Free will and the problem of evil

According to the free-will defence, the exercise of free will by creatures is of such value that God is willing to allow the existence of evil which comes from the misuse of free will. A well-known objection holds that the exercise of free will is compatible with determinism and thus, if God exists, God could have predetermined exactly how the will would be exercised; God could even have predetermined that free will would be exercised sinlessly. Thus, it is held, the free-will defence cannot be used as a partial account of why God should have allowed evil to exist. I investigate this objection using Kripke's apparatus for treating modalities and natural kinds to explore the nature of the incompatibilism required by the free-will defence. I show why the objection fails even if the standard arguments for compatibilism are acceptable. This is because the modality involved in the incompatibilism needed by the free-will defence differs from the modality involved in the compatibilism that is supported by standard compatibilist arguments. Finally, an argument is sketched for a variety of incompatibilism of the kind needed by the free-will defence.