necessary for the salvation of man that certain truths which exceed
human reason should be made known to him by divine revelation. Even as
regards those truths about God which human reason could have
discovered, it was necessary that man should be taught by a divine
revelation; because the truth about God such as reason could discover,
would only be known by a few, and that after a long time, and with the
admixture of many errors. Whereas man's whole salvation, which is in
God, depends upon the knowledge of this truth. Therefore, in order
that the salvation of men might be brought about more fitly and more
surely, it was necessary that they should be taught divine truths by
divine revelation. It was therefore necessary that besides
philosophical science built up by reason, there should be a sacred
science learned through revelation.

Reply Obj. 1: Although those things which are beyond man's
knowledge may not be sought for by man through his reason,
nevertheless, once they are revealed by God, they must be accepted by
faith. Hence the sacred text continues, "For many things are shown to
thee above the understanding of man" (Ecclus. 3:25). And in this, the
sacred science consists.

Reply Obj. 2: Sciences are differentiated according to the
various means through which knowledge is obtained. For the astronomer
and the physicist both may prove the same conclusion: that the earth,
for instance, is round: the astronomer by means of mathematics (i.e.
abstracting from matter), but the physicist by means of matter itself.
Hence there is no reason why those things which may be learned from
philosophical science, so far as they can be known by natural reason,
may not also be taught us by another science so far as they fall
within revelation. Hence theology included in sacred doctrine differs