Article 4: Whether Sacred Doctrine is a Practical Science?
Objection 1: It is evident that Sacred Doctrine is a practical science. For the end of a practical science is an activity, according to the Philosopher in II Metaphysics. Sacred Doctrine is ordered to activity. Secondly, James 1:22 states, "Be doers of the word and not hearers only." Therefore, Sacred Doctrine is a practical science.
Objection 2: Moreover, Sacred Doctrine is divided into Old and New Law. The Law, however, belongs to the science of morality, which is a practical science. Therefore, Sacred Doctrine is a practical science.
But on the contrary, all practical science is concerned with human operations; just as morality is concerned with human acts and architecture with buildings. However, Sacred Doctrine is principally concerned with God, whose best work is mankind. Therefore, it is not a practical science but more speculative.
I respond that Sacred Doctrine, being one, extends to those things which belong to different philosophical sciences, because it considers in each the same formal aspect, that is to say they are divinely illuminated. Hence, it is permitted in the philosophical sciences that some are speculative and others are practical. However, Sacred Doctrine is itself comprehended under both; as God, by the same science, knows Himself and His works. Nevertheless, it is more speculative than practical because it is more concerned with divine things than human actions; though it does treat even of these inasmuch as man is ordained by them to the perfect knowledge of God in which consists eternal bliss. This is a sufficient answer to the objections.