We proceed to the fifth article thus:

1. It seems that sacred doctrine is not nobler than other sciences. For the dignity of a science is indicated by its certainty, and other sciences whose principles cannot be doubted appear to be more certain than sacred doctrine, whose principles, i.e., the articles of faith, are the subject of debate. Thus it seems that other sciences are nobler.

2. Again, a lower science depends on a higher, as music depends on arithmetic. Now sacred doctrine derives something from the philosophical sciences. Hieronymus, indeed, says that "the ancient teachers filled their books with so many philosophical doctrines and opinions that one does not know which to admire the more, their secular learning or their knowledge of the scriptures" (Epist.84 to Magnus the Roman orator). Sacred doctrine is therefore lower than other sciences.

On the other hand: other sciences are said to be subsidiary to this doctrine in Prov.9:3: "She hath sent forth her maidens: she crieth upon the highest places of the city."

I answer: since sacred doctrine is speculative in some things and practical in others, it transcends all other sciences, whether speculative or practical. One speculative science is said to be nobler than another either because it is more certain, or because it treats of a nobler subject. Sacred doctrine surpasses other speculative sciences in both respects. It is more certain, since the certainty of other sciences depends on the natural light of human reason, which is liable to err, whereas its own certainty is founded on the light of divine knowledge, which cannot be deceived. Its subject is also nobler, since it is concerned principally with things above reason, whereas other sciences deal with things within the reach of reason. Finally, one practical science is nobler than another if it serves a more ultimate end. Politics is nobler than military science, because the good of an army is subsidiary to the good of the state. Now in so far as sacred doctrine is practical, its end is eternal happiness, and all other ends of the practical sciences are subsidiary to this as their ultimate end. It is plain, then, that it is nobler than the others in every way.

On the first point: there is nothing to prevent what is in itself the more certain from appearing to us to be the less certain, owing to the weakness of the intellect, "which is to the things most manifest to nature like the eyes of a bat to the light of the sun," as is said in Metaph.2. The doubt felt by some in respect of the articles of faith is not due to any uncertainty in the thing itself. It is due to the weakness of human understanding. Nevertheless, the least knowledge which one can have of higher things is worth more than the most certain knowledge of lesser things, as is said in the De Partibus Animalium (bk.1, ch.5).

On the second point: this science can make use of the philosophical sciences in order to make what it teaches more obvious, not because it stands in need of them. It does not take its principles from other sciences, but receives them directly from God through revelation. It thus derives nothing from other sciences as from superiors, but uses them as ancillary inferiors, as the master sciences use subsidiary sciences, or as politics uses military science. Its use of them is not due to any defect or inadequacy in itself. It is due to the limitation of our understanding. We are more easily led from what is known by natural reason, on which other sciences depend, to the things above reason which this science teaches us.