I’m torn, honestly, on the subject of philosophy’s autonomy. It seems to me that ultimately any sort of philosophy is going to end up playing handmaiden to some theological or atheological queen. So a philosophy’s goodness or badness, in my experiences around philosophy types, derives its goodness or badness at least in significant part from the larger, poetic picture that it serves.

That said, I’ve spent nearly no time around Analytical philosophers, and as I’m sure you know, Continental philosophy and the philosophical theologies derived therefrom tend to wear their atheisms and other confessions on their sleeves.

With regards to secular applications, I’m intended to follow John Milbank’s lead (itself a “postmodern critical Augustinianism,” to use his description) in saying that philosophies (he thinks of them as plural, and I tend to agree) derive their force not from competition in any sort of shared and regulated arena but from their capacities to compel desire. In other words, philosophies/theologies convince not for strictly logical grounds but in a composite moment that is logical and rhetorical and aesthetic.

So gleaning might, you’re right, appeal to a secular audience, but what a Foucauldian says about that appeal and what an Augustinian says are going to differ radically, and ultimately one adjudicates across the radical (incommensurable?) difference (I speak here as an Augustinian/Thomist) when one or the other resonates more beautifully with the reasoning, created-in-imago-dei human soul.

Wow. I do get parenthesis-happy when I start trying to do philosophy.

A distinction between Christian philosophy and Christian theology is needed once these ideas leave the Christian classroom. Rationally, Augustine’s philosophy is subject to the same rigors as any other philosophy. Theology comes with it own set of assumptions beyond the realm of the rational. These assumptions are not universally recognized. For example, with enough strips, I can draw from the texts of Calvin and Hobbes and produce an “intelligibly” Calvin and Hobbesian philosophy. However, as a philosophy, it is no better or worse than its logic. At that point, any label one applies to it is an artificial construct. It is a good or bad philosophy first, a Calvin and Hobbsian philosophy second.
Any appeals I make that invoke the authority of Calvin and Hobbes in service of defending my position are not universal appeals. In practical application outside of Christian academia, in a society of secular and Christian citizens, a discussion of “gleaning” as a principle that informs a discussion of distribution in industrialized society is only as valid as the principle of gleaning itself. Where the principle comes from is irrelevant.

So many bad readers.

Of course, there are no “purely” Christian intellectual positions, largely because the very center of our confession is that the Word of God, through whom all was created and is being redeemed, became incarnate as a Jewish peasant carpenter living in occupied Palestine in the formerly-Seleucid end of the Roman Empire (itself regularly contested and influenced by the Parthian Empire) and educated largely in pre-Hellenistic Hebrew scriptures. If someone can find a “pure” strain in there, he’s likely a great fool, and the very complexity of the roots of Christianity make our intellectual traditions, I think, especially adaptable. It doesn’t hurt that we’ve got a two-millennium history of missionary theology at our disposal.

All of that is to say that, if Christians remember who we are, there’s no need to fear intellectual engagement with all the ideas with which a secular intellectual would engage, largely because we have access to a hermeneutic of memory and recovery that can appropriate the best parts of Continental and Hellenic and all sorts of philosophical matrices and still come out with an intelligibly Christian philosophy.

Integration for those of that faith system is great in theory, but the practice tends to go quite wrong.