I wrote the material below a number of months ago for a semi-private conversation involving myself and a few of my colleagues (including Shane Wilkins and David Congdon). A more recent exchange of comments with Shane brought it to my mind, and I thought that it might be interesting to post it and see what kind of conversation gets going. Anyway, I hope you enjoy it and / or find it helpful in some way. The two addendums (?) at the end are new.
Note: Below, “theology” refers to what might be called Christian dogmatic or systematic theology.
Theology, just like any other discipline, is a "disciplined" mode of inquiry. What is involved in a disciplined mode of inquiry? (1) A subject matter, and (2) a disciplined mode of inquiry about that subject. The subject matter of theology is given to it by its subject matter - God, specifically, God as he has revealed himself as Christ. The disciplined mode of inquiry, in good empirical science fashion, flows out of the subject matter. That is, the "logic" of theology is given to it by God's self-revelation, and the method involved should seek to be fitting to this logic.
However, it is important to note here that theology, as a disciplined mode of inquiry that receives both its subject matter and its disciplined mode of inquiry from God, is still a human endeavor. In as much as theology is a human endeavor, it still takes place within the human realm of possibilities, and this means that it is subject to the boundaries of human language and rationality. This does not mean that God is subject to these boundaries, but theology, although it speaks about God in the manner that God gives to it, is subject to them.
To those of you who think that this account might be contrary to Barth's notion of theology as "witness," you will have to take it on trust that I at least think that this view is consistent and am supremely confident that I could marshal a textual argument from Barth in support of it. Maybe I will do that bit some other time. Furthermore, TF Torrance would almost certainly agree with me about Barth on this point, so I claim his authority.
Philosophy, just like any other discipline, is a "disciplined" mode of inquiry. Its subject matter spans all that is observable, and even some of what is not (i.e., metaphysics)! However, in contrast to theology, the subject matter of philosophy is not revelation, but that which we can know or infer about the world based on our natural capacities. It is a disciplined mode of inquiry
in that it seeks to make its method fitting to the subject matter in question.
Philosophy, like theology, is a human endeavor. This means that it takes place within the human realm of possibilities, and is subject to the boundaries of human language. In these ways, theology and philosophy are similar. They both take their methodological cues from their subject matter, and they both work within the boundaries of human language. The difference lies in their different "logics," but this is ultimately a function of their different subject matters since the logic of a discipline seeks to be fitting for the subject matter.
(This is the tricky one and the one I'm not so sure about...)
Christian philosophy is a sub-set of philosophy, and not of theology. This means that it works with philosophical logic, and thus with the subject matter of philosophy. However, in distinction from ‘secular’ or ‘atheist’ philosophy, Christian philosophy operates within the framework of a confessional, Christian position. This means that, when it comes to the subject matter of philosophy, the Christian philosopher thinks in terms of what he has learned from theology. In other words, the Christian philosopher brings different presuppositions about the subject matter of philosophy to bear in the process of philosophical inquiry.
It must be remembered that the Christian philosopher is doing philosophy, but is attempting to do it ‘Christian-ly.’ This could be seen as an apologetic undertaking, but only in the sense that it is preaching in an entirely different mode. It is seeking to make ‘rational’ - within the confines of philosophical ‘logic’ - the claims of Christian theology.
I in no way want to imply anything like a ‘hierarchy of sciences’ with this typology. It is my goal simply to set out the disparate tasks of these three sorts of intellectual work. And, I hope that it is clear that these three are intended to form a coherent whole even while maintaining particular distinctions. Theology benefits greatly from engagement from philosophy in that its use of language and human rationality is refined and, hopefully, made more serviceable for its own particular task. But, at the same time, God is ultimately beyond the limits of human rationality (much less fallen human rationality), and therefore theology is justified if it finds that it must resist philosophy on certain points. Christian philosophy seeks to translate the dogmatic claims of theology into a coherent philosophy. Thus, on the basis of confession of the Trinity, one undertaking Christian philosophy might develop a ‘Christian’ metaphysic. This metaphysic would not have dogmatic status, but it would none-the-less help theologians perceive weaknesses or strengths in Trinitarian doctrine.
Ultimately, however, those working in each of these three categories posses their own calling, and one should not try to change the other. This is especially true for the theologian and the Christian philosopher. Rather, these tasks should be carried out in conversation with each other, each seeking to learn from the others even if they all might need to resist the others at certain points on the basis of their subject matter and disciplined mode of enquiry.
We can also talk about 'philosophical theology', which would be a philosophical exploration of topics associated with theology. I'm not quite sure what this would look like, but it is at least conceivable. Feel free to fill this bit in for me.