Aristotle · a new plain-English translation from the original language
1| The inquiry concerns substance, for it is the principles and causes of substances that are sought. For if the universe is a kind of whole, substance is its first part; and if it is a matter of succession, even so substance is first, then quality, then quantity. At the same time these latter are, so to speak, not even beings without qualification, but qualities and motions — or else the not-white and the not-straight, since we do say these too are, for instance, we say 'it is not white.' Further, none of the other categories is separable. The ancients too testify to this in their practice, for it was of substance that they sought the principles, elements, and causes. Those of the present day tend rather to posit universals as substances (for genera are universal, and these they say are principles and substances more, because they inquire in a logical manner); but the ancients posited particulars, such as fire and earth, and not the common thing, body. There are three substances: one is perceptible — of which one kind is eternal and one kind perishable, the latter acknowledged by everyone, such as plants and animals, the former eternal — of which it is necessary to grasp the elements, whether one or many; another is unmoved, and this some say is separable, some dividing it into two, some positing the forms and the objects of mathematics as a single nature, and some positing only the objects of mathematics among these.
2| The former belong to natural science (for they involve motion), [1069b] but this latter belongs to a different science, if there is no principle common to them. Perceptible substance is subject to change. And if change proceeds from opposites, or from intermediates, and not from all opposites (for a sound is not not-white) but from the contrary, there must underlie it something that changes into the contrary state — for contraries themselves do not change. Further, one thing persists while its contrary does not persist; there is, then, some third thing besides the contraries, namely the matter. Now if changes are fourfold, either with respect to the what, or with respect to the qualified, the quantified, or the where, and coming-to-be without qualification and perishing are change with respect to the this, growth and diminution are change with respect to the quantified, alteration is change with respect to the affection, and locomotion is change with respect to place, then changes of each kind will be into the corresponding contraries. It is therefore necessary that the matter which changes be capable of both states; and since being is twofold, everything changes from what is potentially to what is actually (for example, from potentially white to actually white, and likewise in growth and diminution), so that it is possible for a thing to come to be not only, as an accident, out of what is not, but also everything comes to be out of what is — out of what is potentially, however, and not out of what is actually.
3| And this is Anaxagoras's One (for it is better than 'all things together') — and Empedocles's mixture, and Anaximander's, and as Democritus puts it: 'all things were together, potentially but not actually.' So these thinkers would have had some grasp of matter. Everything that changes has matter, but a different matter in each case; and among eternal things, those that are not subject to coming-to-be but are moved by locomotion have matter too — not matter for coming-to-be, but matter for moving from one place to another. One might raise the difficulty out of what sort of not-being coming-to-be occurs, since not-being is spoken of in three ways. If, then, a thing is potentially something, still it does not come from just anything, but a different thing comes from a different thing; nor is it enough to say that all things were together, for they differ in their matter — since otherwise, why did infinitely many things come to be, and not one? For intellect is one, so that if the matter too were one, that would have come to be in actuality of which the matter was potentially. There are, then, three causes and three principles: two are the contrariety, of which one member is the account, or form, and the other privation, and the third is the matter. Next, that neither the matter nor the form comes to be — I mean the ultimate terms. For everything that changes is something, and is changed by something, and changes into something:
4| [1070a] that by which is the primary mover; that which changes is the matter; and that into which is the form. It would go on to infinity, then, if not only the bronze comes to be round but also the round or the bronze itself came to be; so it is necessary to stop somewhere. Next, that each substance comes to be out of something that shares its name (for things that exist by nature are substances, and so are the other things too). For a thing comes to be either by craft, or by nature, or by chance, or spontaneously. Now craft is a principle in another thing, while nature is a principle in the thing itself (for a human being begets a human being), and the remaining causes are privations of these. There are three substances: matter, which is a this by appearing so (for whatever is one by contact and not by growing together is matter and substrate); nature, which is a this and a certain state toward which it tends; and further, a third, the particular thing composed of these, for example Socrates or Callias. Now in some cases the this is not found apart from the composite substance — for instance the form of a house, unless it be the craft (nor is there coming-to-be and perishing of these, but they exist and do not exist in another way — a house without matter, and health, and everything that exists in accordance with a craft, exist in this other way) — but if it does occur, it occurs among things that exist by nature:
5| Therefore Plato was not wrong to say that there are as many forms as there are natural kinds, if indeed there are forms distinct from these -- for instance, fire, flesh, head: for all these are matter, and it is the last stage of matter that belongs most of all to substance. Now some causes are moving causes, existing as having come into being before their effects, while others exist just as the account does, simultaneously with the effect. For when a person is healthy, then health also exists, and the shape of the bronze sphere exists at the same time as the bronze sphere (but whether something also persists afterward must be considered: for in some cases nothing prevents it -- for instance, if the soul is of this sort, not the whole soul but the intellect; for perhaps it is impossible for the whole soul to persist). It is clear, then, that there is no need, on these grounds at least, for there to be Forms: for man begets man, this particular man begetting some particular man; and likewise too in the crafts -- for the medical craft is the account of health. And the causes and principles are, in one sense, different for different things, but in another sense -- if one speaks universally and by analogy -- the same for all. For one might raise the puzzle whether the principles and elements of substances and of relatives are different or the same, and similarly for each of the other categories. But it is absurd if they are the same for all things,
6| for then relatives and substances would come from the same things. [1070b] What then would this common thing be? For besides substance and the other things predicated, there is nothing common, and the element is prior to the things of which it is an element. But surely substance is not an element of relatives, nor is any of these an element of substance. Again, how can all things have the same elements? For none of the elements can be identical with the thing composed of elements -- for instance B or A cannot be identical with BA (nor indeed is there an element of the objects of intellect, such as being or the one: for these belong to each thing, even to composite things). None of them, then, will be either a substance or a relative -- yet it is necessary that they be something. So it is not the case that all things have the same elements. Or rather, as we say, in one sense they do, in another they do not -- for instance, perhaps, of perceptible bodies, in one sense the hot is the form, and in another way the cold is the privation, while the matter is that which is primarily and in its own right these things potentially; and substances are these things and what is composed from them, of which these are the principles -- or whatever single thing comes to be from hot and cold, such as flesh or bone: for what comes to be must be different from those. Of these, then, the elements and principles are the same, though different for different things, but it is not possible to say this of all things in the same way -- only by analogy, as if one were to say that there are three principles: the form, the privation, and the matter.
7| But each of these is different for each genus -- for instance in color: white, black, surface; light, darkness, air, and from these, day and night. Since the causes are not only those present within a thing but also those from outside, such as the mover, it is clear that principle and element are different, though both are causes, and the principle divides into these; and that which moves or brings to rest is itself a certain principle and substance. So the elements are, by analogy, three, but the causes and principles are four; and they differ from case to case, and the first cause, as mover, is different for different things. Health, disease, body: the mover is medicine. Form, this particular disorder, bricks: the mover is the builder's craft. And into these the principle divides. Since the mover, in the case of natural things, is man for man, while in the case of things that come from thought it is the form or its contrary, in one way there would be three causes, but in another way four. For medicine is, in a sense, health, and the builder's craft is the form of the house, and man begets man; and besides these there is that which, as first of all, moves all things. Since some things are separable and some are not, the former are substances.
8| [1071a] And for this reason the causes of all things are the same, because without substances there are no affections or motions. Then again these will perhaps be soul and body, or intellect and desire and body. Again, in another way, the principles are the same by analogy -- for instance actuality and potentiality; but these too are different for different things, and different in kind. For in some cases the same thing is at one time in actuality, at another in potentiality -- for instance wine, or flesh, or man (and these too fall under the causes already mentioned: for the form is in actuality, if it is separable, and so is that which is composed of both; and privation too is in actuality, as darkness or sickness; while matter is in potentiality, for this is what is capable of becoming both). But in another way actuality and potentiality differ for things whose matter is not the same, and for some of which the form is not the same but different -- as, for instance, the cause of man is the elements, fire and earth, as matter, and his own proper form, and further something else outside, such as the father, and besides these the sun and the oblique circle, which are neither matter nor form nor privation nor of the same species, but movers.
9| Again one must see that some things can be spoken of universally, others not. Now the first principles of all things are the actual particular thing here, and something else which is potential. Those universal things, then, do not exist as such: for the principle of particulars is a particular. For man in general is the principle of man in general, but there is no such man; rather Peleus is the principle of Achilles, and your father of you, and this B of this BA, and B in general of BA taken without qualification. Then again, if this holds for substances, different things have different causes and elements, as was said, for things not in the same genus -- colors, sounds, substances, quantity -- except by analogy; and even for things in the same species the causes are different, not different in species, but because the particulars are different -- your matter and form and mover, and mine -- though they are the same in their universal account. And as for the inquiry into what the principles or elements of substances and of relatives and of qualities are, whether they are the same or different: it is clear that, since each is spoken of in many ways, once these are distinguished the principles are not the same but different, except in this sense -- that they are the same, or analogous, for all things: namely matter, form, privation, and the mover; and in this sense too, that the causes of substances are, as causes of all things, such that when they are removed, all else is removed along with them --
10| further, that the first thing is first in actuality. But in another sense the first things are different, namely all the contraries that are not spoken of as genera and are not spoken of in many ways; and further, there are the various kinds of matter. [1071b] What the principles of perceptible things are, then, and how many there are, and in what sense they are the same and in what sense different, has now been stated. Since there were three substances, two natural and one immovable, concerning this last one must say that there must necessarily be some eternal immovable substance. For substances are the first of existing things, and if all substances are perishable, then everything is perishable; but it is impossible for motion either to come into being or to perish, for it always existed, and the same holds of time. For it is not possible for there to be a before and after without there being time; and motion, therefore, is continuous in the same way that time is -- for either they are the same thing, or time is some affection of motion. But there is no continuous motion except motion in place, and of this, only circular motion. But further, even if there is something capable of moving or capable of acting, yet not actually active, there will be no motion: for it is possible for that which has a capacity not to be actually exercising it. So it will do no good even if we posit eternal substances, as those who posit the Forms do, unless there is present in them some principle capable of causing change; and indeed not even this is sufficient, nor is any other substance besides the Forms: for if it will not be actually active, there will be no motion. Nor again is it sufficient even if it will be actually active, if its substance is potentiality --
11| For there will be no eternal motion; for what exists potentially can also fail to exist. There must, then, be a principle of this kind, whose substance is actuality. Further, these substances must be without matter; for they must be eternal, if indeed anything else is eternal. Therefore they are actuality. Yet there is a difficulty here: it seems that whatever is actual is capable of being so, but not everything capable acts, so that potentiality would seem to be prior. But if this is so, then nothing that exists will exist at all; for it is possible for a thing to be capable of being and yet not yet be. Yet if we go by what the theologians say, those who generate things out of Night, or by what the natural philosophers say, that all things were together, the same impossibility results. For how will anything be moved, if there is not to be some cause in actuality? For matter will not move itself — the carpenter's craft moves it; nor do the menses move themselves, nor the earth, but the seed and the semen do. That is why some thinkers make actuality eternal — Leucippus, for instance, and Plato: for they say that motion always exists. But they do not say why, nor of what kind, nor, if it goes this way or that way, the cause of it. For nothing moves at random, but there must always be something present as a cause, just as at present a thing moves in one way by nature, but in another way by force, or by intellect, or by something else.
12| (Then which motion is primary? For this makes an enormous difference.) But in fact not even Plato can name the thing he sometimes takes to be a principle —
13| [1072a] the thing that moves itself: for the soul, as he says, comes later, and simultaneously with the heaven. Now the view that potentiality is prior to actuality is in one sense correct and in another sense not (we have said in what way). That actuality is prior is attested by Anaxagoras (for intellect is actuality) and by Empedocles with his Love and Strife, and by those who say motion always exists, such as Leucippus: so that chaos or night did not exist for infinite time, but the same things have always existed, either in a cycle or in some other way, given that actuality is prior to potentiality. If, then, the same thing recurs always in a cycle, something must remain always acting in the same way. But if there is to be coming-to-be and passing-away, there must be something else that acts always, but in different ways at different times. This, then, must of necessity act in one way in its own right, and in another way in virtue of something else — either in virtue of some other thing, or in virtue of the first. It must, then, be in virtue of the first; for that in turn is cause both for itself and for the other thing. The first, then, is the better cause; for it was the cause of what is always the same way, while the other thing is cause of variation, and the two together are plainly the cause of what is always varying. This, then, is in fact how the motions stand. Why, then, do we need to look for other principles? Since it is possible in this way, and if it were not, everything would come from night and from all things together and from what is not, these difficulties would be resolved, and there is something that is always in motion with an unceasing motion, and this motion is circular (and this is evident not merely in argument but in fact), so that the first heaven would be eternal.
14| There is, then, also something that moves it. And since what is moved ...is intermediate, then there is something that moves without being moved, something eternal, both substance and actuality. And the object of desire and the object of thought move in just this way: they move without being moved. Of these, the primary objects are the same. For what is desired by appetite is what appears fine, while what is primarily an object of wish is what is truly fine; and we desire a thing because it seems fine to us, rather than its seeming fine because we desire it — for the thinking is the starting point. Now intellect is moved by the object of thought, and one column of the pair of opposites is intelligible in its own right; and within this column substance is first, and within substance the sort that is simple and in accordance with actuality is first (the one and the simple are not the same: for the one signifies a measure, while the simple signifies a certain condition of the thing itself). But in fact the fine, too, and what is choiceworthy for its own sake, belong to this same column; and the first term is always the best, or analogous to the best.
15| [1072b] That the end exists among unmoved things, the following distinction makes clear: for the end is for someone and of something, and of these the one exists, the other does not. It moves, then, as an object of love; but all the other things cause motion by being themselves moved. Now if a thing is moved, it admits of being otherwise; so that if the primary kind of motion is locomotion, then insofar as a thing is moved by this motion, it admits of being otherwise, in place at least, even if not in substance. But since there is something that moves while itself being unmoved, existing in actuality, this admits of being otherwise in no way at all. For locomotion is the primary kind of change, and of locomotion, circular motion is primary; and this is the motion that mover produces. It exists, therefore, of necessity; and insofar as it exists by necessity, it exists well, and in this way it is a principle. For the necessary has these several senses: the forced, because it runs contrary to impulse; that without which the good cannot be; and that which does not admit of being otherwise, but is so simply and without qualification. On a principle of this kind, then, the heaven and nature depend. And its way of life is like the best that we enjoy, though only for a short time (for that being is always in this state, which is impossible for us), since its actuality is also pleasure — and this is why waking, perception, and thinking are the most pleasant things, and hopes and memories are pleasant on account of these.
16| And thinking in its own right is of what is best in its own right, and thinking in the fullest sense is of what is best in the fullest sense. And intellect thinks itself by partaking of the object of thought; for it becomes an object of thought by making contact with and thinking its object, so that intellect and the object of thought are the same thing. For that which is receptive of the object of thought, that is, of substance, is intellect, and it is in actuality when it possesses its object, so that this possessing, rather than the mere receptivity, is the divine element that intellect seems to have, and contemplation is the most pleasant and the best thing there is. If, then, God is always in that good state in which we sometimes are, this is a wonderful thing; and if he is in it to a greater degree, this is still more wonderful. And this is how he is. And life, too, belongs to him: for the actuality of intellect is life, and God is that actuality; and the actuality that belongs to him in his own right is life at its best and eternal. We say, then, that God is a living being, eternal and best, so that life and a continuous and eternal duration belong to God; for this is what God is. But those who suppose, as the Pythagoreans and Speusippus do, that the finest and best does not exist at the beginning, on the ground that the starting points of both plants and animals are causes, while the fine and the complete are found in what comes from these, do not think correctly. For the seed comes from other things that are prior and complete, and the first thing is not the seed but the complete thing —
17| [1073a] for example, one would say that a man is prior to the seed, not the man produced from this seed, but another man from whom the seed comes. That there is, then, a certain substance that is eternal and unmoved and separate from perceptible things, is clear from what has been said; and it has also been shown that this substance cannot have any magnitude at all, but is without parts and indivisible (for it produces motion for infinite time, and nothing finite has infinite power; and since every magnitude is either infinite or finite, it could not have a finite magnitude, for the reason just given, nor an infinite magnitude, because there is no infinite magnitude at all); but further, that it is also unaffected and unalterable: for all the other kinds of motion are posterior to locomotion. These points, then, make clear that this is how the matter stands. But whether we should posit one such substance or several, and how many, we must not overlook, but must recall as well the assertions of others, namely that on the question of number they have said nothing that can even be stated clearly. For the view concerning the Forms has no separate investigation of its own (for those who speak of Forms call the Forms numbers, and concerning numbers they speak at one time as though they were infinite, at another as though bounded by the decad):
18| As to why the number of these substances is just this many, nothing is said with demonstrative rigor; but we must speak from the premises we have laid down and distinguished. The principle and the first of beings is unmoved, both in its own right and accidentally, but it moves the primary, eternal, and single motion; and since what is moved must be moved by something, and the first mover must be unmoved in its own right, and the eternal motion must be moved by something eternal, and the single motion by something single, and we see that besides the simple motion of the universe as a whole, which we say the primary, unmoved substance moves, there are other motions—those of the planets—which are also eternal (for a body moving in a circle is eternal and never at rest; this has been shown in the works on nature), each of these motions too must be moved, in its own right, by something unmoved and by an eternal substance. For the nature of the stars is a kind of eternal substance, and the mover is eternal and prior to the moved, and what is prior to a substance must be a substance. It is clear, then, that there must be substances of just this number, eternal in their nature and unmoved in their own right, and, for the reason already stated, without magnitude, prior to the others.
19| [1073b] That there are substances, then, and that among them one is first and another second, in the same order as the motions of the stars, is evident. But the number of the motions must now be examined from the mathematical science most akin to philosophy, namely astronomy; for this science makes its study concerning a substance that is perceptible yet eternal, whereas the other mathematical sciences deal with no substance at all, for instance those concerning numbers and geometry. That the motions are more numerous than the bodies that are carried is evident even to those who have given the matter only moderate attention (for each of the wandering stars is carried by more than one motion); but as to how many these motions actually are, we shall now state what some of the mathematicians say, for the sake of giving the mind something of a definite number to grasp; for the rest we must partly investigate ourselves and partly learn from those who investigate, and if anything appears, on inquiry, to conflict with what has now been stated, we should esteem both parties but be persuaded by the more exact. Eudoxus, then, held that the motion of the sun and that of the moon each involve three spheres, of which the first is that of the fixed stars, the second moves along the circle through the middle of the zodiac, and the third moves along a circle inclined across the breadth of the zodiac (the circle along which the moon moves being inclined at a greater breadth than that along which the sun moves); and that the motion of the planets involves, for each, four spheres, of which the first and second are the same as those already mentioned (for the sphere of the fixed stars is the one carrying all the others along, and the one placed beneath it, having its motion along the circle through the middle of the zodiac, is common to all), while the poles of the third sphere for all the planets lie on the circle through the middle of the zodiac, and the motion of the fourth sphere runs along a circle inclined to the equator of the third;
20| and the poles of the third sphere are, for the other planets, particular to each, but for Venus and Mercury the same. Callippus set down the same arrangement of the spheres as Eudoxus—that is, the same ordering of the distances—but as to their number, he assigned to the sphere of Jupiter and to that of Saturn the same number as Eudoxus did, while for the sun and the moon he thought two further spheres still needed to be added, if one is to account for the observed appearances, and for each of the remaining planets one more. But it is necessary, if all the spheres together are to account for the observed appearances,
21| [1074a] that for each of the planets there be other spheres, one fewer than those already given, which unwind and restore to the same position the first sphere belonging to the star ranked next below in each case; for only in this way is it possible for the whole motion of the planets to be produced. Since, then, the spheres by which the planets themselves are carried are, in all, eight and twenty-five, and of these only those need not be unwound in which the lowest-ranked planet is carried, the spheres unwinding those of the first two planets will be six, and those unwinding the spheres of the remaining four will be sixteen; so the total number of all the spheres, both those carrying the planets and those unwinding these, will be fifty-five. But if one does not add to the sun and moon the motions we mentioned, the spheres in all will be forty-seven. Let the number of the spheres, then, be taken as this many, so that it is reasonable to suppose the unmoved substances and principles are likewise this many in number as well (let the necessity of this be left for stronger thinkers to state); but if no motion can fail to be directed toward the motion of a star, and further if every nature and every substance that is free from external affection and exists in its own right must be regarded as attaining the best as its end, then there could be no other nature beside these, and this must be the number of the substances.
22| For if there were others, they would move as being the end of some motion; but it is impossible for there to be other motions besides those already mentioned. This is reasonable to suppose on the basis of the bodies that are carried. For if everything that carries exists by nature for the sake of what is carried, and every motion is the motion of some body carried, then no motion could exist for its own sake or for the sake of another motion, but all must be for the sake of the stars. For if there is to be a motion for the sake of another motion, that other motion too will need to be for the sake of something else; and since this cannot go on to infinity, the end of every motion will be one of the divine bodies that are carried through the heaven. That there is one heaven is evident. For if there were several heavens, as there are several men, the principle governing each would be one in form but many in number. But whatever is many in number has matter (for one and the same account applies to many things, for instance to man, though Socrates is one); but the essence has no matter as its primary character, since it is a realization. The primary unmoved mover is therefore one both in account and in number; and therefore so too is that which is moved always and continuously; therefore there is one heaven alone.
23| [1074b] It has been handed down by the ancients, the very ancient ones, and left in the form of myth for later generations, that these bodies are gods and that the divine encompasses the whole of nature. The rest has already been added in mythical fashion, for the persuasion of the many and for use in support of the laws and of expediency; for they say these gods are human in shape, and like certain of the other animals, and add other things consequent upon and similar to what has been said. But if one were to separate out from these and take only the first point by itself—that they believed the primary substances to be gods—one would think this had been said divinely; and since, in all likelihood, each craft and each philosophy has often been discovered to the extent possible and has again perished, these opinions of theirs have survived, like relics, to the present day. So far, then, and only so far, is the ancestral opinion, the one from the earliest thinkers, clear to us. The matters concerning intellect involve certain difficulties; for it seems to be the most divine of the things that appear, but how it must be constituted to be such involves certain difficulties. For if it thinks nothing, what dignity would it have? It would be just like one who is asleep. But if it thinks, and something else has control over this, then—since that which is its substance is not the act of thinking but a capacity—it would not be the best substance;
24| For it is through thinking that what is precious belongs to it. Further, whether its substance is intellect or is thinking, what does it think? For it thinks either itself or something else; and if something else, then either always the same thing or something different. Does it then make any difference, or none, whether it thinks the fine or thinks whatever happens to be the case? Or would it even be absurd for it to think about some things? Clearly, then, it thinks what is most divine and most precious, and it does not change; for change into something worse would be a change, and something of that sort is already a kind of motion. First, then, if it is not thinking but a capacity, it is reasonable that continuity in thinking would be laborious for it; next, it is clear that something else would be more precious than intellect, namely what is thought. For both thinking and the act of thinking will belong even to one who thinks the worst thing, so that if this is to be avoided (and indeed not seeing some things is better than seeing them), thinking would not be the best thing. It thinks itself, then, if indeed it is the most powerful thing, and its thinking is a thinking of thinking. But knowledge, and perception, and opinion, and thought always appear to be of something else, and to be of themselves only incidentally.
25| Further, if thinking and being thought are different, in respect of which does the good belong to it? For being thinking and being thought are not the same thing either. Or is it that in some cases knowledge is the thing itself, [1075a] in the case of things that are made, the substance and the essence being without matter, while in the case of things that are objects of contemplation the account is the thing and is the thinking? Since, then, what is thought and the intellect are not different in the case of things that have no matter, they will be the same, and the thinking will be one with what is thought. There still remains a puzzle: whether what is thought is composite; for it would then change within the parts of the whole. Or is everything that has no matter indivisible — as the human intellect is, or rather as the intellect of composite things is, in a certain span of time (for it does not possess the good in this part or in that, but the best thing, being something else, belongs to it in some whole) — and is the thinking of itself by itself in this same way for the whole of eternity? We must also examine in which of two ways the nature of the whole possesses the good and the best: whether as something separate and itself by itself, or as the order of the parts. Or is it in both ways, as with an army? For the good of an army lies both in its order and in its general, and more in the general; for it is not because of the order that he exists, but the order exists because of him. And all things are ordered together in some way, though not all alike — things that swim, and things that fly, and plants —
26| and it is not the case that there is nothing between one thing and another, but there is something. For all things are ordered together in relation to one thing, but as in a household, where the free persons are least of all permitted to do whatever they happen to, but everything, or most things, are ordered for them, while for the slaves and the animals there is little that bears on the common good, and mostly they do whatever they happen to; for such is the principle that governs each of them, namely their nature. What I mean is that, for instance, it is necessary for all of them to arrive at being separated out into their parts, and there are other things too in which all of them share, in relation to the whole. But we must not fail to notice how many impossible or absurd results follow for those who speak otherwise, and what sort of things the more refined thinkers say, and on what points the fewest difficulties arise. All of them make all things out of contraries. But neither is it right to say 'all things', nor is it right to say 'out of contraries', nor do they explain, in the cases where the contraries are present, how the things will come to be out of the contraries; for contraries are not affected by one another. For us this is resolved reasonably, by there being some third thing. But they make one of the two contraries into matter, as those do who make the unequal matter for the equal, or the many matter for the one. This too is resolved in the same way:
27| for the one matter is contrary to nothing. Further, on their view all things, apart from the one, will partake of the bad; for the bad is itself one of the two elements. But the other thinkers do not even make the good and the bad principles at all; yet in all things the good is above all a principle. These others are right in saying that it is a principle, but they do not say in what way the good is a principle — whether as an end, or as what set things in motion, or as form.
28| [1075b] Empedocles too speaks absurdly; for he makes love the good, yet this is a principle both as moving (for it brings things together) and as matter (for it is a part of the mixture). Now even if it happens to belong to the same thing to be a principle both as matter and as mover, still their being is not the same. In which respect, then, is love a principle? It is also absurd that strife should be indestructible; for strife is, for him, the very nature of the bad. Anaxagoras makes the good a principle as mover; for intellect moves things. But it moves them for the sake of something, so that this something is different, except in the way we ourselves say it, since medicine is in a sense health. It is also absurd that he did not make a contrary to the good and to intellect. But all who speak of contraries make no use of the contraries, unless someone sets this right for them. And no one explains why some things are destructible and others indestructible; for they make all the things that are out of the same principles. Further, some of them make the things that are out of what is not; others, in order not to be forced into this, make all things one. Further, no one explains why there will always be coming-to-be, and what the cause of coming-to-be is. And for those who posit two principles there must necessarily be another principle more sovereign than these, and for those who posit the forms there must be yet another principle more sovereign still:
29| for why did a thing come to partake, or does it partake, of the forms? And for the others it is necessary that there be something contrary to wisdom and to the most precious knowledge, but for us there is not. For there is nothing contrary to the first principle; for all contraries have matter, and these things exist potentially, and ignorance, as the contrary state, is directed toward the contrary object, but to the first principle there is no contrary. Further, if there will be nothing else besides the perceptible things, there will be no principle, no order, no coming-to-be, and no heavenly things, but always a principle of the principle, as with the theologians and all the natural philosophers. But if the forms or the numbers will exist, they are the cause of nothing; or if not that, at least not of motion. Further, how will there be magnitude and continuity out of things that have no magnitude? For number will not produce continuity, either as mover or as form. But then again, none of the contraries will be at once productive and capable of causing motion; for it could then not exist. But then again, acting is posterior to potentiality. The things that are, then, are not eternal. But they are; so one of these claims must be rejected. How this is to be done has been stated. Further, by what are the numbers one, or the soul and the body, or in general the form and the thing, no one at all explains;
30| nor is it possible to explain it, unless one says, as we do, that what moves them makes them one. Those who say that the mathematical number is first, and so on with one substance after another always dependent on it, and separate principles for each, [1076a] make the substance of the universe episodic (for one substance contributes nothing to another, whether it exists or not) and posit many principles; but the things that are do not choose to be governed badly. 'The rule of many is not good; let there be one ruler.'