The only shame is to have none.

All evil stems from this-that we do. Know how to handle your solitude.

The last advance of reason is to recognize that it is surpassed by innumerable things; it is feeble if it cannot realize that.

If man made himself the first object of study, he would see how incapable he is of going further. How can a part know the whole?

Men never do evil so completely and cheerfully as when they do it from religious conviction.

Those honor nature well, who teach that she can speak on everything...

Earnestness is enthusiasm tempered by reason.