LESSON 17

  Arguments against the View that the Ideas Are Principles of Being and Knowledge

Chapters 9 & 10: 992a 24-993a 27

             133. And, in general, even though wisdom investigates the causes of apparent things, we have neglected this study. For we say nothing about the cause from which motion originates. And while we think that we are stating the substance of these sensible things, we introduce other substances. But the way in which we explain how the latter are the substances of the former is empty talk; for to participate, as we have said before (115), signifies nothing. Moreover, that which we see to be the cause in the sciences, that by reason of which all intellect and all nature operates, on that cause which we say is one of the principles the Forms do not touch in any way. But mathematics has been turned into philosophy by present-day thinkers (566), although they say that mathematics must be treated for the sake of other things.

             134. Further, one might suppose that the underlying substance [which they consider] as matter is too mathematical, and that it is rather a predicate and difference of substance and matter, like the great and small; just as the philosophers of nature speak of the rare and dense (56), which they say are the primary differences of the underlying subject; for these are a kind of excess and defect.

             135. And with regard to motion, if these entities [the great and small] are motion, evidently the Forms are moved; but if they are not, from what does motion come? For [if it has no cause], the whole study of nature is destroyed.

             136. And what seems easy to show is that all things are not one; for from their position all things do not become one. But if someone should assert that all things are some one thing, not even this is true unless one grants that the universal is a class; and in certain other cases this is impossible.

             137. For they do not have any theory about the lengths, widths, and solids which come after the numbers: either as to how they now exist or will exist, or what importance they have. For it is impossible that they should be Forms (since they are not numbers), or intermediate things (for those are the objects of mathematics), or corruptible things; but, on the contrary, it seems that they form a fourth class.

             138. And, in general, to look for the elements of existing things without distinguishing the different senses in which things are said to be, makes it impossible to discover them. And [their view is unsatisfactory] in another way, i.e., in the way in which they seek for the elements of which things are composed. For it is impossible to understand of what things action or passion or straightness is composed. But if this is possible only in the case of substances, then to look for the elements of all existing things, or to think that we have found them, is a mistake.

             139. But how will one acquire knowledge of the elements of all things? For it is clearly impossible to have prior knowledge of anything. For just as one acquiring knowledge of geometry must have a prior knowledge of other things, but not of the things which this science [investigates], and which he is to learn, so it is in the case of the other sciences. Hence, if there is a science of all things (and there must be a science of these), as some say, the one learning this science does not have any prior knowledge of it. But all learning proceeds from things previously known, either all or some of them, whether the learning be by demonstration or by definitions. For [the parts] of which definitions are composed must already be known beforehand and be evident. The same thing is true in the case of things discovered by induction.

             140. But if this science were connatural, it is a wonder how we could be unconscious of having the most important of the sciences.

             141. Again, how is anyone to know the elements of which things are composed, and how is this to be made evident? For this also presents a difficulty; because one might argue in the same way as one does about certain syllables. For some say that sma is made up of s, m and a, whereas others say that it is a totally different sound and not any of those which are known to us.

             142. Again, how could one know the things of which a sense is cognizant without having that sense? Yet this will be necessary if they [i.e., sensible things] are the elements of which all things are composed, just as spoken words are composed of their proper elements.

Chapter 10

             143. From the foregoing, then, it is evident that all [the early philosophers] seem to seek the causes mentioned in the Physics, and that we cannot state any other in addition to these. But they understood these obscurely; and while in one sense all causes have been mentioned before, in another sense they have not been mentioned at all. Indeed, the earliest philosophy seems to speak in a faltering way about all subjects inasmuch as it was new as regards principles and the first of its kind. For even Empedocles says that ratios are present in bone, and that this is the quiddity or substance of a thing. But [if this is true], there must likewise be a ratio of flesh and of every other thing or of nothing. For it is because of this that flesh and bone and every other thing exists, and not because of their matter, which he says is fire, earth, air and water. But if someone else had said this, he would have been forced to agree to the same thing. But he has not said this. Such things as these, then, have been explained before. So let us return again to whatever problems one might raise about the same subject; for perhaps in the light of these we shall be able to make some investigation into subsequent problems.

COMMENTARY

             259. Here Aristotle destroys Plato's opinion about the principles of things. First (133:C 259), he destroys Plato's opinion about principles of being; and second (139:C 268), his opinion about principles of knowledge ("But how will one").

             In regard to the first part he gives six arguments. The first is based on the fact that Plato neglected to deal with the classes of causes. Thus he says that, "in general, wisdom," or philosophy, has as its aim to investigate the causes "of apparent things," i.e., things apparent to the senses. For men began to philosophize because they sought for the causes of things, as was stated in the prologue (27:C 53). But the Platonists, among whom he includes himself, neglected the principles of things, because they said nothing about the efficient cause, which is the source of change. And by positing the Ideas they thought they had given the formal cause of things. But while they thought that they were speaking of the substance of these things, i.e., sensible ones, they posited the existence of certain other separate substances which differ from these. However, the way in which they assigned these separate substances as the substances of sensible things "is empty talk," i.e., it proves nothing and is not true. For they said that the Forms are the substances of sensible things inasmuch as they are participated in by sensible things. But what they said about participation is meaningless, as is clear from what was said above (112:C 225). Furthermore, the Forms which they posited have no connection with the final cause, although we see that this is a cause in certain sciences which demonstrate by means of the final cause, and that it is by reason of this cause that every intellectual agent and every natural one operates, as has been shown in the Physics, Book II. And just as they do not touch on that cause which is called an end [or goal], when they postulate the existence of the Forms (78:C 169), neither do they treat of that cause which is called the source of motion, namely, the efficient cause, which is the opposite, so to speak, of the final cause. But the Platonists by omitting causes of this kind (since they did omit a starting-point and end of motion), have dealt with natural things as if they were objects of mathematics, which lack motion. Hence they said that the objects of mathematics should be studied not only for themselves but for the sake of other things, i.e., natural bodies; inasmuch as they attributed the properties of the objects of mathematics to sensible bodies.

             260. Further, one might (134).

             Here he gives the second argument, which runs thus: that which is posited as the matter of a thing is the substance of a thing, and is predicable of a thing to a greater degree than something which exists apart from it. But a Form exists apart from sensible things. Therefore, according to the opinion of the Platonists, one might suppose that the underlying substance as matter is the substance of the objects of mathematics rather than a separate Form. Furthermore, he admits that it is predicated of a sensible thing rather than the above Form. For the Platonists held that the great and small is a difference of substance or matter; for they referred these two principles to matter, just as the philosophers of nature (56:C 115) held that rarity and density are the primary differences of the "underlying subject," or matter, by which matter is changed, and spoke of them in a sense as the great and small. This is clear from the fact that rarity and density are a kind of excess and defect. For the dense is what contains a great deal of matter under the same dimensions, and the rare is what contains very little matter. Yet the Platonists said that the Forms are the substance of sensible things rather than the objects of mathematics, and that they are predicable of them to a greater degree.

             261. And with regard (135).

             Here he gives the third argument, which runs thus: if those attributes which exist in sensible things are caused by separate Forms, it is necessary to say either that there is an Idea of "motion" among the Forms or there is not. If there is a Form or Idea of motion among the Forms, and there cannot be motion without something that is moved, it also follows that the Forms must be moved. But this is opposed to the Platonists' opinion, for they claimed that the Forms are immobile. On the other hand, if there is no Idea of motion, and these attributes which exist in sensible things are caused by the Ideas, it will be impossible to assign a cause for the motion which occurs in sensible things; and thus the entire investigation of natural philosophy, which studies mobile things, will be destroyed.

             262. And what seems easy (136).

             Then he gives the fourth argument, which runs thus: if unity were the substance of all things, as the Platonists assumed, it would be necessary to say that all things are one, just as the philosophers of nature also did in claiming that the substance of all things is water, and so on for the other elements. But it is easy to show that all things are not one. Hence the position that unity is the substance of all things is not held in high repute.

             263. But let us assume that someone might say that it does not follow, from Plato's position, that all things are one in an unqualified sense but in a qualified sense, just as we say that some things are one generically or specifically. And if someone wished to say that all things are one in this way, even this could be held only if what I call the one were a genus or universal predicate of all things. For then we could say that all things are one specifically, just as we say that both a man and an ass are animal substantially. But in certain cases it seems impossible that there should be one class of all things, because the difference dividing this class would necessarily not be one, as will be said in Book III (229:C 432). Therefore, in no way can it be held that the substance of all things is one.

             264. For they do not have (137).

             Here he gives the fifth argument, which runs thus: Plato placed lengths, widths and solids after numbers as the substances of sensible things, i.e., that of which they are composed. But according to Plato's position there seems to be no reason why they should be held to exist either now or in the future. Nor does this notion seem to have any efficacy to establish them as the causes of sensible things. For things which exist "now" must mean immobile things (because these always exist in the same way), whereas things which "will exist" must mean those which are capable of generation and corruption, which acquire being after non-being. This becomes clear thus: Plato posited three classes of things--sensible things, the Forms and the objects of mathematics, which are an intermediate class. But such lines and surfaces as those of which sensible bodies are composed cannot be Forms; for the Forms are essentially numbers, whereas such things [i.e., the lines and surfaces composing bodies] come after numbers. Nor can such lines and surfaces be said to be an intermediate class between the Forms and sensible things; for the things in this intermediate class are the objects of mathematics, and exist apart from sensible things; but this cannot be said of the lines and surfaces of which sensible bodies are composed. Nor again can such lines and surfaces be sensible things; for the latter are corruptible, whereas these lines and surfaces are incorruptible, as will be proved below in Book III (250:C 466). Therefore these things are either nothing at all or they constitute a fourth class of things, which Plato omitted.

             265. And, in general (138).

             Here he gives the sixth argument, which runs thus: it is impossible to discover the principles of anything that is spoken of in many senses, unless these many senses are distinguished. Now those things which agree in name only and differ in their intelligible structure cannot have common principles; otherwise they would have the same intelligible structure, since the intelligible structure of a thing is derived from its own principles. But it is impossible to assign distinct principles for those things which have only the name in common, unless it be those whose principles must be indicated to differ from each other. Therefore, since being is predicated both of substance and the other genera in different senses and not in the same sense, Plato assigned inadequate principles for things by failing to distinguish beings from each other.

             266. But since someone could assign principles to things which differ in their intelligible structure and have a common name, by adjusting proper principles to each without distinguishing the many senses of the common name, and since the Platonists have not done this, then "in another way," i.e., by another argument, they assigned inadequate principles to things when they looked for the elements of which things are made, i.e., in the way in which they sought for them, inasmuch as they did not assign principles which are sufficient for all things. For from their statements it is impossible to understand the principles of which either action and passion, curvature and straightness, or other such accidents, are composed. For they only indicated the principles of substances and neglected accidents.

             267. But if in defense of Plato someone wished to say that it is possible for the elements of all things to have been acquired or discovered at the moment when the principles of substances alone happen to have been acquired or discovered, this opinion would not be true. For even if the principles of substances are also in a sense the principles of accidents, nevertheless accidents have their own principles. Nor are the principles of all genera the same in all respects, as will be shown below in Book XI (912:C 2173) and Book XII (1042:C 2455) of this work.

             268. But how will one (139).

             Here he argues dialectically against Plato's position that the Ideas are the principles of our scientific knowledge.

             He gives four arguments, of which the first is this: if our scientific knowledge is caused by the Ideas themselves, it is impossible for us to acquire knowledge of the principles of things. But it is evident that we do acquire knowledge. Therefore our knowledge is not caused by the Ideas themselves. That it would be impossible to acquire knowledge of anything, he proves thus: no one has any prior knowledge of that object of which he ought to acquire knowledge; for example, even though in the case of geometry one has prior knowledge of other things which are necessary for demonstration, nevertheless the objects of which he ought to acquire knowledge he must not know beforehand. The same thing is also true in the case of the other sciences. But if the Ideas are the cause of our knowledge, men must have knowledge of all things, because the Ideas are the intelligible structures of all knowable things. Therefore we cannot acquire knowledge of anything, unless one might be said to acquire knowledge of something which he already knew. If it is held, then, that someone acquires knowledge, he must not have any prior knowledge of the thing which he comes to know, but only of certain other things through which he becomes instructed; i.e., one acquires knowledge through things previously known, [either] "all," i.e., universals, "or some of them," i.e., singular things. One learns through universals in the case of those things which are discovered by demonstration and definition, for in the case of demonstrations and definitions the things of which definitions or universals are composed must be known first. And in the case of things which are discovered by induction singular things must be known first.

             269. But if this science (140).

             Here he gives the second argument, which runs thus: if the Ideas are the cause of our knowledge, it must be connatural to us; for men grasp sensible things through this proper nature, because sensible things participate in Ideas according to the Platonists. But the most important knowledge or science is one that is connatural to us and which we cannot forget, as is evident of our knowledge of the first principles of demonstration, of which no one is ignorant. Hence there is no way in which we can forget the knowledge of all things caused in us by the Ideas. But this is contrary to the Platonists' opinion, who said that the soul as a result of its union with the body forgets the knowledge which it has of all things by nature, and that by teaching a man acquires knowledge of something that he previously knew, as though the process of acquiring knowledge were merely one of remembering.

             270. Again, how is anyone (141).

             Here he gives the third argument, which runs thus: in order to know things a man must acquire knowledge not only of the forms of things but also of the material principles of which they are composed. This is evident from the fact that occasionally questions arise regarding these; for example, with regard to this syllable sma, some raise the question whether it is composed of the three letters s, m and a, or whether it is one letter which is distinct from these and has its own sound. But only the formal principles of things can be known through the Ideas, because the Ideas are the forms of things. Hence the Ideas are not a sufficient cause of our knowledge of things when material principles remain unknown.

             271. Again, how could (142).

             Here he gives the fourth argument, which runs thus: in order to know reality we must know sensible things, because sensible things are the apparent material element of which all things are composed, just as complex sounds (such as syllables and words) are composed of their proper elements. If, then, knowledge is caused in us by the Ideas, our knowledge of sensible things must be caused by the Ideas. But the knowledge which is caused in us by the Ideas is grasped without the senses, because we have no connection with the Ideas through the senses. Therefore in the act of perception it follows that anyone who does not have a sense can apprehend the object of that sense. This is clearly false; for a man born blind cannot have any knowledge of colors.

             272. From the foregoing (143).

             Here he summarizes the statements made by the ancient philosophers. He says that from what has been said above it is evident that the ancient philosophers attempted to investigate the cause which he [Aristotle] dealt with in the Physics, and that in their statements we find no cause in addition to those established in that work. However, these men discussed these causes obscurely; and while in a sense they have mentioned all of these causes, in another sense they have not mentioned any of them. For just as young children at first speak imperfectly and in a stammering way, in a similar fashion this philosophy, since it was new, seems to speak imperfectly and in a stammering way about the principles of all things. This is borne out by the fact that Empedocles was the first to say that bones have a certain ratio, or proportional mixture [of the elements], and that this is a thing's quiddity or substance. But the same thing must also be true of flesh and of every other single thing or of none of them, for all of these things are mixtures of the elements. And for this reason it is evident that flesh and bone and all things of this kind are not what they are because of their matter, which he identified with the four elements, but because of this principle--their form. However, Empedocles, compelled as it were by the need for truth, would have maintained this view if it had been expressed more clearly by someone else, but he did not express it clearly. And just as the ancient philosophers have not clearly expressed the nature of form, neither have they clearly expressed the nature of matter, as was said above about Anaxagoras (44:C 90). Nor have they clearly expressed the nature of any other principles. Therefore, concerning such things as have been stated imperfectly, we have spoken of this before (94:C 190). And with regard to these matters we will restate again in Book III (220:C 423) whatever difficulties can be raised on both sides of the question. For perhaps from such difficulties we will discover some useful information for dealing with the problems which must be examined and solved later on throughout this whole science.