Two Aspects of the Problem
The problem of evil can be phrased in several ways. One approach addresses the origin of evil, prompting the syllogism (a series of statements that form a reasoned argument): 1) God created all things; 2) evil is a thing; 3) therefore, God created evil. If the first two premises are true, the conclusion is inescapable. This formulation, if sustained, is devastating for Christianity. God would not be good if He knowingly created evil. Augustine realized that the solution was tied to the question: What is evil? The argument above depends on the idea that evil is a thing (note the second premise). But what if evil is not a "thing" in that sense? Then evil did not need creating. If so, our search for the source of evil will take us in a another direction Augustine approached the problem from a different angle. He asked: Do we have any convincing evidence that a good God exists? If independent evidence leads us to conclude that God exists and is good, then He would be incapable of creating evil. Something else, then, must be its source. If Augustine's approach is fair, it prompts a pair of syllogisms that lead to a different conclusion. First: 1) All things that God created are good; 2) evil is not good; 3) therefore, evil was not created by God. Second: 1) God created every thing; 2) God did not create evil; 3) therefore, evil is not a thing. The key to success here, is the truthfulness of two premises. If Augustine can offer evidence through natural theology that God exists as Creator and also that God is good, making everything He created also good, then the conclusion--evil is not a thing--automatically follows. This is Augustine's strategy. If evil is not a thing, then the case against Christianity stated in the original syllogism is unsound because one of its premises is false. The critical question is: What is evil?
Digging a Hole in Goodness
Central to Augustine's idea of goodness (and, consequently, evil) was the notion of being. To Augustine, anything that had being was good. God as the ground of being was perfectly good, along with everything he brought into being. This goodness was a property that came in varying degrees. With this foundation Augustine was now prepared to answer the key issue: "Where is evil then, and whence, and how crept it in hither? What is its root, and what its seed? Or hath it no being?"[i] To this Augustine answered: "Evil has no positive nature; but the loss of good has received the name 'evil.'"[ii] Augustine observed that evil always injures, and such injury is a deprivation of good. If there were no deprivation, there would be no injury. Since all things were made with goodness, evil must be the privation of goodness: "All which is corrupted is deprived of good."[iii] The diminution of the property of goodness is what's called evil. Good has substantial being; evil does not. It is like a moral hole, a nothingness that results when goodness is removed. Just as a shadow is no more than a "hole" in light, evil is a hole in goodness. To say that something is evil, then, is a shorthand way of saying it either lacks goodness, or is a lower order of goodness than what ought to have been. But the question remains: "Whence and how crept it in hither?" Augustine observed that evil could not be chosen because there is no evil thing to choose. One...