The notion of a yawning, unbridgeable, antithetical chasm between all things non-Christian and all things Christian is a serious exaggeration of the truth. On the other hand, the idea that even after the Fall man’s rational powers remain able to discern, explain, and preserve really substantial outlines of truth such that perhaps only by changing a few words and phrases Plato or Aristotle might be thought of as Christians-in-disguise is a serious exaggeration of the truth. Yet, like all great myths, both of these exaggerations have a kergyma of the truth buried deep inside. The pessimistic antithesis idea retains the truth that whatever prisca theologia might actually exist, it always has to be subject to ongoing dialogue with and correction by the final theology, the revelation of God in Christ. The optimistic continuity idea retains the truth that at the end of the day God’s creation does actually reveal something and men are actually able to understand it in more than a trivial manner.
(From Tim Enloe's excellent post "Prisca Theologia and Pia Philosophia" at Evangelical Catholicity, emphasis added.)