Part I (Prima Pars) Part 117 (1/2)

Therefore the powers are distinguished according to their acts and objects.

_I answer that,_ A power as such is directed to an act. Wherefore we seek to know the nature of a power from the act to which it is directed, and consequently the nature of a power is diversified, as the nature of the act is diversified. Now the nature of an act is diversified according to the various natures of the objects. For every act is either of an active power or of a pa.s.sive power. Now, the object is to the act of a pa.s.sive power, as the principle and moving cause: for color is the principle of vision, inasmuch as it moves the sight. On the other hand, to the act of an active power the object is a term and end; as the object of the power of growth is perfect quant.i.ty, which is the end of growth. Now, from these two things an act receives its species, namely, from its principle, or from its end or term; for the act of heating differs from the act of cooling, in this, that the former proceeds from something hot, which is the active principle, to heat; the latter from something cold, which is the active principle, to cold. Therefore the powers are of necessity distinguished by their acts and objects.

Nevertheless, we must observe that things which are accidental do not change the species. For since to be colored is accidental to an animal, its species is not changed by a difference of color, but by a difference in that which belongs to the nature of an animal, that is to say, by a difference in the sensitive soul, which is sometimes rational, and sometimes otherwise. Hence ”rational” and ”irrational”

are differences dividing animal, const.i.tuting its various species. In like manner therefore, not any variety of objects diversifies the powers of the soul, but a difference in that to which the power of its very nature is directed. Thus the senses of their very nature are directed to the pa.s.sive quality which of itself is divided into color, sound, and the like, and therefore there is one sensitive power with regard to color, namely, the sight, and another with regard to sound, namely, hearing. But it is accidental to a pa.s.sive quality, for instance, to something colored, to be a musician or a grammarian, great or small, a man or a stone. Therefore by reason of such differences the powers of the soul are not distinct.

Reply Obj. 1: Act, though subsequent in existence to power, is, nevertheless, prior to it in intention and logically; as the end is with regard to the agent. And the object, although extrinsic, is, nevertheless, the principle or end of the action; and those conditions which are intrinsic to a thing, are proportionate to its principle and end.

Reply Obj. 2: If any power were to have one of two contraries as such for its object, the other contrary would belong to another power. But the power of the soul does not regard the nature of the contrary as such, but rather the common aspect of both contraries; as sight does not regard white as such, but as color. This is because of two contraries one, in a manner, includes the idea of the other, since they are to one another as perfect and imperfect.

Reply Obj. 3: Nothing prevents things which coincide in subject, from being considered under different aspects; therefore they can belong to various powers of the soul.

Reply Obj. 4: The higher power of itself regards a more universal formality of the object than the lower power; because the higher a power is, to a greater number of things does it extend. Therefore many things are combined in the one formality of the object, which the higher power considers of itself; while they differ in the formalities regarded by the lower powers of themselves. Thus it is that various objects belong to various lower powers; which objects, however, are subject to one higher power.

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FOURTH ARTICLE [I, Q. 77, Art. 4]

Whether Among the Powers of the Soul There Is Order?

Objection 1: It would seem that there is no order among the powers of the soul. For in those things which come under one division, there is no before and after, but all are naturally simultaneous. But the powers of the soul are contradistinguished from one another. Therefore there is no order among them.

Obj. 2: Further, the powers of the soul are referred to their objects and to the soul itself. On the part of the soul, there is not order among them, because the soul is one. In like manner the objects are various and dissimilar, as color and sound. Therefore there is no order among the powers of the soul.

Obj. 3: Further, where there is order among powers, we find that the operation of one depends on the operation of another. But the action of one power of the soul does not depend on that of another; for sight can act independently of hearing, and conversely. Therefore there is no order among the powers of the soul.

_On the contrary,_ The Philosopher (De Anima ii, 3) compares the parts or powers of the soul to figures. But figures have an order among themselves. Therefore the powers of the soul have order.

_I answer that,_ Since the soul is one, and the powers are many; and since a number of things that proceed from one must proceed in a certain order; there must be some order among the powers of the soul.

Accordingly we may observe a triple order among them, two of which correspond to the dependence of one power on another; while the third is taken from the order of the objects. Now the dependence of one power on another can be taken in two ways; according to the order of nature, forasmuch as perfect things are by their nature prior to imperfect things; and according to the order of generation and time; forasmuch as from being imperfect, a thing comes to be perfect. Thus, according to the first kind of order among the powers, the intellectual powers are prior to the sensitive powers; wherefore they direct them and command them. Likewise the sensitive powers are prior in this order to the powers of the nutritive soul.

In the second kind of order, it is the other way about. For the powers of the nutritive soul are prior by way of generation to the powers of the sensitive soul; for which, therefore, they prepare the body. The same is to be said of the sensitive powers with regard to the intellectual. But in the third kind of order, certain sensitive powers are ordered among themselves, namely, sight, hearing, and smelling.

For the visible naturally comes first; since it is common to higher and lower bodies. But sound is audible in the air, which is naturally prior to the mingling of elements, of which smell is the result.

Reply Obj. 1: The species of a given genus are to one another as before and after, like numbers and figures, if considered in their nature; although they may be said to be simultaneous, according as they receive the predication of the common genus.

Reply Obj. 2: This order among the powers of the soul is both on the part of the soul (which, though it be one according to its essence, has a certain apt.i.tude to various acts in a certain order) and on the part of the objects, and furthermore on the part of the acts, as we have said above.

Reply Obj. 3: This argument is verified as regards those powers among which order of the third kind exists. Those powers among which the two other kinds of order exist are such that the action of one depends on another.

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FIFTH ARTICLE [I, Q. 77, Art. 5]

Whether All the Powers of the Soul Are in the Soul As Their Subject?

Objection 1: It would seem that all the powers of the soul are in the soul as their subject. For as the powers of the body are to the body; so are the powers of the soul to the soul. But the body is the subject of the corporeal powers. Therefore the soul is the subject of the powers of the soul.

Obj. 2: Further, the operations of the powers of the soul are attributed to the body by reason of the soul; because, as the Philosopher says (De Anima ii, 2), ”The soul is that by which we sense and understand primarily.” But the natural principles of the operations of the soul are the powers. Therefore the powers are primarily in the soul.

Obj. 3: Further, Augustine says (Gen. ad lit. xii, 7,24) that the soul senses certain things, not through the body, in fact, without the body, as fear and such like; and some things through the body.

But if the sensitive powers were not in the soul alone as their subject, the soul could not sense anything without the body.