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 supreme mystery of despotism, its prop and stay, is to keep men in a state of deception, and with the specious title of religion to cloak the fear by which they must be held in check, so that they will fight for their servitude as if for salvation.

Hatred which is completely vanquished by love passes into love: and love is thereupon greater than if hatred had not preceded it.

Whatsoever is contrary to nature is contrary to reason, and whatsoever is contrary to reason is absurd.

God is a thing that thinks.

The human mind cannot be absolutely destroyed along with the body, but something of it remains, which is eternal.

Simply from the fact that we have regarded a thing with the emotion of pleasure or pain, though that thing be not the efficient cause of the emotion, we can either love or hate it.