Chapter 06. Powers of the Soul.

Does our soul have several powers?

“Brother Thomas, besides having the power to animate my body, and leaving and returning to my body, does our soul have other powers?”

         -Brother Raymond,-

         “Of necessity we must place several powers in the soul. To make this evident, we observe that, as the Philosopher says (De Coelo ii, 12) the lowest order of things cannot acquire perfect goodness, but they acquire a certain imperfect goodness, by few movements; and those which belong to a higher order acquire perfect goodness by many movements; and those yet higher acquire perfect goodness by few movements; and the highest perfection is found in those things which acquire perfect goodness without any movement whatever.

         Thus he is least of all disposed of health, who can only acquire imperfect health by means of a few remedies; better disposed is he who can acquire perfect health by means of many remedies; and better still, he who can by few remedies; best of all is he who has perfect health without any remedies.

         We conclude, therefore, that things which are below man acquire a certain limited goodness; and so they have a few determinate operations and powers. But man can acquire universal and perfect goodness, because he can acquire beatitude. Yet he is in the last degree, according to his nature, of those to whom beatitude is possible; therefore the human soul requires many and various operations and powers. But to angels a smaller variety of powers is sufficient. In God there is no power or action beyond his own Essence.

         There is yet another reason why the human soul abounds in a variety of powers--because it is on the confines of spiritual and corporeal creatures; and therefore the powers of both meet together in the soul.[1]

         -Brother Raymond, while we are on the subject of our souls, may I add another word on this?-

         “Yes, of course Brother Thomas.”

         -Brother Raymond, This may look complicated, but if read two or three times, slowly and with attention, my message will be quite clear.-

         “Continue.” I replied.

         “There are five genera of powers of the soul . . . Of these, three are called souls, and four are called modes of living. The reason of this diversity lies in the various souls being distinguished accordingly as the operation of the soul transcends the operation of the corporeal nature in various ways; for the whole corporeal nature is subject to the soul, and is related to it as its matter and instrument.

         Rational power.

         There exists, therefore, an operation of the soul, which so far exceeds the corporeal nature that it is not even performed by any corporeal organ; and such is the operation of the rational soul.

         Sensitive power.

         Below this, there is another operation of the soul, which is indeed performed through a corporeal organ, but not through a corporeal quality, and this is the operation of the "sensitive soul"; for though hot and cold, wet and dry, and other such corporeal qualities are required for the work of the senses, yet they are not required in such a way that the operation of the senses takes place by virtue of such qualities; but only for the proper disposition of the organ.

         Vegetative power.

         The lowest of the operations of the soul is that which is performed by a corporeal organ, and by virtue of a corporeal quality. Yet this transcends the operation of the corporeal nature; because the movements of bodies are caused by an extrinsic principle, while these operations are from an intrinsic principle; for this is common to all the operations of the soul; since every animate thing, in some way, moves itself. Such is the operation of the "vegetative soul"; for digestion, and what follows, is caused instrumentally by the action of heat, as the Philosopher says (De Anima ii, 4).

         Now the powers of the soul are distinguished generically by their objects. For the higher a power is, the more universal is the object to which it extends, as we have said above (Question [77], Article [3], ad 4). But the object of the soul's operation may be considered in a triple order.

         For in the soul there is a power the object of which is only the body that is united to that soul; the powers of this genus are called "vegetative" for the vegetative power acts only on the body to which the soul is united.

         There is another genus in the powers of the soul, which genus regards a more universal object--namely, every sensible body, not only the body to which the soul is united.

         And there is yet another genus in the powers of the soul, which genus regards a still more universal object--namely, not only the sensible body, but all being in universal.

         Wherefore it is evident that the latter two genera of the soul's powers have an operation in regard not merely to that which is united to them, but also to something extrinsic. Now, since whatever operates must in some way be united to the object about which it operates, it follows of necessity that this something extrinsic, which is the object of the soul's operation, must be related to the soul in a twofold manner. First, inasmuch as this something extrinsic has a natural aptitude to be united to the soul, and to be by its likeness in the soul. In this way there are two kinds of powers --namely, the "sensitive" in regard to the less common object--the sensible body; and the "intellectual," in regard to the most common object--universal being. Secondly, forasmuch as the soul itself has an inclination and tendency to the something extrinsic.

         Appetitive power.

         And in this way there are again two kinds of powers in the soul: one--the "appetitive"--in respect of which the soul is referred to something extrinsic as to an end, which is first in the intention; (continued under locomotive power)

         Locomotive power.

         “. . . the other--the "locomotive" power--in respect of which the soul is referred to something extrinsic as to the term of its operation and movement; for every animal is moved for the purpose of realizing its desires and intentions.”

         -Consequently,- “The modes of living are distinguished according to the degrees of living things. There are some living things in which there exists only vegetative power, as the plants.

         There are others in which with the vegetative there exists also the sensitive, but not the locomotive power; such as immovable animals, as shellfish.

         There are others which besides this have locomotive powers, as perfect animals, which require many things for their life, and consequently movement to seek necessaries of life from a distance.

         And there are some living things which with these have intellectual power--namely, men. But the appetitive power does not constitute a degree of living things; because wherever there is sense there is also appetite (De Anima ii, 3).” [2]

         “Brother Thomas, what a wonderful learning experience.”


[1] Summa Theologica First Part Question: 77 Article: 2 Whether there are several powers of the soul? This was my experience.

[2] Summa Theologica First Part Question: 78 Article: 1 Whether there are to be distinguished five genera of powers in the soul?


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