Good and Evil

I think one may be quite rid of the old haunting suspicion—which raises its head in every temptation—that there is something else than God—some other country [. . .] into which He forbids us to trespass—some kind of delight wh. He “doesn’t appreciate” or just chooses to forbid, but which wd. be real delight if only we were allowed to get it. The thing just isn’t there. Whatever we desire is either what God is trying to give us as quickly as He can, or else a false picture of what He is trying to give us—a false picture or else a false picture wh. would not attract us for a moment if we saw the real thing.

Therefore God does really in a sense contain evil—i.e. contains what is the real motive power behind all our evil desires. He knows what we want, even in our vilest acts: He is longing to give it to us. He is not looking on from the outside at some new “taste” or “separate desire of our own.” Only because he has laid up real goods for us to desire are we able to go wrong by snatching at them in greedy, misdirected ways. The truth is that evil is not a real thing at all, like God. It is simply good spoiled. That is why I say there can be good without evil, but no evil without good. You know what the biologists mean by a parasite—an animal that lives on another animal. Evil is a parasite. It is there only because good is there for it to spoil and confuse.

- The Letters of C. S. Lewis to Arthur Greeves
If you do not take the distinction between good and bad very seriously, then it is easy to say that anything you find in this world is a part of God. But, of course, if you think some things really bad, and God really good, then you cannot talk like that. You must believe that God is separate from the world and that some of the things we see in it are contrary to His will. Confronted with a cancer or a slum the Pantheist can say, ‘If you could only see it from the divine point of view, you would realise that this also is God.’ The Christian replies, ‘Don’t talk damned nonsense.’ For Christianity is a fighting religion. It thinks God made the world—that space and time, heat and cold, and all the colours and tastes, and all the animals and vegetables, are things that God ‘made up out of His head’ as a man makes up a story. But it also thinks that a great many things have gone wrong with the world that God made and that God insists, and insists very loudly, on our putting them right again.

- Mere Christianity