Commentary Aristotle Physics
Lecture 2
Nature is both matter and form, but primarily form
Some identify the nature or substance of a natural object with that immediate constituent of it that, taken by itself, is without arrangement—for instance, the wood is the “nature” of the bed and the bronze the “nature” of the statue.
As an indication of this, Antiphon points out that, if you planted a bed and the rotting wood acquired the power of sending up a shoot, it would not be a bed that would come up, but wood—which shows that the arrangement in accordance with the rules of the art is accidental, while the real nature is the other, which, further, persists continuously through the process of making.
But, if the material of each of these objects has itself the same relation to something else—say bronze (or gold) to water, bones (or wood) to earth and so on—they say that would be their nature and essence.
Consequently, some assert earth, and others fire or air or water or some or all of these, to be the nature of the things that are. For whatever any one of them supposed to have this character—whether one thing or more than one thing—this or such is said to be the whole of substance, all else being its passions, states, or dispositions. Every such thing they held to be eternal (for it could not pass into anything else), but they held other things to come into being and cease to be times without number. This, then, is one account of nature—namely, that it is the immediate material substratum of things that have in themselves a principle of motion or change.
In another way, nature is the form and species which is according to the account. For the word “nature” is applied to what is according to nature and the natural in the same way as “art” is applied to what is artificial or a work of art. We should not say in the latter case that there is anything artificial about a thing, if it is a bed only potentially, not yet having the form of a bed; nor should we call it a work of art. The same is true of natural compounds.
What is potentially flesh or bone has not yet its own nature and does not exist until it receives the form specified in the account, which we name in defining what flesh or bone is. Thus, in the second sense of “nature,” it would be the form and species (not separable except in account) of things that have in themselves a source of motion.
(The combination of the two, such as man, is not “nature,” but “from nature” or “natural.”)
The form indeed is nature more than is the matter; for a thing is more properly said to be what it is when it has attained to fulfilment than when it exists potentially.
Again, man is born from man, but not bed from bed. That is why people say that the figure is not the nature of a bed, but the wood is—if the bed sprouted, a bed would not come up, but wood. But, even if the figure is art, then on the same principle, the form of man is his nature. For man is born from man.
We also speak of a thing’s nature in the sense of generation by which its nature is attained.
“Nature” in this sense is not like doctoring, which leads not to the art of doctoring, but to health. Doctoring must start from the art, not lead to it.
But it is not in this way that nature [in the one sense] is related to nature [in the other].
What grows, qua growing, grows from something into something. Into what, then, does it grow?
Not into that from which it arose, but into that to which it tends. The form, then, is nature.
“Form” and “nature,” it should be added, are in two senses. For the privation too is in a way form. But whether in unqualified generation there is privation—that is, a contrary to what comes to be—we must consider later.
149. Having shown what nature is, the Philosopher here points out the number of ways in which “nature” is used.
He shows first that nature is predicated of matter;
second, that it is predicated of form, at “another account” (193a30; [151]).
Concerning the first point, we must note that the ancient natural philosophers, being unable to arrive at prime matter, as was said above, held that some sensible body, such as fire or air or water, is the prime matter of all things. And so it followed that all forms come to matter as to something existing in act, as happens in artificial things. For the form of knife comes to iron already existing in act. And so they adopted an opinion about natural forms similar to that which is true of artificial forms.
Therefore, he says first that it seems to some that that which is primarily in each thing and that, considered in itself, is unformed is the substance and nature of natural things, as if we would say that the nature of a bed is wood, and the nature of a statue is bronze. For wood is in the bed and is, when considered in itself, not formed. And Antiphon said that the following is a sign of this. If one should bury a bed in the earth, and if the wood by rotting should acquire the potency to germinate something, that which is generated will not be a bed, but wood. Now, since the substance is that which remains permanent, and since it belongs to nature to generate what is like itself, he concluded that every disposition in respect to any law of reason or art is an accident. And that which remains permanent is substance, which continually undergoes change of dispositions of this sort.
Having supposed, therefore, that the forms of artificial things are accidents, and that matter is substance, Antiphon assumed the other proposition: just as the bed and statue are related to bronze and wood, so also each natural thing is related to some other thing that is its matter. Thus, bronze and gold are related to water (because the matter of all meltable things seems to be water), and bone and wood are related to earth, and it is the same with all other natural things. Hence, he concluded that the material things that subsist under natural forms are their nature and substance. And, because of this, some have said that earth is the nature and substance of all things (for example, the first theological poets); but the later philosophers chose fire or air or water, or some of these or all of them, as is clear from what was said above.
For they said that there are as many substances of things as there are material principles. And they said that all other things are accidents of these material principles, either as passions, or as habits, or as dispositions, or as anything else that is reduced to the genus of accident. Thus, one difference they posited between material and formal principles is that they said that they differed as substance and accident. There is, however, another difference, for they also said that these principles differ as the permanent and the corruptible. Since they held that each of the aforementioned simple bodies is a material principle, they said it was permanent, for they did not say that they were changed into each other. But they said that all other things come to be and are corrupted infinitely. For example, if water is the material principle, they said that water is never corrupted, but remains water in all things as their substance. But they said that bronze and gold and other things of this sort are corrupted and generated infinitely.
150. This position is in part true and in part false. With reference to the point that matter is the substance and the nature of natural things, it is true. For matter enters into the constitution of the substance of each natural thing. But, insofar as they said that all forms are accidents, this position is false. Thus, from this opinion and from his argument, Aristotle comes to the true conclusion: nature in one way is called matter, which underlies each natural thing that has in itself a principle of motion or of some sort of change. For motion is a species of change, as will be said in book 5.
151. Next, at “another account” (193a30), he shows that the form is also called nature.
Concerning this, he makes two points.
First, he states his position, namely, that form is nature;
second, at “form” and “nature” (193b18; [156]), he explains the diversity of forms.
He explains the first point with three arguments.
He first says, therefore, that “nature” is used in another way to refer to the form and species, which is according to the account—that is, from which the account of the thing is constituted. He proves this by the following argument.
Just as art belongs to a thing insofar as it is according to art and the artificial, so also nature belongs to a thing insofar as it is according to nature and the natural. But we do not say that that which is only in potency to that which is artificial has anything of art, because it does not yet have the species of a bed (for instance). Therefore, in natural things, that which is potentially flesh and bone does not have the nature of flesh and bone before it takes on the form in respect to which the definitive account of the thing is established (namely, that through which we know what flesh and bone are).
The nature is not yet in it before it has the form. Therefore, the nature of natural things that have in themselves a principle of motion is in another way the form. And this form, although it is not separated from the matter in the thing, still differs from the matter by reason. For as bronze and the shapeless, although one in subject, are different in account, so also are matter and form. He says this because, unless form were other than matter according to the account, the ways in which matter is called nature and form is called nature would not be different.
152. Moreover, one might believe that, since both matter and form are called nature, then the composite could also be called nature. For substance is predicated of form and of matter and of the composite. But he denies this, saying that the composite of matter and form, such as a man, is not the nature itself, but is some thing from nature. For nature has the account of a principle, but the composite has the account of being from a principle.
153. From the foregoing argument, he proceeds further to show that form is nature more than is matter. For a thing is said to be greater insofar as it is in act, rather than insofar as it is in potency. Hence form, according to which a thing is natural in act, is nature more than matter, according to which a thing is something natural in potency.
154. He gives the second argument at “again, man is” (193b8). He says that, although a bed does not come to be from a bed, as Antiphon said, man does come to be from man.
Hence, what they say is true, namely, that the form of bed is not the nature, but the wood is. For if wood should germinate, a bed would not come to be, but wood. Therefore, as this form, which does not arise through germination, is not nature, but art, so the form that arises from generation is nature. But the form of a natural thing does arise through generation, for man comes to be from man. Therefore, the form of a natural thing is nature.
155. He gives his third argument at “we also speak” (193b12). Nature can be signified as a generation—for instance, if we should call it birth. Thus, “nature” in the sense of generation—that is, birth—is the way to nature. For the difference between actions and passions is that actions are named from their principles while passions are named from their terminations. For each thing is named from act, which is the principle of action and the termination of passion.
But naming is not the same in passions and actions. For medication is not called the way to medicine, but the way to health. It is necessary for medication to proceed from medicine, not to medicine. But nature in the sense of generation, or birth, is not related to nature in the way in which medication is related to medicine.
Rather, it is related to nature as to a termination, since it is a passion. For that which is born, insofar as it is born, comes from something to something. Hence, that which is born is named from that to which it proceeds, and not from that from which it proceeds. But that to which birth tends is form. Therefore, form is nature.
156. Next, at “form” and “nature” (193b18), he shows that the nature that is form is used in two ways, namely, of the incomplete form and the complete form. This is clear in accidental generation, for example, when something becomes white. For whiteness is a complete form, and the privation of whiteness is in some way a species, insofar as it is joined to blackness, which is an imperfect form. But whether or not, in simple generation, which is the generation of substances, there is something that is a privation and also a contrary, such that substantial forms are contraries, must be considered later in book 5 and in De generatione et corruptione.