Commentary Aristotle Metaphysics
Lecture 14. Critique of the Platonic Ideas
But those who posited ideas, and were the first to seek an understanding of the causes of sensible things, introduced other principles equal in number to these—as though one who wishes to count things thinks that this cannot be done when they are few, but believes that he can count them after he has increased their number.
For the separate forms are almost equal to, or not fewer than, these sensible things in the search for whose causes these thinkers have proceeded from sensible things to the forms.
For to each thing there corresponds some homogeneous entity bearing the same name, and with regard to the substances of other things there is a one-in-many, both in the case of these sensible things and in those which are eternal.
Furthermore, the forms do not become evident from any of the ways in which we prove that they exist. From some, no syllogism necessarily follows, but from others there does. According to these, there are forms of things of which we do not think there are forms.
According to those arguments from the sciences, there will be forms of all things of which there are sciences; according to the argument of the one-in-many there will also be forms of negations.
Again, according to the argument that there is some understanding of corruption, there will be forms of corruptible things; for of these there is some sensible image.
Again, according to the most certain arguments, some establish forms of relations, of which they deny there is any essential genus; but others lead to the third man.
And in general the arguments for the forms do away with the existence of the things that those who speak of the forms are more anxious to retain than the forms themselves. For it happens that the dyad is not first, but that number is, and that the relative is prior to that which exists of itself.
And all the other conclusions which some reach by following up the opinions about the ideas are opposed to the principles of the theory.
Again, according to the opinion whereby we claim that there are ideas, there will be forms not only of substances but also of many other things. For there is one concept not only of substances, but also of other things; and there are sciences not only of substance itself but also of other things. And a thousand other such difficulties face them.
But according to logical necessity and the opinions about the ideas, if the forms are participated in, there must be ideas only of substances.
For they are not participated in according to what is accidental. But things must participate in each form in this respect: insofar as each form is not predicated of a subject.
I mean that if anything participates in doubleness itself, it also participates in the eternal, but only accidentally; for it is an accident of doubleness to be eternal. Hence the forms will be substances.
But these things signify substance both here and in the ideal world; otherwise, why is it necessary that a one-in-many appear in addition to these sensible things? Indeed, if the form of the ideas and that of the things that participate in them are the same, there will be something in common.
For why should duality be one and the same in the case of corruptible twos and in those which are many but eternal, rather than in the case of this idea of duality and a particular two? But if the form is not the same, there will be pure equivocation; just as if one were to call both Callias and a piece of wood man, without observing any common attribute which they might have.
208. Here he argues disputatively against Plato’s opinion. This is divided into two parts.
First, he argues against Plato’s opinion with reference to his position about the substances of things;
second, with reference to his position about the principles of things, at and in general.
The first is divided into two parts.
First, he argues against Plato’s position that the forms are substances;
second, against the things that he posited about the objects of mathematics, at further, if the forms.
In regard to the first he does two things.
First, he argues against this position of Plato;
second, against the reasoning behind it, furthermore, the forms.
He first says that the Platonists, in holding that the ideas are certain separate substances, seemed to be at fault in that when they sought for the causes of these sensible beings, they neglected sensible beings and invented certain other new entities equal in number to sensible beings.
This seems to be absurd, because one who seeks the causes of certain things ought to make these evident and not add other things, the premising of which only adds to the number of points which have to be investigated. For it would be similar if a man who wished to count certain things, which he did not think he was able to count because they are few, believed that he could count them by increasing their number through the addition of certain other things.
But it is evident that such a man acts foolishly, because the path is clearer when there are fewer things; it is better and easier to make certain of fewer things than of many. And the smaller a number is, the more certain it is to us, inasmuch as it is nearer to the unit, which is the most accurate measure. And just as the process of counting things is the measure we use to make certain of their number, in a similar fashion an investigation of the causes of things is the accurate measure for making certain of their natures. Therefore, just as the number of fewer numerable things is made certain of more easily, in a similar way the nature of fewer things is made certain of more easily.
Hence, when Plato increased the genera of beings to the extent that he did with a view to explaining sensible things, he added to the number of difficulties by taking what is more difficult in order to explain what is less difficult. This is absurd.
209. That the ideas are equal in number to, or not fewer than, sensible things, whose causes the Platonists seek (and Aristotle includes himself among their number because he was Plato’s disciple), and which they established by going from sensible things to the aforesaid forms, becomes evident if one considers by what reasoning the Platonists introduced the ideas. Now they reasoned thus: they saw that there is a one-in-many for all things having the same name. Hence they claimed that this one-in-many is a form.
Yet with respect to all substances of things other than the ideas, we see that there is found to be a one-in-many which is predicated of them univocally inasmuch as there are found to be many things that are specifically one. This occurs not only in the case of sensible things but also in that of the objects of mathematics, which are eternal; because among these there are also many things that are specifically one, as was stated above.
Hence it follows that some idea corresponds to each species of sensible things; and therefore each idea is something having the same name as these sensible things, because the ideas agree with them in name. For just as Socrates is called man, so also is the idea of man. Yet they differ conceptually; for the intelligible structure of Socrates contains matter, whereas that of the ideal man is devoid of matter. Or, according to another reading, each form is said to be something having the same name as these sensible things inasmuch as it is a one-in-many and agrees with the things of which it is predicated so far as the intelligible structure of the species is concerned.
Therefore he says that they are equal to, or not fewer than, these things. For either there are held to be ideas only of species, and then they would be equal in number to these sensible things (granted that things are counted here insofar as they differ specifically and not individually, for the latter difference is infinite); or there are held to be ideas not only of species but also of genera, and then there would be more ideas than there are species of sensible things, because all species would be ideas and in addition to these each and every genus would be an idea.
This is why he says that they are either not fewer than or more. Or, in another way, they are said to be equal inasmuch as he claimed that they are the forms of sensible things. And he says not “fewer than” but “more” inasmuch as he held that they are the forms not only of sensible things but also of the objects of mathematics.
210. Furthermore, the forms. Here he argues dialectically against the reasoning behind Plato’s position; in regard to this he does two things.
First, he gives a general account of the ways in which Plato’s arguments fail.
Second, he explains them in detail, at according to those arguments.
He says, first, that with regard to the ways in which we Platonists prove the existence of the forms, according to none of these are the forms seen to exist. The reason is that no syllogism follows necessarily from some of these ways—that is, from certain arguments of Plato—because they cannot demonstrate with necessity the existence of the ideas. However, from other arguments a syllogism does follow, although it does not support Plato’s thesis; for by certain of his arguments there are proved to be forms of certain things of which the Platonists did not think there are forms, just as there are proved to be forms of those things of which they think there are forms.
211. According to those arguments. Here he examines in detail the arguments by which the Platonists establish ideas.
First, he examines the second argument, and he does this by showing that from Plato’s argument it follows that there are forms of some things for which the Platonists did not posit forms.
Second, he examines the first argument, and he does this by showing that Plato’s arguments are not sufficient to prove that ideas exist, at but the most.
In regard to the first member of this division he gives seven arguments. The first is this. One of the arguments that induced Plato to posit ideas is taken from scientific knowledge. For, since science is concerned with necessary things, it cannot be concerned with sensible things, which are corruptible, but must be concerned with separate entities, which are incorruptible. According to the argument taken from the sciences, then, it follows that there are forms of every sort of thing of which there are sciences. Now there are sciences not only of that which is one-in-many, which is affirmative, but also of negations; for just as there are some demonstrations which conclude with an affirmative proposition, in a similar way there are demonstrations which conclude with a negative proposition. Hence it is also necessary to posit ideas of negations.
212. Again, according to the argument. Here he gives the second argument. In the sciences it is understood not only that some things always exist in the same way, but also that some things are destroyed; otherwise, the philosophy of nature, which deals with motion, would be destroyed. Therefore, if there must be ideas of all the things that are comprehended in the sciences, there must be ideas of corruptible things insofar as they are such, that is, insofar as these are singular sensible things; for thus are things corruptible.