In Canto XXII of the Purgatory, Dante has the pagan historian Statius tell the pagan poet Virgil that he, Virgil, had been instrumental in Statius’ conversion to Christianity. Dante had already noted that like many other great and virtuous pagans (Aristotle, Plato, Cicero, etc.), Virgil himself was forever cut off from God not because of what he did, but because of what he didn’t do. In this connection, Statius notes that Virgil held the light of prefigured Christian truth behind him as he walked, such that while the light didn’t do Virgil himself any good it was of the utmost usefulness to those who followed after him.
I like that metaphor a lot. It seems so much more fruitful a way to deal with unbelieving thought than the type of Reformed “radical antithesis” thought that treats the whole of unbelieving thought like sheer Godless nonsense fit only for being mocked and used as a foil for a supposedly “consistent” Christianity – where consistency is defined by those who advocate it. Remember that those who measure themselves by themselves are not wise (2 Cor. 10:12). By admitting other standards outside of Scripture and outside of our own narrow theological views about what Scripture teaches, we can better avoid the error of measuring ourselves by ourselves and instead make very profitable use of those who held the light of truth behind them, lighting the way for those who came after.