METAPHYSICS, BOOK XII

LESSON I: Metaphysics Studies Substance

ARISTOTLE’S TEXT Chapter 1: 1069a 18-1069a 30

1023. The study here is concerned with substance; for it is the principles and causes of substances which are being investigated.

1024. For if the totality of things is a kind of whole, substance is its first part; and if things constitute a whole by reason of succession, substance is also first, and then quality or quantity.

1025. And in like manner the latter are not to be regarded as beings in an unqualified sense, but as qualities and motions of being. Otherwise the not-straight and not-white would be beings; for we say that they are, for example, “the not-white is.”

1026. Again, none of the other genera can exist separately.

1027. The ancient philosophers testify to this in practice, for it was of substance that they sought the principles, elements and causes. Present-day thinkers [Platonists] however, maintain that universals are substances; for genera are universals, and they say that these are principles and substances to a greater degree because they investigate the matter dialectically. But the ancient philosophers regarded particular things as substances, for example, fire and earth, and not a common body.

COMMENTARY

2416. Having summarized in the preceding book the points that were previously made regarding imperfect being both in this work and in the Physics, in this book the Philosopher aims to summarize the things that have been said about being in its unqualified sense, i.e., substance, both in Books VII and VIII of this work and in Book I of the Physics, and to add anything that is missing in order to make his study of substances complete. This is divided into two parts. First (1023:C 2416), he shows that this science is chiefly concerned with substances. Second (1028:C 2424), he gives his views about the classes of substances (“Now there are three”).

In regard to the first he does two things. First, he states his thesis. He says that in this science “the study,” i.e., the principal inquiry, has to do with substances. For since this science, being the first and the one called wisdom, investigates the first principles of beings, the principles and causes of substances must constitute its main object of study; for these are the first principles of beings. The way in which principle and cause differ has been pointed out in Book V (403:C 760).

2417. For if the totality (1024)

He proves his thesis in four ways. The first proof runs thus. Since substance is prior to the other kinds of beings, the first science should be one that is chiefly concerned with the primary kind of being. He shows that substance is the primary kind of being by using an analogous case in the realm of sensible things, among which order is found in two ways. One kind of order is found among sensible things inasmuch as the parts of any whole have a certain natural arrangement; for example, the first part of an animal is the heart, and the first part of a house the foundation. Another kind of order is found among sensible things inasmuch as some follow others and one thing is not constituted from them either by continuity or by contact. It is in this sense that one speaks of the first and second lines of an army. Hence, just as there is some first part in any whole, and also some first entity among things that follow one another, so too substance is the first of all other beings. This is what he means when he says “For if the totality,” i.e., the universe of beings, is a kind of whole, substance is its first part, just as the foundation is the first part of a house. And if beings are like things that follow one another, substance again will be first, and then quantity, and then the other categories.

2418. But Averroes, failing to consider that this statement is analogical because he considered it impossible for anyone to think that all the other genera of beings should be parts of one continuous whole, departs from the obvious sense of the text and explains it in a different way. He says that by these two orders Aristotle meant the twofold relationship which can be conceived between things. The first is that beings are related as things having one nature and one genus, which would be true if being were their common genus, or in whatever way it might be common to them. He says that this is Aristotle’s meaning when he says “If the totality of things is a kind of whole.” The second is that beings are related as things having nothing in common. He says that this is Aristotle’s meaning when he says “And if things constitute a whole by reason of succession”; for in either case it follows that substance is prior to the other kinds of being.

2419. But in like manner (1025).

Then he gives a second proof of his thesis. He says that quantity and quality and the like are not beings in an unqualified sense, as will be said below. For being means something having existence, but it is substance alone that subsists. And accidents are called beings, not because they are but rather because by them something is; for example, whiteness is said to be because by it the subject is white. Hence Aristotle says that accidents, as quality and motion, are not called beings in an unqualified sense, but beings of a being.

2420. Nor is it surprising if accidents are called beings even though they are not beings in an unqualified sense, because even privations and negations are called beings in a sense, for example, the not-white and the not-straight. For we say that the not-white is, not because the not-white has being, but because some subject is deprived of whiteness. Accidents and privations have this in common, then, that being is predicated of both by reason of their subject. Yet they differ in this respect that, while a subject has being of some kind by reason of its accidents, it does not have being of any kind by reason of privations, but is deficient in being.

2421. Therefore, since accidents are not beings in an unqualified sense, but only substances are, this science, which considers being as being, is not chiefly concerned with accidents but with substances.

2422. Again, none (1026).

Then he gives a third proof of his thesis that the other kinds of beings cannot exist apart from substance. For accidents can exist only in a subject, and therefore the study of accidents is included in that of substance.

2423. The ancient philosophers (1027).

He gives a fourth proof of his thesis. He says that the ancient philosophers also testify to the fact that the philosopher is concerned with substances, because in seeking the causes of being they looked for the causes only of substance. And some of the moderns also did this, but in a different way; for they did not seek principles, causes and elements in the same way, but differently. For the moderns—the Platonists—claimed that universals are substances to a greater degree than particular things; for they said that genera, which are universals, are principles and causes of substances to a greater degree than particular things. They did this because they investigated things from the viewpoint of dialectics; for they thought that universals, which are separate according to their mode of definition from sensible things, are also separate in reality, and that they are the principles of particular things. But the ancient philosophers, such as Democritus and Empedocles, claimed that the substances and principles of things are particular entities, such as fire and earth, but not this common principle, body.

LESSON 2

Three Classes of Substances

ARISTOTLE’S TEXT Chapters 1 & 2: 1069a 30-1069b 32

1028. Now there are three classes of substances. One is sensible, and of this class one kind is eternal and another perishable. The latter, such as plants and animals, all men recognize. But it is the eternal whose elements we must grasp, whether they are one or many. Another class is the immovable, which certain thinkers claim to have separate existence, some dividing it into two kinds, others maintaining that the separate Forms and the objects of mathematics are of one nature, and still others a holding that only the objects of mathematics belong to this class. The first two classes of substance belong to the philosophy of nature since they involve motion; but the last belongs to a different science if there is no principle common to these three.

Chapter 2

1029. Sensible substance is capable of being changed. And if change proceeds from opposites or from intermediates, yet not from all opposites (for the spoken word is not white) but only from a contrary, then there must be some underlying subject which can be changed from one contrary to another; for contraries themselves are not changed (730). Further, this subject remains, whereas a contrary does not remain. Therefore there is some third thing besides the contraries, and this is matter.

1030. If, then, there are four kinds of change: either in substance or in quality or in quantity or in place, and if change in substance is generation and destruction without qualification, and change in quantity is increase and decrease, and change in attribute is alteration, and change in place is local motion, then the changes occurring in each case must be changes to contrary states. Therefore it must be the matter which is capable of being changed to both states.

1031. And since being is twofold, every change is from potential being to actual being, for example, from potentially white to actually white. The same is true of increase and decrease. Hence not only can a thing come to be accidentally from nonbeing, but all things come to be from being, i.e., from potential being, not from actual being.

1032. And this is the “One” of Anaxagoras; for it is better to maintain this view than to claim that “all things were together.” And this is the “Mixture” of Empedocles and Anaximander, and it recalls the statement of Democritus that all things were together potentially but not at all actually.s Hence all these thinkers were touching upon matter.

1033. Now all things which undergo change have matter, but different things have different matters; and of eternal things, those which are incapable of being generated but can be moved by local motion have matter. Yet they do not have that kind of matter which is subject to generation, but only such as is subject to motion from one place to another (697).

1034. And one might raise the question from what kind of non-being generation could come about; for non-being is spoken of in three senses. If, then, one kind of non-being is potentiality, still it is not from anything at all that a thing comes to be, but different things come from different things. Nor is it enough to say that “all things were together,” since they differ in their matter, for otherwise why would an infinite number of things be generated and not just one thing? For mind is one, so that if matter were also one, only that could come to be actually whose matter was in potentiality.

COMMENTARY

2424. Having explained that philosophy is concerned chiefly with substances, here the Philosopher begins to deal with substances. This is divided into two parts. In the first (1028:C 2424) he makes a division of substance; and in the second (1029:C 2428) he treats the parts of this division (“Sensible substance”).

He accordingly says, first (1028), that there are three classes of substances. One is sensible, and this is divided into two kinds; for some sensible substances are eternal (the celestial bodies) and others perishable. Sensible and perishable substances, such as animals and plants, are recognized by all.

2425. But it is “the other class of sensible substance,” i.e., the eternal, whose principles we aim to discover in this book, whether their principles are one or many. He will investigate this by considering the separate substances, which arc both the sources of motion and the ends of the celestial bodies, as will be made clear below (1086:C 2590-92). He uses elements in the broad sense here in place of principles; for strictly an element is only an intrinsic cause.

2426. The third class of substance is the immovable and imperceptible. This class is not evident to all, but some men claim that it is separate from sensible things. The opinions of these men differ; for some divide separate substances into two kinds—the separate Forms, which they call Ideas, and the objects of mathematics. For just as a twofold method of separating is found in reason, one by which the objects of mathematics are separated from sensible matter, and another by which universals are separated from particular things, in a similar way they maintained that both universals, which they called separate Forms, and also the objects of mathematics, are separate in reality. But others reduced these two classes—the separate Forms and the objects of mathematics—to one nature. Both of these groups were Platonists. But another group, the Pythagoreans, did not posit separate Forms, but only the objects of mathematics.

2427. Among these three classes of substances there is this difference, namely, that sensible substances, whether they are perishable or eternal, belong to the consideration of the philosophy of nature, which establishes the nature of movable being; for sensible substances of this kind are in motion. But separable and immovable substances belong to the study of a different science and not to the, same science if there is no principle common to both kinds of substance; for if there were a common principle, the study of both kinds of substance would belong to the science which considers that common principle. The philosophy of nature, then, considers sensible substances only inasmuch as they are actual and in motion. Hence this science (first philosophy) considers both sensible substances and immovable substances inasmuch as both are beings and substances.

2428. Sensible substance (1029).

Then he establishes the truth about the above-mentioned substances. He does this, first (1029:C 2429), with regard to sensible substances; and second (1055:C 2488), with regard to immovable substances (“And since there are three”).

The first is divided into two parts. First, he investigates the principles of sensible substances; and second (1042:C 2455), he inquires whether the principles of substances and those of the other categories are the same (“In one sense”).

In regard to the first he does two things. First, he investigates the nature of matter; and second (1035:C 2440, the nature of form (“The causes or principles”).

In regard to the first he does two things. First, he states his views about matter. Second (1034:C 2437), he meets a difficulty (“And one might raise the question”).

In regard to the first he does two things. First, he shows that there is matter in sensible substances; and he also shows what kind of being matter is. Second (1033:C 2436), he shows how matter differs in different kinds of sensible substances (“Now all things”).

In regard to the first he does two things. First, he proceeds as described. Second (1031:C 2432), he meets an argument by which some of the ancient philosophers denied generation (“And since being is twofold”).

In regard to the first he does two things. First, he shows that there is matter in sensible substances. Second (1030:C 431), he shows what kind of being matter is (“If, then, there are”).

He accordingly says, first (1029), that sensible substance is changeable, as has been pointed out, and every change is either from opposites or from intermediates, as has been shown above (384:C 723-24). Yet change does not proceed from any opposites whatever; for the white comes from the not-white, but not from just any not-white; for a word is not-white, yet a body does not become white from a word, but from a not-white which is black or some intermediate color. Hence he says that change proceeds from an opposite which is a contrary. And there can be no rejoinder based on change in substance on the ground that there is nothing contrary to substance. For in substance there is privation which is included in a sense among contraries, as has been shown in Book X (853:C 2050-53).

2429. Hence, since every change is from one contrary to another, there must be some underlying subject which can be changed from one contrary to another. The Philosopher proves this in two ways. First, he argues on the ground that one contrary is not changed into another; for blackness itself does not become whiteness, so that, if there is a change from black to white, there must be something besides blackness which becomes white.

2430. He proves the same point in another way, namely, from the fact that throughout every change something is found to remain. For example, in a change from black to white a body remains, whereas the other thing —the contrary black—does not remain. Therefore it is evident that matter is some third entity besides the contraries.

2431. If, then, there are (1030).

He now shows what kind of being matter is. He says that there are four kinds of change: simple generation and destruction, which is change in substance; increase and decrease, which is change in quantity; alteration, which is change in affections (and constitutes the third species of quality); and “local motion,” or change of place, which pertains to the where of a thing. Now it has been shown that all of these changes involve the contrarieties that belong to each of these classes; for example, alteration involves contrariety of quality, increase involves contrariety of quantity, and so on for the others. And since in every change there is besides the contraries some third entity which is called matter, the thing undergoing the change, i.e., the subject of the change, considered just in itself, must be in potentiality to both contraries, otherwise it would not be susceptible of both or admit of change from one to the other. Thus, just as a body which is changed from white to black, qua body, is in potentiality to each of the two contraries, in a similar way in the generation of substance the matter, as the subject of generation and destruction, is of itself in potentiality both to form and to privation, and has actually of itself neither form nor privation.

2432. And since being (1031).

Here the Philosopher establishes the truth about matter itself, and in regard to this he does two things. First, he meets a difficulty. Second (1032:C 2435), he shows how some of the ancient philosophers offered a solution similar to the one mentioned above (“And this is the ‘One’”).

He meets the difficulty of the ancient philosophers who did away with generation because they did not think that anything could come from non-being, since nothing comes from nothing, or that anything could come from being, since a thing would then be before it came to be.

2433. The Philosopher meets this difficulty by showing how a thing comes to be both from being and from non-being. He says that being is twofold—actual and potential. Hence everything which is changed is changed from a state of potential being to one of actual being; for example, a thing is changed from being potentially white to being actually white. The same thing holds true of the motion of increase and decrease, since something is changed from being potentially large or small to being actually large or small. In the category of substance, then, all things come to be both from being and from non-being. A thing comes to be accidentally from non-being inasmuch as it comes to be from a matter subject to privation, in reference to which it is called non-being. And a thing comes to be essentially from being—not actual being but potential being—i.e., from matter, which is potential being, as has been shown above (1030:C 2431).

2434. Now it should be borne in mind that certain later thinkers wanted to oppose the above-mentioned principle of the ancient philosophers of nature (who denied generation and destruction and claimed that generation is merely alteration) when they said that generation comes about through detachment from some mixture or confused mass.

2435. Hence, when the Philosopher in the third part of his division says “And this is the one (1032),” he shows that all who expressed this view wanted to adopt a position similar to the one mentioned above, but did not succeed in doing so. Therefore he says that this, namely, matter, which is in potentiality to all forms, is the “One” of which Anaxagoras spoke; for Anaxagoras said that everything which is generated from something else is present in that thing from which it comes to be. And so, not knowing how to distinguish between potentiality and actuality, he said that in the beginning all things were mixed together in one whole. But it is more fitting to posit a matter in which all things are present potentially than to posit one in which all things are present actually and simultaneously, as seems to be the case from what Anaxagoras said. This is what Empedocles also claimed, namely, that in the beginning all things were mixed or mingled together by friendship and later were separated out by strife. Anaximander similarly held that all contraries originally existed in one confused mass. And Democritus said that everything which comes to be first exists potentially and then actually. Hence it is evident that all these philosophers touched upon matter to some extent but did not fully comprehend it.

2436. Now all things (1033).

He shows that matter is not present in all sensible substances in the same way. He says that all things which undergo change must have matter, but of a different kind. For things which “are changed substantially,” i.e., generated and destroyed, have a matter which is subject to generation and destruction, i.e., one which is in itself in potentiality both to forms and to privations. But the celestial bodies, which are eternal and not subject to generation, yet admit of change of place, have matter—not one which admits of generation and destruction or one which is in potentiality to form and to privation, but one which is in potentiality to the termini of local motion, i.e., the point from which motion begins and the point to which it tends.

2437. And one might raise (1034).

Then he meets a difficulty that pertains to the points established above. He says that, since generation is a change from non-being to being, one can ask from what sort of non-being generation proceeds; for non-being is said of three things. First, it is said of what does not exist in any way; and from this kind of non-being nothing is generated, because in reality nothing comes from nothing. Second, it is said of privation, which is considered in a/,subject; and while something is generated from this kind of non-being, the generation is accidental, i.e., inasmuch as something is generated from a subject to which some privation occurs. Third, it is said of matter itself, which, taken in itself, is not an actual being but a potential one. And from this kind of non-being something is generated essentially; or in his words, if one kind of non-being is potentiality, then from such a principle, i.e., non-being, something is generated essentially.

2438. Yet even though something is generated from that kind of non-being which is being in potentiality, still a thing is not generated from every kind of non-being, but different things come from different matters. For everything capable of being generated has a definite matter from which it comes to be, because there must be a proportion between form and matter. For even though first matter is in potentiality to all forms, it nevertheless receives them in a certain order. For first of all it is in potency to the forms of the elements, and through the intermediary of these, insofar as they are mixed in different proportions, it is in potency to different forms. Hence not everything can come to be directly from everything else unless perhaps by being resolved into first matter.

2439. This view is opposed to that of Anaxagoras, who claimed that anything at all comes to be from anything else. Nor is his assumption that all things were together in the beginning sufficient to support this view. For things differ by reason of matter inasmuch as there are different matters for different things. For if the matter of all things were one, as it is according to the opinion of Anaxagoras, why would an infinite number of things be generated and not just one thing? For Anaxagoras claimed that there is one agent, mind; and therefore, if matter too were one, only one thing would necessarily come to be, namely, that to which matter is in potentiality. For where there is one agent and one matter there must be one effect, as has been stated in Book X.

2440. This argument holds good against Anaxagoras inasmuch as he claimed that mind needs matter in order to produce some effect. And if he claims that the first principle of things is mind, which produces matter itself, the first principle of the diversity of things will proceed from the order apprehended by the above-mentioned mind, which, inasmuch as it aims to produce different things, establishes different matters having an aptitude for a diversity of things.

LESSON 3

Characteristics of Forms

ARISTOTLE’S TEXT Chapters 2 & 3: 1069b 32-1070a 30

1035. The causes or principles of things, then, are three. Two of these are the pair of contraries, of which one is the formal determinant or specifying principle, and the other the privation, and the third, matter.

Chapter 3

1036. It should be noted next that neither matter nor form comes to be, and I mean the last matter and form. For everything which changes something else changes it from something to something. That by which it is changed is the first [i.e., immediate] mover; that which is changed is the matter; and that to which it is changed is the form. Hence there will be an infinite regress if not only the bronze becomes round but also roundness itself or bronze comes to be. Therefore there must be some stopping point.

1037. Again, it should be noted that every substance comes to be from something having the same name; for both things which are by nature as well as other things are substances. For things come to be either by art or by nature or by luck or spontaneously. Art is a principle in another, but nature is a principle in the subject itself; for man begets man. The remaining causes are the privations of these.

1038. There are three kinds of substance. First, there is matter, which is a particular thing in appearance; for whatever things are one by contact and not by natural union are matter and subject. Second, there is the nature [i.e., the form], which is a determinate thing inasmuch as it is a kind of positive state; and third, there is the singular thing which is composed of these, such as Socrates or Callias.

1039. Now in some cases the “this” [i.e., the form] does not exist apart from the composite substance; for example, the form of a house, unless it is the art. Nor is there generation and destruction of these forms, but it is in a different sense that house apart from matter, and health, and everything which comes to be by art, do and do not exist. But if the “this” does exist apart from matter, it is only in the case of those things which are by nature. Hence Plato was not wrong in saying that the Forms are things which exist by nature, i.e., if there are separate Forms different from these other things, such as fire, flesh and head. For all of these are matter, and they are the ultimate matter of substance in the fullest sense.

1040. Hence efficient causes are causes as things which are prior to their effects; but those things which are causes in the sense of the formal determinant are simultaneous with their effects. For it is when a man becomes healthy that health also exists; and the shape of the bronze sphere comes to be at the same time as the bronze sphere. But whether any form continues to exist afterwards is a question that requires investigation. For nothing prevents this from being so in certain cases, for example, if the soul is of this sort, not every soul but the intellectual; for perhaps it is impossible that every soul should continue to exist.

1041. It is evident, then, that it is not necessary on these grounds that the Ideas should exist; for man begets man, and the singular man begets a singular man. The same thing also holds true in the case of the arts; for the art of medicine is the formal determinant of health.

COMMENTARY

2441. Having stated his views about matter, the Philosopher now considers form, and in regard to this he does two things. First (1035:C 2440, he deals with form in itself; and second (1038:C 2446), with form in relation to the composite (“There are three kinds”).

In regard to the first part he does three things. First, he points out that form is a principle. He says that there are three causes, or three principles, of changeable substances. Two of these are contraries: one being “the specifying principle,” i.e., the form, the other privation, which is in a sense a contrary, and the third, matter. For it has been shown already (1029:C 2428-29) that in every change there must be a subject and two contraries, and therefore these are required in the generation of substance.

2442. It should be noted (1036).

Second, he shows that neither matter nor form is generated. He says that neither matter nor “form comes to be,” or is generated.—But this must be understood of the last matter and the last form; for some matter is generated, namely, the subject of alteration, since it is a composite substance.

2443. That neither the last matter nor the last form is generated he proves thus. In every change there must he some subject of the change, which is matter; and something by which it is changed, which is the principle imparting motion; and something to which it is changed, which is the specifying principle or form. Hence if both the form and the matter are generated, for example, if not only this whole—bronze sphere—is generated, but also the sphericity and the bronze, it follows that both form and matter have matter and form; and thus there will be an infinite regress in matters and forms. This is impossible. Hence, in the process of generation there must be some stopping point, so that the last matter and last form are not generated.

2444. Again, it should be (1037).

Third, he points out that things acquire their form from agents like themselves. He says that every substance comes to be “from an agent having the same name,” i.e., an agent similar in form. For all substances which are generated come to be either by nature or by art or by luck or “spontaneously,” namely, by chance; i.e., they are not directly an object of design. Art differs from nature, because art is a principle of action in something other than the thing moved, whereas nature is a principle of action and motion in the thing in which it is present. Now things produced by art obviously come to be from something similar to themselves in form; for it is by means of the form of the house in his mind that the builder causes the house which exists in matter. The same thing is also apparent in the case of natural things, for man begets man. However, this does not seem to be true in some cases, for some things are not generated by agents similar to themselves in species; for example, the heat found in lower bodies is generated by the sun, not by heat. Yet while there is no likeness in species, there must still be some kind of likeness, even though it is an imperfect one, because the matter of lower bodies cannot acquire perfect likeness to a higher agent. And since this is true in the case of things which come to be both by art and by nature, it is evident that each thing is generated by its like.

2445. For “the remaining causes,” luck and chance, are defects and privations as it were of nature and of art; for luck is intellect producing an effect over and above the one at which it aims; and chance is nature producing an effect over and above the one at which it aims. Hence those things which come to be by luck and by chance are not similar to their agents in form, since luck and chance are not causes in the strict sense but only accidentally. Therefore in a sense animals which are generated from decomposed matter seem to come into being by chance inasmuch as they are not generated by agents similar to themselves in species. Nor do they have a definite efficient cause in the realm of lower bodies, but only a higher efficient cause.

2446. There are three kinds (1038).

Then he establishes what is true of form in relation to the composite substance, and in regard to this he does three things. First, he divides substance into matter, form and composite. He says that there are three kinds of substance. First, according to appearances, matter seems to be substance and a determinate thing; and it was for this reason that the first natural philosophers claimed that matter alone is substance. They did this because they saw that in the case of artifacts, which come to be by contact and not by natural union, only the matter or underlying subject seems to be substance; for artificial forms are accidents. Second, the nature of a thing also seems to be substance and a determinate thing—the nature of a thing being that in which the process of natural generation is terminated, i.e., the form, which is as it were a kind of permanent state. The third kind of substance is the composite of matter and form, for example, singular things such as Callias and Socrates.

2447. Now in some cases (1039).

Second, he says that some forms evidently do not exist apart from the composite substance, for example, the form of a house does not exist apart from matter; for the form of a house is an accident, and the matter of a house is a substance, and an accident exists only in a substance.

2448. 1 say that this is true unless the form of the house should be taken “as the art,” i.e., as existing in the mind of the artisan, for in this way it does exist apart from matter. But there is neither generation nor destruction of these artificial forms as existing in the mind of the artisan; for the house which exists in the mind without matter, and health, and all things of this kind, begin to be and cease to be in a different way from those things which come to be by generation and destruction, i.e., by teaching or by discovery.

2449. But if any forms do exist apart from composite substances, this will be true of those natural forms which are substances. Hence Plato was not wrong in saying “that the Forms,” i.e., the separate Forms, are things which exist by nature. But I say that he was not wrong, not in an unqualified sense, but only if there are other forms which differ from sensible ones, such as flesh, head and the like, which are the last matter of a particular composite substance, which is substance in the fullest sense.

2450. Hence efficient causes (1040).

Third, he shows that there are no universal forms apart from composite substances. In regard to this he does two things. First, he makes his purpose clear by differentiating between formal and efficient causes. He says that efficient causes are prior to their effects; and this must be so because efficient causes are the source of the motion which terminates in the thing made. But the formal cause, which is a cause in the sense of the intelligible structure of a thing, begins to be when the thing of which it is the form begins to be. For health begins to be when a man is healed, and the shape of a bronze sphere begins to be when the bronze sphere comes into being. It is evident, then, that forms are not separate from composite substances; for if they were separate, they would have to be eternal, since of such things there is directly neither generation nor destruction, as has been shown (611:C 1420; 696:C 1687); and thus they would be prior to the substances of which they are the forms.

2451. But even though forms are not prior to composite substances, it is still necessary to investigate whether any form remains after the composite substance has been destroyed. For nothing prevents some forms from continuing to exist after the composite ceases to exist; for example, we might say that the soul is of this sort—not every soul but only the intellective. For perhaps it is impossible that every soul should be such that it continues to exist after the body has been destroyed, because the other parts of the soul do not operate without bodily organs, whereas the intellect does not operate by way of a bodily organ. He says “perhaps” because it is not his present intention to demonstrate this point; but this belongs to the science which treats of the soul. And just as the parts of the soul other than the intellect do not continue to exist after the composite substance has been destroyed, in a similar fashion neither do other forms of perishable things.

2452. Now we should observe that it is Aristotle’s view regarding the intellective soul that it did not exist before the body as Plato claimed, and also that it is not destroyed when the body is, as the ancient philosophers held inasmuch as they failed to distinguish between intellect and sense. For he did not exclude the intellective soul from the generality of other forms as regards their not existing prior to composite substances, but only as regards their not continuing to exist after the composite substances have been destroyed.

2453. From this consideration it is also evident that one cannot degrade the intellective soul as some men attempt to do, saying that the possible intellect alone or the agent intellect alone is imperishable. For these men claim not only that the intellect which they say is imperishable (whether it be the possible or the agent intellect) is a separate substance and thus not a form, but also that, if it is a form of the kind which remains after the body has perished, it must exist prior to the body. And in this respect there would be no difference between those who hold that a separate intellect is the form of man and those who hold that separate Forms are the forms of sensible things. This is the view which Aristotle aims to reject here.

2454. It is evident (1041).

Second, he rejects the argument by which they maintained that there are separate Ideas. For the Platonists said that it was necessary to posit Ideas in order that particular things might be formed in likeness to them. But this is not necessary, because in the realm of lower bodies one finds an adequate cause of the formation of everything that comes to be. For a natural agent produces something like itself. For man begets man; but it is not the universal man who begets a singular man, but the singular man begets a singular man. Hence it is not necessary to hold that there is a separate universal man by reason of which the singular man here receives, or shares in, the form of the species. The same thing is evident of those things which come to be by art, because the medical art is the formal determinant and likeness of health in the mind, as has also been shown above (1040:C 2450).

LESSON 4

The Principles of Movable Substances

ARISTOTLE’S TEXT Chapters 4 & 5: 1070a 31-1071b 2

1042. In one sense the causes and principles of different things are different; but in another sense they are not, for, if one speaks universally and proportionally, they are the same for all.

1043. And one might raise the question whether the principles and elements of substances and of relations are the same or different; and the same question may be asked of each of the other categories.

1044. But it would be absurd if the principles and elements of all things were the same; for then substance and relations would be derived from the same principles. How then will this be [common]? For there is nothing common existing apart from substance and the other categories; and an element is prior to the things of which it is the element. But substance is not an element of relations, nor is any of these an element of substance.

1045. Further, how is it possible for the elements of all things to be the same? For none of the elements can be the same as a composite of elements; for example, neither b nor a is the same as ba; nor can any of the intelligibles, such as being and unity, be an element; for these belong to each composite thing. Hence none of them can be either a substance or a relation. But it must be one or the other. Therefore the elements of all things are not the same.

1046. Or, as we say, there is a sense in which they are the same and a sense in which they are not; for example, perhaps the elements of sensible bodies are the hot as form, the cold as privation, and that which primarily and of its own nature is potentially both of these as matter. And not only these are substances, but so also are the things of which they are the principles. And so also is any unity which comes to be from the hot and the cold, as flesh and bone; for the thing produced from these must differ from them. The elements and principles of these things, then, are the same, although the elements of different things are different. However, it cannot be said that the elements of all things are the same in this sense, but only proportionally, just as if one were to say that there are three principles, form, privation and matter. But each of these is different in each class of things; for example, in the case of colors there is white, black and surface; and there is darkness, light and air, from which day and night are derived.

1047. And since not only the things which are intrinsic to a being are its causes, but also certain external things, as the moving cause, it is evident that principle and element differ, although both are causes. And principle is divided into these two kinds; and whatever causes motion or makes it cease is a kind of principle. Hence analogically there are three elements and four causes or principles; but they differ in different things, and the first cause of motion is different in different things: for example, health, sickness and body, and the moving cause is the art of medicine. form, a certain kind of disorder, and bricks, and the moving cause is the art of building. Principle is also divided into these.

1048. And since in the case of physical things the moving cause of man is man, while in the case of objects of thought the moving cause is the form or its contrary, in one sense there will be three causes and in another sense four. For in a sense the art of medicine is health, and the art of building is the form of a house, and man begets man.

1049. And besides these there is that which as the first of all things imparts motion to all things.

Chapter 5

1050. Since some things are separable and some are not, it is the former which are substances. And for this reason these (substances) are the causes of all things, because without substances there can be no affections and motions.

1051. Next, all of these causes are perhaps soul and body, or intellect, appetite and body.

11052. Again, there is another sense in which the principles of things are proportionally the same, i.e., as actuality and potentiality; but these are different for different things and apply to them in different ways. For in some cases the same thing is at one time actual and at another time potential, as wine, flesh or man. Now these principles fall into the classes of causes mentioned; for a form is an actuality if it can exist apart, and so also is the thing composed of matter and form, and so also is a privation, such as darkness and suffering; but matter is in potentiality, for it is what is capable of becoming both. But it is in another way that the distinction of actuality and potentiality applies to those things of which the matter is not the same, and the form is not the same but different. For example, the cause of man is his elements—fire and earth as matter, and his proper form—and if there is anything external, such as his father; and besides these there is the sun and the oblique circle, which are neither matter nor species nor privation nor form, but are moving causes.

1053. Further, we must note that some of these causes can be expressed universally and some. not. The first principles of all things are those first “this, one actually, one potentially. Therefore these principles are not universals, for the principle of a singular thing is a singular thing. For while man taken universally is a principle of man, there is no universal man, but Peleus is the cause of Achilles, and your father is the cause of you; and b and a taken either absolutely or particularly are the causes of the syllable ba. Further, there are different causes and elements of different things, as has been stated (1046), and the causes of things which do not belong to the same genus, as colors, sounds, substances and quantity, are different, except in a proportional way. And the causes of things which belong to the same species are different, not specifically, but in the sense that the causes of singular things are different; that is, your matter and form and moving cause are different from mine, although they are the same in their universal intelligibility.

1054. And to ask whether the principles and elements of substances and of relations and of qualities are the same or different, is clearly to raise questions about terms that are used in many senses. But the principles of different things are not the same but different, except that in a sense they are the same for all. They are the same for all proportionally because each thing has matter, form, privation and a moving cause. And the causes of substances may be regarded as the causes of all things because when they are destroyed all things are destroyed, And again that which is first in complete reality is the cause of all things. However, in a sense the primary [i.e., proximate] causes of things are different, i.e., all the contraries which are not predicated either as genera or as terms having many meanings. And again the matter of different things is different. We have stated what the principles of sensible things are, then, and how many there are, and how they are the same and how different.

COMMENTARY

2455. Having stated his position regarding the principles of sensible substances, the Philosopher’s aim here is to investigate whether the principles of substances and those of the other classes of things are the same or different. For if they are the same, it is evident that, when the principles of substances are given, the principles of all the other classes of things are also given. In regard to this be does three things. First (1042:C 2455), he states what is true. Second (1043:C 2456), he introduces a question relating to the answer proposed (“And one might”). Third (1054:C 2484), he gives a summary of what is true (“And to ask”).

He says, first, that in one sense the principles and causes of different things are different, and in another sense they are the same for all things, i.e., universally and proportionally.

2456. And one might (1043).

Then he examines the true answer given above, by raising a question; and in regard to this he does three things. First (1043:C 2456), he raises the question. Second (1044:C 2458), he argues on one side of the question (“But it would be”). Third (1046:C 2464), he settles the issue (“Or, as we say”).

He accordingly says, first (1043), that one might raise the question whether the principles of substances and those of relations, and also those of the other categories, are the same or different.

2457. He makes special reference to relations because they seem to be farther removed from substance than the rest of the categories are inasmuch as they have a more imperfect mode of being. And for this reason they inhere in substance by means of the other categories; for example, equal and unequal, double and half, inhere in substance by way of quantity; and mover and thing moved, father and son, master and slave, inhere in substance by way of action and passion. The reason is that, while substance is something which exists of itself, and quantity and quality are things which exist in something else, relations are things which not only exist in something else but also have being in reference to something else.

2458. But it would be (1044).

Then he argues on one side of the question mentioned above. He gives two arguments to show that the principles of substance and those of the other classes of things are not the same. The first argument is as follows. If the principles of substance and those of the other classes of things are the same, the same principles must either exist apart from substance and from the other categories, or they must belong to the category of substance or to some other category.

2459. But it cannot be said that they exist apart from substance and from the other categories, because then they would have to be prior both to substance and to the other categories; for a principle is prior to the things which come from it. Therefore, since what is prior is found to be more common, as animal is prior to man, it follows that, if some principle is prior both to substance and to the other categories, there must be some principle which is common both to substance and to the other categories. This applies especially to the opinion of the Platonists, who claimed that universals are principles—particularly being and unity as the most common principles of all things.

2460. Neither can it be said that the most common principles of all categories belong either to the category of substance or to that of relation or to any other category. For since principles are of the same kind as the things which come from them, it seems impossible that substance should be a principle of relations, or vice versa. Therefore the principles of substance and those of the other categories are not the same.

2461. Further, how is it (1045).

He gives a second argument, which runs thus: no element is the same as a composite of elements, for nothing is the cause or element of itself; for example, an element of this syllable ba is the letter b or the letter a.

2462. And since there would seem to be a rejoinder to this based on the principles laid down by Plato, namely, being and unity, since each thing composed of principles is one and a being, he therefore next rejects this argument. He says that it is also impossible that any of the intelligible elements—unity and being—should be the same as the things which are derived from them. He calls them intelligible, both because universals are grasped by the intellect, and because Plato claimed that they are separate from sensible things.

2463. He proves that elements of this kind differ from the things of which they are the elements, because “elements of this kind,” i.e., unity and being, are found in each of the things composed of them, whereas no one of the things composed of them is found in other things. Hence it is evident that these elements also differ from the things composed of them. If it is true, then, that elements are not the same as the things composed of them; and if the elements of substances and those of the other classes of things are the same, it follows that none of them belong either to the category of substance or to any other category. But this is impossible, because everything which exists must belong to some category. Hence it is impossible that all the categories should have the same principles.

2464. Or, as we say (1046).

Then he solves the question which was raised, and in regard to this he does two things. First (1046:C 2464), shows that the principles of all categories are proportionally the same; and second (1053:C 2482), that they are universally the same (“Further, we must note”). For he laid down these two qualifications above (1042:C 2455) when he said that there are the same first principles for all things universally and proportionally.

The first part is divided into two members inasmuch as he gives two ways in which the principles of all things are proportionally the same. He begins to treat the second (1052:C 2477) where he says, “Again, there is.”

In regard to the first he does two things. First, he shows how the principles of all things are proportionally the same. Second (1049:C 2474), he shows how they are the same without qualification (“And besides”).

In regard to the first he does two things. First, he shows that the principles of all things are proportionally the same as regards their intrinsic causes; and second (1047:C 2468), as regards both their intrinsic and their extrinsic causes (“And since not only”).

He accordingly says, first (1046), that in one respect it is true to say that the principles of all things are the same, and in another respect it is not.

2465. He explains this by saying that it would be the same as if we were to hold that the principle of sensible bodies in the line of specifying principle or form is the hot and in the line of privation is the cold, and that the matter of sensible bodies is what is of itself in potentiality to these two; for matter taken in itself is a principle that is susceptible both of form and of privation. He says “perhaps” because, while heat is not a substantial form of sensible bodies and cold is not a privation but both are qualities, still he uses them as form and privation in the category of substance in order to make the case more evident. Hence he adds that principles of this kind are substances, not as species in a genus, but as principles.

2466. Again, we say that things which are composed of these, i.e., the things of which these are the principles, namely, fire and water, are substances, granted that we understand fire to be composed of hot as a form and of its own matter, and water of cold as a privation and of matter; or again, granted that some one thing comes to be from the mixture of hot and cold, the above-mentioned contraries, hot and cold, and matter are the principles of these things; because that which comes to be from hot and cold must be something different from hot and cold, i.e., from the first bodies of which we imagine these to be the forms.

2467. Therefore the principles and elements of these things, i.e., of the simple bodies and the things composed of them, are the same. But other things have different proximate principles. However, the principles and elements of all these things are the same only proportionally. We might, for example, say that, just as the three things mentioned above—hot, cold, and their subject—have the character of form, privation and matter respectively in the generation of simple bodies, so too in every other genus there are three things which are proportioned to each other as form, privation and matter. But these three differ for different classes of things. For example, in the genus of color, white has the character of form, black the character of privation, and surface the character of matter or subject; and in the genus of distinctions of time, light has the character of form, darkness the character of privation, and air the character of matter or subject; and from these three principles day and night come to be.

2468. And since not only (1047).

Then he shows that the same thing is true of intrinsic and extrinsic causes, and in regard to this he does two things. First (1047:C 2468), he shows that, when we enumerate the intrinsic and extrinsic causes together, there are four causes proportionally of all things. Second (1048:C 2473), he shows how they are reduced to three (“And since in the case”).

He accordingly says, first (1047), that, since not only what is intrinsic is a cause, but also what is extrinsic, i.e., a mover, it is evident that principle and element differ. For principle in the strict sense means an extrinsic cause, as a mover, since it is from this that motion proceeds; whereas element in the strict sense means an intrinsic cause, of which a thing is composed.

2469. Yet both are called causes, i.e., both extrinsic principles and intrinsic ones. And in a sense principle is divided into these, i.e., into intrinsic causes and extrinsic causes. For there are certain intrinsic principles, as has been shown in Book V (403:C 755-56); for example, the foundation of a house is a principle of it in the sense of matter, and a soul is a principle of a man in the sense of form. But that which causes motion or makes it cease, i.e., which brings it to rest, is a principle but not an element; because an element is an intrinsic principle from which a thing comes to be, as has been stated in Book V (411:C 795-98).

2470. It is clear, then, that analogously, or proportionally, the elements of all things are three in numbermatter, form and privation. For privations are called elements not essentially but accidentally, i.e., because. the matter to which a privation is accidentally related is an element. For matter existing under one form contains within itself the privation of another form. But the causes and principles of things are four in number inasmuch as we may add the moving cause to the three elements. Aristotle does not mention the final cause, however, because a goal is a principle only inasmuch as it is present in the intention of the moving cause.

2471. Therefore the causes and principles of all things analogously are four in number—matter, form, privation, and the source of motion. Yet they are not the same in all cases, but differ in different things. For just as it has been said above (1046:C 2467) that matter form and privation differ in different things, so too the first of the causes, which has the character of a mover, differs in different cases.

2472. He clarifies this by giving examples. In the case of things healed, health has the character of form, sickness the character of privation, the body the character of matter, and the art of medicine the character of a mover; and in the case of things built, the shape of a house is the form, “a certain kind of disorder,” i.e., the opposite of the order which the house requires, is the privation, bricks are the matter, and the art of building is the mover. Principles, then, are divided into these four kinds.

2473. And since in the case (1048).

He now reduces these four kinds of causes to three on the ground that in the case of artifacts and in that of natural things the mover and the form are specifically the same. He accordingly says that this is clear because (a) in the case of natural things man is a mover inasmuch as he has a form; and (b) in the case of things which are made by mind or intellect the cause of motion is the form conceived by the mind, or even the contrary of the form through whose removal the form is induced. Therefore it is evident that in one sense there are three causes, inasmuch as the mover and the form are specifically the same, and in another sense there are four, inasmuch as these two causes differ numerically. For in a sense the art of medicine is health, and the art of building is the form of the house, i.e., inasmuch as the art itself is a kind of likeness and intelligible representation of the form which is in the matter. And similarly in the case of things which come to be through generation the generator is similar in form to the thing generated; for man begets man.

2474. And besides these (1049).

Then he shows that, although first principles are not identically the same beings in all things but only proportionally the same, none the less the first principles of all things are the same in an unqualified sense. He proves this by three arguments. First, he shows that the moving cause is the first of the causes which have been given because it is the one which makes the form or the privation exist in matter. Now in the class of movers it is possible to reach a single cause, as has been proved in Book VIII of the Physics. Therefore this first mover, which is one and the same for all, is the first principle of all things.

2475. Since some things (1050).

Second, he proves the same point in a different way. For some beings (substances) are capable of separate existence, and others (accidents) are not, because modifications and motions and accidents of this kind cannot exist apart from substances. It is evident, then, that the first principles in the category of substance are also the causes of all the other categories. This applies not only to the first moving cause but also to intrinsic causes; for the matter and form of a substance are the causes of its accidents.

2476. Next, all of these (1051).

Third, he shows that we must also reach certain first principles in the category of substance; for first principles in the category of substance are living animated substances according to the thought of Aristotle, who claimed that the celestial bodies are animated. Hence in the category of substance the first principles which have the character of form and matter will be soul and body, or also body and intellect or appetite; for assuming that a celestial body is animated, its soul has none of the different parts of the soul except intellect and appetite; for the other parts of the soul are directed to the preservation of bodies which are capable of being generated and destroyed. Intellect and appetite also have the character of a mover.

2477. Again, there is another sense (1052).

Then he gives a second way in which the principles of all things are proportionally the same. He says that the principles of all things are proportionally the same in another sense inasmuch as we say that actuality and potentiality are the principles of all things.

2478. But in this case two differences are to be observed. The first is that a different potentiality and a different actuality are principles in different things. The second is that potentiality and actuality are found in different things in different ways.

2479. Then the second difference is first clarified. He says that in some cases the same thing is at one time actual and at another time potential, as is evident of all things which admit of generation and destruction and are movable and contingent; for example, wine, flesh and man are at one time actual and at another potential. But some things are always actual, as the eternal substances.

2480. And since he had said that the way in which the principles of all things are proportionally the same differs from the one previously given, he next shows how these principles (actuality and potentiality) are reduced to the.same class. He says that these principles (actuality and potentiality) fall under the classes of causes mentioned above, which are form, privation, matter and mover; because form is an actuality, whether it is separable from the composite, as the Platonists claimed, or whether there is something composed of both, i.e., of form and matter. And similarly privation is in a sense an actuality, for example, darkness or “suffering,” i.e., sickness. But matter is in potentiality, because of itself it is capabie of receiving both form and privation. It is evident, then, that actuality and potentiality amount to the same thing as matter, form and privation; and that in a sense actuality and potentiality differ in different things, because they are not present in all things in the same way but in different ways.

2481. And since he had said that actuality and potentiality not only apply to different things in different ways but also differ for different things, he next explains this by saying that it is in a different way that the distinction of actuality and potentiality applies to different things of which the matter, which is in potentiality, is not the same, and the form, which is actuality, is not the same but different. For example, the material cause of a man is his elements, namely, fire and the like, and his formal cause is “his proper form,” i.e., his soul, and his moving cause is something extrinsic—his father being a proximate efficient cause, and the sun and “the oblique circle,” or zodiac, through which the sun moves together with the other planets which cause generation in lower bodies by their motion, being remote efficient causes. But extrinsic causes of this sort are neither matter nor form nor privation nor anything conforming to or specifically the same as these so that it could be said that they are reduced to these causes as actuality and potentiality. They are reduced to a different class of cause because they are movers, and these are also reduced to actuality. But things which differ from man have a different proper matter anA a different proper form and some proper agent.

2482. Further, we must note (1053).

Since it has been shown already (1046:C 2467) how the principles of all things are proportionally the same, Aristotle now wishes to show how the principles of all things are universally the same; for both of these points were mentioned above (1046:C 2464). He accordingly says that we must see how some principles are predicated universally and how some are not. The first principles which are understood to be most universal are actuality and potentiality, for these divide being as being. They are called universal principles because they are signified and understood in a universal way, but not so that universals themselves are subsisting principles, as the Platonists claimed, because the principle of each singular thing can only be a singular thing; for the principle of an effect taken universally is a universal, as man of man. But since there is no subsisting universal man, there will be no universal principle of universal man, but only this particular man will be the principle of this particular man; for example, Peleus is the father of Achilles, and your father is the father of you. And this particular letter b is a principle of this particular syllable ba, but b taken universally is a principle of ba taken universally. Therefore principles signified universally are the same for all things.

2483. Then he introduces a third way in which the principles of substances are universally the principles of all things, i.e., inasmuch as accidents are caused by substances. Now just as actuality and potentiality are the universal principles of all things because they flow from being as being, so also, to the extent that the community of things caused is lessened, the community of the principles must also be lessened. For things which do not belong to the same genus, as colors, sounds, substance and quantity, have different causes and elements, as has been pointed out (1046:C 2467), even though these are proportionally the same for all things. And things which belong to the same genus but are numerically different have different principles, not formally, but numerically. For example, your matter and form and moving cause are one thing and mine are another, but in their universal intelligibility they are the same; for soul and body are the form and matter of man, but this soul and this body are the form and the matter of this man.

2484. And to ask (1054).

Here he summarizes what has been said in this chapter. He says that to ask whether the principles and elements of substances and of relations and of qualities and of the other categories are the same or different is to raise questions about terms which are used in various senses, because the principles of different things are not the same except in a certain respect but different.

2485. For the principles of all things are the same in a certain respect, either proportionally, as when we say that in each class of things we find certain principles which have the character of matter, form, privation and moving cause; or in the sense that the causes of substances are the causes of all things, because when they are destroyed other things are destroyed; or because the principles are “complete reality,” i.e., actuality, and potentiality. The principles of all things, then, are the same in these three ways.

2486. But in another respect the principles are different, because contraries, which are principles of things, and matter itself are not predicated in the same way; for they are not genera, nor are they even predicated of things in many ways as though they were equivocal. Hence we cannot say that they are the same without qualification but only analogously.

2487. Last, he concludes by saying that he has shown the number of principles which sensible substances have and how they are the same or different.

LESSON 5

An Eternal Immovable Substance Must Exist

ARISTOTLE’S TEXT Chapter 6: 1071b 3-1071b 22

1055. Since there are three classes of substance (1028), two of which are physical and one immovable, concerning the latter it is necessary to affirm that an eternal immovable substance must exist. For substances are the primary kind of beings, and if all of them are perishable, all things are perishable. But it is impossible either that motion should have come to be or that it should perish, for it always existed; and the same is true of time, for there cannot be a before and an after if there is no time. Motion is continuous, then, in the sense that time is; for time is either the same as motion or a property of it. Now the only continuous motion is that which pertains to place, and of this only that which is circular.

1056. But even if there is something which is capable of imparting or producing motion, but is not actually doing so, motion will still not exist; for that which has a potentiality may possibly not exercise it. Hence nothing is to be gained if we invent certain eternal substances, as do those who posit the separate Forms, unless there is some principle among them which is capable of causing change (83). This is not sufficient, then, nor is another substance besides the separate Forms sufficient; for if it does not act, there will be no eternal motion.

1057. And even if it does act this will still not be sufficient, if its essence is a potentiality; for there will be no eternal motion, since what is potential may possibly not be. Hence there must be a principle of the kind whose substance is an actuality.

1058. Further, such substances must also be immaterial; for they must be eternal if anything else is. Hence they are actualities.

COMMENTARY

2488. After having shown what the principles of sensible substances are, here the Philosopher begins to establish the truth about the immovable substances, which are separate from matter. This topic is divided into two parts. First (1055:C 2488), he treats substances of this sort by giving his own opinion. Second, he treats them by giving the opinions of other thinkers. He does this in the following book (“Concerning the substance of sensible things”).

The first part is divided into two members. First, he proves that there is a substance which is eternal, immovable and separate from matter. Second (1067:C 2519) he investigates the attributes of this substance (“Now the first mover”).

In regard to the first he does three things. First, he proves that an eternal substance must exist. Second (1059:C 2500), he deals with a question arising from the foregoing discussion (“There is a difficulty, however”); and third (1064:C 2508), from the answer given to the question which was raised he proceeds to clarify a truth previously ,established (“Hence, Chaos or Night”).

In regard to the first he does two things. First, he shows that it is necessary to posit an eternal substance. Second (1056:C 2492), he shows what kind of substance it must be (“But even if there is”).

He accordingly says, first (1055), that it has been pointed out above (1028:C 2424) that there are three classes of substances. Two of these are natural substances, because they undergo motion—one being eternal, as the heavens, and the other perishable, as plants and animals. And besides these there is a third class, which is immovable and not natural; and of this kind of substance it is now necessary to speak. With a view to investigating this kind of substance it is first necessary to prove that an eternal immovable substance must exist. He proceeds as follows.

2489. Substances are the primary kind of beings, as has been shown above (1024:C 2417-23), and when primary things are destroyed none of the others remain. Therefore, if no substance is eternal but all are perishable, it follows that nothing is eternal but that “all things are perishable,” i.e., they do not always exist. But this is impossible. Hence there must be an eternal substance.

2490. That it is impossible for nothing to be eternal he proves from the fact that motion cannot have come to be or “perish,” i.e., it cannot have come to be anew or at some time totally cease to be. For it has been shown in Book VIII of the Physics that motion is eternal without qualification. It also seems impossible that time should not be eternal; for if time began to be at some time or will cease to be at some time it would follow that prior to time there was the non-being of time, and also that there will be time after the non-being of time. But this seems to be impossible, because there could be no before or after if time did not exist, since time is nothing else than the measure of before and after in motion. Thus it would follow that time existed before it began to be, and that it will exist iifter it ceases to be. Hence it seems that time must be eternal.

2491. And if time is continuous and eternal, motion must be continuous and eternal, because motion and time are either the same thing, as some claimed, or time is a property of motion, as is really the case. For time is the measure of motion, as is evident in Book IV of the Physics. However, it must not be thought that every motion can be eternal and continuous, since this can be true only of local motion; and among local motions this is true only of circular motion, as is proved in Book VIII of the Physics.

2492. But even if (1056).

Then he shows what kind of substance this eternal substance must be, and in regard to this he does three things. First, he shows that in order to account for the eternity of motion it is necessary to posit an eternal sub~ stance which is always moving or acting. He says that, since it is necessary, on the assumption that motion is eternal, that there be an eternal substance which is capable of imparting or producing motion, it is also necessary that this be a mover or agent which is always acting, because if it were “capable of imparting or producing motion,” i.e., if it had the power to produce or cause motion, and was not actually doing so, it would follow that there would be no actual motion. For that which has the power of causing motion may possibly not be causing it, since that which has the power of acting may possibly not act; and thus motion would not be eternal. Assuming, then, that motion is eternal, it is necessary to posit an eternal substance which is actually moving or acting.

2493. Next, he concludes from this that nothing is to be gained by accepting the opinion of Plato, who posited eternal substances, since this is not sufficient to account for the eternity of motion. For the assumption that there are certain separate and eternal substances is not sufficient to account for this unless there is some principle among them which can ~ause change; but this does not seem to fit the separate Forms. For Plato claimed that the separate Forms are nothing else than universals existing apart from matter. But universals as such do not cause motion; for every active or motive principle is a singular thing, as has been pointed out above (1053:C 2482). Neither the separate Forms, then, nor any other separate substances besides the Forms, such as the separate mathematical entities posited by some, are sufficient to account for the eternity of motion, because even the objects of mathematics as such are not principles of motion. And if there is no eternal active substance, there will be no eternal motion, because the principle of motion is an eternal substance which is a mover or agent.

2494. And even if (1057).

Second, be shows that, in order for motion to be eternal it is necessary not only that an eternal substance exist, which is a mover or agent, but also that its essence be an actuality. Hence he says that the eternity of motion is not adequately accounted for even if it is supposed that an eternal substance does act yet is potential in essence. For example, it would not be sufficient to hold that the first principles are fire or water, as the ancient natural philosophers did, because then motion could not be eternal. For if a mover is such that its essence contains potentiality, it can possibly not be, because whatever is in potentiality may possibly not be. Hence it would be possible for motion not to be, and so it would not be necessary and eternal. Therefore it follows that there must be a first principle of motion of the sort whose essence is not in potentiality but is only an actuality.

2495. Further, such substances (1058).

Third, he further concludes that this kind of substance must be immaterial. He says that it also follows from the foregoing (1055-57:C 2488-94) that substances of this kind, which are the principles of eternal motion, must be free from matter; for matter is in potentiality. Therefore they must be eternal if something else is eternal, as motion and time. Thus it follows that they are actualities.

2496. He concludes in this way last because of the question which be will next raise. From this reasoning, then, it is evident that here Aristotle firmly thought and believed that motion must be eternal and also time; otherwise he would not have based his plan of investigating immaterial substances on this conviction.

2497. Yet it should be noted that the arguments which he introduces in Book VIII of the Physics, which he assumes as the basis of his procedure here, are not demonstrations in the strict sense but only dialectical arguments; unless perhaps they are arguments against the positions of the ancient natural philosophers regarding the beginning of motion, inasmuch as he aims to destroy these positions.

2498. And aside from the other arguments which he does not touch upon here, it is evident that the argument which he does give here to prove that time is eternal is not demonstrative. For if we suppose that at some moment time began to be, it is not necessary to assume a prior moment except in imaginary time; just as when we say that there is no body outside of the heavens what we mean by “outside” is merely an imaginary something. Hence, just as it is not necessary to posit some place outside of the heavens, even though “outside” seems to signify place, so too neither is it necessary that there be a time before time began to be or a time after time will cease to be, even though before and after signify time.

2499. But even if the arguments which prove that motion and time are eternal are not demonstrative and necessarily conclusive, still the things which are proved about the eternity and immateriality of the first substance necessarily follow; for, even if the world were not eternal, it would still have to be brought into being by something that has prior existence. And if this cause were not eternal, it too would have to be produced by something else. But since there cannot be an infinite series, as has been proved in Book II (153:C 301-4), it is necessary to posit an eternal substance whose essence contains no potentiality and is therefore immaterial.

LESSON 6

Eternal Motion Requires An Eternal Mover

ARISTOTLE’S TEXT Chapters 6 & 7: 1071b 22-1072a 26

1059. There is a difficulty, however; for it seems that, while everything which is acting is able to act, not everything which is able to act is acting; so potentiality is prior.

1060. But if this is so, no beings will exist; for everything may be capable of being, but still not be. And if we take what the theologians say, who generate everything from Night, or what the— philosophers of nature say, who affirm that “all things were together,” they express the same impossible view. For how will things be moved, if there is no actual cause? Matter will not move itself, but technical knowledge will move it; nor will menstrual blood or earth move themselves, but semen or seed will move them.

1061. This is the reason why some men, such as Leucippus and Plato, posit something which is always actual; for they say that motion always exists. But they do not say why it exists, or what it is, or how this is so, or what its cause is. For nothing is moved by chance, but there must always be something existing which moves it. Now things are moved in one way by nature, and in another by force or by mind or by some other agent. What kind of motion, then, is prior? For this makes the greatest difference. Plato cannot explain what it is that he sometimes thinks is the source of motion, i.e., what moves itself; for according to him the soul is later than motion and simultaneous with the heavens.

1062. Now to think that potentiality is prior to actuality is in one sense right and in another not; and we have explained how this is so (1059).

1063. That actuality is prior is affirmed by Anaxagoras (for mind is an actuality), and by Empedolces in his theory of love and strife (50), and by those who say that motion always existed, as Plato and Leucippus.

1064. Hence Chaos or Night did not exist for an infinite time, but the same things have always existed, either in a cycle or in some other way, granted that actuality is prior to potentiality.

1065. Therefore, if something is always moved in the same cycle, there must be something which always continues to act in the same way. But if there is to be generation and destruction, there must be something else “ which acts in different ways. Hence this must act in one way of itself, and in another way in virtue of something else, i.e., either in virtue of some third agent or of the first. Now it must be in virtue of the first; for this is the cause both of the second and of the third. The first is preferable, then; for it was the cause of that whose being is always to be the same, and something else was the cause of that whose being is to be different; and obviously both of these account for eternal diversity. Therefore, if motion always exhibits these characteristics, why is it necessary to look for other principles?

Chapter 7

And since this is a possible account of the matter, and if this is not so all things will come from Night (1060) or “all things were together” (1060) or something comes from non-being (1034), these difficulties are solved. And there is something which is always being moved with an unceasing motion, and this is circular motion. This is evident not only in theory but in fact; and for this reason the first heaven will be eternal.

1066. Therefore there is also something which causes it to move. And since that which is moved and causes motion is intermediate, there must be something which causes motion and is unmoved, which is eternal and both a substance and an actuality.

COMMENTARY

2500. He raises a question about a point already dealt with. The question is whether actuality is prior absolutely to potentiality so that the first principle of things can be held to be one whose substance is actuality. In regard to this he does three things. First (1059:C 2500), he gives an argument to show what is false, namely, that potentiality is prior absolutely to actuality. Second (1060:C 2501), he argues on the other side of the question (“But if this is so”). Third (1062:C 25o6), he answers the question (“Now to think”).

He accordingly says, first (1059), that it has been pointed out that an eternal substance is an actuality, although there is a difficulty regarding this. For potentiality seems to be prior to actuality, since one thing is prior to another when the sequence of their being cannot be reversed (465:C 950)Now potentiality seems to be related to actuality in this way, because everything which is acting seems to be able to act, but not everything which is able to act is acting; and so it seems that potentiality is prior to actuality.

2501. But if this is so (1060).

Then he argues on the opposite side of the question, and in regard to this he does two things. First, he gives an argument reducing the counter-position to absurdity. He says that, if potentiality is prior absolutely to actuality, it follows that at some time nothing may exist; for the contingent is what can come to be but has not yet done so. Hence, if the first beings are potential, it follows that they do not exist actually; and so no other being will exist.

2502. This can be taken in two ways. First, according to the opinion of certain of the ancients, who were called the theological poets, such as Orpheus and certain others, who claimed that the world “is generated from Night,” i.e., from a simple pre-existent privation. Second, according to the later physicists, i.e., philosophers of nature and their followers, who, when they saw that nothing comes from nothing in the natural world, claimed that all things were together in a kind of mixture, which they called Chaos. (Anaxagoras, for example, held this view.) Thus they held that all things exist potentially and not actually.

2503. But whether this position is stated in the former or in the latter way the same impossible conclusion follows, provided that potentiality is prior absolutely to actuality. For those things which are in potentiality only, or which come entirely under privation, or belong to some confused mass, cannot be moved so as to be brought to actuality unless there is some moving cause which is existing actually. For in things made by art the matter does not move itself, but an agent moves it, i.e., “technical knowledge,” or art. Neither does the menstrual blood, which is the matter from which an animal is generated, move itself, but “semen,” i.e., the sperm of the animal, moves it. Nor does earth, which is the material from which plants are generated, move itself, but “the seed,” i.e., the seeds of plants, move it.

2504. This is the reason (1061).

Second, he shows how some of the philosophers of nature agreed with this argument. He says that this is the reason why some philosophers—Leucippus, the companion of Democritus, and Plato—claimed that something actual always exists. For they said that motion had always existed even before the world; Leucippus attributed motion to the atoms, which are mobile of themselves, from which he supposed the world to be composed; and Plato attributed it to the elements, which he said were moved by disorderly motions before the formation of the world, and afterwards were brought into order by God.

2505. Now they seem to be right in claiming that motion has always existed. But they were wrong in failing to point out which kind of motion has always existed; nor did they give the cause of motion, either by stating this in an absolute sense or by giving the reason for their own position. Yet “nothing is moved by chance,” i.e., without some fixed cause, but there must always be something existing which is the cause of motion. For example, we now see that some things are moved in this way by nature or by force or by mind or by some other agent. Hence they should also have stated what the first cause of motion is, whether nature or force or mind; for it makes a great deal of difference which of these is held to be the cause of motion.—Plato cannot be excused on the ground that he held the principle of motion to be something that moves itself, which he asserted to be a soul, since the soul did not exist of itself before the formation of the world, but only existed after the disorderly state of motion. For according to him the soul was created at the same time as the heavens, which he claimed to be animated; and thus it could not be the principle of that disorderly motion.

2506. Now to think (1062).

Then he answers the question which was raised, and concerning this he does two things. First, he returns to the points established in Book IX regarding the relationship of potentiality to actuality. He says that the opinion that potentiality is prior to actuality is in one sense right and in another not. The sense in which it is right has been explained in Book IX (778-80:C 1844-49); for it was stated there that actuality is prior absolutely to potentiality. But in one and the same subject which is being moved from potentiality to actuality, potentiality is prior to actuality in time, although actuality is prior both in nature and in perfection.

2507. That actuality is prior (1063).

Second, he strengthens his answer by giving the opinions of some of the philosophers. He says that the absolute priority of actuality is asserted by Anaxagoras, because he claimed that the first principle of motion is an intellect; for intellect is a kind of actuality. The same thing is also asserted by Empedocles, who claimed that love and strife are the causes of motion; and also by Leucippus and Plato, who claimed that motion has always existed.

2508. Hence Chaos or Night (1064).

Then he uses the answer to the question given above to clarify a point previously established, and in regard to this he does three things. First (1064:C 25o8), in the light of the things established above he concludes that generation must be eternal. Second (1065:C 2510), on the ground that generation is eternal he concludes that the motion of the heavens must be eternal (“Therefore, if something”). Third (1066:C 2517), on the ground that the motion of the heavens is eternal he concludes that the first unmoved mover must be eternal (“Therefore there is”).

He accordingly says, first (1064), that, if actuality is prior absolutely to potentiality, it follows that it is false to hold, with the ancient philosophers of nature, who thought potentiality to be prior absolutely to actuality, that all things pre-existed potentially for an infinite time in a kind of confused mass, which they called Chaos. And false also is the opinion of the theological poets, who claimed for the same reason that the simple privation of things had existed for an infinite time before things began to be actually. Some called this privation of things “Night,” and perhaps the reason for their doing so is that among qualities and simple forms light is found to be more common and prior (since they thought that nothing exists except sensible things), and night is the privation of light. Both opinions are false, then, if actuality is prior to potentiality.

2509. But since we see that things which are generated and destroyed pass from potentiality to actuality, it will be necessary to say that the same things which begin to be actually after being potentially have always existed in some way. Either the very things which begin to be actually after being potentially have always existed according to circular generation, inasmuch as they claimed that things which are generated were formerly the same specifically but not numerically, and this is what occurs 2 in circular generation. For from the moist earth vapors are derived, and these turn into rain, by which the earth is again made moist. Similarly sperm comes from a man, and from sperm a man again comes to be. Thus things which come to be are brought back the same in species by reason of circular generation. Or again those things which come to be actually after being potentially have always been the same things in a different way, as Anaxagoras claimed that they had actual prior existence in the things from which they are generated.

2510. Therefore, if something (1065).

Then he concludes that the motion of the celestial bodies must be eternal on the ground that generation is eternal. Therefore, granted that there is no other motion by which things that pass from potentiality to actuality have always been the same except that which proceeds according to the cycle of generation, he concludes from what has been shown in the philosophy of nature (especially in Book II of Generation ) that, if something remains the same throughout the cycle of generation, something must also remain numerically the same, which will act in the same way so as to cause the eternal motion of things. For none of the things which are generated and destroyed can be the cause of the eternality which is found in generation and destruction, because no one of them always exists, nor even all of them, since they do not exist at the same time, as has been shown in Book VIII of the Physics. It follows, then, that there must be some eternal, agent which always acts in a uniform way so as to cause the eternal motion of things. This is the first heaven, which is moved and causes all things to be changed by its daily motion.

2511. But that which always acts in the same way only causes something that is always in the same state; and obviously those things which ~re generated and destroyed do not remain in the same state, for at one time they are generated and at another destroyed. This being so, if generation and destruction are to occur in the realm of lower bodies, it is necessary to posit some agent which is always in different states when it acts. He says that this agent is the body [the sun] which is moved in the oblique circle called the zodiac. For since this circle falls away on either side of the equinoctial circle, the body which is moved circularly through the zodiac must be at one time nearer and at another farther away; and by reason of its being near or far away it causes contraries. For we see that those things which are generated when the sun comes closer to the earth are destroyed when the sun recedes (for example, plants are born in the spring and wither away in the autumn); for both the sun and the other planets are moved in the circle of the zodiac. But the fixed stars are also said to be moved over the poles of the zodiac and not over the equinoctial poles, as Ptolemy proved. And the coming to be and ceasing to be of everything which is generated and destroyed is caused by the motion of these stars, but more evidently by the motion of the sun.

2512. Therefore this mover which acts in different ways must be one that “acts in one way of itself,” i.e., by its own power, inasmuch as it causes the diversity found in generation and destruction. And it must act “in another way in virtue of something else,” i.e., by the power of some other agent, inasmuch as it causes eternal generation and destruction. Hence this second agent must act either “in virtue of some third agent,” i.e., by the power of some other agent, “or of the first,” i.e., by the power of the first agent, which always acts in the same way. And since it is not possible to assign some other agent by whose power this first agent brings about the eternal motion of things, it is therefore necessary according to this “that it act in the same way”; that is, that by its power it causes the eternal generation and destruction of things. For it—the first agent—which always acts in the same way, is the cause of that which acts in different ways. For that which acts in different ways acts eternally, and that which acts in the same way is the cause of the eternality of any motion. Hence it is the cause of the eternality of that which acts in different ways inasmuch as the latter acts eternally in this way; and it is also the cause of that which is produced by it, namely, eternal generation and destruction. From this it is also evident that the second agent, which acts in different ways, acts by the power “of the first agent,” i.e., the first heaven or first orb, which always acts in the same way.

2513. Hence it is clear that the first agent, which always acts in the same way, is more powerful and nobler, because it is the cause of that “whose being is always to be the same,” i.e., of eternality. But the cause of that whose being is to be different is another agent, which acts in different ways. And it is evident that both of these combined, i.e., both the first agent, which always acts in the same way, and the second agent, which acts in different ways, are the cause of that which both always is and is in different states, namely, the fact that generation and destruction are eternal.

2514. Again, he concludes from this that, if the motions of the heavens are such that eternal generation and destruction in the realm of lower bodies can be caused by them, it is not necessary to look for any other principles (such as the Ideas, which the Platonists posited, or love and hate, which Empedocles posited), because it is possible to account for the eternal generation and destruction of things in the above way.

2515. And if this way is not accepted, the untenable conclusions to which the first philosophers were led will follow namely, that all things “will come from Night,” i.e., from a simple privation, or “all things were together,” or something comes from non-being.

296. Therefore it is evident that, if the above-mentioned position is accepted, i.e., that eternal generation and destruction are caused by the eternal motion of the heavens, the foregoing untenable conclusions are eliminated. And it will follow that something is always being moved in an unceasing motion, which is circular motion. This becomes apparent not only by reasoning but from the effect itself and by perception. Hence, since the first heaven always causes motion by means of this motion, it must be eternal.

2517. Therefore, there is (1066).

From what has been said above he next infers that there is an eternal unmoved mover. For since everything which is being moved is being moved by something else, as has been proved in the Physics, if both the heavens and their motion are eternal, there must be an eternal mover. But since three classes are found among movers and things moved: the lowest of which is something that is merely moved, the highest something that moves but is unmoved, and the intermediate something that both moves and is moved, we must assume that there is an eternal mover which is unmoved. For it has been proved in Book VIII of the Physics that, since there cannot be an infinite number of movers and things moved, we must come to some first unmoved mover. For even if one might come to something that moves itself, it would again be necessary for the above reason to come to some unmoved mover, as has been proved in that work.

2518. Again, if the first mover is eternal and unmoved, it must not be a potential being (because any potential being is naturally fitted to be moved) but an independent substance whose essence is actuality.—This is the conclusion which he drew above (1058:C 2499). But it was necessary to raise this question, which was discussed among the ancients, in order that when it has been solved the course to be followed in reaching a first being whose substance is actuality will be made more evident.

LESSON 7

How the First Mover Causes Motion

ARISTOTLE’S TEXT Chapter 7: 1072a 26-1072b 14

1067. Now the first mover causes motion as something intelligible and something appetible; for these alone cause motion without being moved. And what is first in the class of the appetible and in that of the intelligible is the same; for it is the apparent good w1iich is the object of concupiscible appetite, and the real good which is the primary object of will. For we desire a thing because it seems good rather than consider it good because we desire it; for understanding is the principle of desire. And the intellect is moved by an intelligible object.

1068. And one of the two columns of opposites (60) is the intelligible in itself; and in this class primary substance is first, and in substance that which is simple and exists actually. However, one and simple are not the same; for one signifies a measure (432; 825), and simple signifies a state.

1069. But that which is good and that which is desirable in itself are in the same column of opposites; and that which is first in each class is always best, or analogous to the best. That the final cause belongs to the class of immovable things is shown by a process of division; for the final cause of a thing is either that which exists or that which does not.

1070. And it causes motion as something loved, whereas by that which is [first] moved other things are moved. Therefore, if a thing is moved, it is possible for it to be other than it. is. Hence, local motion, which is the primary kind of motion, is also the actuality of that which is [first] moved; and in this respect the thing first moved can differ in place though not in substance. But since there is something which moves yet is itself imm ovable and exists actually, this can in no way be other than it is. For the primary kind of change is local motion, and of local motion the first is circular motion; and this is the motion which the first mover causes. Hence the first mover necessarily exists; and insofar as it is necessary it is good, and thus is a principle. For necessary has all of these meanings: that which seems to be done by force; that without which something does not fare well; and that which cannot be other than it is, but is absolutely necessary (416-22). It is on such a principle, then, that the heavens and the natural world depend.

COMMENTARY

299. After having shown that there is an eternal, immaterial, immovable substance whose essence is actuality, the Philosopher now proceeds to investigate the attributes of this substance. In treating this he does three things. First (1061:C 2519), he considers the perfection of this substance. Second (1078:C 2553), he asks whether it is one or many (“We must not”). Third (1089:C 2600), he considers its operation (“The things which pertain”).

In regard to the first he does two things. First, he shows the perfection of this substance. Second (1076:C 2548), he proves that it is incorporeal (“And it has been shown”).

In regard to the first he does two things. First, he shows its perfection. Second (1075:C 2545), he rejects a contrary opinion (“And all those”).

In regard to the first he does two things. First, he explains how the unmoved mover causes motion; and second (1068:C 2523), he infers from this what is comprised in its perfection (“And one of the two”).

He accordingly says, first (1067), that, since it has been shown that the first mover is unmoved, it must cause motion in the way in which the desirable and the intelligible do; for only these, the desirable and the intelligible, are found to cause motion without being moved.

2520. He proves this as follows. Motion is twofold: natural and voluntary, or according to appetite. Now that which causes motion by means of natural motion necessarily undergoes motion, since a natural mover is one that begets and alters things. For both heavy and light bodies are moved locally directly by their begetter. But that which begets and alters things directly must exist in different states. Hence it has also been pointed out above (1065:C 2510) that the cause of generation and destruction acts in different ways. Now in the case of voluntary and appetitive motion, will and appetite have the character of moved movers, as is evident in Book III of The Soul. Hence it remains that only that which causes motion as something appetible is an unmoved mover.

2521. Now it is said that the first mover causes motion as something appetible because the motion of the heavens has this mover as its end or goal, for this motion is caused by some proximate mover which moves on account of the first unmoved mover in order that it may be assimilated in its causality to the first mover and bring to actuality whatever is virtually contained in it. For the motion of the heavens does not have the generation and destruction of lower bodies as its end, since an end or goal is nobler than the things ordained to it. Therefore the first mover causes motion as something appetible.

2522. But in our own case that which causes motion as a desirable good differs from that which causes motion as an intelligible good, though each causes motion as an unmoved mover. This is particularly evident in the case of an incontinent person; for according to his reason he is moved by an intelligible good, but according to his concupiscible power he is moved by something pleasant to the senses, which, while it seems to be good, is not good absolutely but only with some qualification.—However, this kind of difference cannot be found in the first intelligible and the first desirable good. But the first intelligible and the first desirable good must be the same. The reason is that a concupiscible good, which is not an intelligible good, is merely an apparent good; but the first good “must be an object of will,” i.e., an object desired by intellectual appetite. For will belongs to the intellectual order and not merely to that of concupiscible appetite. And this is so because what is desired by the concupiscible power seems to be good because it is desired; for concupiscence perverts the judgment of reason insofar as something pleasant to sense seems to be good to reason. But what is desired by intellectual appetite is desired because it seems to be good in itself. For “understanding” as such, i.e., the act of intellection, which is moved in a way by an intelligible object, “is the principle of desire.” Therefore it is evident that the object of concupiscible appetite is good only when it is desired through a dictate of reason. Hence it cannot be the first good, but only that which, because it is good, moves desire and is at once both appetible and intelligible.

2523. And one of the two (1068).

Since he has proved that the first mover is both intelligible and appetible, it now remains to show from this how perfection is found in the first mover. In regard to thi8 he does three things. First (1068:C 2523), he shows the perfection of the first mover in itself by considering the formal character of the intelligible and the appetible; second (1070:C 2529), in relation to the first sphere (“And it causes motion”); and third (107:C 2536), in relation to the thing that desires and understands it (“And its course of life”).

In treating the first part he does two things. First, he proves that the first mover is perfect on the ground that it is intelligible; and second (106g:C 2526), on the ground that it is appetible (“But that which is good”).

He says, first (1068), that, just as movers and things moved are related to one another, so also are intelligible things. He calls this latter relationship an intelligible column of opposites because one intelligible is the first principle for understanding another, just as one mover is also the cause of the motion of another.

2524. Therefore, just as it has been shown (1066:C 298) from the series of movers and things moved that the first mover is a simple substance and an actuality, in a similar fashion the same thing is found to be true from the series of intelligible things. For it is evident that substance is the first of intelligible things, because we understand accidents only by means of substance, through which they are defined; and among substances a simple intelligible substance is prior to a composite one; for simple things are included in the concept of composite things. And of the simple entities contained in the class of substance the actually intelligible are prior to the potentially intelligible; for potentiality is defined by means of actuality. It follows, then, that the first intelligible entity is a simple substance which is an actuality.

2525. And lest he should seem to be adopting the opinion of Plato, who claimed that the first principle of things is the intelligible one-in-itself, he therefore explains the difference between being one and being simple. He says that one and simple do not signify the same thing, but one signifies a measure, as has been pointed out in Book X (825:C 1950-52), and simple signifies that state whereby something is such as not to be composed of many things.

2526. But that which is good (1069).

Then he proves the same point from the formal character of the appetible. He says that that which is good and that which is desirable in itself belong to the same class. For that which is prior in the class of intelligible things is also a greater good in the class of appetible things, or is something analogous to it. He says this because intelligible things are actual insofar as they exist in the intellect, whereas appetible things are actual insofar as they exist in reality; for good and evil are in things, as has been pointed out in Book VI (558:C 1240).

2527. Hence, just as the concept of intelligible substance is prior to that of intelligible accidents, the same relationship holds for the goods which correspond proportionally to these concepts. Therefore the greatest good will be a simple substance, which is an actuality, because it is the first of intelligible things. It is evident, then, that the first mover is identical with the first intelligible and the first appetible good, which is the greatest good.

2528. But since what is appetible and what is good have the character of an end or goal, and there does not seem to be an end in the realm of immovable things, as has been explained in the dialectical discussions in Book III (192:C 374-75), he therefore removes this difficulty. He says that the division in which the various senses of end or goal are distinguished shows that a final cause can be found in a way in the realm of immovable things. Now one thing can be the goal of another in two ways: first, as something having prior existence, as the center of the world is said to be a goal which is prior to the motion of heavy bodies; and nothing prevents a goal of this kind from existing in the realm of immovable things. For a thing can tend by its motion to participate in some degree in something immovable; and the first mover can be a goal in this way. Second, one thing is said to be the goal of another, not as something that exists actually, but only as existing in the intention of the agent by whose activity it is produced, is health is the goal of the activity of the medical art. An end or goal of this kind does not exist in the realm of immovable things.

2529. And it causes motion (1070).

He now relates the first unmoved mover to the first sphere. He says that, since the first unmoved mover causes motion as something loved, there must be something which is first moved by it, through which it moves other things. This is the first heaven. Therefore, since we suppose motion to be eternal, the first sphere must be moved eternally, and it in turn must move other things. And it is better to speak of it as something loved rather than as something desired, since there is desire only of something that is not yet possessed, but there is love even of something that is possessed.

2530. And if it must be moved eternally, it must be incapable of being other than it is but must always remain substantially the same. Hence the primary kind of motion, by which “the first sphere” is moved, necessarily “is local motion,” i.e., motion as regards place; because that which is moved “according to the other kinds of motion,” i.e., generation and destruction, increase and decrease, and alteration, must differ as regards something intrinsic, namely, substance, quantity or quality. But that which is moved with local motion differs as regards place, which is extrinsic to the thing in place, but not as regards substance or any intrinsic disposition of substance.

2531. Therefore, since the first sphere differs as regards place but not as regards substance, the first mover, which is immovable and always actual, can in no way be other than it is, because it cannot be moved. For if it were moved, it would be moved especially with the primary kind of motion, which is local motion, of which the first type is circular. But it is not moved with this motion, since it moves other things with this motion. For the first mover is not moved with that kind of motion by which it imparts motion, just as the first cause of alteration is not itself altered. Hence it is not moved circularly, and so cannot be moved in any way. Therefore it cannot be other than it is; and thus it follows that the primary kind of motion exists in that which is moved of necessity; for that is necessary which cannot not be. But it is not necessary in the sense in which things forced are necessary, but its necessity consists in its good state. And the thing which moves it is a principle of motion as an object of desire, or a goal.

2532. That its necessity is such becomes evident from the different meanings of the term necessary, for it is used in three senses. First it means that which happens by force, i.e., what cannot fail to happen because of the power exerted by the thing applying force. Second, it means that without which a thing does not fare well—either that without which a goal cannot be attained at all (as food is necessary for the life of an animal), or that without which something is not in a perfect state (as a horse is necessary for a journey in the sense that it is not easy to make a journey without one). Third, it means that which cannot be other than it is, but is necessary absolutely and essentially.

2533. Therefore, when it is said that an orb is moved of necessity, such necessity cannot be called necessity of force; for in imperishable things there is not found anything that is outside their nature, but in the case of things which are forced what occurs is not natural. Similarly such necessity cannot be absolute necessity, because the first thing which is moved moves itself, as is proved in Book VIII of the Physics, and what moves itself has within itself the power to move or not move. It follows, then, that the necessity of the first motion is necessity from the end, inasmuch as there cannot be a fitting order to the end unless such motion is eternal.

2534. Hence it is on this principle, i.e., the first mover viewed as an end, that the heavens depend both for the eternality of their substance and the eternality of their motion. Consequently the whole of nature depends on such a principle, because all natural things depend on the heavens and on such motion as they possess.

2535. It should also be noted that Aristotle says here that the necessity of the first motion is not absolute necessity but necessity from the end, and the end is the principle which he later calls God inasmuch as things are assimilated to God through motion. Now assimilation to a being that wills and understands (as he shows God to be) is in the line of will and understanding, just as things made by art are assimilated to the artist inasmuch as his will is fulfilled in them. This being so, it follows that the necessity of the first motion is totally subject to the will of God.

LESSON 8

The Perfection of the First Substance

ARISTOTLE’S TEXT Chapter 7: 1072b 14-1073a 13

1071. And its course of life is like the best which we enjoy for a short time; for it is always in that state, though this is impossible for us.

1072. For its operation is also pleasure. This is why being awake, sensing and understanding are most pleasant, and hopes and memories are pleasant because of them. Now understanding in itself has to do with what is best in itself, and the highest type of understanding has to do with what is best in the highest degree.

1073. And an intellect understands itself insofar as it takes on its intelligible object; for it becomes intelligible by attaining and understanding its object, so that an intellect and its intelligible object are the same. For that which is receptive of something intelligible and of substance is an intellect; and it is actual when it possesses this. Hence it is the latter rather than the former state which seems to constitute the divine state of intellect; and its act of understanding is the most pleasant and best. Therefore, if God is in that pleasurable state in which we