Lecture 12 — The subject of growth is not something incorporeal or lacking size.

But how are we to conceive the 'sphere' of the change which is growth and diminution? The sphere' of growing and diminishing is believed to be magnitude.

Are we to suppose that body and magnitude come-to-be out of something which, though potentially magnitude and body, is actually incorporeal and devoid of magnitude? And since this description may be understood in two different ways, in which of these two ways are we to apply it to the process of growth? Is the matter, out of which growth takes place, (i) 'separate' and existing alone by itself, or (ii) 'separate' but contained in another body?

Perhaps it is impossible for growth to take place in either of these ways. For since the matter is 'separate', either (a) it will occupy no place (as if it were a point), or (b) it will be a 'void', i.e. a non-perceptible body. But the first of these alternatives is impossible. For since what comes-to-be out of this incorporeal and sizeless something will always be 'somewhere', it too must be 'somewhere'—either intrinsically or indirectly.

And the second alternative necessarily implies that the matter is contained in some other body. But if it is to be 'in' another body and yet remains 'separate' in such a way that it is in no sense a part of that body (neither a part of its substantial being nor an 'accident' of it), many impossibilities will result. It is as if we were to suppose that when, e.g. air comes-to-be out of water the process were due not to a change of the but to the matter of the air being 'contained in' the water as in a vessel. This is impossible.

For (i) there is nothing to prevent an indeterminate number of matters being thus 'contained in' the water, so that they might come-to-be actually an indeterminate quantity of air;

and (ii) we do not in fact see air coming-to-be out of water in this fashion, viz. withdrawing out of it and leaving it unchanged.

It is therefore better to suppose that in all instances of coming-to-be the matter is inseparable, being numerically identical and one with the 'containing' body, though isolable from it by definition.

87. After showing how growth differs from generation and alteration, the Philosopher here begins to inquire into the manner in which growth takes place.

First, with respect to the subject which grows;

second, with respect to that by which something grows, at we must therefore come (320b34; [97]).

About the first he does two things:

first, he raises a question;

second, he investigates the truth of the question, at perhaps it is impossible (320a32; [88]).

About the first he does two things.

First (320a27), he sets forth what is evident about growth and asks around what the change of growth and diminution occurs. And he answers that the motion of growth and diminution is seen to be concerned with magnitude [size].

Second, at are we to suppose (320a29), he shows what still remains to be investigated and says that we must further decide how growth and diminution take place. And as to the subject of growth, he first raises this question: Are we to suppose that by growth there is produced both magnitude and body out of that which is in potency to magnitude and corporeity, in such a way, namely, that it [this source] is incorporeal in act and without magnitude? Then he subdivides the first part of the question. For there are two ways in which there may be said to be some matter existing in act without corporeity and magnitude. Hence it is reasonable to ask, if such matter is the subject of growth, how growth is produced from it. Does the matter that exists without corporeity and magnitude have a separate existence by itself, or is it in some body but not a part of it (for if it were a part, it would be subjected to its corporeity and magnitude)?

88. Then, at perhaps it is impossible (320a32), he answers the question he raised:

first, with an argument based on the matter or subject;

second, with an argument based on growth, at moreover, a change of that kind (320b28; [96]).

About the first he does two things:

first, he answers the aforesaid question with a reason based on matter, as he views it;

second, based on matter as viewed by the Platonists, at but the same reasons (320b14; [91]).

Concerning the first he does three things:

first, he rejects the first member of the second division, namely, that matter without quantity should exist as an isolated entity;

second, he rejects the second member of the second division, namely, that matter existing without magnitude be present in some body, at and the second alternative (320b5; [89]).

third, he concludes to his proposition, at it is therefore better (320b12; [90]).

He says therefore first (320a32) that both members of the second division are impossible. First he shows this as to the impossibility of matter existing without magnitude, having a separated existence. If it were separated, one of two things would have to follow. One is that it would possess no place, as in the case of a point, which has no place, since every place has some dimension. Or else, if the matter existing without quantity should occupy a place, it would have to be an empty place (for we call "void" a place not filled with a perceptible body); or it would have to be a certain imperceptible body (for some hold that the void is nothing but an imperceptible body). It is indeed necessary to call the void a body on account of the dimensions of space, yet an imperceptible one, on account of the emptiness. Of these two, one is impossible, namely, that there be a void or an imperceptible body.

Likewise, it is impossible for separately existing matter to possess no place. For matter is that from which sensible bodies are generated. But that from which sensible bodies are generated must exist in some place. For we always observe that whatever is generated from it is "somewhere," i.e., in some definite place: that which is generated out of something is in the same place where that out of which it is generated was. Therefore that from which something is generated, namely, matter, must be somewhere, either per se or per accidens: per se, indeed, according to the opinion of the early philosophers who posited the matter of natural bodies to be some body in act, such as fire or air or water; per accidens, however, according to the opinion of Plato and his own, who assumed that matter is being in potency.

89. Then, at and the second alternative (320b5), he rejects the second member by showing that matter separated from magnitude is not present in anything.

First he states his intention and says that, if matter existing without magnitude should be in a body separated from the substance of the body in such a way as not to pertain to the body either per se or per accidens, then many impossibilities follow. And he gives an example of this manner of assumption: for example, we might posit that when air is generated from water, this does not take place by means of a change of the water, in such a way that the matter of the water loses the form of water and receives the form of air, but as though the matter of air were in the water as in a container.

Second, at for there is nothing (320b10), he presents arguments that lead to impossibility.

The first is that, if there is in the water not only its own matter but also the matter of air, then for the same reason other matter could be there, and so on ad infinitum, especially since it is possible from one to generate an infinitude successively. Consequently, there would be nothing to prevent an infinitude of matters in water. But given any matter whatsoever, something can be generated in act. Therefore, it would follow that an infinitude of things could be generated in act out of one and the same water, on the basis, namely, that whatever is able to be generated in potency, can be all at one time generated in act.

The second argument is at **and we do not in fact **(320b11). And he says that we do not observe anything being so generated out of anything (for example, air out of water) as that which comes out of something permanent, in the way, for example, that wine flows out of a cask that remains unchanged. For we see things being generated from what has been corrupted, as was said above. But one must take that which is evident to sense as the principle [starting-point] in natural science.

90. Then, at it is therefore better (320b12), he concludes to the truth and says that it is better to say that matter is present in all things, in such a way as not to be separated from them, as though being no part of them, and that the matter of all things is numerically one and the same and differs only in conception, as was said above. According to this, it will not be separated from magnitude but will be subject to magnitude in act in each and every thing.