Chapter 12

Act and potency

854. By 'act' I understand any entity whatsoever. However, 'act' also expresses entity in its relationship to potency. Consequently, we have to turn to the concept of potency in order to determine fully the notion of act.

855. At the same time, we must note that the notion of act involves sometimes a positive, sometimes a negative relationship with the notion of potency. The involvement is positive if potency is opposed to act as though potency were not itself an act. The involvement is negative if potency is excluded from the act as, for instance, when we speak about an act for which there is no corresponding potency.

856. As we said, the intrinsic order of ens cannot be deduced a priori, but has to be gained through experience of those entia which come within our feeling. These are bodies, and our soul. We considered these entia carefully, therefore, to know their intrinsic order, that is, how they are internally constructed and, as it were, organated. We concluded that every ens presents us with an entity, but that we mentally discern several elements in this single entity. These elements are ordered in such a way that one is conceived prior to another. In other words, the second element cannot be thought to exist except with the element that precedes it in the logical order. The second is said to exist in and through the first. The first element of all, which can be conceived by itself before all the others, is said to contain and sustain the others, and make them exist. We call this element substance.

However, amongst all these elements (which I also call 'entities') not all are equally necessary to think an ens and to name it substantively. The elements or entities which can vary without our losing the concept of an ens and without our having to change the noun with which we name it, are called accidental forms or accidents. Accidents, therefore, are certain actualities or entities which are not necessary for the concept of an ens. However, they either perfect it, or are privations of these actualities, or are entities subject to variation. But even these accidental actualities cannot be conceived without the substantial form of an ens. They are said, therefore, to exist in and through substance.

857. It follows that an ens can be conceived either furnished with or lacking these actualities. When we conceive an ens without them, we also see that it can have them and, having them, remain the same ens. In this case, we consider the ens as a potency. We also say that these actualities exist in the ens in potency, not in act. This means that the ens is susceptive of such actualities even though it does not possess them. Potency, therefore, is the relationship that the mind conceives between an ens and its accidental actualities in their variation or absence.

858. Several consequences flow from this concept.
First, we realise that it is not possible to have a mere potency without any act. The potentiality of an ens always supposes the ens and the act by which the ens is as substance, and as substantial form.
Second, we see that absolutely speaking act precedes potency. Substance is a first act, of which substantial form is the perfection necessary for its constitution. As we said, potency is only the relationship that the mind conceives between first act and accidental acts, their variations and their privations.

859. Third, it is clear that every potency is joined to an act without forming an ens different from that to which it adheres. On the other hand, acts can depend on and receive their existence from other, previous acts in such a way that the previous acts constitute different entia. This explains St. Thomas' very acute teaching:

860. We can go on now to consider the internal construction of entia that fall within our experience. Here, we easily recognise that the potentialities of which we are speaking possess three modes. This explains the division of potencies into three classes. Sometimes, we see that one ens can receive another in itself without being confused with that which it receives. For example, known objects are in the soul which knows them. Such potentiality gives rise to a class which I call receptive potencies.(51) Sometimes one ens, in receiving the action of another, is modified by the other in some way. This passivity gives rise to another class, that of passive potencies. Finally, the ens itself can posit acts accidental to itself. In this case, we attribute to it the relationship I call active potencies.(52)

861. Note carefully that everything said about acts in potency is also said, but in a contrary sense, of their privation. Being able to be deprived of such actualities, etc., takes the form of negative potencies.

862. Wherever a substance is united to an idea, an ens is present. Substance is the first act that we conceive. This first act makes other acts subsist in a given mode.

I have distinguished substances, and consequently entia, into two classes, which I called principle-entia and term-entia (cf. 842-845).

Term-entia are those not conceived as sentient. Matter is of this kind.
Principle-entia are those conceived as sentient. The soul, and all intelligences, are of this kind.

Both principle-entia and term-entia are substances because a first act is conceived in them through which all other acts exist, active and passive, which are mentally discernible in them.
Some of these (active and passive) acts distinct from substance are necessary (substantial forms), others are accidental (accidental forms).

863. Because accidental acts are present both in principle-entia and in term-entia, potency must be distinguished from act in them. Again, receptive, active and passive potencies are found in entia that pertain to the classes of both principle-entia and term-entia, which can therefore undergo development. In other words, both classes are subject to modifications and actualities that can perfect them, and to privations or negative potencies that can cause them to deteriorate.

864. We must note, however, that both principle-ens and term-ens retain their nature as principle and term in all their development. Principle and term pertain to their essence, which cannot change without ceasing to be the ens it was previously and becoming something else.

Notes

(50) S.T ., I, q. 75, art. 5, ad 1. Cardinal Cajetan explains this teaching of Aquinas with his usual extraordinary perspicacity: 'Note the beautiful teaching: in the order of acts, which is the order of efficient cause, we can reduce things to one in number, from which all other acts are. But in the order of potency, which is the order of material cause (that is, material cause pertains to the order of potency, although the order of potency does not always pertain to material cause, properly speaking ), there is no reduction of the universal order to one potency in number, but to one by analogy. The reduction is to many potencies ordered to different acts and harmonising amongst themselves in a certain proportion. In other words, each potency is related to its own act as other potencies are related to their acts. The order between potencies depends on the acts of which they are capable. Hence, reduction in the genus of material cause can be understood in a threefold way. First, reduction is appropriate to all potencies of the same genus, and so to one potency in number (This would not seem completely correct. They are not always reduced to one in number, but sometimes to one in essence. This happens in the case of matter, one part of which, although of the same essence as the other, differs through its different reality. This is why acts pertain to different parts of matter ). Second, we have reduction of all potencies to one through analogy. Third, we have reduction of the potencies themselves. In this case, one is not reduced to another universally speaking because the potency of the intellect cannot be reduced to the potency of matter, nor vice versa, although one — first matter, for example — is the lowest in the order of imperfection. St. Thomas offers an extremely subtle explanation of this: even the first potency, IS INTRINSIC TO THE THING TO WHICH IT PERTAINS, and must therefore be different for different things. The FIRST EFFICIENT CAUSE, however, IS TOTALLY INDEPENDENT OF THINGS and, as such, stands as the one on which all are dependent. MATERIAL CAUSE (and, more generally, potentialcause ) IS INTRINSIC (or, as we say, 'connected with act'); EFFECTIVE CAUSE IS EXTRINSIC.'

(51) Receivable forms correspond to receptive potencies. Being is a receivable form; it is essentially objective. But it is in three modes: ideal, real and moral. — If received in its ideal mode, it informs the soul by rendering it intelligent, and becomes the soul's substantial form. In this case, the sentient soul is the receptive potency . Cajetan, although maintaining that phantasms receive nothing positive from the light of the intellect, again comments very acutely: 'The acting intellect is turned OBJECTIVELY, not formally on the phantasms, just as colours are illuminated.' He explains specific abstraction as follows: 'Abstraction consists simply in producing species by use of phantasms as REPRESENTATIVE OF NATURE, not as they are individually' (In S.T. , I, 85, q. 1). But what is this nature represented by phantasms? Not the phantasms. Where is it found then? This nature is ens, seen by the mind as object, and clothed with phantasms as a result of primal synthesis , whose theory we have outlined in A New Essay (vol. 2). - If ens is received as real being, real things are posited in being. St. Thomas says that being 'is not compared with other things in the way that what receives is compared with what is received, but rather as what is received is compared to what receives' (S.T ., I, q. 4, art. 1, ad 3). — Finally, if being is taken in its moral mode, the result is moral virtue, holiness, the supernatural order.

(52) Philosophers did not always distinguish receptivity from passivity , as we see in St. Thomas. Consequently, they considered understanding as passivity when, in fact, it is properly speaking receptivity . 'All receiving is called "experiencing" and "being moved", as the Philosopher says in his De Anima (bk. 3, t. 7): understanding is a kind of experiencing' (In I Sent ., d. 8, q. 3, art. 2).