In contemporary discussions of natural evil, one classically important theodicy—variously called warfare theodicy, fallen angel theodicy, or the Satan hypothesis—is rarely mentioned, let alone defended. This is the view that so-called natural evil, the evil suffered by sentient beings that is not caused by human agency, is caused by angelic agency, specifically that of Satan and other fallen angels. Although the Satan hypothesis has received scant attention in contemporary philosophy of religion, Richard Swinburne, Michael Martin, Robert Adams, and David O’Connor (...) have each brought separate objections against it, but their objections fail. The real problem with the Satan hypothesis lies elsewhere. This paper begins by stating the Satan hypothesis and briefly sketching its scriptural and theological warrants in the Christian tradition. Second, it canvasses the objections that have been brought against the hypothesis and shows how each objection fails. Third, it isolates the real problem for the Satan hypothesis, namely the lack of any satisfactory account of how malevolent angelic agency could conceivably be the cause of natural evil. Finally, the paper offers three speculative proposals for such an account, highlighting problems with each. The upshot is that although the Satan hypothesis is a prominent theodicy in the history of Christian thought and in popular Christianity, it confronts philosophical challenges not yet met by its proponents. (shrink)