Radication of All the Faculties in the Essence of the Soul

Not only the agent intellect and the possible intellect, but also all the other powers that are principles of the soul’s operations, are united in the essence of the soul. All such powers are somehow rooted in the soul. Some of them, indeed, such as the powers of the vegetative and sensitive parts, are in the soul as in their principle, but in the composite as in their subject, because their activities pertain to the composite, not to the soul alone; for power and action belong to the same subject. Some of them, on the other hand, are in the soul both as principle and as subject, for their operations pertain to the soul apart from any bodily organ. These are the powers of the intellectual part. But a man cannot have several souls. Accordingly all the powers must pertain to the same soul.

Reference

St. Thomas Aquinas. (1265-1274). Compendium Theologiae: Radication of All the Faculties in the Essence of the Soul, trans. by Cyril Vollert. St. Louis & London: B. Herder Book Co., 1947

All scripture is given by inspiration of God and is profitable for doctrine, reproof, correction, and instruction in righteousness (2 Timothy 3:16).

Agere Sequitur Esse