vengeance taken will often tear the heart and torment the conscience.

It is most important to allow the brain the full measure of sleep which is required to restore it; for sleep is to a man's whole nature what winding up is to a clock.

It is the courage to make a clean breast of it in the face of every question that makes the philosopher. He must be like Sophocles' Oedipus, who, seeking enlightenment concerning his terrible fate, pursues his indefatigable inquiry even though he divines that appalling horror awaits him in the answer. But most of us carry with us the Jocasta in our hearts, who begs Oedipus, for God's sake, not to inquire further.

With people of limited ability modesty is merely honesty. But with those who possess great talent it is hypocrisy.

Pantheism is only a polite form of atheism.