In Karl Barth (first published in 1951), the fundamental reconcilability of Catholic and Protestant theology is described at the point where each is most consistently itself. For Barth, this means that, despite everything, the truly evangelical element in Protestantism lies beyond Luther (and all the more beyond Calvin) in Schleiermacher: in the opening of the concrete universal that is Christ to the world-embracing Logos. For the Catholic, it means that the concept of nature that Catholic theology is accustomed to presuppose undialectically can in reality only be grasped dialectically, in accord with Henri de Lubac’s renewed vision of patristic-high-scholastic theology. If unity is once achieved at this depth, then in principle everything else is open for ecumenical discussion.

Hans Urs von Balthasar in My Work in Retrospect, 1965