I'm not put out by the existence of evil. That is, I do not think it is some sort of terrible mystery, nor a thing to make one doubt the existence of God. You have heard it said: "A truly good God would never allow this! So there is no good God; indeed, no God at all." But that is not an argument. It is a kind of tantrum, really.
Still, let me offer a response — a parable I recently heard at Mass. True, a parable is not an argument either; but at least it is not a tantrum.Jesus said (Matt. 13:24-30):The kingdom of heaven is likened to a man that sowed good seeds in his field. But while men were asleep, his enemy came and oversowed cockle among the wheat and went his way. And when the blade was sprung up, and had brought forth fruit, then appeared also the cockle. And the servants of the goodman of the house coming said to him: Sir, didst thou not sow good seed in thy field? whence then hath it cockle? And he said to them: An enemy hath done this. And the servants said to him: Wilt thou that we go and gather it up? And he said: No, lest perhaps gathering up the cockle, you root up the wheat also together with it. Suffer both to grow until the harvest, and in the time of the harvest I will say to the reapers: Gather up first the cockle, and bind it into bundles to burn, but the wheat gather ye into my barn.There you go. God plants the wheat. It is not He who plants the cockle. And why does God not immediately uproot the cockle? Because doing so risks uprooting the wheat."Suffer both to grow."
Again, the point of a parable is not a QED. Parables illuminate
. Simply see it: Removing the evil cockle would uproot the good wheat. Not because good requires evil; but because good would be ruined by the act of removal. And though one could here begin a great exegesis, leading to some great theodicean schema, that endeavor would be against the spirit of a parable; and of a post in a blog.