Still searching for the truth, Augustine encounters the Manichees. He is taken in by their objections to the literal sense of the Bible and by the physicality of their mythology, because he fails to understand that only the spiritual reality is the true one, while the physical reality is merely the reflection of spiritual reality. He also does not realize that right and wrong are not determined by the customs of different places or times but by the unchangeable law of God. Augustine considers the nature of sin: Some sins offend God's laws, and some sins offend others by causing harm or suffering. Sin springs from three causes: lust for power, carnal lust, and lust of the eyes. But because Augustine is ignorant of all of this, he accepts the absurd mythologies of the Manichees as the literal truth.
Meanwhile, Monica is grieved by Augustine's conversion to Manichaeism. She has a dream in which she sees herself and Augustine standing on the same measuring stick. She goes to a bishop to plead with him to talk to Augustine, but he tells her that Augustine will recognize the errors of the Manichees soon enough on his own.
