The Bishop of Hippo spells out the proposition in On Christian Doctrine. But in his Confessions, he lives it out. “Let every good and true Christian understand that wherever truth may be found, it belongs to his Master,” he says in bk. II of On Christian Doctrine. In his spiritual autobiography, he restates the idea with a figure involving food:
But Thou, O my God, hadst already taught me by wonderful and secret ways, and therefore I believe that Thou taughtest me, because it is truth, nor is there besides Thee any teacher of truth, where or whencesoever it may shine upon us. Of Thyself therefore had I now learned, that neither ought any thing to seem to be spoken truly, because eloquently; nor therefore falsely, because the utterance of the lips is inharmonious; nor, again, therefore true, because rudely delivered; nor therefore false, because the language is rich; but that wisdom and folly are as wholesome and unwholesome food; and adorned or unadorned phrases as courtly or country vessels; either kind of meats may be served up in either kind of dishes.And he goes on with concrete examples. Cicero, he explains in book III of the Confessions, taught him to love wisdom – not the wisdom of this philosophy or that, but Wisdom itself (or as Augustine would have put it later, Himself). Later in the book, he explains that the Platonists taught him that God is incorporeal and even taught him to revere the Word. These lessons provided stepping stones on Augustine’s path to Christian faith, so how could he not later approve of Christians studying the pagan classics?
I’m sure some Christians then (as do many Christians now) didn’t see how people without the enlightenment of God come upon truths that would benefit believers, much less help lead a sinner like Augustine to Christ. Augustine’s explanation is that all the faculties of knowledge come from God; how could those who seek truth using God’s given tools not find some? But also, not all truth is spiritual truth, even though it might all be applied to spiritual understading. The Platonists Augustine learned so much from could never, he points out, have discovered that the Word humbly left his divine station and came to earth to die. But that doesn’t mean that pagan astronomers can’t learn about the movements of the planets.
This last particular point played a significant role in Augustine’s conversion away from the Manichean religion. Natural philosophers had learned astronomical motions well enough to predict eclipses, so their outlook must be essentially correct, he reasoned. But Mani, the founder of the gnostic heresy that both charmed and troubled Augustine for so long, taught propositions about the planets in conflict with those of the scientists. If he’s wrong about the skies, and his religious doctrine rests on his planetary system, Augustine concluded, Mani’s religious doctrine must be wrong. (Isn’t it interesting that astronomy would cause another significant religious debate a mellennium later!)
The most heartwarming detail concerning pagan philosophy I came across in my meeting with Augustine this year didn’t have to do with a particular teaching, but rather with a particular teacher. When Augustine started asking skeptical questions about Manicheism, his friends all told him that Faustus would have the answers that would satisfy him. But Faustus couldn’t answer the questions either.
When I proposed [these questions] to be considered and discussed, he, so far modestly, shrunk from the burthen. For he knew that he knew not these things, and was not ashamed to confess it. For he was not one of those talking persons, many of whom I had endured, who undertook to teach me these things, and said nothing. But this man had a heart, though not right towards Thee, yet neither altogether treacherous to himself. For he was not altogether ignorant of his own ignorance, nor would he rashly be entangled in a dispute, whence he could neither retreat nor extricate himself fairly. Even for this I liked him the better.Instead of laughing or railing, Augustine admired Faustus’s humility. At that moment, Augustine held people as more important than answers, a priority we all need reminding of.