We now possess four principles of morality: 1) a philosophical: do good for its own sake, out of respect for the law; 2) a religious: do good because it is God's will, out of love of God; 3) a human: do good because it will promote your happiness, out of self-love; 4) a political: do good because it will promote the welfare of the society of which you are a part, out of love of society having regard to yourself. But is this not all one single principle, only viewed from different sides?

There is no greater impediment to progress in the sciences than the desire to see it take place too quickly.

Man is a masterpiece of creation, if only because no amount of determinism can prevent him from believing that he acts as a free being.

Perhaps pure reason without heart would never have thought of God.

Whenever he composes a critical review, I have been told, he gets an enormous erection.

I would give something to know for whose sake precisely those deeds were really done which report says were done for the fatherland.

You believe I run after the strange because I do not know the beautiful; no, it is because you do not know the beautiful that I seek the strange.