He who lets the world choose his plan of life for him has need of no other faculty than that of ape-like imitation.

The fatal tendency of mankind to leave off thinking about a thing when it is no longer doubtful is the cause of half their errors.

Complete liberty of contradicting and disproving our opinion, is the very condition which justifies us in assuming its truth for purposes of action.

Not the violent conflict between parts of the truth, but the quiet suppression of half of it, is the formidable evil; there is always hope when people are forced to listen to both sides; it is when they attend to only one that errors harden into prejudices, and truth itself ceases to have the effect of truth, by being exaggerated into falsehood.

There is always need of persons not only to discover new truths, and point out when what were once truths are true no longer, but also to commence new practices, and set the example of more enlightened conduct, and better taste and sense in human life.

All desirable things... are desirable either for the pleasure inherent in themselves, or as a means to the promotion of pleasure and the prevention of pain.

The best state for human nature is that in which, while no one is poor, no one desires to be richer, nor has any reason to fear from thrust back, by the efforts of others to push themselves forward.