Peace is not the absence of war, but a virtue based on strength of character.

The greatest secret of monarchic rule...is to keep men deceived and to cloak in the specious name of religion the fear by which they must be checked, so that they will fight for slavery as they would for salvation, and will think it not shameful, but a most honorable achievement, to give their life and blood that one man may have a ground for boasting.

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 more intelligible a thing is, the more easily it is retained in the memory, and counterwise, the less intelligible it is, the more easily we forget it.

Self-complacency is pleasure accompanied by the idea of oneself as cause.

Laws which prescribe what everyone must believe, and forbid men to say or write anything against this or that opinion, are often passed to gratify, or rather to appease the anger of those who cannot abide independent minds.

Blessedness is not the reward of virtue but virtue itself.