I have made a ceaseless effort not to ridicule, not to bewail, not to scorn human actions, but to understand them.

The proper study of a wise man is not how to die but how to live.

The greatest pride, or the greatest despondency, is the greatest ignorance of one's self.

I should attempt to treat human vice and folly geometrically... the passions of hatred, anger, envy, and so on, considered in themselves, follow from the necessity and efficacy of nature... I shall, therefore, treat the nature and strength of the emotion in exactly the same manner, as though I were concerned with lines, planes, and solids.

The highest activity a human being can attain is learning for understanding, because to understand is to be free.

From what has been said we can clearly understand the nature of Love and Hate. Love is nothing else but pleasure accompanied by the idea of an external cause: Hate is nothing else but pain accompanied by the idea of an external cause. We further see, that he who loves necessarily endeavors to have, and to keep present to him, the object of his love; while he who hates endeavors to remove and destroy the object of his hatred.

Blessedness is not the reward of virtue but virtue itself.