My good friend Br. Chris Coucheron-Aamot has written a wonderful paper on Justin's Apology. I thoroughly enjoyed every word of it, but especially appreciated this paragraph.
Philosophers then contain some truth, but can't be wholly trusted. They are like witnesses who can be trusted in a few areas, but not in others. This is consistent with the paradigm of a legal defense: one doesn't ask an expert witness questions that are outside of his area of expertise because he is not authoritative outside of his area of expertise. Philosophers, then, are authorities on matters that can be deduced from the world by properly applied exercise of the intellect without the benefit of special inspiration. These matters can be surprising, such as the Stoic belief in the destruction of the world, or Menander's comedy against the worship of crafted idols. It seems like much of that truth which is learnable is accessible through Reason; the exception being truth that concerns the nature of God Himself. Reason has its limits, and revelation is what allows men to go beyond it. The measure of the worth of the philosophers is the Christian revelation: the fulfilled prophecies and the teachings of the apostles that were just starting to be codified into the New Testament. One cannot accept them wholesale, but must carefully sift through them to see what is true and what is false. Their authority is not absolute like the prophets, but neither do they intentionally deceive like the pagans.
And, in his conclusion:
Revelation may well stand on it own, as God chooses to make known the deep truths of the world in paradoxical ways. If God turns philosophy on its ear by confounding the wise with simple things, this must shape our hermeneutics in profound ways, as we are careful to understand authority within the grid of God's wider purposes. The simple or rough may contain truth that the eloquent miss for all their wisdom, and we must remain humble to perceive it.
In my opinion, appeals to worldly wisdom or the usefulness of our faith and the ethic incumbant upon disciples weakens our argument, and leaves us vulnerable to charges of manipulating the evidence in an effort to persuade.
It is not our place to attempt to persuade. We don't get any points for winning souls to Christ. It is our resonsibility to walk in the ethic provided to us in mere imitation of Christ. And thus, men, seeing your good works, will glorify God in heaven. Which is the ultimate goal. Let us be jealous for the glory of God.