I acknowledge that four thousand volumes of metaphysics will not teach us what our soul is.

The superfluous is the most necessary.

If there had been a censorship of the press in Rome we should have had today neither Horace nor Juvenal, nor the philosophical writings of Cicero.

Which is more dangerous: fanaticism or atheism? Fanaticism is certainly a thousand times more deadly; for atheism inspires no bloody passion whereas fanaticism does; atheism is opposed to crime and fanaticism causes crimes to be committed.

Answer me, you who believe that animals are only machines. Has nature arranged for this animal to have all the machinery of feelings only in order for it not to have any at all?

Virtue debases itself in justifying itself.

The best is the enemy of the good.