“Should a traveler, returning from a far country, bring us an account of men wholly different from any with whom we were ever acquainted, men who were entirely divested of avarice, ambition, or revenge, who knew no pleasure but friendship, generosity, and public spirit, we should immediately, from these circumstances, detect the falsehood and prove him a liar with the same certainty as if he had stuffed his narration with stories of centaurs and dragons, miracles and prodigies.”