Revealed truth and philosophy

Using the doctrine of the Immaculate Conception as a case study, Mark of Minute Particulars shows how the philosopher can take advantage of revealed truth in his own discipline. The key quote:

While it's true that any discipline which purports to work exclusively in the light of reason cannot come to conclusions that depend on revealed truths, such disciplines can use the light of faith to point them in the right direction and eliminate some avenues of speculation.

Precisely. The philosopher -- knowing that x is true -- can eliminate certain solutions to a particular problem in light of x, thus aiding him in solving the problem at hand.

This reminds me of the discussion in the mid to late 80's between a number of theologians: David Schindler one one side, George Weigel, Michael Novak, and Fr. Richard Neuhaus on the other. While I think highly of the second bunch, and appreciate and agree with much of their work, I think Schindler was in the right. The discussion is to wide ranging to attempt to summarize, but in a nutshell (which will probably be less than helpful to anyone who isn't familiar with the debate) it concerns the relationship between nature & grace and faith & reason, democracy, and public policy.

Why am I reminded of this discussion? Because what Mark is saying reminds me of part of Schindler's argument: IIRC, he argues that we should use the meaning of person as indicated by revelation (i.e. its communitarian dimension as seen in the Trinity) to a greater extent, rather than relying on a purely philosophical concept. That's not to say that public policy discussions should include references to Scripture or Nicea I, but that those concepts should be utilized when "person" is being discussed in the public square.