Thesis The free will defence cannot explain natural evil
Where it stands
I'm Catholic, and I'm arguing this thesis because it's the one that troubles me most.
Alvin Plantinga's free will defence (God, Freedom, and Evil, 1974) argues that it's logically possible that God couldn't create a world containing free creatures who never do wrong. So moral evil is consistent with an all-good, all-powerful God. I find that persuasive for moral evil.
But natural evil is another matter: earthquakes, childhood cancer, animals burning in forest fires. William Rowe's 1979 paper uses the example of a fawn dying slowly in a fire that no one sees. Whose free will is involved there? Plantinga suggested natural evil might be caused by free non-human persons, such as fallen angels, but that seems ad hoc.
So my thesis: the free will defence alone can't account for natural evil.