What is the difference between philosophy and theology if it’s not the personal belief stance of the thinker in question? What makes the pursuit of something like theology distinctive compared to what one would normally call philosophy? I should say from the first that I think this has to be regarded as an open problem, because philosophy and theology are both critical and speculative discourses undertaken in dialogue with a historical tradition. Given such similarities, it is understandable that one would cast about for factors external to the discourse itself, such as the “personal belief” of the thinker. I think that such a difference is both nonsensical and boring, however, and I propose that a more reasonable and interesting difference must be found within theological discourse itself.
One potential starting point is the very formalistic definition of theology familiar from Tillich: theology is discourse about the “ultimate concern.” Such a formalistic view informs Goodchild’s Theology of Money, where he elaborates the theological system implied by money’s status as the highest value which gives all other values their value. Yet that distinction is unsatisfying, as it seems as though Platonism, surely a particularly exemplary example of philosophy, is a discourse about the ultimate concern or the highest, value-giving value. Hence the difference collapses and the door opens for all manner of boring, extrinsic claims: “Philosophy posits reason as the highest value, while theology thinks it’s faith!” No matter that such a claim can’t stand up to the most cursory historical understanding of philosophy and theology — apparently it’s very satisfying to say.
A potentially more productive difference could be drawn from the work of Kierkegaard: what makes theological discourse distinctive from philosophy is the decisive importance of historical events for theology. One can look to Philosophical Fragments for an elaboration of this view, albeit in a way that is biased in a specifically Christian direction (i.e., Kierkegaard wants to posit the structure of what we might call the truth-event in such a way that the Christian revelation is the only possible candidate). We don’t need to accept Kierkegaard’s Christian bias, however — it’s obvious that a structure works for other major religions, above all Judaism and Islam. And a theological “style” of thought could easily be applied to other types of events, such as the French revolution.
Does this last example collapse the two discourses again? I’d contend, rather, that it illustrates the continual interpenetration of theology and philosophy, in the sense that what is historically revealed, the historical event of decisive importance, nonetheless feels like it should put forth something that is “always” true. Taking the French revolution as the decisive event — one will then claim that the rights claimed in that revolution represent self-evident truths of human nature, etc., just as in the patristic and medieval periods Christian theologians were concerned to demonstrate that the decisive event of the incarnation resonated with the truths uncovered by the most prestigious philosophical discourses (above all Platonism).
Hence we can see that questions that presuppose a clear demarcation between the two discourses aren’t getting at what is really going on. Instead of asking whether theology is a subcategory of philosophy, or a “style” of doing philosophy, or philosophy done “within” a particular religious tradition (i.e., with certain axioms), or whether philosophy is a tool to be subordinated to the higher truth of theology, etc., a truly interesting investigation will see the relationship between the two as one of continual struggle — or at the very least, one will see the two as part of one continuum defined by the poles of the eternal or unchanging (philosophy) or the decisively important historical event (theology). With this in mind, one can make interesting and counterintuitive claims — for instance, that Christian theology in the patristic and medieval periods became increasingly philosophical in orientation, while certain important strains of modern philosophy have been genuinely theological in their approach.
Why is this important? It’s important because it’s incredibly boring to let these questions be preemptively answered by the same old boring dichotomy between faith and reason, religion and the secular. Those dichotomies are so boring because they’re ultimately about institutional and political “turf” — namely, they’re about vindicating the modern secular nation-state against the specter of “religion” with its supposedly inherent irrationality and violence. The approach I outline here moves the stakes of the struggle between theology and philosophy back to where the really belong: to the realm of thought.