Another perennial problem is of compatibility of evil and God’s goodness. But formidable though it is for a theist, evil is not necessarily better evidence for naturalism than it is for theism, because theism, too, predicts a battlefield Earth, a bleak yet full of potential, vast but finite world suspended between heaven and hell, in which human souls are forged.
This fairly standard soul-making theodicy explains evil. But does it explain all of it? In psychology there is the notion of “optimal frustration,” an obstacle for a person to overcome that is neither too easy, such that no growth or skill acquisition occurs, nor too hard, so that one quits in despair and self-loathing, but one that engenders, as a result of the person’s overcoming it, some form of personal improvement.
But surely, a great deal of suffering and pain and sin in this life is hardly optimal. The world seems full of suffering that’s pointless and suffering that’s too intense to be useful or redemptive. This is called sometimes “gratuitous” evil. Now this is just a hint. I may be wrong. But an argument can be made that the world could contain less pain and sorrow and still conduce to creating human beings in all their glory.
If so, then there is some evil in the world that soul-making does not account for. The idea of Original Sin is especially well-suited to explain gratuitous evil and defend theism and goodness of God.
Original Sin claims something like the following. However it was actually contracted, there was a time when “Adam and Eve,” our first parents, lived in pretty decent conditions. At some point, however, Adam decided that he wanted to personally experience, both by himself and through his descendants, a full gamut of sin and evil, perhaps to be able to choose between good and evil intelligently. He wanted to taste the poison of sin, to drink freely of it, and still hopefully barely survive in the end.
If it were just some evil Adam wanted to feel (rather like the Most Interesting Man in the World “once having an awkward moment, just to see how it feels”), that could’ve been dealt with by God giving Adam a knife and telling him to cut his finger. Then God would go, “Do you like that? Unpleasant, isn’t it? Let me heal it for you real quick, and I trust you won’t want to experience pain, etc. again? I’m glad we have an understanding.”
Unfortunately, Adam was apparently interested in all manner of super-sophisticated evil, and God had no choice but to grant his perverse desire. Evil in the presence of a good God is now explained as Adam getting exactly what he wished for, with the overarching purpose perhaps to enable man to choose between good and evil with full experiential knowledge of both.