The Unity of Faith and Reason in Christian Theology

Grant Kaplan begins his theological essay with a seemingly innocuous postulate: the meaning of the terms “faith” and “reason,” he asserts, have shifted throughout the 2,000 or so years since Christ walked among us. Demonstrating their relation through such an extended period, Kaplan explains, is like building a bridge between two shifting landmasses.   

On one level, it is a manifestly obvious observation, which may cause the reader to pass it by without much thought. The meaning of faith and reason have, throughout the history of Christian theology, moved with the contours of the times, from Tertullian’s famous dictum “What has Athens to do with Jerusalem?” to Gotthold Lessing’s declaration that “Revelation . . . gives the human race nothing which human reason, left to itself, could not also arrive at.” But as Kaplan’s work unfolds, it becomes clear that this insight informs the entire work. To his great credit, Kaplan avoids the temptation to adopt a single notion of the relation and dogmatically analyzes the history of this topic through his own lens. In fact, if anything, his study is marked by a singular ability to handle each topic with equanimity and balance. He gives nearly every theologian or philosopher a fair reading, knitting together an analysis that invites his reader to engage in the age-old project of determining how these two most fundamental concepts relate.

Yet Kaplan’s analysis is not without a center. He writes as a Catholic, who is nevertheless aware of the “shamefully parochial” limits of his inquiry. This comes out most obviously in his exploration of the meaning of faith as presented in the Bible. There, faith is “both the content of things believed . . . and the mode of knowing by which one acquires this knowledge.” This means that “the matter of reconciling faith and reason involves taking up both the content of faith, the things believed, and the mode by which one knows these things.”

All this makes for an exceptionally balanced journey through Christian intellectual history which is yet further improved by its eminent readability. Though he is constrained to brevity because of the introductory nature of the book, Kaplan cuts to the core of each thinker’s approach to the problem of faith and reason with concision. He provides his readers with a clear and fair statement on where each lies, and he sticks to these methodological commitments with admirable tenacity throughout the work. Since the book touches on many of the central figures of Western Christian theology through the ages, I cannot possibly hope to provide anything resembling a comprehensive overview here. Instead, I will provide some highlights that demonstrate the flavor and merits of Kaplan’s work.

Kaplan begins with a chapter briefly covering the early Christians down to Augustine. He carefully highlights the tensions between these thinkers while still conveying a sense of what binds them together. Justin, on trial for his life, faced the unique problem of trying to persuade Roman authorities that anyone using right reason could see that Christ was reason personified: “For these errors were not only condemned among the Greeks by reason, through Socrates, but among the barbarians, by Reason (logos) himself, who took form and became man and was called Jesus Christ.” But within this capacity for all to use reason as a route to the gospel, there arose the problem of dealing with error. Early heresies and questions of right practice for spreading the gospel to the masses demanded the attention of the leading thinkers of the time. Irenaeus of Lyon’s appeal to tradition and authority, Origen’s appeal to proper exegesis, and Athanasius’s hagiography provided the most influential responses to these problems.

But it is in the work of Augustine that one finds the “formative seedbed” for medieval thinking on faith and reason. Augustine “accepted and even exalted the use of reason in order to experience God as Being.” Yet reason in its discursive or autonomous form is hopelessly marred by the Fall. So to know the greatest truths, to achieve in some sense knowledge of God, one is wholly reliant on grace. In Augustine’s words: “I entered and with my soul’s eye, such as it was, saw above that same eye of my soul the immutable light higher than my mind—not the light of every day, obvious to anyone nor a larger version of the same kind . . . It was superior because it made me, and I was inferior because I was made by it.” Yet experiences like these must be complemented by a trusting relation with the historical truths and scriptural interpretation.

Augustine’s influence flowed into medieval thought, yet in the eleventh century, Anselm of Canterbury breaks the norm in his Monologion and Proslogion: a defense of the teachings of scripture with no reference to scripture itself. This radical new approach still moved within the framework of Anselm’s famous definition of theology: fides quaerens intellectum (faith seeking understanding). It is only a short jump, however, from here to Peter Abelard, viewed by many as the logic-chopping herald of a spiritually destitute Scholastic theology. Yet for Kaplan, Abelard’s approach has value insofar as he exhibits a profound intellectual openness and highlights the limits of appeals to authority in argument.

Kaplan’s chapter on the high medieval period focuses on the work of Thomas Aquinas, Bonaventure, and Duns Scotus. He steps up to the daunting task of summarizing this nuanced and subtle period with characteristic elegance. For Kaplan’s Aquinas, the articles of Christian faith are “principles, not conclusions.” Kaplan explains that “the process of reasoning from these principles produces understanding that does not provide greater certainty . . . though it does give rise to greater comprehension.” Consequently, the truths of faith and those of reason by nature cannot contradict one another. The same goes for the work of Bonaventure, who brings this approach into a more Neo-Platonist framework. In Kaplan’s formulation, Bonaventure holds that “what rational philosophy does, by conveying the intelligibility of truths from speaker to hearer, from author to reader, can be reduced to the incarnational pattern of all of created reality, for the world is a sacrament of God.” This results in a symphonic integration of the arts, sciences, and theology as a hierarchically integrated illumination of the fullness of truth as God himself.

A key turning point comes in the figure of John Duns Scotus, whose reflections on the foundational importance of the divine will (what would later be called the ordained will, the voluntas ordinata), called into question the elegant syntheses of Aquinas and Bonaventure. This leads to “an impression” that “God’s freedom might be an arbitrary freedom.” Once again in his evenhanded style, Kaplan sums up the importance these thinkers would have moving forward: “One finds both in Aquinas and in Scotus arguments and frameworks that seem to lead toward a backdrop in which theology and philosophy occupy realms that become easier to imagine as sharply divided from one another.” The opening left by these two allows Ockham to propose that “‘God cannot be known in himself’ through natural reasoning.”

Jumping ahead to Martin Luther, Kaplan again provides his characteristically balanced analysis: while Luther, following the humanistic tendencies of the Renaissance, certainly revolted against the view of the relation between faith and reason put forth by the Scholastics, such views “do not do justice to the complexity of Luther’s thought.” Instead, for Kaplan “as his theology developed, Luther came to place greater emphasis on the proper order between faith and reason than focusing on affirming the inherent incompatibility between the two.” Luther was addressing what he saw as the central problem of his age: the squelching of personal faith under the wet blanket of reason. For Kaplan, Luther actually aimed, through his admittedly hyperbolic methods, to bring the two back into a healthier balance. This is shown by the copresence of the two movements spawned by Lutheran’s thought after his death: Lutheran Scholasticism and Pietism. Similarly, John Calvin’s “total depravity” which supposedly makes unredeemed reason ultimately useless for the soul’s ascent to God masks later manifestations of Reformed Christianity’s more equitable synthesis.

In his helpful chapter on early modernity, Kaplan argues that, rather than some generalization of Protestant theology, it was a wave of science and philosophy that increasingly led to the divorce of reason and faith. In the wake of the saga of Galileo (which Kaplan argues was an “anomaly” in the history of the Church) and the work of René Descartes and Baruch Spinoza, reason was increasingly seen as “instrumental” or “autonomous.” Hence “modern philosophy forged its identity in large part by distinguishing its method and first principles from those of theology.” Herein lies the real source of the distinctly modern conception of faith and reason as opposed modes of knowing.

If there is one section where Kaplan’s normally equitable approach lapses ever so slightly, it is in his treatment of Immanuel Kant. He seemingly accepts at face value the conventional view on Kant’s epistemological dualism, which “made the conflict with faith and reason inevitable.” This is because “Kant allowed a place for God in his system, but it was through ethics, not metaphysics. This, of course, represented a drastic departure from the mainstream tradition [of Augustine and Aquinas].” According to Kaplan, Kant’s radical emphasis on universality leads him to discount the historical truths of Christianity as mere parochialisms. To be sure, for the Christian, Kant cannot be considered an authoritative thinker on faith and reason. But as Kant scholars like Richard Velkley have shown, Kant’s early meditations on the ends of reason seem to indicate that Kant was actually more concerned with the unified moral telos of speculative and practical reason than has been traditionally thought. In other words, like Pascal before him, Kant aimed to demonstrate the limits of pure speculative reason, thereby exhibiting the reality of mankind’s existential search for something which it can never fully grasp.

Kaplan’s investigation turns in the succeeding chapters to the nineteenth and twentieth centuries. His analyses of the Tübingen school of theologians in the nineteenth century and John Henry Newman particularly shine through, as these seem to be his central areas of expertise. As usual, each thinker is presented with facility and penetrating insight; I reluctantly pass over them here for the sake of brevity.

In his section on the postmodern “a/theology,” Kaplan’s equipoised method is perhaps on its fullest display. Quoting Graham Ward, he identifies the rejection of the “transcendental signifier” and the notion of any possibility of universal truth as the central insight of postmodern theology: “The death of God is the death of a transcendental signifier stabilizing identity and truth. It is the death of identity, telos, and therefore meaning in anything but a local and pragmatic sense.” Such universalizing tendencies in the Christian tradition “penetrate the social, political and economic realms” leading to the perpetuation of “poverty, racism, sexism, and ableism.”

Kaplan takes postmodern theological arguments seriously and responds to them by asserting that “if certain groups, can on the basis of class, ethnicity, or gender, be dismissed as epistemologically insufficient, then must one not say the same of traditions, especially those that tilt heavily toward a certain gender class or ethnicity?” Kaplan interprets this as the “[elimination of] any path for relating faith and reason because reason itself [is] to be jettisoned for its universalizing tendencies.” These approaches therefore “necessitate a wholesale dismissal of almost any canonical account of Christianity.”

Thus, “feminist and liberationist hermeneutic practices and acts of retrieval are involved in their own project of faith seeking moral legitimacy, rather than faith seeking understanding.” In other words, they amount to a wholesale repudiation of the faith/reason paradigm.

Perhaps in response to these currents in recent theology, the book ends with an examination of Pope John Paul II’s Fides et Ratio and Pope Benedict XVI’s “Regensburg Address.” For Benedict, this dialogue between faith and reason is baked into the tradition, going back to the Greek appropriation of the Hebrew Bible in the work of the translation of the Greek Old Testament. According to John Paul II, the crisis of meaning in the modern world is irretrievably linked to the abandonment of the search for the one truth as manifested in Christ as Logos or reason himself. Taking the two together, one gets a sense of where Kaplan ends his analysis of the nature of faith/reason debate: we cannot simply stop asking how the two relate. They are always essentially bound up with the Christian religion. To stop asking the question is to no longer be Christian in an important sense.

Accordingly, Kaplan closes with the assertion that “the premodern tradition frequently presumed a participatory notion of human cognition. In this model reason itself was already a graced, supernatural activity in which the human participated in the divine mind.” Thus, “there can be no question of definitively solving the relation of faith and reason.” Kaplan’s book as a whole shows that to abandon the search, assert final answers, or create artificial barriers in this ever-unfolding aspect of the human story is the only definitively wrong answer. Kaplan’s book is a valuable and admirable contribution to that story.

Faith and Reason Through Christian History: A Theological Essay
By Grant Kaplan
Washington, D.C.: Catholic University of America Press, 2022; 336pp

Print