The anti-theistic argument from evil--or, as it is sometimes called, the problem of evil--begins with a worry that almost every religious person thinks about at one time or another, namely this: How can we square the idea of an all-loving and all-powerful God with the mess that the world seems to be in or with the profound misery and suffering found almost everywhere in the world? How can we possibly affirm the love of God in the face of, for example, heart wrenching pictures of starving children in Somalia or suffering children in war-torn Bosnia? Many good and sensitive souls, such as my own very first philosophy professor, have reflected upon such questions and have concluded, perhaps even reluctantly, that they pose an insoluble problem for traditional theism; as these persons see it, the horrendous quantity of suffering in the world is inconsistent with, or at least is strong evidence against, the existence of God, as traditionally conceived.

The argument, in brief, is this: If God were truly omnipotent, he would have the power to prevent every instance of human suffering; if he were perfectly loving, he would want to exercise that power; so if he were both omnipotent and perfectly loving, there would be no suffering at all in the world. But there clearly is suffering. Therefore, a God who is both omnipotent and perfectly loving does not exist.