If mankind were born tomorrow it would divide into groups; each would scramble to invent their one and only god, and set about butchering each-other.

It must be confessed that the inventors of the mechanical arts have been much more useful to men than the inventors of syllogisms.

One day everything will be well, that is our hope. Everything's fine today, that is our illusion.

All is a miracle. The stupendous order of nature, the revolution of a hundred millions of worlds around a million of stars, the activity of light, the life of all animals, all are grand and perpetual miracles.

Doubt is not a pleasant condition, but certainty is absurd.

Fear could never make virtue.

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.