I answer that, In those things which proceed from one according to a natural order, as the first is the cause of all, so that which is nearer to the first is, in a way, the cause of those which are more remote. Now it has been shown above (A. 4) that among the powers of the soul there are several kinds of order. Therefore one power of the soul proceeds from the essence of the soul by the medium of another. But since the essence of the soul is compared to the powers both as a principle active and final, and as a receptive principle, either separately by itself, or together with the body; and since the agent and the end are more perfect, while the receptive principle, as such, is less perfect; it follows that those powers of the soul which precede the others, in the order of perfection and nature, are the principles of the others, after the manner of the end and active principle. For we see that the senses are for the sake of the intelligence, and not the other way about. The senses, moreover, are a certain imperfect participation of the intelligence; wherefore, according to their natural origin, they proceed from the intelligence as the imperfect from the perfect. But considered as receptive principles, the more perfect powers are principles with regard to the others; thus the soul, according as it has the sensitive power, is considered as the subject, and as something material with regard to the intelligence. On this account, the more imperfect powers precede the others in the order of generation, for the animal is generated before the man.
Reply Obj. 1: As the power of the soul flows from the essence, not by a transmutation, but by a certain natural resultance, and is simultaneous with the soul, so is it the case with one power as regards another.
Reply Obj. 2: An accident cannot of itself be the subject of an accident; but one accident is received prior to another into substance, as quantity prior to quality. In this sense one accident is said to be the subject of another; as surface is of color, inasmuch as substance receives an accident through the means of another. The same thing may be said of the powers of the soul.
Reply Obj. 3: The powers of the soul are opposed to one another, as perfect and imperfect; as also are the species of numbers and figures. But this opposition does not prevent the origin of one from another, because imperfect things naturally proceed from perfect things. _______________________
EIGHTH ARTICLE [I, Q. 77, Art. 8]
Whether All the Powers Remain in the Soul When Separated from the
Body?
Objection 1: It would seem that all the powers of the soul remain in the soul separated from the body. For we read in the book De Spiritu et Anima that "the soul withdraws from the body, taking with itself sense and imagination, reason and intelligence, concupiscibility and irascibility."
Obj. 2: Further, the powers of the soul are its natural properties. But properties are always in that to which they belong; and are never separated from it. Therefore the powers of the soul are in it even after death.
Obj. 3: Further, the powers even of the sensitive soul are not weakened when the body becomes weak; because, as the Philosopher says (De Anima i, 4), "If an old man were given the eye of a young man, he would see even as well as a young man." But weakness is the road to corruption. Therefore the powers of the soul are not corrupted when the body is corrupted, but remain in the separated soul.
Obj. 4: Further, memory is a power of the sensitive soul, as the Philosopher proves (De Memor. et Remin. 1). But memory remains in the separated soul; for it was said to the rich glutton whose soul was in hell: "Remember that thou didst receive good things during thy lifetime" (Luke 16:25). Therefore memory remains in the separated soul; and consequently the other powers of the sensitive part.