Lecture 11 — Growth differs from generation and alteration both as to subject and to manner.

But we have still to treat of growth. We must explain (i) wherein growth differs from coming-to-be and from 'alteration', and ii) what is the process of growing and the sprocess of diminishing in each and all of the things that grow and diminish.

Hence our first question is this: Do these changes differ from one another solely because of a difference in their respective 'spheres'? In other words, do they differ because, while a change from this to that (viz. from potential to actual substance) is coming-to-be, a change in the sphere of magnitude is growth and one in the sphere of quality is 'alteration'—both growth and 'alteration' being changes from what is-potentially to what is-actually magnitude and quality respectively?

Or is there also a difference in the manner of the change, since it is evident that, whereas neither what is 'altering' nor what is coming-to-be necessarily changes its place, what is growing or diminishing changes its spatial position of necessity,

though in a different manner from that in which the moving thing does so? For that which is being moved changes its place as a whole: but the growing thing changes its place like a metal that is being beaten, retaining its position as a whole while its parts change their places. They change their places,

but not in the same way as the parts of a revolving globe. For the parts of the globe change their places while the whole continues to occupy an equal place: but the parts of the rowing thing expand over an ever-increasing place and the parts of the diminishing thing contract within an ever-diminishing area.

It is clear, then, that these changes—the changes of that which is coming-to-be, of that which is 'altering', and of that which is growing—differ in manner as well as in sphere.

82. After concluding concerning generation and alteration, the Philosopher here determines concerning growth and diminution.

First he states his intention (320a8) and says that after generation and corruption, something must be said about growth, about which there are two things to consider:

first, in what it differs from generation and alteration;

second, in what manner augmentation and diminution take place in things augmented and diminished.

Second, he carries out his intention, at hence our first question (320a10; [83]).

First, he shows how growth differs from generation and alteration;

second, he inquires how augmentation takes place, at but how are we to conceive (320a27; [87]).

About the first he does two things:

first, he assumes one difference;

second, he inquires about another difference, at or is there also a difference (320a16; [84]).

83. He says therefore first (320a10) that the first point of inquiry about growth is that one must ask whether it differs from generation and alteration only with respect to that about which, i.e., the genus in which these changes occur. For this difference is plain, namely, that the change which is from this into this, i.e., from substance that is being in potency into substance which is being in act, is generation; while the change that respects magnitude is growth (through which something is changed from small into large) and diminution (through which something is changed from large into small); while the change that respects passions, i.e., passible qualities, is alteration.

And because he had said that generation is a change from substance in potency into substance in act, then, that the same may be understood of the other two changes mentioned above, he adds that the change of both the aforesaid, namely, of magnitude and passions, proceeds from potency to act—for motion is the act of a thing existing in potency, as is said in Physics III.

84. Then, at **or is there also a difference **(320a16), he assigns another difference, i.e., one based on the manner of change.

First, he mentions the difference;

second, he explains it, at though in a different manner (320a19; [85]).

He says therefore first (320a16) that in the above-mentioned changes, the manner of change also differs. (And it does not matter whether the statement is read interrogatively or rhetorically.) For the mode of the aforesaid changes differs in that what is altered does not necessarily undergo a change of place and neither does a thing that is generated. But anything that is augmented or diminished must undergo a change in place. The reason for this difference is that place is co-extensive with the thing in place, and this is according to magnitude [size] and not according to quality or substance. Consequently, it is necessary that, when the magnitude [size] of a thing in place is changed, there be a change according to place, but not when something is changed in substance or quality.

Now just as the commensurateness of that which is in place to the place which contains it is in terms of its size, so the connaturality of the thing is in terms of the substantial form, and consequently, of some quality—for example, of heaviness or lightness. Consequently, although generation and alteration can occur without any change of place, yet in certain cases generation and alteration are the cause of a thing's being moved naturally with respect to place, as, when for example, when fire or earth comes to be, something light or heavy comes to be.

But the difference between growth and the other changes, with respect to local motion, is not entirely per accidens, for it has been shows in Physics VIII that local motion is the first and chiefest of motions, as well as the cause of the other motions.

85. Then, at though in a different manner (320a19), he shows what he had said, namely, that whatever is augmented or diminished is changed with respect to place.

First, he manifests this in rectilinear local motion;

second, in spherical local motion, at but not in the same way (320a22; [86]).

He says therefore first (320a19) that a thing which is increased or decreased changes place differently from that which is carried, i.e., moved with a rectilinear motion. For in the case of that which is carried, namely, in rectilinear motion, the thing universally, i.e., in its wholeness, changes place. But something changes its place like that which is drawn out, for example, like metal by beating or also something liquid as poured into a receptacle, or any other body of this sort. In these cases, while the object remains in the same place, its parts are changed with respect to place either by extension or in some other way.

86. Then, at but not in the same way (320a22), he manifests what he had said by the difference with respect to spherical local motion. And he says that the parts of a thing which grows do indeed change their place, but not in the same way as the parts of a sphere. For the parts of a sphere are changed while the whole remains in the same place, namely, as to subject (although the whole too changes its place conceptually, as is said in Physics VI, but the parts change their place even as to subject, as when the part of the heaven which is now in the east, comes to be in the west. However, such a change of the parts of a sphere takes place in a place that is similar, i.e., neither larger nor smaller. But the parts of a body that is growing are always extending into a larger place, while the parts of a body that is diminishing are always being contracted so as to occupy a smaller place.

In summary he concludes (320a25) that it is clear from the aforesaid that these changes—the changes of that which is generated and altered and grows—differ not only with respect to that about which, i.e., the genus in which the changes take place, but thus, i.e., in the manner of the changing.