Even now that we've divided the gods into the "Select" gods who are better known and more commonly worshiped than their lesser counterparts, we see that these select gods are not actually treated better. Not only are the worst crimes attributed to them, but even the least terrible of them (Janus, in Augustine's recollection) are submitted to the infamy of having their images carved into grotesque statues.
The pagan argument put forth by Varro is that the statues are not actually gods themselves, but merely physical representations of spiritual realities--realities about both the gods themselves and the immortal nature of the human soul. These images were to be both an object of veneration and a theology lesson rolled up into one.
Augustine rejects this completely, holding forth the glorious truth that
Thy soul, so learned and so clever (and for this I grieve much for thee), could never through these mysteries have reached its God; that is, the God by whom, not with whom, it was made, of whom it is not a part, but a work,—that God who is not the soul of all things, but who made every soul, and in whose light alone every soul is blessed, if it be not ungrateful for His grace.We cannot learn about God, according to Augustine, by the use of idols. Grace alone reveals the Lord to us, in ourselves we cannot see beyond the created world to the the Author of Creation. (This is not a condemnation of art or public decoration, Augustine is speaking of worship only here.)
Hopefully we can see how foolish (and sinful) it is to rebuke Varro's position not by agreeing with Augustine, but by claiming that Varro simply chose the wrong gods to image. Augustine's take is certainly not that Varro and the pagans just picked false gods, and that if they had used images of the Christian God everything would have been fine. Augustine is clear that no one should ever attempt to commune with God through a representation or statue or any other created object. (Here, we have to side with the wisdom of the Medieval Church in struggling so mightily to condemn the use of images.)
How then are we to worship? Through Christ, who alone is the image of the invisible God, and who is displayed to us in Scripture. When we interpose between us and Christ the works of our own hands, we violate the commandment by degrading the Incarnation (by trying to add to it our own creation) and the Crucifixion (by attempting to come to God other than through the Atoning blood of Christ) and the Resurrection (by attempting to jump-start in stone the promised physical presence of Jesus on earth).
I think I've mentioned this before (apologies if I'm being repetitive, but blogging every day quickly runs through my stock of publicly appropriate stories), but one of the most effective teaching devices I've seen was at an all-church Bible study (~200 people or so) when the pastor reached I Corinthians 10:14 and asked everyone in the room who had been converted out of a religion that worships idols to raise their hands. 20-25 people did so, and then we spent some time hearing the stories from each of them (many were from East Asia, Africa, and Latin America, but some were from the United States and Western Europe as well). We all too often allegorize these portions of Scriptures and talk about the idolatry of the heart and idolizing food, work, family, etc, while forgetting that the primary definition of the work is the worship of created things. Augustine's comments here are a useful reminder of that definitions...