“[E]veryone who does evil is the cause of his own evildoing.”

One of the fundamental truths Augustine takes pains to explain and prove in this work is that all evil is directly the cause of human sin, and that God is not the source of sin and evil. Human beings, he argues, are the direct or indirect causes of their own evil actions.

“We believe that everything that exists comes from the one God, and yet we believe that God is not the cause of sins. What is troubling is that if you admit that sins come from the souls that God created, and those souls come from God, pretty soon you’ll be tracing those sins back to God.”

Augustine summarizes the basic objection to the idea that a good God and human free will can coexist: if God is the cause of all that exists, and if sins come from God’s creations (humans), how is God not the cause of sin? That God produces evil seems to be a logical conclusion, but it is unacceptable to Augustine because it contradicts the proposition that God is good. By bringing up this powerful objection to his own argument, Augustine indicates that it needs to be addressed and refuses to avoid the question even though it contradicts his own logic.

“[I]t is clear now that inordinate desire is what drives every kind of evildoing.”

Augustine has just told Evodius that evil cannot be identified through external acts alone because in fact evil exists in human desires. Here, Evodius replies that Augustine has convincingly described the nature of evil: to act in a way that gives in to inordinate desires.