Modern philosophy of religion has developed two main theodicies, systematic attempts to justify God's permission of evil, plus a distinction that has reshaped the debate entirely.
The free will defense (Alvin Plantinga's rigorous version, 1974) argues that a world with free creatures who can choose good or evil is more valuable than a world of automata who always do the right thing. God, being omnibenevolent, preferred to create free beings, and granting genuine freedom means permitting the possibility of evil. God could have prevented moral evil (evil caused by human choices, murder, war, cruelty) by making us puppets, but a puppet world has less value than a free one.
Plantinga's argument is technically sophisticated. He showed that the logical problem of evil, the claim that God's existence and evil's existence are logically incompatible, fails, because it is at least possible that God could not have created free beings who always choose good. If this is even possible, the logical incompatibility vanishes.
But free will only addresses moral evil, evil caused by human choices. It doesn't touch natural evil, earthquakes, tsunamis, childhood leukemia, the parasitic wasp that lays its eggs inside a living caterpillar so its larvae can eat their way out. These are not human choices. They are the operating conditions of a biological world. The free will defense has nothing to say about them.
Soul-making theodicy (John Hick, following Irenaeus) takes a different approach. God's purpose in creation is not to produce maximal comfort but to develop human souls, to create beings capable of deep moral character, genuine compassion, and spiritual maturity. A world of painless hedonic contentment would produce shallow beings. Suffering, adversity, and genuine moral challenge are the conditions under which deep humanity develops. The world is not a pleasure garden but a vale of soul-making (Keats's phrase, adopted by Hick).
The analogy: a gym is full of things that cause discomfort, heavy weights, resistance machines, aching muscles. But no one calls the gym cruel. The point of the gym is not your comfort in the moment but your strength over time. On Hick's view, the world is something like God's gymnasium.
The problem: this analogy breaks down exactly where it matters most. In a gym, the discomfort is proportionate and purposive, you choose the resistance, you can stop, the suffering produces the strength. In the real world, suffering is wildly disproportionate to any plausible soul-making purpose. The problem of horrendous evils, a term developed by Marilyn McCord Adams, is the hardest version of this challenge: not everyday suffering but events so terrible, so crushing, so beyond any plausible purpose that they seem to defeat even the most ambitious theodicy. The Holocaust. Children born with brutal congenital diseases who die without having developed anything. What soul-making is occurring here?
This leads to the evidential problem of evil, the contemporary successor to the logical problem, developed most sharply by William Rowe (1979). Rowe doesn't claim God's existence is logically incompatible with evil. He claims that the amount and distribution of suffering we observe is strong evidence against the existence of a good God. The argument:
- There exist instances of intense suffering that an omnipotent, omniscient being could have prevented without thereby losing some greater good or permitting some equally bad or worse evil. 2. An omniscient, wholly good being would prevent the occurrence of any intense suffering it could, unless it could not do so without thereby losing some greater good or permitting some equally bad or worse evil. 3. Therefore there does not exist an omnipotent, omniscient, wholly good being.
The key battle is over premise 1. Theists who defend skeptical theism reply: we are not in a position to say that God has no justifying reason for permitting specific horrendous evils. Given the limits of human cognition relative to divine wisdom, we should expect that God's reasons would often be opaque to us. Our inability to see a justifying reason is not evidence that there is none, just as a child's inability to understand why a painful medical procedure is being performed does not mean the doctor has no good reason.