Commentary Aristotle Physics
Lecture 5. Whether action and passion are the same motion
This view has a rational defect. Perhaps it is necessary that the act of the agent and that of the patient should not be the same. The one is “agency” and the other “patiency,” and the outcome and completion of the one is an “action,” while that of the other is a “passion.”
Since, then, they are both motions, we may ask in what they are, if they are different? Either both are in what is acted on and moved, or the agency is in the agent and the patiency in the patient. (If we ought to also call the latter “agency,” the word would be used in two senses.)
Now, if the latter is so, the motion will be in the mover, for the same statement will hold of the mover and the moved. Hence, either every mover will be moved or, though having motion, it will not be moved.
If, on the other hand, both are in what is moved and acted on—both the agency and the patiency (for instance, both teaching and learning, though they are two, in the learner)—then, first, the act of each will not be present in each, and a second absurdity is that a thing will have two motions at the same time.
How will there be two alterations of quality in one subject toward one definite quality? The thing is impossible.
But will the act be one? Someone will say it is contrary to reason to suppose that there should be one identical act of two things that are different in kind.
Yet there will be, if teaching and learning are the same, and agency and patiency. To teach will be the same as to learn, and to act the same as to be acted on—the teacher will necessarily be learning everything that he teaches, and the agent will be acted on.
One may reply that it is not absurd that the act of one thing should be in another. Teaching is the activity of a person who can teach, yet the operation is performed on some patient—it is not cut adrift from a subject, but is of this on that.
There is nothing to prevent two things having one and the same act, provided the acts are not described in the same way, but are related as what can act to what is acting.
Nor is it necessary that the teacher should learn, even if to act and to be acted on are one and the same, provided they are not the same in definition (like “raiment” and “dress”), but are the same merely in the sense in which the road from Thebes to Athens and the road from Athens to Thebes are the same, as has been explained above. For it is not things that are in a way the same that have all their attributes the same, but only such as have the same definition.
But, indeed, it by no means follows from the fact that teaching is the same as learning that to learn is the same as to teach, any more than it follows from the fact that there is one distance between two things that are at a distance from each other, that the two vectors AB and BA are one and the same.
To generalize: teaching is not the same as learning, or action as passion, in the full sense, though they belong to the same subject, the motion; for the “act of this in that” and the “act of this through the action of that” differ in definition.
What motion is, then, has been stated both generally and particularly. It is not difficult to see how each of its types will be defined—alteration is the act of the alterable qua alterable (or, more scientifically, an act of the potency of that which is active and of that which is passive, as such)—generally and again in each particular case, such as building, healing, and the like. A similar definition will apply to each of the other kinds of motion.
308. After showing that motion is the act both of the mobile and of the mover, the Philosopher now raises a difficulty on this point.
First, he raises the difficulty;
second, he solves it, at “one may reply” (202b5; [314]).
Regarding the first, he does two things:
first, he prefaces certain things to the difficulty;
second, he pursues the difficulty, at “since, then, they are both” (202a25; [310]).
309. He therefore says (202a21) that what has been said above now causes a rational—that is, logical—defect, or doubt, by virtue of there being tenable reasons for both sides. In introducing the difficulty, he says that there is an act in that which is active and there is an act in that which is passive, just as above, there was stated to be an act of the mover and of the moved. As a matter of fact, the act of the active is called action and the act of the passive is called passion. This he proves by saying that the work and end of anything is its act and perfection; hence, since the work and end of the agent is action and that of the patient is passion, it follows that action is the act of the agent and passion that of the patient.
310. Then, at “since, then, they are both” (202a25) he pursues this doubt. For it is clear that both action and passion are motion, for each is the same as motion. Therefore, action and passion are either the same motion or diverse motions. If they are diverse, then each of them must be in some subject. Either both will be in the patient, the thing moved, or one of them is in the agent and the other is in the patient.
To say the opposite—namely, that what is in the agent is passion and what is in the patient is action—is to speak equivocally, for it would be calling passion action and vice versa.
The fourth possibility—namely, that both are in the agent—is left out, but this is because it has already been shown that motion is in the mobile, which excludes the fourth possibility, that neither be in the patient, but both in the agent.
311. Of the two possibilities listed, he develops the second one first, at “now, if the latter is so” (202a28). For if anyone says that action is in the agent and passion in the patient, then, since action is a certain motion, as was stated, it follows that motion is in the mover. For the same thing should be true both of the mover and of the moved: if motion is in either one, it is being moved. Or else what is true of the mover and of the moved is also true of the patient and of the agent. Now, if motion is in something, that thing is being moved; therefore, it follows either that every mover is being moved or that something has motion but is not being moved. Each of these seems unreasonable.
312. Then, at “if, on the other hand” (202a31), he develops the other possibility given above. He says that, if anyone should say that both of them—namely, action and passion—since they are two motions, are in the patient (which is equivalent to saying that teaching, which is on the part of the teacher, and learning, which is on the part of the learner, are both in the learner), then two conflicts arise.
The first is that, if what we said previously is true—namely, that action is an act of the agent—then, if action is not in the agent but in the patient, it will follow that the proper act of each thing is not in the thing of which it is the act.
Then another conflict follows: one and the same thing is being moved according to two motions. For action and passion are now supposed to be two motions. Now, in whatever thing there is a motion, that thing is being moved according to that motion. So, if action and passion are in the mobile, it follows that the mobile is being moved according to two motions. This would be tantamount to having two alterations in one subject, both of them specifically the same, such as one subject being moved to two whitenings, which is impossible. This does not mean that one subject could not be moved by two alterations tending toward two specifically different terms, such as whitening and heating. Nevertheless, it is clear that action and passion terminate at the same specific term; for what the agent does and what the patient receives are one and the same.