Commentary Aristotle Metaphysics
192. And concerning the cause. Here he gives the second absurdity, which has to do with the cause of motion. For to posit many and contrary causes of motion is not at all correct or reasonable; because if the causes of motion are understood to be proximate ones, they must be contraries, since their effects seem to be contraries. But if the first cause is understood, then it must be unique, as is apparent in book 12 of this work, and in Physics 8. Therefore, since he intends to posit the first causes of motion, his position that they are contraries is untenable.
193. And in general. Here he gives the third argument which leads to an absurdity: in every process of alteration it must be the same subject which undergoes contraries. This is true because one contrary does not come from another in such a way that one is converted into the other. For example, the cold does not come from the hot in such a way that heat itself becomes cold or the reverse, although the cold does come from the hot when the underlying subject is one only inasmuch as the single subject which is now the subject of heat is afterwards the subject of cold. But Empedocles did not hold that contraries have one subject. In fact, he held that they are found in different subjects, as heat in fire and cold in water. Nor again did he hold that there is one nature underlying these two. Therefore, he could not posit alteration in any way. Yet it is absurd that alteration should be done away with altogether.
194. But if anyone. Here he deals with Anaxagoras’ opinion, and in regard to this he does two things.
First, he shows in general in what respect Anaxagoras’ opinion should be accepted as true, and in what respect not.
Second, he explains each of these in particular, at for to say.
He says, first, that if anyone wishes to maintain that Anaxagoras’ opinion is true insofar as he posited two principles—the material and the efficient cause—let him understand this according to the reasoning which Anaxagoras himself seems to have followed, as if compelled by some need for truth, inasmuch as he would have followed those who expressed this theory, which he himself has not stated articulately, that is, he has not expressed it distinctly. Therefore, with reference to what he has not expressly stated, his opinion is true; but with reference to what he has expressly stated his opinion is false.
195. This is made clear in particular as follows. If his opinion is taken in its entirety according to a superficial understanding of his statements, a greater absurdity will appear for four reasons.
First, his opinion that all things were mixed together at the beginning of the world is absurd, for in Aristotle’s opinion the distinction between the parts of the world is thought to be eternal.
The second reason is that what is unmixed is related to what is mixed as the simple to the composite. But simple bodies are prior to composite ones, and not the reverse. Therefore, what is unmixed must be prior to what is mixed. This is the opposite of what Anaxagoras said.
The third reason is this: in the case of bodies not anything at all is naturally disposed to be mixed with anything else, but only those things are naturally disposed to be mixed which are naturally inclined to pass over into each other by some kind of alteration. For a mixture is a union of the altered things that are capable of being mixed. But Anaxagoras held that anything is mixed with just anything.
The fourth reason is this: there is both mixture and separation of the same things, for only those things are said to be mixed which are naturally disposed to exist apart. But properties and accidents are mixed with substances, as Anaxagoras said. Therefore, it follows that properties and accidents can exist apart from substances. This is evidently false. These absurdities appear then, if Anaxagoras’ opinion is considered in a superficial way.
196. Yet if anyone were to follow him up and articulate, that is, investigate clearly and distinctly, the things that Anaxagoras means, or his intellect held, although he did not know how to express this, his statement would appear to be more astonishing and subtler than those of the preceding philosophers. This will be so for two reasons.
First, he came closer to a true understanding of matter. This is clear from the fact that in that mixture of things, when nothing was distinguished from anything else but all things were mixed together, nothing could be truly predicated of that substance which is so mixed, which he held to be the matter of things. This is clear in the case of colors, for no special color could be predicated of it so that it might be said to be white or black or have some other color, because, according to this, that color would necessarily be unmixed with other things. Similarly, neither could color in general be predicated of it so that it might be said to be colored, because everything of which a generic term is predicated must also have a specific term predicated of it, whether the predication be univocal or denominative. Hence, if that substance were colored, it would necessarily have some special color. But this is opposed to the foregoing statement. And the argument is similar with respect to humors (that is, flavors), and to all other things of this kind.
Hence the primary genera themselves could not be predicated of it in such a way that it would have quality or quantity or some attribute of this kind. For if these genera were predicated of it, some particular species would necessarily belong to it. But this is impossible, if all things are held to be mixed together. For this species which would be predicated of that substance would already be distinguished from the others.
And this is the true nature of matter: it does not have any form actually but is in potency to all forms. For the mixed body itself does not have actually any of the things that combine in its mixture, but has them only potentially. And it is because of this likeness between prime matter and what is mixed that he seems to have posited the above mixture, although there is some difference between the potency of matter and that of a mixture.
For even though the elements which constitute a mixture are present in the mixture potentially, they are still not present in a state of pure passive potency, for they remain virtually in the mixture. This can be shown from the fact that a mixture has motion and operations as a result of the bodies of which the mixture is composed. But this cannot be said of the things that are present potentially in prime matter.
And there is also another difference, namely, that even though a mixture is not actually any of the mixed bodies which it contains, yet it is something actual. This cannot be said of prime matter. But Anaxagoras seems to do away with this difference, because he has not posited any particular mixture but the universal mixture of all things.
197. The second reason is this: he spoke more subtly than the others because he came closer to a true understanding of the first active principle. For he said that all things are mixed together except intellect, and that this alone is unmixed and pure.
198. From these things it is clear that he posited two principles: one of these he claimed to be the intellect itself, insofar as it is simple and unmixed with other things; the other is prime matter, which we claim is like the indeterminate before it is limited and participates in a form. For since prime matter is the subject of an infinite number of forms, it is limited by a form and acquires some species by means of it.
199. It is clear, then, that, in regard to the things that he stated expressly, Anaxagoras neither spoke correctly nor clearly. Yet he would seem to say something directly which comes closer to the opinions of the later philosophers, which are truer (namely, to those of Plato and Aristotle, whose judgments about prime matter were correct) and which were then more apparent.
200. In concluding, Aristotle excuses himself from a more diligent investigation of these opinions, because the statements of these philosophers belong to the realm of physical discussions, which treat of generation and corruption. For these men usually posited principles and causes of this kind of substance (that is, of material and corruptible substance). He says usually because, while they did not treat other substances, certain of the principles laid down by them can also be extended to other substances. This is most evident in the case of intellect. Therefore, since they have not posited principles common to all substances, which pertains to this science, but only principles of corruptible substances, which pertains to the philosophy of nature, a diligent study of the foregoing opinions belongs rather to the philosophy of nature than to this science.