By pointing at the non-integratibility of evil, the problem of theodicy shows us that evil is, indeed, a horror. But the problem can reveal that horror only if no solution to it is finally satisfactory. As I said in my criticism of Leibniz, any solution to the problem of evil, any integration of it into a rational theology, amounts to an argument that there is, in fact, no real evil and that stoicism rather than horror ought to be our response to suffering. It follows that if a theodicy solves the problem of evil, then it justifies Satan. Only if the problem of theodicy is genuinely a problem—only if all solutions ultimately fail—can we continue to know that evil is genuinely evil.

Once we know what is true, reason provides a wonderful tool for sorting out our obligations, anticipating consequences, and persuading others that what we know is true. Truth, I am convinced, can be rendered reasonable, but it does not arise from reason.