By Ryan Patrick Hoselton
How should Christians interact with non-Christian moral reasoning? Christians throughout the centuries have revisited this question, dividing over whether divine revelation exclusively provides our moral guidance or whether we can benefit from “natural” moral philosophy.
I’ve been working through Norman Fiering’s work, Moral Philosophy at Seventeenth-Century Harvard (1981), and he offers helpful categories for working through this question. Although his points are descriptive rather than prescriptive, believers today can greatly benefit from observing how Christians throughout history have thought through the relationship between Christian theology and natural moral reasoning. It may not necessarily be wrong to incorporate natural moral thought, but we should be aware how and why we’re doing it.
Fiering identifies five general solutions that Christians have devised to reconcile Christian and natural moral thought. The fifth is more of a method than a theory, so I will only summarize the first four:
1) Christian hegemony: In this model, Christians borrow pagan cultural ideas and resources in “the interest of higher purposes (12).” Christians exploit external thought and sanctify and purpose it for the glory of God and the church.
2) Common Grace: This position’s greatest defender is Thomas Aquinas, the medieval Catholic theologian. The adherents of this position argue that despite the Fall, human nature maintains remarkable natural abilities in regards to creativity, discovery, knowledge, and even moral reasoning. As Fiering stresses, this doctrine is not necessarily meant to authorize natural moral philosophy but rather to make sense of non-Christian intellectual and moral achievement.
3) Prisca theologia: followers of this third category espouse that “behind the best pagan writings was the influence of the ‘ancient history’ (prisca theologia) that originated with Moses (14).” In other words, the reason why pagan thinkers have produced sound ideas is because they directly or indirectly borrowed from Christian thought. Thus, they are worthy of study insofar as they reflect Christian teaching.
4) Disparity: The fourth model for reconciling Christian theology and pagan moral philosophy was to compartmentalize the utility of each for either the outer or inner person. Natural knowledge was sufficient to guide external actions, while spiritual knowledge was necessary to reform the inner and spiritual person. Thus, believers rested on natural moral philosophy for personal, social, and political moral conduct, and they reserved special revelation to guide their spiritual life.
 Norman Fiering, Moral Philosophy at Seventeenth-Century Harvard (Chapel Hill, NC: University of North Carolina Press, 1981).