It was precisely owing to moral philosophers’ knowing the moral facts imperfectly, in an arbitrary epitome, or an accidental abridgement—perhaps as the morality of their environment, their position, their church, their Zeitgeist, their climate and zone—it was precisely because they were badly instructed with regard to nations, eras, and past ages, and were by no means eager to know about these matters, that they did not even come in sight of the real problems of morals—problems which only disclose themselves by a comparison of many kinds of morality.
Friedrich Nietzsche
Beyond Good and Evil