Continuing my recent comments on Étienne Gilson are some notes on the relationship of philosophy to religion. Metaphysics is the philosophical study of being and first causes in nature. As such it can include the study of deity as the “prime mover” in the universe. Theology, on the other hand, is grounded on faith and revelation (though it draws on philosophical ideas, as Thomism does with the methodology of Aristotle). Gilson insists that philosophy and theology be treated as distinct disciplines without one unduly claiming prerogatives over the other. In his memoir The Philosopher and Theology Gilson urges that “philosophy needs to keep its rationality to be of service to theology, just as theology must preserve its own transcendence if it is to make use of philosophy.” Religion is there to answer the why of the universe. As to the what and how, that belongs to the hard sciences. Their discoveries can in no way upset theology, especially since they are often in flux and can at least point to the possibility of some orderly design in the universe. The problem isn’t always one of religious men trying to play scientists. It is also that many self-proclaimed agnostics are not that at all, but are “misguided theologians” who attempt to answer why with tools outside their specialized training.
It is also helpful to see how the relationship of secular and sacred branches of learning first came about. In his monograph God and Philosophy Gilson explains that in early centuries the “Christian convert who was at all familiar with Greek philosophy was… bound to realize the metaphysical import of his new religious belief. His philosophical first principle had to be one with his religious first principle.” But Christian faith is not simply a school of thought on par with Platonism or Stoicism. “It was essentially religious doctrine of the salvation of men through Christ.” Newman once said that “it is not merely probability which makes us intellectually certain [of religion], but probability as it is put to account by faith and love. It is faith and love which give to probability a force which it has not in itself.” In other words, the sources of religion are not in any philosophy; they are beyond it. Religion is its own source. Nevertheless it is possible for the natural intellection of metaphysics to take us to the outskirts of belief, not so much in terms of positive conviction but in removing potential obstacles to our assent to faith. See my related post on Gilson and Benedict XVI on this subject.