"All sects are different, because they come from men; morality is everywhere the same, because it comes from God."

"Doctors are men who prescribe medicines of which they know little, to cure diseases of which they know less, in human beings of whom they know nothing."

"Man is born to live and to die, and to be deceived."

"The instruction we have received, the example we have seen, the books we have read, the conversations we have had, all these make us what we are."

"The more I read, the more I acquire, the more certain I am that I know nothing."