And how can evil be the mere absence of good? Is genocide the absence of something, of what? Of kindness? Were there no kind Nazis? Of love? Were there no Maoist revolutionaries who loved their families? Evil is an act, we commit evil proactively, it doesn't simply emerge in the absence of good. When you don't put a dollar in the donation tin in the front of the convenience store it doesn't mean that an ax murderer was created. We human beings have one set of actions described as "good" and another set described as "evil.