Philip Schaff on Aquinas’s Distinction b/twn Theology and Philosophy

Thomas made a clear distinction between philosophy and religion, reason and revelation, than had been made before by any of the Schoolmen. The reason is not competent by its own powers to discover the higher truths pertaining to God, such as the doctrine of the Trinity. The ideas which the natural mind can reach are the preambula fidei, that is, the ideas which pertain to the vestibule of faith. Theology utilizes the reason, not it is true, to prove faith, for such a process would take away the merit of faith, but to throw light on doctrines which are furnished by revelation. Theology is the higher science, both because of the certainty of its data and on account of the superior excellence of its subject-matter. There is no contradiction between philosophy and theology. Both are fountains of knowledge. Both come from the same God. (History of the Christian Church, Vol. 5: The Middle Ages 1049-1294, pp. 666, 667).