Commentary Aristotle Metaphysics
But according to Plato’s theory, it cannot be said that those sciences by which we understand the processes of corruption in the world attain any understanding of the processes of corruption in sensible things, for there is no comprehension of these sensible things, but only imagination or phantasy, which is a motion produced by the senses in their act of sensing, as is pointed out in On the Soul 2.
213. Again, according to the most. Here he gives the third argument, which contains two conclusions that he says are drawn from the most certain arguments of Plato.
One conclusion is this: if there are ideas of all things of which there are sciences, and there are sciences not only of absolutes but also of things predicated relatively, then in giving this argument it follows that there are also ideas of relations. This is opposed to Plato’s view. For, since the separate ideas are things that exist of themselves, which is opposed to the intelligibility of a relation, Plato did not hold that there is a genus of ideas of relations, because the ideas are said to exist of themselves.
214. The second conclusion is one which follows from other most certain arguments, namely, that there is a third man. This phrase can be understood in three ways.
First, it can mean that the ideal man is a third man distinct from two men perceived by the senses, who have the common name “man” predicated of both of them. But this does not seem to be what he has in mind, granted that it is not mentioned in the Sophistical Refutations 2, because he argues against the position. Hence, according to this, it would not lead to an absurdity.
215. The second way in which this expression can be understood is this: the third man means one that is common to the ideal man and to one perceived by the senses.
For, since both a man perceived by the senses and the ideal man have a common intelligible structure (like two men perceived by the senses), then just as the ideal man is held to be a third man in addition to two men perceived by the senses, in a similar way there should be held to be another third man in addition to the ideal man and one perceived by the senses.
But neither does this seem to be what he has in mind here, because he leads us immediately to this absurdity by means of another argument. Hence it would be pointless to lead us to the same absurdity here.
216. The third way in which this expression can be understood is this. Plato posited three kinds of entities in certain genera of things, namely, sensible substances, the objects of mathematics, and the forms. He does this, for example, in the case of numbers, lines, and the like.
But there is no reason why intermediate things should be held to exist in certain genera rather than in others. Hence in the species of man it was also necessary to posit an intermediate man, who will be a third man midway between the man perceived by the senses and the ideal man. Aristotle also gives this argument in the later books of this work.
217. And in general. Here he gives the fourth argument, which runs as follows. Whoever by his own reason does away with certain principles which are better known to him than the ones which he posits adopts an absurd position. But these theories about the forms which Plato held do away with certain principles whose reality the Platonists (when they said that there are ideas) were more convinced of than the existence of the ideas. Therefore, Plato’s position is absurd.
The minor premise is proved in this way. According to Plato the ideas are prior both to sensible things and to the objects of mathematics. But according to him the ideas themselves are numbers, and they are odd numbers rather than even ones, because he attributed odd number to form and even number to matter. Hence he also said that the dyad is matter. Therefore, it follows that other numbers are prior to the dyad, which he held to be the matter of sensible things, and identified with the great and small. Yet the Platonists asserted the very opposite of this, namely, that the dyad is first in the genus of number.
218. Again, if, as has been proved by the above argument, there must be ideas of relations, which are self-subsistent relations, and if the idea itself is prior to whatever participates in the idea, it follows that the relative is prior to the absolute, which is said to exist of itself. For sensible substances of this kind, which participate in ideas, are said to be in an unqualified sense. And in like manner whatever those who follow the opinion about the ideas say of all things is opposed to self-evident principles which even they themselves are most ready to acknowledge.
219. Again, according to the opinion. Here he gives the fifth argument, which is as follows. Ideas were posited by Plato in order that the intelligible structures and definitions of things given in the sciences might correspond to them, and in order that there could be sciences of them.
But there is one concept, a simple and indivisible concept, by which the quiddity of each thing is known—that is, not only the quiddity of substances but also of other things, namely, of accidents. And in a similar way there are sciences not only of substance and about substance, but there are also found to be sciences of other things, namely, of accidents. Hence, according to the opinion by which you, Platonists, acknowledge the existence of ideas, it evidently follows that there will be forms not only of substances but also of many other things, namely, of accidents.
This same conclusion follows not only because of definitions and the sciences, but there also happen to be many other such, or very many, reasons why it is necessary to posit ideas of accidents according to Plato’s arguments. For example, he held that the ideas are the principles of being and of becoming in the world, and of many such aspects which apply to accidents.
220. But, on the other hand, according to Plato’s opinion about the ideas and according to logical necessity, insofar as the ideas are indispensable to sensible things—namely, insofar as they are capable of being participated in by sensible things—it is necessary to posit ideas only of substances.
This is proved thus. Things that are accidental are not participated in. But an idea must be participated in by each thing insofar as it is not predicated of a subject.
This becomes clear as follows. If any sensible thing participates in doubleness itself, that is, in a separate doubleness (for Plato spoke of all separated things in this way, namely, as self-subsisting things), it must participate in the eternal. But it does not do this per se (because then it would follow that any double perceived by the senses would be eternal), but accidentally, insofar as doubleness itself, which is participated in, is eternal.
And from this it is evident that there is no participation in things that are accidental, but only in substances. Hence, according to Plato’s position a separate form was not an accident but only a substance. Yet according to the argument taken from the sciences there must also be forms of accidents, as was stated above.
221. But these things. Then he gives the sixth argument, which runs thus. These sensible things signify substance both in the case of things perceived by the senses and in that of those in the ideal world, namely, in the case of intelligible things, which signify substance (because they held that both intelligible things and sensible ones are substance). Therefore, it is necessary to posit in addition to both of these substances—intelligible and sensible ones—some common entity which is a one-in-many. For the Platonists maintained that the ideas exist on the grounds that they found a one-in-many which they believed to be separate from the many.
222. The need for positing a one apart from both sensible substances and the forms he proves thus. The ideas and the sensible things that participate in them either belong to one species or not. If they belong to one species, and it is necessary to posit, according to Plato’s position, one common separate form for all things having a common nature, then it will be necessary to posit some entity common to both sensible things and the ideas themselves which exists apart from both.
Now one cannot answer this argument by saying that the ideas, which are incorporeal and immaterial, do not stand in need of any higher forms. For the objects of mathematics, which Plato places midway between sensible substances and the forms, are similarly incorporeal and immaterial. Yet since many of them are found to belong to one species, Plato held that there is a common form for these things, in which not only the objects of mathematics participate but also sensible substances.
Therefore, if the two-ness which is the form or idea of two-ness is identical with that found in sensible twos, which are corruptible (just as a pattern is found in the things fashioned after it), and with that found in mathematical twos, which are many in one species (but are nevertheless eternal), then for the same reason in the case of the same two-ness (the idea two) and in that of the other two-ness (which is either mathematical or sensible), there will be another separate two-ness. For no reason can be given why the former should exist and the latter should not.
223. But if the other alternative is admitted—that sensible things, which participate in the ideas, do not have the same form as the ideas—it follows that the name which is predicated of both the ideas and sensible substances is predicated in a purely equivocal way. For those things are said to be equivocal which have only a common name and differ in their intelligible structure. And it follows that they are not only equivocal in every way but equivocal in an absolute sense, like those things on which one name is imposed without regard for any common attribute, which are said to be equivocal by chance—for example, if one were to call both Callias and a piece of wood man.
224. Now Aristotle added this because someone might say that a name is not predicated of an idea and of a sensible substance in a purely equivocal way, since a name is predicated of an idea per se and of a sensible substance by participation. For, according to Plato, the idea of man is called man in himself, whereas this man whom we apprehend by the senses is said to be a man by participation. However, such an equivocation is not pure equivocation. But a name which is predicated by participation is predicated with reference to something that is predicated per se; this is not pure equivocation, but the multiplicity of analogy. However, if an idea and a sensible substance were altogether equivocal by chance, it would follow that one could not be known through the other, as one equivocal thing cannot be known through another.