Without doubt, the great debate of the 20th century and continuing today has been the relationship between nature and grace. Alan P. F. Sell, author of numerous interesting books, once wrote a book called, The Great Debate, a historical-theological survey of the disputes between Calvinists and Arminians. That debate continues, especially in American evangelical circles, but the great debate in recent history, occupying the attention of every leading theologian, has concerned nature and grace. For the young student of theology, it’s a daunting subject, made especially difficult since it requires an understanding of both the Protestant participants and the Catholic participants.
Their concerns overlap, but differ in regard to historical readings and appropriation of key figures in the respective traditions. So, the Protestants have been concerned with a certain reading of the Reformers over-against their successors, the Lutheran and Reformed scholastics. Emil Brunner, Karl Barth, T. F. Torrance, et al. agreed that the scholastics, as opposed to the Reformers, were working with a more heightened view of the province of philosophy and the epistemic situation of natural man. Similarly, the Catholics have been concerned with a certain reading of Thomas Aquinas over-against his successors. Etienne Gilson, Henri de Lubac, Hans Urs von Balthasar, et al. agreed that the Thomist commentators (Cajetan, et al.), and the later manual tradition influencing (and influenced by) the First Vatican Council, posited a strict delineation between the gains of philosophy and the dogmas of faith; whereas Thomas himself blurred the lines. Thus, both the Protestants and the Catholics believed that a certain rationalism had crept into the successor traditions of, respectively, Reformational and Thomist theology.
In more recent decades, these historical readings have been vigorously challenged. Paul Helm, Richard Muller, and numerous others have argued for an essential continuity between the Reformers and the scholastics; and, likewise, Romanus Cessario, Lawrence Feingold, and numerous others have argued for a greater continuity between Thomas and his Thomist successors. For various reasons, I lean toward the first group discussed above: the loosely-labeled “neo-orthodox” or “neo-reformational,” on the Protestant side, and la nouvelle théologie of the resourcement movement, on the Catholic side. Though, I’m willing to concede some of the historical points to the new crop of scholars.
That’s a very brief sketch. If you would like to read a great presentation of this debate on the Catholic side, I highly recommend Nicholas Healy’s article, “Henri de Lubac on Nature and Grace,” from Communio 35:4. Healy gives an overview of the controversy from de Lubac’s perspective, the recent criticisms of de Lubac, and where these criticisms fall short.