LECTURE 2 (193 a 9-b 21)

NATURE IS BOTH MATTER AND FORM, BUT PRIMARILY FORM

             149. Having shown what nature is, the Philosopher here points out the number of ways in which the name 'nature' is used. He shows first that nature is predicated of matter, secondly that it is predicated of form, where he says, 'Another account . . .' (193 a 30).

             Concerning the first point we must note that the ancient natural philosophers, being unable to arrive at primary matter, as was said above, held that some sensible body, such as fire or air or water, is the first 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.

             He says, therefore, first that it seems to some that that which is primarily in each thing and which 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 [ratio] 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, namely, that just as the bed and statue are related to bronze and wood, so also each natural thing is related to some other thing which is its matter. Thus bronze and gold are related to water (because the matter of all liquifiable 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 which 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; whereas 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 which is reduced to the genus of accident.

             Thus one difference which 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.

             Whence from this opinion and from his argument, Aristotle concludes to that which is true, namely, that nature in one way is called matter, which underlies each natural thing which has in itself a principle of motion or of some sort of mutation. For motion is a species of mutation, as will be said in Book V.

             151. Next where he says, 'Another account . . .' (193 a 30), he shows that the form is also called nature.

             Concerning this he makes two points. First he states his position, i.e., that form is nature. Secondly, where he says, 'Shape and nature . . .' (193 b 19), he explains the diversity of forms.

             He explains the first point with three arguments. He says, therefore, first that nature is used in another way to refer to the form and species, from which the nature [ratio] 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 artistic, 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 artistic has anything of art, because it does not yet have the species [e.g.] of a bed. 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 nature [ratio] of the thing is established (i.e. 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 which 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 [ratio]. For as bronze and the shapeless, although one in subject, are different in reason [ratio], so also are matter and form.

             He says this because unless form were other than matter according to reason [ratio], 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 [natura] has the nature [ratio] of a principle, but the composite has the nature [ratio] of 'being from a principle'.

             153. From the foregoing argument he proceeds further to show that form is nature more than matter. For a thing is said to be greater insofar as it is in act rather than insofar as it is in potency. Whence 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 where he says, 'Again man is . . .' (193 b 8). He says that although a bed does not come to be from a bed, as Antiphon said, man does come to be from man. Whence 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 which 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 where he says, 'We also speak . . .' (193 b 13). Nature can be signified as a generation, for instance, if we should call it birth. Thus nature in the sense of generation, i.e., 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, i.e., birth, is not related to nature as 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. That, however, to which birth tends is form. Therefore form is nature.

             156. Next where he says, 'Shape and nature . . .' (193 b 19), he shows that the nature which is form is used in two ways, i.e., 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 which is a privation and also a contrary, so that substantial forms are contraries, must be considered later in Book V and in De Generatione et Corruptione.