“In practical life we are compelled to follow what is most probable ; in speculative thought we are compelled to follow truth.”

“everyone endeavors as much as possible to make others love what he loves, and to hate what he hates... This effort to make everyone approve what we love or hate is in truth ambition, and so we see that each person by nature desires that other persons should live according to his way of thinking...”

“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.”

“Of all the things that are beyond my power, I value nothing more highly than to be allowed the honor of entering into bonds of friendship with people who sincerely love truth. For, of things beyond our power, I believe there is nothing in the world which we can love with tranquility except such men.”

“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.”

“These are the prejudices which I undertook to notice here. If any others of a similar character remain, they can easily be rectified with a little thought by anyone.”

“He who seeks to regulate everything by law is more likely to arouse vices than to reform them. It is best to grant what cannot be abolished, even though it be in itself harmful. How many evils spring from luxury, envy, avarice, drunkenness and the like, yet these are tolerated because they cannot be prevented by legal enactments.”