Chapter 17

The third special law of practical reason:
practical reason has an intelligent substance as its term

1441. The following four laws of reason simply define that which cannot constitute the term of reason. They are equally effective, in a negative sense, for practical reason. They show that there can be no term proper to practical reason when this term lacks either a first act, or unity, or duration, or determination. This all means that the term of practical reason must be some substance. An accident cannot constitute the proper term for practical reason which must refer what is accidental to what is substantial. We have already seen this when speaking about the law of prudence.

1442. Moreover, that which is corporeal, because it has no unity of its own (it borrows this from the sentient principle in which alone it has continuity), cannot be the true term of practical reason.
The same applies to the merely sentient-animal principle which, because it is not a complete ens but only a rudiment of an ens, cannot constitute the final term of practical reason. As such, it is on its way to being an ens. Moreover, practical reason, having always to thrust towards the infinite in order to be moral, cannot have the animal principle (totally devoid of anything infinite) as its term. Intelligent being, on the contrary, has its seat in the infinite, in ideal being, in the essence of ens as universal and, in so far as it focuses on and rests in this essence, shares in the infinite dignity of ideal being to which it is ordered. Consequently, it is known as end , and as term of practical reason.

1443. Moreover, there is an order among intelligent-real beings. What is finite and real is produced by the infinite, which creates it. Thus practical reason has to adhere to a finite, intelligent ens in such a way as to refer it to its principle, to God the Creator, in whom alone this ens rests totally as in its final, complete, absolute term.
We have dealt sufficiently with the ontological laws to which the rational principle is subject. We now pass to the second kind of laws, that is, to psychological laws.