There are few things wholly evil or wholly good. Men never do evil so completely and cheerfully as when they do it from religious conviction. There are a thousand hacking at the branches of evil to one who is striking at the root. It is some compensation for great evils that they enforce great lessons. It is almost impossible systematically to constitute a natural moral law.
Nature has no principles.
She furnishes us with no reason to believe that human life is to be respected. Nature, in her indifference, makes no distinction between good and evil. The belief in a supernatural source of evil is not necessary, men alone are quite capable of every wickedness. Non-cooperation with evil is as much a duty as is cooperation with good. One may say that evil does not exist for subjective man at all, that there exist only different conceptions of good.