Lecture 15 — Solution of the difficulty proposed in the previous lecture.

We have now developed the difficulties sufficiently and must therefore try to find a solution of the problem. Our solution must preserve intact the three characteristics of growth—that the growing thing persists, that it grows by the accession (and diminishes by the departure) of something, and further that every perceptible particle of it has become either larger or smaller. We must recognize also (a) that the growing body is not 'void' and that yet there are not two magnitudes in the same place, and (b) that it does not grow by the accession of something incorporeal.

Two preliminary distinctions will prepare us to grasp the cause of growth. We must note (i) that the organic parts grow by the growth of the tissues (for every organ is composed of these as its constituents); and (ii) that flesh, bone, and every such part—like every other thing which has its form immersed in matter—has a twofold nature: for the form as well as the matter is called 'flesh' or 'bone'.

Now, that any and every part of the tissue qua form should grow—and grow by the accession of something—is possible, but not that any and every part of the tissue qua matter should do so.

For we must think of the tissue after the image of flowing water that is measured by one and the same measure: particle after particle comes-to-be, and each successive particle is different. And it is in this sense that the matter of the flesh grows, some flowing out and some flowing in fresh; not in the sense that fresh matter accedes to every particle of it. There is, however, an accession to every part of its figure or 'form'.

That growth has taken place proportionally, is more manifest in the organic parts—e.g. in the hand. For there the fact that the matter is distinct from the form is more manifest than in flesh, i.e. than in the tissues. That is why there is a greater tendency to suppose that a corpse still possesses flesh and bone than that it still has a hand or an arm.

Hence in one sense it is true that any and every part of the flesh has grown; but in another sense it is false. For there has been an accession to every part of the flesh in respect to its form, but not in respect to its matter.

104. After raising a question concerning that by which something is increased, and solving this question, which he had interposed, the Philosopher here undertakes to solve the main question.

First, he solves the question;

second, the difficulty having been removed, he shows how growth takes place, at the whole, however (321b35; [110]).

About the first he does two things:

first, he shows what is required in the solution;

second, he presents the solution, at two preliminary distinctions (321b16; [105]).

A true solution must preserve whatever belongs to the notion of a thing in question and exclude all impossibilities. Consequently, he first shows how he intends to save everything that pertains to the notion of growth (321b10). And he says that, since we have paid sufficient attention to the foregoing, it is time now to try, i.e., to apply effort, to find a solution to our question such as will preserve the three things stated above of the notion of growth.

The first of these is that the thing increased remain; the second is that growth take place by means of something coming, and diminution by means of something departing; the third is that each sensed sign, i.e., each perceptible part, of that which grows, become larger in the case of growth, and smaller in the case of diminution.

Second, he shows how he intends to avoid three impossibilities: first, that we not posit the body which grows to be void; second, that we not posit two magnitudes, i.e., two bodies, to be in the same place; third, that we not posit growth as taking place by the addition of something incorporeal. For it seems that after one has laid down the aforesaid suppositions, some one of the impossibilities will necessarily follow. For if every part grows of that which grows, and nothing grows save by something coming to it, it is necessary that, to every part of that which grows, something come. If, then, that which comes is not incorporeal, two bodies must be in the same place—unless the body which grows is assumed to be void.

105. Then, at two preliminary distinctions (321b16), he solves the difficulty.

First, he states certain things needed for solving the question;

second, he gives the solution, at now, that any and every part (321b22; [106]).

In regard to the first he proposes two things.

As to the first of these, he says that a cause that will both preserve the three things aforesaid and avoid impossibilities must be taken. But we must do this after first determining certain things. One of these is that anomoemera, i.e., members having dissimilar parts, for example, the hand or foot, or similar things, grow by means of the growth of their respective similar parts, which he calls homoeomera, such as bone and flesh and other such. He gives the reason for this, which is that each member of the dissimilar parts is composed of those things which have similar parts as, for example, a hand is composed of flesh and bone and sinew. Therefore, the whole must be increased by the increase of the parts.

Second, he posits that flesh and bone, and each of such parts that he says to grow first, are twofold, as occurs in all things that have a species in matter: for flesh and bone can be considered either as the matter or flesh or the species of flesh.

Now some look at this statement as meaning that there is one signate flesh which is according to matter and another which is according to species. For they say that flesh and bone and whatever is such, are said to be according to species in so far as they are generated from the prime seminal moisture in which the power of the species was, but flesh and bone are said to be according to matter in so far as they are generated from the nutritive moisture. This latter comes to the first seminal moisture as a certain matter thereof, in that the first moisture is extended through the other members, the second moisture having been mixed with it, in order to complete the quantity of the living thing and of all its parts. This was the view of Alexander (as Averroes says in his explanation of this passage), and several later followed him.

But such a view does not agree with the words Aristotle uses here. For he says that flesh, bone, and every such part has a twofold nature as do other things whose form [species] is immersed in matter. Now it is plain that not only things that are generated from seed and are nourished, in which the aforesaid meaning could be to some extent sustained, but also inanimate things, such as stones, gold and silver, have their form immersed in matter. Therefore, Aristotle intends that "species" and "matter" be taken in flesh and bone, just as in stone and gold, in which there is no seminal and nutritive moisture. Therefore, it should be said that, according to Aristotle's intention, one and the same flesh is stated according to species in so far as there is considered in it that which pertains to the species of flesh, and according to matter in so far as we consider in it that which is of matter. And the same goes for all other things composed of matter and form.

106. Then, at now, that any and every part (321b22), he presents the solution:

first, he presents it;

second, he manifests it with an example, at for we must think (321b24; [107]);

third, he concludes by summarizing the solution, at hence in one sense (321b32; [109]).

He says therefore first (321b22) that the statement made above, namely, that each part grows of that which grows, and that each thing grows by the advent of something, is true if "part" is considered from the aspect of the species. For to each part considered according to species something is added as to something permanent. Consequently each part considered under the aspect of species is increased. But an addition is not made to each part considered according to matter; nor does each part, considered according to matter, grow. For it was said that what grows must remain. But each part considered according to matter does not remain, but only as considered according to species.

107. Then, at for we must think (321b24), he manifests the proposed solution by examples.

First, he gives the examples;

second, he shows in which parts the aforesaid solution is more evident, at that growth has taken place (321b29; [108]).

He says therefore first (321b24) that what has been said about flesh according to species and according to matter should be understood as though someone were to measure water with the same measure, but in such a way, however, that the water was always other and other—for example, if from a vessel full of water, water were to flow out drop by drop and were to be constantly poured in drop by drop. It will always be the same so far as the measure of the water is concerned, but not, however, as to the matter of the water. Now species is compared to matter as the measure to what is measured, because the form is the end of matter, as is said in Physics II. Therefore, we must understand that the species of flesh remains the same, as a certain measure, but the matter in which such species is received does not remain the same. The case of a river is similar—it always remains the same so far as the species of river is concerned, but the material water is always other and other. Fire is also similar—whose species and figure always remains the same, although the pieces of wood in which the fire burns materially, are consumed and other and other pieces are added. The same also appears in the populace of a city which always remains the same as to that which is of its species, although, of the men who constitute the populace, some die and others take their place. In like manner, that which pertains to the species of flesh always remains, although the matter in which that species is based is little by little consumed by the action of heat and other matter newly arrives through food.

Thus, therefore, when a body grows, so indeed does the matter of the flesh, since more is generated by food than is lost by the action of heat, and so, as the matter is multiplied, the augmentative power, which pertains to the species, proportionally spreads out the whole matter into greater quantity. Yet the matter of flesh is not increased in such a way that to each part of the matter something is added — for not every part of the matter remains but some falls away, having been consumed by heat, and some comes, having been restored by food. Therefore, there is no need for things to be increased by something incorporeal, nor for two bodies to be in the same place, nor for the body that grows to be void. For if what is renewed through food does not exceed what has been consumed by heat, the natural power, which pertains to the species, restores what comes in the place of that which was lost. But if what is generated from the food exceeds, the natural power extends it into a larger quantity according to some dimension, and thus it occupies a greater place. But because the species remains constant, we must say that something comes proportionally to each part of the form or species and that each part is increased proportionally. But it does not follow from this that there are two bodies in the same place, because place is not assigned to form or species except by reason of the matter in which it is based and which is properly the subject of dimensive quantity.

But if one should understand by "flesh according to species" that which is generated from the seminal moisture, and by "flesh according to matter" that which is generated from the nutritive moisture, as Alexander posited, then this statement of Aristotle, namely, that flesh according to matter flows out and comes in, but not flesh according to species, appears to be more in the nature of something probable, than as having any necessary foundation. For, since it is necessary for both moistures to be combined into one mass in order to perfect the quantity of the whole body and all its parts, one cannot prove with necessity that heat so consumes the one in such a way as to leave the other always remaining. But it is not easy to think that Aristotle in such a matter would state something without a necessary reason, as Averroes says in his exposition of this passage.

108. Then, at that growth has taken place (321b29), he points out the parts in which this solution is more evident. And he says that what has been stated is more evident in anomoeomera, i.e., members that possess unlike parts, such as the hand, which we observe to grow proportionally—for the entire hand and each finger and also each joint grow proportionally. The reason is that the distinction between species and matter is more plain in these members than in flesh and bone and other similar members. For the closer the members are to the whole the more fully they receive the perfection of the form which is principally the act of the whole. Consequently, the operations of the soul are more evident in members whose parts are unlike than in those that are alike. And therefore, although after death (in which the soul is separated from the body) not only does the animal not remain but no part of the animal remains, except equivocally, as is said in On the Soul II; yet flesh and bone would seem to remain more after death than-hand or arm, in which the operations of the soul are more evident.

109. Then, at** hence in one sense** (321b32), he concludes by giving a summary of the solution, namely, that in a certain sense each part of flesh is increased, i.e. if flesh is considered according to species; but in another sense each part is not increased, i.e., if flesh is considered according to matter.