Lecture 8 — Priority of act to potency in substance

But act is also prior in substance, because those things that are subsequent in generation are prior in form and substance. For example, man is prior to boy, and human being to seed, for the one already has its form, but the other has not.

This is also because everything which comes to be moves toward a principle, namely, its end. For that for the sake of which a thing comes to be is a principle, and generation is for the sake of the goal. And act is the goal, and it is for the sake of this that potency is acquired.

For animals do not see in order that they may have the power of sight, but they have the power of sight in order that they may see.

And similarly, men have the science of building in order to build, and they have theoretical knowledge in order to speculate. But they do not speculate in order to have theoretical knowledge, unless they are learning by practice. And these latter do not speculate except in a qualified sense, or because they do not need to speculate.

Further, matter is in potency up to the time at which it attains its form, but when it exists actually, it then possesses its form. And the same holds true in the case of other things, even of those whose goal is motion. And for this reason, just as those who are teaching think that they have reached their goal when they exhibit their student performing, so it is with nature.

For if this were not so, Paxonas and Mercury would exist again, because it would not be more evident whether scientific knowledge is internal or external, as is the case with the figure of Mercury. For the activity is the goal, and the activity is the work. And for this reason, the term “act” is used in reference to activity, and it is extended to completeness.

But while, in the case of some things, the ultimate effect is the use (as, for example, in the case of sight, the ultimate effect is the act of seeing, and no other work besides this results from the power of sight), still, from some potencies, something else is produced.

For example, the art of building produces a house in addition to the act of building.

Yet, in neither case is the act any less or any more the end of the potency, for the act of building is in the thing being built, and it comes into being and exists simultaneously with the house.

Therefore, in those cases in which the result is something other than the use, the act is in the thing being produced—for example, the act of building is in the thing being built, and the act of weaving in the thing being woven. The same holds true in all other cases.

And in general, motion is in the thing being moved. But, in the case of those things in which nothing else is produced besides the action, the action is present in these, as the action of seeing is in the one seeing, and the action of speculating in the one speculating, and life in the soul. Accordingly, happiness is in the soul, for it is a kind of life.

It is evident, then, that substance or form is act. Hence it is clear, according to this argument, that act is prior to potency in substance. And, as we have said (1049b17), one act is always prior to another in time right back to that act which is always the first principle of motion.

1856. Having shown that act is prior to potency in intelligibility and in one sense in time, the Philosopher now shows that it is prior in substance. This was the third way given above [1845] in which act is prior to potency. This is divided into two parts.

In the first part, he proves his thesis by arguments taken from things that are sometimes potential and sometimes actual.

In the second part (1050b6; [1867]), he proves his thesis by comparing eternal things, which are always actual, with mobile things, which are sometimes actual and sometimes potential, at but act.

And, since to be prior in substance is to be prior in perfection, and since perfection is attributed to two things (namely, to the form and to the end), in the first part, he uses two arguments to prove his thesis.

The first of these pertains to the form,

and the second (1050a7; [1857]) to the goal, given at the words, this is also because.

He accordingly first says that act is prior to potency not only in intelligibility and in time, but in substance, that is, in perfection; for the form by which something is perfected is customarily signified by the term “substance.”

This first part is made clear by this argument: those things that are subsequent in generation are prior in substance and form, that is, in perfection, because the process of generation always goes from what is imperfect to what is perfect. For example, in the process of generation, man is subsequent to boy, because man comes from boy, and human being is subsequent to seed. The reason is that man and human being already have a perfect form, whereas boy and seed do not yet have such a form. Hence, since, in numerically one and the same subject, act is subsequent to potency both in generation and in time, as is evident from the above, it follows that act is prior to potency in substance and in intelligibility.

Priority of act substantially

1857. This is also because (1050a7). Here he proves the same point by an argument involving the goal of activity.

First, he sets forth the argument.

Second (1050a10; [1858]), he explains one of the principles assumed in his argument, at for animals.

Third (1050a23; [1862]), he settles an issue which could cause difficulty in the above argument, at but while.

He accordingly first says that everything which comes to be when it moves toward its end moves toward a principle. For an end, or that for the sake of which a thing comes to be, is a principle because it is the first thing intended by an agent, since it is that for the sake of which generation takes place. But act is the goal of potency, and therefore act is prior to potency and is one of its principles.

1858. For animals (1050a10). He now explains the position which he maintained above, namely, that act is the goal of potency.

He first makes this clear in the case of natural active potencies. He says that animals do not see in order that they may have the power of sight, but they rather have the power of sight in order that they may see. Thus it is clear that potency exists for the sake of act and not vice versa.

1859. And similarly (1050a11). Second, he makes the same thing clear in the case of rational potencies. He says that men have the power of building in order in order to build, and they have theoretical knowledge, or speculative science, in order to speculate.

However, they do not speculate in order that they may have theoretical knowledge, unless they are learning and meditating about those matters which belong to a speculative science in order that they may acquire it. And these do not speculate perfectly, but to some degree and imperfectly, as has been said above [1853–55], because speculation is not undertaken because of some need, but for the sake of using science already acquired. But there is speculation on the part of those who are learning because they need to acquire science.

1860. Further, matter (1050a15). Third, he makes the same point clear in the case of passive potencies. He says that matter is in potency until it receives a form or species, but then it is first in a state of act when it receives its form. And this is what occurs in the case of all other things that are moved for the sake of a goal.

Hence, just as those who are teaching think they have attained their goal when they exhibit their pupil whom they have instructed performing those activities which belong to his art, in a similar fashion, nature attains its goal when it attains act. Hence it is made evident in the case of natural motion that act is the goal of potency.

1861. For if this were not (1050a19). Fourth, he proves his thesis by an argument from the untenable consequences. He says that, if a thing’s perfection and goal do not consist in act, there would then seem to be no difference between someone wise, as Mercury was, and someone foolish, as Paxonas was. For if the perfection of science were not in the one acting, Mercury would not have exhibited it in his own science, whether scientific knowledge is internal, that is, in reference to its internal activity, or external, that is, in reference to its external activity, as neither would Paxonas. For it is by means of the actual use of scientific knowledge, and not by means of the potency or power, that one is shown to have a science, because activity is the goal of a science, and activity is a kind of act.

And for this reason, the term “act” is derived from “activity,” as has been stated above [1805]; and from this it was extended to form, which is called completeness or perfection.

1862. But while (1050a23). He explains a point which could cause a difficulty in the foregoing argument. For since he had said that some product is the goal of action, one could think that this is true in all cases. But he denies this, saying that the ultimate goal or end of some active potencies consists in the mere use of those potencies, and not in something produced by their action. For example, the ultimate goal of the power of sight is the action of seeing, and there is no product resulting from the power of sight in addition to this action. But in the case of some active potencies something else is produced in addition to the action; for example, the art of building also produces a house in addition to the action of building.

1863. However, this difference does not cause act to be the goal of potency to a lesser degree in the case of some of these potencies and to a greater degree in the case of others; for the action is in the thing produced, as the action of building in the thing being built; and it comes into being and exists simultaneously with the house. Hence, if the house or the thing built is the goal, this does not exclude act from being the goal of potency.

1864. Now it is necessary to consider such a difference among the aforesaid potencies, for when something else is produced besides the act of these potencies (which is action), the action of such potencies is in the thing being produced and is their act, just as the act of building is in the thing being built, and the act of weaving in the thing being woven, and in general, motion in the thing being moved.

And this is true, because, when some product results from the action of a potency, the action perfects the thing being produced and not the one performing it. Hence it is in the thing being produced as an action and perfection of it, but not in the one who is acting.

1865. But when nothing else is produced in addition to the action of the potency, the action then exists in the agent as its perfection and does not pass over into something external in order to perfect it. For example, the act of seeing is in the one seeing as his perfection, and the act of speculating is in the one speculating, and life is in the soul (if we understand by “life” vital activity).

Hence it has been shown that happiness also consists in an action of the kind which exists in the one acting, and not of the kind which passes over into something external; for happiness is a good of the one who is happy, namely, his perfect life. Hence, just as life is in one who lives, in a similar fashion, happiness is in one who is happy. Thus it is evident that happiness does not consist either in building or in any action of the kind which passes over into something external, but it consists in understanding and willing.

1866. It is evident (1050b2). Lastly, he retraces his steps in order to draw the main conclusion which he has in mind. He says that it has been shown from the above discussion that a thing’s substance or form or species is a kind of act, and from this, it is evident that act is prior to potency in substance or form. And it is prior in time, as has been stated above [1848], because the act whereby the generator or mover or maker is actual must always exist first before the other act by which the thing generated or produced becomes actual after being potential. And this goes on until one comes to the first mover, which is act alone, for whatever passes from potency to act requires a prior act in the agent, which brings it to act.