Augustine examines the second verse of Genesis: "The earth was invisible and formless, darkness was over the deep." He says that "heaven" does not mean the sky, but the immaterial "heaven of heavens," and "earth" does not mean the ground, but the formless matter that is the basis of all physical forms. Augustine imagines opponents who disagree with his interpretation. They say that Moses intended "heaven and earth" to mean the visible world only. Augustine proposes other possible interpretations. He concludes that multiple true interpretations of the passage exist and do not contradict each other. Augustine and his opponents can say with confidence that the message Moses conveyed is true, but they cannot be so confident that they know precisely what Moses intended his words to mean. Surely Moses would have tried to make his words convey as much depth of meaning as possible.
Book 12 finds Augustine engaged even more deeply in the practice of exegesis that he began in Book 11. Exegesis is the act of interpreting a Biblical text, and few Christian thinkers have raised it to such an art form as Augustine. In Book 12, you can see some of Augustine's principles of exegesis in action, although he lays out his theories more explicitly in On Christian Doctrine, which he was writing at about the same time as the Confessions. Most notably, Augustine's interpretation of Genesis 1:2 moves immediately beyond the literal sense of the words to a spiritual, almost metaphorical sense. Augustine's understanding of the Creation is heavily influenced by the ideas of Platonism, as his descriptions of the realms of immaterial intellect and formless matter reflect. Heaven, for Augustine, is instantly identifiable as the "heaven of heavens" of Psalm 155:16: "The heaven of heaven is the Lord's: but the earth he has given to the children of men." This "heaven of heavens" has multiple properties: It is immaterial and it is outside time, although it is not co-eternal with God and is not made of God's own substance — only the Word, the first Wisdom, Jesus Christ, has that distinction. But the "heaven of heavens" is also identified with God's wisdom; see Ecclesiasticus 1:3-4: "Who has searched out the wisdom of God that goes before all things? Wisdom has been created before all things, and the understanding of prudence from everlasting." Furthermore, Augustine also identifies the "heaven of heavens" with the immaterial realm of the intellect, where knowledge is received directly, without mediation, and simultaneously, without the passage of time. This may refer both to God's intellect and to the human intellect, created in the image of the divine. In this way, the "heaven of heavens" sounds very much like the beatific vision of Books 7 and 10, which human minds can attain, but not for long.
Heaven's opposite number is earth; not the literal ground underfoot, but the formless matter from which God later created all physical forms. The existence of such undifferentiated matter is a tenet of Platonism, here placed into a Christian framework. Augustine has almost as much difficulty trying to visualize truly formless matter as he previously did trying to visualize a truly immaterial God. Formless matter was created from nothing and is only a little above nothingness, but from it, God created the physical world, including what people normally think of as heaven and earth. That process of differentiation and assigning forms is described in Genesis' account of the different "days" of creation.
Augustine's method of exegesis is rich and multi-layered. Every Biblical text is influenced by a web of other scriptural texts that touch on it and expand its meaning, as Psalm 116 does for Genesis 1:2. The meaning of a particular word may include its literal sense, but it also includes spiritual, metaphorical, and symbolic meanings as well. Here, you see demonstrated the qualities that so perplexed Augustine when he attempted to study the Bible in Books 3.5 and 9.5: The words of the Bible appear simple enough, but for those attentive students who examine them closely, they unfold complex and multivalent possibilities.
While Augustine shows the greatest respect for his text, giving each word the most detailed consideration, and while he believes without question that the text is divinely inspired, he does acknowledge an important limitation: Words are only words. Readers cannot question Moses about exactly what he intended when he wrote those words. One can only look at the words, and words are necessarily limited, imprecise, subject to interpretation. Augustine decides to err on the side of charity: If a passage supports multiple interpretations, then why not allow all of them to be true? Only human vanity insists that one's own interpretation is the sole correct interpretation. Contemporary scholars of literature and language have been intrigued by Augustine's very modern concern with the shortcomings of language, the unknowable intent of the author and the multiplicity of meanings. However, Augustine would never support the modern assertion that all possible interpretations are equally valid or that the meaning of a text can never be located with certainty. Interpretations that offend basic Christian doctrine cannot be true, and logic can be applied as a test, as well — we see Augustine logically analyzing different possible interpretations in 12.28-29. Incidentally, the opponents Augustine invents to argue with him about exegesis do not seem to refer to any specific group. They may simply function in the text as a sounding board for Augustine's ideas. The dialogue form was a common classical device for writing about philosophical ideas.
How, then, does this Neo-Platonic exegetical exercise function within the structure of the Confessions? As with Augustine's interpretations, several possibilities exist. If one of the subjects of the Confessions is Augustine's attempt to understand God and his own relationship to God, then exegesis of Genesis does further that goal. The story of the Creation defines what the divine and the human are, and the subsequent story of the Fall defines how their relationship to one another went wrong. This extended attempt at interpretation also demonstrates that Augustine's spiritual journey is far from over, as Augustine must continue to expand and deepen his understanding of God. Throughout his career as a bishop, Augustine is pressed explain the mysteries of scripture in the sermons he gives to his congregation, and many of his major works consist of in-depth examinations of Biblical passages, so Book 12 may serve a teaching function, as well. Finally, Augustine uses the opportunity to explain, and, therefore, to defend, his Neo-Platonic influences by showing how seamlessly they fit with Christian beliefs.