Nature, more of a stepmother than a mother in several ways, has sown a seed of evil in the hearts of mortals, especially in the more thoughtful men, which makes them dissatisfied with their own lot and envious of another s.
I don't believe in evil, I believe only in horror. In nature there is no evil, only an abundance of horror: the plagues and the blights and the ants and the maggots.
We study the injustices of history for the same reason that we study genocide, and for the same reason that psychologists study the minds of murderers and rapists... to understand how those evil things came about.