[314a1] 1 · Our next task is to study coming-to-be and passing-away. We are to distinguish the causes, and to state the definitions, of these processes considered in general—as they apply uniformly to all the things that come-to-be and pass-away by nature. Further, we are to study growth and alteration. We must inquire what [5] each of them is; and whether alteration has the same nature as coming-to-be, or whether to these different names there correspond two separate processes with distinct natures.
On this question, indeed, the early philosophers are divided. Some of them assert that the so-called unqualified coming-to-be is alteration, while others maintain that alteration and coming-to-be are distinct. For those who say that the universe is one something (i.e. those who generate all things out of one thing) are [10] bound to assert that coming-to-be is alteration, and that whatever comes-to-be in the proper sense of the term is being altered; but those who make the matter of things more than one must distinguish coming-to-be from alteration. To this latter class belong Empedocles, Anaxagoras, and Leucippus. And yet Anaxagoras failed to understand his own utterance. He says, at all events, that coming-to-be and passing-away are the same as being altered; yet, in common with other thinkers, he [15] affirms that the elements are many. Thus Empedocles holds that the corporeal elements are four, while all the elements—including those which initiate movement—are six in number; whereas Anaxagoras agrees with Leucippus and Democritus that the elements are infinite.
20 (Anaxagoras posits as elements the ‘homoeomeries’, viz. bone, flesh, marrow, and everything else which is such that part and whole are synonymous; while Democritus and Leucippus say that there are indivisible bodies, infinite both in number and in the varieties of their shapes, of which everything else is composed—the compounds differing one from another according to their constituents and to the positions, and groupings of their constituents.)
For the views of the school of Anaxagoras seem diametrically opposed to those [25] of the followers of Empedocles. Empedocles says that Fire, Water, Air, and Earth are four elements, and are thus simple, rather than flesh, bone, and bodies which, like these, are ‘homoeomeries’. But the followers of Anaxagoras regard the ‘homoeomeries’ as simple and elements, whilst they affirm that Earth, Fire, Water, and Air are composite; for each of these is (according to them) a seed-bed of the ‘homoeomeries’.
Those, then, who construct all things out of a single element, must maintain [314b1] that coming-to-be and passing-away are alteration. For they must affirm that the underlying something always remains identical and one; and change of such a kind is what we call altering. Those, on the other hand, who make the ultimate kinds of [5] things more than one, must maintain that alteration is distinct from coming-to-be; for coming-to-be and passing-away result from the consilience and the dissolution of the many kinds. That is why Empedocles too uses language to this effect, when he says ‘There is no coming-to-be of anything, but only a mingling and a divorce of what has been mingled’. 1 Thus it is clear that their account in these terms is in accordance with their assumption, and that they do in fact so describe things; [10] nevertheless, they too must recognize alteration as a fact distinct from coming-to-be, though it is impossible for them to do so consistently with what they say.
That we are right in this criticism is easy to perceive. For while the substance of the thing remains unchanged, we see it altering just as we see in it the changes of magnitude called growth and diminution. Nevertheless, the statements of those who [15] posit more principles than one make alteration impossible. For the affections in respect of which we say that alteration occurs (I mean, e.g., hot-cold, white-black, dry-moist, soft-hard, and so forth) are differences characterizing the elements. Empedocles says: [20]
The sun everywhere bright to see, and hot;
The rain everywhere dark and cold;2
and he characterizes his remaining elements in a similar manner. Since, therefore, it is not possible for Fire to become Water, or Water to become Earth, neither will it be possible for anything white to become black, or anything soft to become hard; and the same argument applies to all the other qualities. Yet this is what alteration [25] essentially is.
It follows, as an obvious corollary, that a single matter must always be assumed as underlying the contraries in any change—whether change of place, or growth and diminution, or alteration; further, that the being of this matter and the being of alteration must stand and fall together. For if the change is alteration, then the substratum is a single element; i.e. all things which admit of change into one [315a1] another have a single matter. And, conversely, if the substratum is one, there is alteration.
Empedocles, indeed, seems to contradict his own statements as well as the [5] phenomena. For he denies that any one of his elements comes-to-be out of any other, insisting on the contrary that they are the things out of which everything else comes-to-be; and yet (having brought the entirety of existing things, except Strife, together into one) he maintains, simultaneously with this denial, that each thing once more comes-to-be out of the One. Hence it was clearly out of a One that this came-to-be Water, and that Fire, various portions of it being separated off by [10] certain characteristic differences or affections—as indeed he calls the sun white and hot, and the earth heavy and hard. If, therefore, these differences be taken away (for they can be taken away, since they came-to-be), it will clearly be inevitable for Earth to come-to-be out of Water and Water out of Earth, and for each of the other elements to undergo a similar transformation—not only then, but [15] also now—if they change their affections. And, to judge by what he says, they can be attached to things and can again be separated from them, especially since Strife and Love are still fighting with one another. It was owing to this same conflict that the elements were generated from a One at the former period for presumably Fire, Earth, and Water had no distinctive existence at all while merged in one.
It is not clear either whether we should regard as his first principle the One or [20] the Many—i.e. Fire and Earth, and the bodies co-ordinate with these. For the One is an element in so far as it underlies the process as matter—as that out of which Earth and Fire come-to-be through a change due to the motion. On the other hand, in so far as the One results from composition (by a consilience of the Many), whereas they result from disintegration, the Many are more elementary than the [25] One, and prior to it in their nature.
2 · We have therefore to discuss the whole subject of unqualified coming-to-be and passing-away; we have to inquire whether they do or do not occur and, if they occur, to explain how they occur. We must also discuss the remaining forms of movement, viz. growth and alteration. For Plato only investigated the conditions [30] under which things come-to-be and pass-away; and he discussed not all coming-to-be, but only that of the elements. He asked no questions as to how flesh or bones, or any of the other similar things, come-to-be; nor again did he examine the conditions under which alteration or growth are attributable to things.
In general, no one except Democritus has applied himself to any of these matters in a more than superficial way. Democritus, however, does seem not only to [315b1] have thought about all the problems, but also to be distinguished from the outset by his method. For, as we are saying, none of the other philosophers made any definite statement about growth, except such as any amateur might have made. They said that things grow by the accession of like to like, but they did not proceed to explain the manner of this accession. Nor did they give any account of combination; and they neglected almost every single one of the remaining problems, offering no [5] explanation, e.g., of action or passion—how in natural actions one thing acts and the other undergoes action. Democritus and Leucippus, however, postulate the ‘figures’, and make alteration and coming-to-be result from them. They explain coming-to-be and passing-away by their dissociation and association, but alteration by their grouping and position. And since they thought that the truth lay in the appearance, and the appearances are conflicting and infinitely many, they made the [10] ‘figures’ infinite in number. Hence—owing to the changes of the compound—the same thing seems different to different people: it is transposed by a small additional ingredient, and appears utterly other by the transposition of a single constituent. For Tragedy and Comedy are both composed of the same letters. [15]
Since almost all our predecessors think that coming-to-be is distinct from alteration, and that, whereas things alter by change of their affections, it is by association and dissociation that they come-to-be and pass-away, we must concentrate our attention on these theses. For they lead to many well-grounded dilemmas. If, on the one hand, coming-to-be is association, many impossible consequences [20] result; and yet there are other arguments, not easy to unravel, which force the conclusion upon us that coming-to-be cannot possibly be anything else. If, on the other hand, coming-to-be is not association, either there is no such thing as coming-to-be at all or it is alteration; or else we must endeavour to unravel this dilemma too—and a stubborn one we shall find it.
The starting-point, in dealing with all these difficulties, is this: ‘Do things [25] come-to-be and alter and grow, and undergo the contrary changes, because the primary things are indivisible magnitudes? Or is no magnitude indivisible?’ For the answer we give to this question makes the greatest difference. And again, if the primary things are indivisible magnitudes, are these bodies, as Democritus and Leucippus maintain? Or are they planes, as is asserted in the Timaeus? [30]
To resolve bodies into planes and no further—this, as we have also remarked elsewhere, is in itself unreasonable. Hence there is more to be said for the view that there are indivisible bodies. Yet even these involve much that is unreasonable. Still, as we have said, it is possible to construct alteration and coming-to-be with them, if one transposes the same by ‘turning’ and ‘intercontact’, and by the varieties of the figures, as Democritus does. (His denial of the reality of colour is a corollary from [316a1] this position; for, according to him, things get coloured by ‘turning’.) But the possibility of such a construction no longer exists for those who divide bodies into planes. For nothing except solids results from putting planes together: they do not even attempt to generate any affection from them.
Lack of experience diminishes our power of taking a comprehensive view of the [5] admitted facts. Hence those who dwell in intimate association with nature and its phenomena are more able to lay down principles such as to admit of a wide and coherent development; while those whom devotion to abstract discussions has rendered unobservant of the facts are too ready to dogmatize on the basis of a few observations. The rival treatments of the subject now before us will serve to [10] illustrate how great is the difference between a scientific and a dialectical method of inquiry. For, whereas the one school argues that there must be atomic magnitudes because otherwise The Triangle will be more than one, Democritus would appear to have been convinced by arguments appropriate to the subject, i.e. drawn from the science of nature. Our meaning will become clear as we proceed.
[15] For to suppose that a body (i.e. a magnitude) is divisible through and through, and that this division is possible, involves a difficulty. What will there be in the body which escapes the division?
If it is divisible through and through, and if this division is possible, then it might be, at one and the same moment, divided through and through, even though the dividings had not been effected simultaneously; and the actual occurrence of this result would involve no impossibility. Hence whenever a body is by nature [20] divisible through and through, whether by bisection, or generally by any method whatever nothing impossible will have resulted if it has actually been divided—for if it has been divided into innumerable parts, themselves divided innumerable times, nothing impossible will have resulted, though perhaps nobody in fact could so divide it.
Since, therefore, the body is divisible through and through, let it have been divided. What, then, will remain? A magnitude? No: that is impossible, since then [25] there will be something not divided, whereas ex hypothesi the body was divisible through and through. But if it be admitted that neither a body nor a magnitude will remain, and yet division is to take place, the body will either consist of points (and its constituents will be without magnitude) or it will be absolutely nothing. If the latter, then it might both come-to-be out of nothing and exist as a composite of nothing; and thus presumably the whole body will be nothing but an appearance. [30] But if it consists of points, it will not possess any magnitude. For when the points were in contact and coincided to form a single magnitude, they did not make the whole any bigger (since, when the body was divided into two or more parts, the whole was not a bit smaller or bigger than it was before the division); hence, even if all the points be put together, they will not make any magnitude.
But suppose that, as the body is being divided, something like sawdust is [316b1] produced, and that in this sense a body comes away from the magnitude, even then the same argument applies. For in what sense is that divisible? But if what came away was not a body but a separable form or affection, and if the magnitude is points or contacts thus qualified, it is absurd that a magnitude should consist of [5] things which are not magnitudes. Moreover, where will the points be? And are they motionless or moving? And every contact is always a contact of two somethings, i.e. there is always something besides the contact or the division or the point.
These, then, are the difficulties resulting from the supposition that any and every body, whatever its size, is divisible through and through. There is, besides, this further consideration. If, having divided a piece of wood or anything else, I put it [10] together, it is again equal to what it was, and is one. Clearly this is so, whatever the point at which I cut the wood. The wood, therefore, has been divided potentially through and through. What, then, is there in the wood besides the division? For even if we suppose there is some affection, yet how is the wood dissolved into such constituents and how does it come-to-be out of them? Or how are such constituents separated?
[15] Since, therefore, it is impossible for magnitudes to consist of contacts or points, there must be indivisible bodies and magnitudes. Yet, if we do postulate the latter, we are confronted with equally impossible consequences, which we have examined in other works. But we must try to disentangle these perplexities, and must therefore formulate the whole problem over again.
On the one hand, then, it is in no way absurd that every perceptible body should be indivisible as well as divisible at any and every point. For the second [20] predicate will attach to it potentially, but the first actually. On the other hand, it would seem to be impossible for a body to be potentially divisible at all points simultaneously. For if it were possible, then it might actually occur, with the result, not that the body would simultaneously be actually both (indivisible and divided), but that it would be simultaneously divided at any and every point. Consequently, [25] nothing will remain and the body will have passed-away into what is incorporeal; and so it might come-to-be again either out of points or absolutely out of nothing. And how is that possible?
But now it is obvious that a body is in fact divided into separable magnitudes which are smaller at each division—into magnitudes which fall apart from one another and are actually separated. Hence the process of dividing a body part by part is not a breaking up which could continue ad infinitum; nor can a body be [30] simultaneously divided at every point (for that is not possible) but only up to a certain limit. The necessary consequence—especially if coming-to-be and passing-away are to take place by association and dissociation respectively—is that a body must contain atomic magnitudes which are invisible.
Such is the argument which is believed to establish the necessity of atomic [317a] magnitudes: we must now show that it conceals a faulty inference, and exactly where it conceals it.
For, since no point is contiguous to another point, magnitudes are divisible through and through in one sense, and yet not in another. When, however, it is admitted that a magnitude is divisible through and through, it is thought that there is a point not only anywhere, but also everywhere, in it: hence it follows that the [5] magnitude must be divided away into nothing. For there is a point everywhere within it, so that it consists either of contacts or of points. But it is only in one sense that the magnitude is divisible through and through, viz. in so far as there is one point anywhere within it and all its points are everywhere within it if you take them singly. But there are not more points than one anywhere within it, for the points are not consecutive; hence it is not divisible through and through. For if it were, then, if it be divisible at its centre, it will be divisible also at a contiguous point. But it is not [10] so divisible; for position is not contiguous to position, nor point to point (i.e. division or composition).
Hence there are both association and dissociation, though neither into, and out of, atomic magnitudes (for that involves many impossibilities), nor so that division takes place through and through—for this would have resulted if point had been [15] contiguous to point; but dissociation takes place into small (i.e. relatively small) parts, and association takes place out of relatively small parts.
It is wrong, however, to suppose, as some assert, that coming-to-be in the unqualified and complete sense is defined by association and dissociation, while the change that takes place in what is continuous is alteration. On the contrary, this is where the whole error lies. For unqualified coming-to-be and passing-away are not [20] effected by association and dissociation. They take place when a thing changes, from this to that, as a whole. But they suppose that all such change is alteration; whereas in fact there is a difference. For in that which underlies the change there is a factor corresponding to the definition and there is a material factor. When, then, [25] the change is in these factors, there will be coming-to-be or passing-away; but when it is in the thing’s affections and accidental, there will be alteration.
Dissociation and association make a thing susceptible to passing-away. For if water has first been dissociated into smallish drops, air comes-to-be out of it more quickly; while, if drops of water have first been associated, air comes-to-be more [30] slowly. This will become clearer in the sequel. Meantime, so much may be taken as established—viz. that coming-to-be cannot be association of the kind some assert it to be.
3 · Now that we have established that we must first consider whether there is anything which comes-to-be and passes-away in the unqualified sense; or whether nothing comes-to-be in this strict sense, but everything always comes-to-be something and out of something—I mean, e.g., comes-to-be healthy out of being ill and ill out of being healthy, comes-to-be small out of being big and big out of being [317b1] small, and so on in every other instance. For if there is to be coming-to-be without qualification, something must—without qualification—come-to-be out of not-being, so that it would be true to say that not-being is an attribute of some things. For qualified coming-to-be is a process out of qualified not-being (e.g. out of [5] not-white or not-beautiful), but unqualified coming-to-be is a process out of unqualified not being.
Now ‘unqualified’ means either the primary within each category, or the universal, i.e. the all-comprehensive. Hence, if it signifies the primary, there will be a coming-to-be of a substance out of not-substance. But that which is not a substance or a ‘this’ clearly cannot possess predicates drawn from any of the other [10] categories either—e.g. we cannot attribute to it any quality, quantity, or position. Otherwise, properties would admit of existence in separation from substances. If, on the other hand, it means what is not in any sense at all, it will be a universal negation of all forms of being, so that what comes-to-be will have to come-to-be out of nothing.
Although we have rehearsed and settled these problems at greater length in another work,3 we must mention them briefly here too.
[15] In one sense things come-to-be out of that which has no being without qualification; yet in another sense they come-to-be always out of what is. For there must pre-exist something which potentially is, but actually is not; and this something is spoken of both as being and as not-being.
These distinctions may be taken as established; but even then it is extraordinarily difficult to see how there can be unqualified coming-to-be (whether we [20] suppose it to occur out of what potentially is, or in some other way), and we must recall this problem for further examination. For the question might be raised whether substance (i.e. the ‘this’) comes-to-be at all. Is it not rather the ‘such’, the ‘so great’, or the ‘somewhere’, which comes-to-be? And the same question might be raised about ‘passing-away’ also. For if a substantial thing comes-to-be, it is clear that there will be (not actually, but potentially) a substance, out of which its coming-to-be will proceed and into which the thing that is passing-away will necessarily change. Then will any predicate belonging to the [25] remaining categories attach actually to this? In other words, will that which is only potentially a ‘this’ (which only potentially is), while without qualification it is not a ‘this’ (i.e. is not), possess, e.g., any determinate size or quality or position? For if it possesses none, but all of them potentially, the result is that a being, which is not a determinate being, is capable of separate existence; and in addition that coming-to-be proceeds out of nothing pre-existing—a thesis which, more than any other, preoccupied and alarmed the earliest philosophers. On the other hand if, although it [30] is not a ‘this somewhat’ or a substance, it is to possess some of the remaining determinations quoted above, then (as we said) properties will be separable from substances.
We must therefore concentrate all our powers on the discussion of these difficulties and on the solution of a further question—viz. What is the cause of the perpetuity of coming-to-be? Why is there always unqualified, as well as partial, coming-to-be?
Now the cause is either the source from which, as we say, the movement [318a1] originates, or the matter. It is the material cause that we have here to state. For, as to the other cause, we have already explained (in our treatise on Motion)4 that it involves something immovable through all time and something always being moved. And the treatment of the first of these—of the immovable source—belongs to the [5] province of the other and prior philosophy; while as regards that which sets everything else in motion by being itself continuously moved, we shall have to explain later5 which amongst the particular causes exhibits this character. But at present we are to state the cause classed under the head of matter, to which it is due that passing-away and coming-to-be never fail to occur in nature. For perhaps, if [10] we succeed in clearing up this question, it will simultaneously become clear what account we ought to give of that which perplexed us just now, i.e. of unqualified passing-away and coming-to-be.
Our new question too—viz. What is the cause of the unbroken continuity of coming-to-be?—is sufficiently perplexing, if in fact what passes-away vanishes into what is not and what is not is nothing (since what is not is neither a thing, nor possessed of a quality or quantity, nor in any place). If, then, some one of the things which are is constantly disappearing, why has not the universe been used up long ago and vanished away—assuming of course that the material of all the several comings-to-be was finite? For, presumably, the unfailing continuity of coming-to-be cannot be attributed to the infinity of the material. That is impossible; for [20] nothing is actually infinite, and potentially things are infinite by way of division; so that we should have to suppose there is only one kind of coming-to-be, viz. one which never fails, such that what comes-to-be is on each successive occasion smaller than before. But in fact this is not what we see occurring.
Why, then, is this form of change necessarily ceaseless? Is it because the passing-away of this is a coming-to-be of something else, and the coming-to-be of [25] this a passing-away of something else?
The cause implied in this solution must be considered adequate to account for coming-to-be and passing-away in their general character as they occur in all existing things alike. Yet, if the same process is a coming-to-be of this but a [30] passing-away of that, and a passing-away of this but a coming-to-be of that, why are some things said to come-to-be and pass-away without qualification, but others only with a qualification?
This question must be investigated once more, for it demands some explanation. For we say ‘it is now passing-away’ without qualification, and not merely ‘this is passing-away’; and we call this change coming-to-be, and that passing-away, without qualification. And so-and-so comes-to-be something, but does not come-to-be without qualification; for we say that the student comes-to-be learned, not comes-to-be without qualification.
[318b1] Now we often divide terms into those which signify a ‘this somewhat’ and those which do not. And the issue we are investigating results from this; for it makes a difference into what the changing thing changes. Perhaps, e.g., the passage into Fire is coming-to-be unqualified, but passing-away-of something (e.g. of Earth); [5] whilst the coming-to-be of Earth is qualified (not unqualified) coming-to-be, though unqualified passing-away (e.g. of Fire). This would be the case on the theory set forth by Parmenides; for he says that the things into which change takes place are two, and he asserts that these two, viz. what is and what is not, are Fire and Earth. Whether we postulate these, or other things of a similar kind, makes no difference. For we are trying to discover not what undergoes these changes, but what is their characteristic manner. The passage, then, into what without qualification [10] is not is unqualified passing-away, while the passage into what is without qualification is unqualified coming-to-be. Hence however they are characterized—whether as Fire and Earth, or as some other couple—the one of them will be a being and the other a not-being.
We have thus stated one way in which unqualified will be distinguished from qualified coming-to-be and passing-away; but they are also distinguished according to the material of the changing thing. For a material, whose constitutive differences signify [15] more a ‘this somewhat’, is itself more a substance while a material, whose constitutive differences signify privation, is more not-being. (Suppose, e.g., that the hot is a positive predication, i.e. a form, whereas cold is a privation, and that Earth and Fire differ from one another by these constitutive differences.)
The opinion, however, which most people are inclined to prefer, is that the distinction depends upon the difference between the perceptible and the imperceptible. [20] Thus, when there is a change into perceptible material, people say there is coming-to-be; but when there is a change into invisible material, they call it passing-away. For they distinguish what is and what is not by their perceiving and not perceiving, just as what is knowable is and what is unknowable is not—perception on their view having the force of knowledge. Hence, just as they deem themselves to live and to be in virtue of their perceiving or their capacity to perceive, [25] so too they deem the things to be qua perceived or perceptible—and in this they are in a sense on the track of the truth, though what they actually say is not true.
Thus unqualified coming-to-be and passing-away turn out to be different according to common opinion from what they are in truth. For Wind and Air are in truth more a ‘this somewhat’ or a ‘form’ than Earth. But they are less real to perception—which explains why things are commonly said to ‘pass-away’ without [30] qualification when they change into Wind and Air, and to ‘come-to-be’ when they change into what is tangible, i.e. into Earth.
We have now explained why there is unqualified coming-to-be (though it is a passing-away-of-something) and unqualified passing-away (though it is a coming-to-be-of-something). For this distinction depends upon a difference in the material—upon whether the material is or is not a substance, or upon whether it is more or [319a1] less substantial, or upon whether the material out of which and into which the change occurs is more or less perceptible.
But why are some things said to come-to-be without qualification, and others only to come-to-be so-and-so, in cases different from the one we have been considering where two things come-to-be reciprocally out of one another? For at present we have explained no more than why, when two things change reciprocally [5] into one another, we do not attribute coming-to-be and passing-away uniformly to them both, although every coming-to-be is a passing-away of something else and every passing-away some other thing’s coming-to-be. But the question subsequently formulated involves a different problem—viz. why, although the learning thing is said to come-to-be learned but not to come-to-be without qualification, yet the [10] growing thing is said to come-to-be.
The distinction here turns upon the difference of the Categories. For some things signify a this somewhat, others a such, and others a so-much. Those things, then, which do not signify substance, are not said to come-to-be without qualification, but only to come-to-be so-and-so. Nevertheless, in all changing things alike, we speak of coming-to-be when the thing comes-to-be something in one of the two columns—e.g. in substance, if it comes-to-be fire but not if it comes-to-be earth; and [15] in quality, if it comes-to-be learned but not when it comes-to-be ignorant.
We have explained why some things come-to-be without qualification, but not others—both in general, and also when the changing things are substances; and we have stated that the substratum is the material cause of the continuous occurrence of coming-to-be, because it is such as to change from contrary to contrary and [20] because, in substances, the coming-to-be of one thing is always a passing-away of another, and the passing-away of one thing is always another’s coming-to-be. But there is no need even to discuss why coming-to-be continues though things are constantly being destroyed. For just as people speak of a passing-away without qualification when a thing has passed into what is imperceptible and what is not, so also they speak of a coming-to-be out of a not-being when a thing emerges from an [25] imperceptible. Whether, therefore, the substratum is or is not something, what comes-to-be emerges out of a not-being; so that a thing comes-to-be out of a not-being just as much as passes-away into what is not. Hence it is reasonable enough that coming-to-be should never fail. For coming-to-be is a passing-away of what is not and passing-away is a coming-to-be of what is not.
But what about that which without qualification is not? Is it one of the two [30] contrary poles of the change—e.g. is earth (i.e. the heavy) a not-being, but fire (i.e. the light) a being? Or, on the contrary, does what is include earth as well as fire, whereas what is not is matter—the matter of earth and fire alike? And again, is the matter of each different? Or is it the same, since otherwise they would not [319b1] come-to-be reciprocally out of one another, i.e. contraries out of contraries? For these things—fire, earth, water, air—are characterized by the contraries.
4 · Perhaps the solution is that their matter is in one sense the same, but in another sense different. For that which underlies them, whatever its nature may be [5] is the same; but its being is not the same. So much, then, on these topics. Next we must state what the difference is between coming-to-be and alteration—for we maintain that these changes are distinct from one another.
Since, then, we must distinguish the substratum, and the property whose nature it is to be predicated of the substratum; and since change of each of these [10] occurs; there is alteration when the substratum is perceptible and persists, but changes in its own properties, the properties in question being either contraries or intermediates. The body, e.g., although persisting as the same body, is now healthy and now ill; and the bronze is now spherical and at another time angular, and yet remains the same bronze. But when nothing perceptible persists in its identity as a [15] substratum, and the thing changes as a whole (when e.g. the seed as a whole is converted into blood, or water into air, or air as a whole into water), such an occurrence is a coming-to-be of one substance and a passing-away of the other—especially if the change proceeds from an imperceptible something to something perceptible (either to touch or to all the senses), as when water comes-to-be out of, [20] or passes-away into, air; for air is pretty well imperceptible. If, however, in such cases, any property (being one of a pair of contraries) persists, in the thing that has come-to-be, the same as it was in the thing which has passed-away—if, e.g., when water comes-to-be out of air, both are transparent or cold—the second thing, into which the first changes, must not be a property of this. Otherwise the change will be alteration.
[25] Suppose, e.g., that the musical man passed-away and an unmusical man came-to-be, and that the man persists as something identical. Now, if musicalness (and unmusicalness) had not been in itself a property of the man, these changes would have been a coming-to-be of unmusicalness and a passing-away of musicalness; but in fact a property of the persistent thing. (Hence these are properties of the [30] man, and of musical man and unmusical man, there is a passing-away and a coming-to-be.) Consequently such changes are alteration.
When the change from contrary to contrary is in quantity, it is growth and diminution; when it is in place, it is locomotion; when it is in property, i.e. in quality, it is alteration; but when nothing persists of which the resultant is a property (or an [320a1] accident in any sense of the term), it is coming-to-be, and the converse change is passing-away.
5 · Matter, in the most proper sense of the term, is to be identified with the substratum which is receptive of coming-to-be and passing-away; but the substratum of the remaining kinds of change is also, in a certain sense, matter, because all these substrata are receptive of contrarieties of some kind. So much, then, as an answer to the questions whether coming-to-be occurs or not, and how it occurs, and [5] what alteration is; but we have still to treat of growth. We must explain wherein growth differs from coming-to-be and from alteration, and what is the process of growing and the process of diminishing in each and all of the things that grow and diminish. [10]
Hence our first question is this: Do these changes differ from one another solely because of a difference in their respective spheres? In other words, do they differ because, while a change from this to that (viz. from potential substance to actual substance) is coming-to-be, a change in the sphere of magnitude is growth and one in the sphere of quality is alteration—both growth and alteration being changes from what is potentially to what is actually? Or is there also a difference in [15] the manner of the change, since it is evident that, whereas neither what is altering nor what is coming-to-be necessarily changes its place, what is growing or diminishing does, though in a different manner from that in which the moving thing does? For that which is being moved changes its place as a whole; but the growing [20] thing changes its place like a metal that is being beaten, retaining its position as a whole while its parts change their places. (But not in the same way as the parts of a sphere; for they change their places while the whole continues to occupy an equal place, but the parts of the growing thing change over an ever-increasing place and the parts of the diminishing thing over an ever-diminishing area.)
It is clear, then, that these changes—the changes of that which is coming-to-be, [25] of that which is altering, and of that which is growing—differ in manner as well as in sphere. But how are we to conceive the sphere of the change which is growth and diminution? The sphere of growing and diminishing is believed to be magnitude. Are we to suppose that body and magnitude come-to-be out of something which, though potentially magnitude and body, is actually incorporeal and devoid of magnitude? And since this description may be understood in two different ways, in which of these two ways are we to apply it to the process of [30] growth? Is the matter, out of which growth takes place, separate and existing alone by itself, or contained in another body?
Perhaps it is impossible for growth to take place in either of these ways. For since the matter is separate, either it will occupy no place (as if it were a point), or it [320b1] will be a void, i.e. a non-perceptible body. But the first of these is impossible, and in the second the matter must be in something. For since what comes-to-be out of it will always be somewhere, it too must be somewhere—either intrinsically or indirectly. But if it is to be in something and yet remains separate in such a way that [5] it is in no sense a part of that body (neither intrinsically nor accidentally, many impossibilities will result. It is as if we were to suppose that when, e.g., air comes-to-be out of water the process were due not to a change of the water, but to the matter of the air being contained in the water as in a vessel. For there is nothing [10] to prevent an indeterminate number of matters being thus contained in the water, so that they might come-to-be actually; and we do not in fact see air coming-to-be out of water in this fashion, viz. withdrawing out of it and leaving it to persist.
It is therefore better to suppose that in all instances of coming-to-be the matter is inseparable, being numerically identical and one, though not one in definition. [15] But the same reasons also forbid us to regard the matter of the body as points or lines. The matter is that of which points and lines are limits, and it is something that can never exist without quality and without form.
Now it is no doubt true, as we have also established elsewhere, that one thing comes-to-be (in the unqualified sense) out of another thing; and further it is true that the efficient cause of its coming-to-be is either an actual thing (which is the [20] same as the effect either generically or specifically, as e.g. fire is the efficient cause of fire or one man of another), or an actuality (for what is hard does not come-to-be through what is hard).6 Nevertheless, since there is also a matter out of which corporeal substance itself comes-to-be (corporeal substance, however, already characterized as such-and-such a determinate body, for there is no such thing as body in general), this same matter is also the matter of magnitude and quality—being separable from these matters in definition, but not separable in place unless [25] qualities are, in their turn, separable.
It is evident, from the preceding discussion of difficulties, that growth is not a change out of something which, though potentially a magnitude, actually possesses no magnitude. For, if it were, the void would exist in separation; but we have explained in a former work7 that this is impossible. Moreover, a change of that kind is not peculiarly distinctive of growth, but characterizes coming-to-be in general. [30] For growth is an increase, and diminution is a lessening, of the magnitude which is there already—that, indeed, is why the growing thing must possess some magnitude. Hence growth must not be regarded as a process from a matter without magnitude to an actuality of magnitude; for this would be a body’s coming-to-be rather than its growth.
We must therefore come to closer quarters and as it were grapple with our [321a1] enquiry from its beginning to determine the precise character of the growing and diminishing whose causes we are investigating.
It is evident that any and every part of the growing thing has increased, and that similarly in diminution every part has become smaller; also that a thing grows by the accession, and diminishes by the departure, of something. Hence it must [5] grow by the accession either of something incorporeal or of a body. Now, if it grows by the accession of something incorporeal, there will exist separate a void; but (as we have stated before) it is impossible for a matter of magnitude to exist separate. If, on the other hand, it grows by the accession of a body, there will be two bodies—that which grows and that which increases it—in the same place; and this too is impossible.
But neither is it open to us to say that growth or diminution occurs in the way [10] in which e.g. air is generated from water. For, although the volume has then become greater, the change will not be growth, but a coming-to-be of the one—viz. of that into which the change is taking place—and a passing-away of the contrasted body. It is not a growth of either. Nothing grows in the process; unless indeed there be something common to both things (to that which is coming-to-be and to that which passed-away), e.g. body, and this grows. The water has not grown, nor has the air; [15] but the former has passed-away and the latter has come-to-be, and—if anything has grown—there has been a growth of body. Yet this too is impossible. For our account of growth must preserve the characteristics of that which is growing and diminishing. And these characteristics are three: any and every part of the growing magnitude is made bigger (e.g. if flesh grows, every particle of the flesh gets [20] bigger); by the accession of something; and thirdly in such a way that the growing thing is preserved and persists. For whereas a thing does not persist in the processes of unqualified coming-to-be or passing-away, that which grows or alters persists in its identity through the altering and through the growing or diminishing, though the quality (in alteration) and the size (in growth) do not remain the same. Now if [25] the generation of air from water is to be regarded as growth, a thing might grow without the accession (and without the persistence) of anything, and diminish without the departure of anything—and that which grows need not persist. But this characteristic must be preserved; for the growth we are discussing has been assumed to be thus characterized.
One might raise a further difficulty. What is that which grows? Is it that to [30] which something is added? If, e.g., a man grows in his shin, is it the shin which is greater—but not that whereby he grows, viz. not the food? Then why have not both grown? For when A is added to B, both A and B are greater, as when you mix wine with water; for each ingredient is alike increased in volume. Perhaps the explanation is that the substance of the one remains unchanged, but the substance of the other (viz. of the food) does not. For indeed, even in the mixture of wine and water, it is the prevailing ingredient which is said to have increased in volume. We say, e.g., that the wine has increased, because the whole mixture acts as wine but not as [321b1] water. A similar principle applies also to alteration. Flesh is said to have been altered if, while its character and essence remain, some property which was not there before, now qualifies it in its own right; on the other hand, that whereby it has been altered may have undergone no change, though sometimes it too has been [5] affected. The altering agent, however, and the source of the process are in the growing thing and in that which is being altered; for the mover is in these. No doubt what has come in, may sometimes expand as well as the body that has consumed it (that is so, e.g., if, after having come in, it is converted into wind), but when it has undergone this change it has passed-away; and the mover is not in it. [10]
We have now developed the difficulties sufficiently and must therefore try to find a solution of the problem while preserving the theses that the growing thing persists, that it grows by the accession (and diminishes by the departure) of something, further that every perceptible particle of it has become either larger or [15] smaller, the growing body is not void and that yet there are not two magnitudes in the same place, and that it does not grow by the accession of something incorporeal.
We must grasp the cause after previously determining, first, that the non-homoeomerous parts grow by the growth of the homoeomerous parts (for every organ is composed of these); and secondly, that flesh, bone, and every such [20] part—like every other thing which has its form in matter—has a twofold nature; for the form as well as the matter is called flesh or bone.
Now, that any and every part should grow—and grow by the accession of something—is possible in respect of form, but not in respect of matter. For we must think of the process as being like what happens when a man measures water with [25] the same measure; for what comes-to-be is always different. And it is in this sense that the matter of the flesh grows, some flowing out and some flowing in; not in the sense that fresh matter accedes to every particle of it. There is, however, an accession to every part of its figure or form.
That growth has taken place proportionally, is more manifest in the non-homoeomerous parts—e.g. in the hand. For there the fact that the matter is distinct [30] from the form is more manifest than in flesh and the homoeomeries. That is why there is a greater tendency to suppose that a corpse still possesses flesh and bone than that it still has a hand or an arm.
Hence in one sense it is true that any and every part of the flesh has grown; but in another sense it is false. For there has been an accession to every part of the flesh in respect to its form, but not in respect to its matter. The whole, however, has [322a1] become larger because of the accession of something, which is called food and is contrary to flesh, and the transformation of this food into the same form as that of flesh—as if, e.g., moist were to accede to dry and, having acceded, were to be transformed and to become dry. For in one sense like grows by like, but in another sense by unlike.
One might discuss what must be the character of that whereby a thing grows. [5] Clearly it must be potentially that which is growing—potentially flesh, e.g., if it is flesh that is growing. Actually, therefore, it must be other than the growing thing. This, then, has passed-away and come-to-be flesh. But it has not been transformed into flesh alone by itself (for that would have been a coming-to-be, not a growth); rather, the growing thing has done so by the food. In what way, then, has the food been modified by the growing thing? Perhaps we should say that it has been mixed with it, as if one were to pour water into wine and the wine were able to convert the [10] new ingredient into wine. And as fire lays hold of the inflammable, so the active principle of growth, dwelling in the growing thing (i.e. in that which is actually flesh), lays hold of an acceding food which is potentially flesh and converts it into actual flesh. The acceding food, therefore, must be together with the growing thing; for if it were apart from it, the change would be a coming-to-be. For it is possible to [15] produce fire by piling logs on to the already burning fire. That is growth. But when the logs themselves are set on fire, that is coming-to-be.
Quantity in general does not come-to-be any more than animal which is neither man nor any other of the specific forms of animal—the universal in this case corresponds to the quantity in that. But what does come-to-be in growth is flesh or bone—or a hand or arm and their homoeomeries. Such things come-to-be, then, by the accession not of a quantity of flesh but of a quantity of something. In so far as [20] this acceding food is potentially the double result—e.g. is potentially a quantity of flesh—it produces growth; for it is bound to become actually both a quantity and flesh. But in so far as it is potentially flesh only, it nourishes; for it is thus that nutrition and growth differ by their definition. That is why a body’s nutrition continues so long as it is kept alive (even when it is diminishing), though not its growth; and why nutrition, though the same as growth, is yet different from it in its [25] being. For in so far as that which accedes is potentially a quantity of flesh it tends to increase flesh; whereas, in so far as it is potentially flesh only, it is nourishment.
The form is a kind of power in matter—a duct, as it were. If, then, a matter accedes which is potentially a duct and also potentially possesses determinate [30] quantity, then these ducts will become bigger. But if it is no longer able to act just as water, continually mixed in greater and greater quantity with wine, in the end makes the wine watery and converts it into water—then it will cause a diminution of the quantum; though still the form persists.
6 · We must first investigate the matter, i.e. the so-called elements. We must [322b1] ask whether they really are elements or not, i.e. whether each of them is eternal or whether there is a sense in which they come-to-be; and, if they do come-to-be, whether all of them come-to-be in the same manner, reciprocally out of one another, or whether one amongst them is something primary. Hence we must begin by explaining certain matters about which the statements now current are vague. [5]
For all those who generate the elements as well as those who generate the bodies that are compounded of the elements—make use of dissociation and association, and of action and passion. Now association is combination; but the meaning of combining has not been clearly explained. Again, without an agent and a patient there cannot be altering any more than there can be dissociating and [10] associating. For not only those who postulate a plurality of elements employ their reciprocal action and passion to generate the compounds: those who derive things from a single element are equally compelled to introduce acting. And in this respect Diogenes is right when he argues that unless all things were derived from one, reciprocal action and passion could not occur. The hot thing, e.g., would not be [15] cooled and the cold thing in turn be warmed; for heat and cold do not change reciprocally into one another, but what changes (it is clear) is the substratum. Hence, whenever there is action and passion between things, that which underlies them must be a single something. No doubt, it is not true to say that all things are of [20] this character; but it is true of all things between which there is reciprocal action and passion.
But if we must investigate action and passion and combination, we must also investigate contact. For action and passion (in the proper sense of the terms) can [25] only occur between things which are such as to touch one another; nor can things enter into combination at all unless they have come into a certain kind of contact. Hence we must give a definite account of these three things—of contact, combination, and acting.
Let us start as follows. All things which admit of combination must be capable of reciprocal contact; and the same is true of any two things, of which one acts and the other suffers action in the proper sense of the terms. For this reason we must treat of contact first.
[30] Now no doubt, just as every other name is used in many senses (in some cases homonymously, in others one use being derived from other and prior uses), so too is it with contact. Nevertheless contact in the proper sense applies only to things which have position. And position belongs only to those things which also have a [323a1] place; for in so far as we attribute contact to the mathematical things, we must also attribute place to them, whether they exist in separation or in some other fashion. Assuming, therefore, that to touch is—as we have defined it in a previous work 8—to have the extremes together, only those things will touch one another which, being [5] separate magnitudes and possessing position, have their extremes together. And since position belongs only to those things which also have a place, while the primary differentiation of place is the above and the below (and the similar pairs of opposites), all things which touch one another will have weight or lightness—either both these qualities or one or the other of them. But bodies which are heavy or light [10] are such as to act and suffer action. Hence it is clear that those things are by nature such as to touch one another, which (being separate magnitudes) have their extremes together and are able to move, and be moved by, one another.
The manner in which the mover moves the moved is not always the same: whereas one kind of mover can only impart motion by being itself moved, another kind can do so though remaining itself unmoved. Clearly therefore we must [15] recognize a corresponding variety in speaking of the acting thing too; for the mover is said to act and the acting thing to impart motion. Nevertheless there is a difference and we must draw a distinction. For not every mover can act, if we are to contrast agent with patient and patient is to be applied only to those things whose motion is a quality—i.e. a quality, like white or hot, in respect to which they are [20] altered: on the contrary, moving is wider than acting. Still, so much, at any rate, is clear: the things which are such as to impart motion in one sense will touch the things which are such as to be moved by them, but in another sense they will not. But the definition of touching in general applies to things which, having position, are such that one is able to impart motion and the other to be moved, while reciprocal touching holds between two things, one able to impart motion and the other able to be moved in such a way that action and passion are predicable of them.
[25] As a rule, no doubt, if A touches B, B touches A. For indeed practically all the movers within our ordinary experience impart motion by being moved: in their case, what touches must, and evidently does, touch something which touches it. Yet it is possible—as we sometimes say—for the mover merely to touch the moved, and that which touches need not touch a thing which touches it. Nevertheless it is commonly supposed that touching must be reciprocal, because movers which belong to the [30] same kind as the moved impart motion by being moved. Hence if anything imparts motion without itself being moved, it may touch the moved and yet itself be touched by nothing—for we say sometimes that the man who grieves us touches us, but not that we touch him.
7 · The account just given may serve to define the contact which occurs in [323b1] the things of nature. Next in order we must discuss action and passion. Our predecessors’ theories on the subject are conflicting. For most thinkers are unanimous in maintaining that like is always unaffected by like, because (as they argue) neither is more apt than the other either to act or to suffer action, since all [5] the properties which belong to the one belong identically and in the same degree to the other; and that unlikes, i.e. differents, are by nature such as to act and suffer action reciprocally. For even when the smaller fire is destroyed by the greater, it suffers this effect (they say) owing to its contrariety—since the great is contrary to the small. But Democritus dissented from all the other thinkers and maintained [10] a theory peculiar to himself. He asserts that agent and patient are identical, i.e. like. It is not possible (he says) that others, i.e. differents, should suffer action from one another: on the contrary, even if two things, being others, do act in some way on one another, this happens to them not qua others but qua possessing an identical property.
Such, then, are the views, and it looks as if the statements of their advocates [15] were in manifest conflict. But the reason of this conflict is that each group is in fact stating a part, whereas they ought to have taken a view of the subject as a whole. For if two things are like—absolutely and in all respects without difference from one another—it is reasonable to infer that neither is in any way affected by the other. Why, indeed, should the one of them tend to act any more than the other? [20] Moreover, if like can be affected by like, a thing can also be affected by itself; and yet if that were so—if like tended in fact to act qua like—there would be nothing indestructible or immovable, for everything would move itself. And the same consequence follows if the two things are absolutely other, i.e. in no respect identical. Whiteness could not be affected in any way by a line nor a line by [25] whiteness—except perhaps accidentally, viz. if the line happened to be white or black; for unless two things either are, or are composed of, contraries, neither drives the other out of its natural condition. But since only those things which either involve a contrariety or are contraries—and not any things selected at random—are [30] such as to suffer action and to act, agent and patient must be like (i.e. identical) in kind and yet unlike (i.e. contrary) in species. (For by nature body is affected by body, flavour by flavour, colour by colour, and so in general what belongs to any kind by a member of the same kind—the reason being that contraries are in every [324a1] case within a single identical kind, and it is contraries which reciprocally act and suffer action.) Hence agent and patient must be in one sense identical, but in another sense other than (i.e. unlike) one another. And since patient and agent are [5] generically identical (i.e. like) but specifically unlike, while it is contraries that exhibit this character: it is clear that contraries and their intermediates are such as to suffer action and to act reciprocally—for indeed it is these that constitute the entire sphere of passing-away and coming-to-be.
We can now understand why fire heats and the cold thing cools, and in general [10] why the active thing assimilates to itself the patient. For agent and patient are contrary to one another, and coming-to-be is a process into the contrary: hence the patient must change into the agent, since it is only thus that coming-to-be will be a process into the contrary. And, again, it is intelligible that the advocates of both [15] views, although their theories are not the same, are yet in contact with the nature of the facts. For sometimes we speak of the substratum as suffering action (e.g. of the man as being healed, being warmed and chilled, and similarly in all the other cases), but at other times we say what is cold is being warmed, what is sick is being healed: and in both these ways of speaking we express the truth, since in one sense it is the matter, while in another sense it is the contrary, which suffers action. (We make the [20] same distinction in speaking of the agent; for sometimes we say that the man, but at other times that what is hot, produces heat.) Now the one group of thinkers supposed that agent and patient must possess something identical because they fastened their attention on the matter; while the other group maintained the opposite because their attention was concentrated on the contraries.
[25] We must conceive the same account to hold of action and passion as that which is true of being moved and imparting motion. For things are called movers in two ways. Both that which contains the origin of the motion is thought to impart motion (for the origin is first amongst the causes), and also that which is last in relation to the moved thing and to the coming-to-be. A similar distinction holds also of the [30] agent; for we speak both of the doctor and of the wine as healing. Now, in motion, there is nothing to prevent the first mover being unmoved (indeed, as regards some this is actually necessary) although the last mover always imparts motion by being itself moved; and, in action, there is nothing to prevent the first agent being unaffected, while the last agent only acts by suffering action itself. For if things have not the same matter, the agent acts without being affected; thus the art of healing produces health without itself being acted upon in any way by that which is [324b1] being healed. But the food, in acting, is itself in some way acted upon: for, in acting, it is simultaneously heated or cooled or otherwise affected. Now the art of healing corresponds to an origin, while the food corresponds to the last (i.e. contiguous) mover.
Those active powers, then, whose forms are not embodied in matter, are [5] unaffected; but those whose forms are in matter are such as to be affected in acting. For we maintain that one and the same matter is equally, so to say, the basis of either of the two opposed things—being as it were a kind; and that that which can be hot must be made hot, provided the heating agent is there, i.e. comes near. Hence [10] (as we have said) some of the active powers are unaffected while others are such as to be affected; and what holds of motion is true also of the active powers. For as in motion the first mover is unmoved, so among the active powers the first agent is unaffected.
The active power is a cause in the sense of that from which the process originates; but the end, for the sake of which it takes place, is not active. (That is [15] why health is not active, except metaphorically.) For when the agent is there, the patient becomes something; but when states are there, the patient no longer becomes but already is—and forms (i.e. ends) are a kind of state. As to the matter, it (qua matter) is passive. Now fire contains the hot embodied in matter; but a hot separate from matter (if such a thing existed) could not suffer any action. Perhaps, indeed, it is impossible that the hot should exist in separation from matter; but if [20] there are any entities thus separable, what we are saying would be true of them.
We have thus explained what action and passion are, what things exhibit them, why they do so, and in what manner. We must go on to discuss how it is possible for action and passion to take place.
8 · Some philosophers think that the last agent—the agent in the strictest [25] sense—enters in through certain pores, and so the patient suffers action. It is in this way, they assert, that we see and hear and exercise all our other senses. Moreover, according to them, things are seen through air and water and other transparent bodies, because such bodies possess pores, invisible indeed owing to their minute-ness, [30]but close-set and arranged in rows—the more transparent the body, the more so.
Such was the theory which some philosophers (including Empedocles) advanced in regard to the structure of certain bodies. They do not restrict it to the bodies which act and suffer action; but combination too, they say, takes place only between bodies whose pores are in reciprocal symmetry. The most systematic theory, however, and one that applied to all bodies, was advanced by Leucippus and [325a1] Democritus: and, in maintaining it, they took as their starting-point what naturally comes first.
For some of the older philosophers thought that what is must of necessity be one and immovable. The void, they argue, is not; but unless there is a void with a separate being of its own, what is cannot be moved—nor again can it be many, since [5] there is nothing to keep things apart. And they hold that the view that the universe is not continuous but consists of separate things in contact is no different from the view that there are many (and not one) and a void. For if it is divisible through and through, there is no one, and no many either, but the Whole is void; while to maintain that it is divisible at some points, but not at others, looks like an [10] arbitrary fiction. For up to what limit is it divisible? And for what reason is part of the Whole indivisible, i.e. a plenum, and part divided? Further, they maintain, it is equally necessary to deny the existence of motion.
Arguing in this way, therefore, they were led to transcend sense-perception, and to disregard it on the ground that one ought to follow reason; and so they assert that the universe is one and immovable. Some of them add that it is infinite, since [15] the limit (if it had one) would be a limit against the void.
There were, then, certain thinkers who, for the reasons we have stated, enunciated views of this kind about the truth . . . Moreover,9 although these opinions appear to follow logically, yet to believe them seems next door to madness when one considers the facts. For indeed no lunatic seems to be so far out of his [20] senses as to suppose that fire and ice are one: it is only between what is right, and what seems right from habit, that some people are mad enough to see no difference.
Leucippus, however, thought he had a theory which harmonized with sense-perception [25] and would not abolish either coming-to-be and passing-away or motion and the multiplicity of things. Making these concessions to the phenomena and conceding to the Monists that there could be no motion without a void, he states that void is not-being, and no part of what is is not-being; for what is in the strict sense of the term is an absolute plenum. This plenum, however, is not one: on the contrary, it [30] is a many infinite in number and invisible owing to the minuteness of their bulk. The many move in the void (for there is a void); and by coming together they produce coming-to-be, while by separating they produce passing-away. Moreover, they act and suffer action wherever they chance to be in contact (for they are not thereby one), and they generate by being put together and becoming intertwined. From the genuinely one, on the other hand, there never could have come-to-be a multiplicity, nor from the genuinely many a one: that is impossible. But just as [325b1] Empedocles and some of the other philosophers say that things suffer action through their pores, so all alteration and all passion take place in this way, breaking-up (i.e. passing-away) being affected by means of the void, and so too [5] growth—solids creeping in to fill the void places.
Empedocles too is practically bound to adopt the same theory as Leucippus. For he must say that there are certain solids which, however, are indivisible—unless there are continuous pores all through the body. But this is impossible; for then there will be nothing solid beside the pores but all of it will be void. It is necessary, therefore, for his contiguous things to be indivisible, while the intervals between [10] them—which he calls pores—must be void. But this is precisely Leucippus’s theory of action and passion.
Such, approximately, are the accounts of the manner in which some things act while others suffer action. And as regards the Atomists, it is not only clear what their explanation is: it is also obvious that it stands in tolerable consistency with the [15] assumptions they employ. But this is less clear in the case of the other thinkers. It is not clear, for instance, how, on the theory of Empedocles, there is to be passing-away as well as alteration. For the primary bodies of the Atomists—the primary constituents of which bodies are composed, and the ultimate elements into which they are dissolved—are indivisible, differing from one another only in figure. In the [20] philosophy of Empedocles, on the other hand, it is evident that all the other bodies down to the elements have their coming-to-be and their passing-away; but it is not clear how the elements themselves, severally in their aggregated masses, come-to-be and pass-away. Nor is it possible for Empedocles to explain how they do so, since he does not assert that Fire too (and similarly every one of his other elements) [25] possesses elementary constituents of itself, as Plato does in the Timaeus10. For Plato differs from Leucippus inasmuch as the indivisibles of Leucippus are solids, while those of Plato are planes, and are characterized by an infinite variety of figures, while the characterizing figures employed by Plato are limited in number—though both hold that the elements are indivisible and are determined by figures. Thus the [30] comings-to-be and the dissociations result from the indivisibles according to Leucippus through the void and through contact (for it is at the point of contact that each of the composite bodies is divisible), but according to Plato in virtue of contact alone, since he denies there is a void.
Now we have discussed indivisible planes in our earlier discussions.11 But with regard to the assumption of indivisible solids, although we must not now enter upon [35] a detailed study of its consequences, let us make a short digression.
They are committed to the view that every indivisible is incapable alike of [326a1] being acted upon (for nothing can suffer action except through the void) and of producing a quality—no indivisible can be either hard or cold. Yet it is surely absurd that an exception is made of the hot—the hot being assigned as peculiar to the spherical figure; for, that being so, its contrary also (the cold) is bound to belong [5] to another of the figures. If, however, these properties (heat and cold) do belong to the indivisibles, it is a further absurdity that they should not possess heaviness and lightness, and hardness and softness. And yet Democritus says that the more any indivisible exceeds, the heavier it is—so that clearly it will also be hotter. But if that [10] is their character, it is impossible they should not be affected by one another: the slightly hot indivisible, e.g., will suffer action from one which far exceeds it in heat. Again, if any indivisible is hard, there must also be one which is soft; but the soft derives its very name from the fact that it suffers a certain action—for soft is that which yields to pressure. But further, not only is it absurd that no property except [15] figure should belong to the indivisibles: it is also absurd that, if other properties do belong to them, one only of these additional properties should attach to each—e.g. that this indivisible should be cold and that indivisible hot. For, on that supposition, their nature would not even be uniform. And it is equally impossible that more than one of these additional properties should belong to the single indivisible. For, being indivisible, it will possess these properties in the same point—so that, if it suffers action by being chilled, it will also, qua chilled, act or suffer action in some other [20] way. And the same line of argument applies to all the other properties too; for the difficulty we have just raised confronts all who advocate indivisibles (whether solids or planes), since their indivisibles cannot become either rarer or denser inasmuch as there is no void in them. It is a further absurdity that there should be small indivisibles, but not large ones. For it is in fact reasonable that larger bodies should [25] be more liable to fracture than the small ones, since they (viz. the large bodies) are easily broken up because they collide with many other bodies. But why should indivisibility as such be the property of small, rather than of large, bodies? Again, is the nature of all those solids uniform, or do they differ from one another—as if, e.g., [30] some of them were fiery, others earthy in their bulk? For if all of them are uniform in nature, what is it that separated one from another? Or why, when they come into contact, do they not coalesce into one, as drops of water run together when drop touches drop (for the two cases are precisely parallel)? On the other hand if they differ, how are they characterized? It is clear, too, that these, rather than the figures, ought to be postulated as principles and causes from which the phenomena result. Moreover, if they differed in nature, they would both act and suffer action on [326b1] coming into reciprocal contact. Again, what is it which sets them moving? For if their mover is other than themselves, they are such as to suffer action. If, on the other hand, each of them sets itself in motion, either it will be divisible (imparting [5] motion here, being moved there), or contrary properties will attach to it in the same respect and its matter will be identical in potentiality as well as numerically identical.
As to the thinkers who explain modification of property through the movement in the pores, if this is supposed to occur notwithstanding the fact that the pores are filled their postulate of pores is superfluous. For if the whole body suffers action under these conditions, it would suffer action in the same way even if it had no pores [10] but were just its own continuous self. Moreover, how can their account of vision through a medium be correct? It is impossible to penetrate the transparent bodies at their contacts or through their pores if every pore be full. For how will that differ from having no pores at all? The body will be uniformly full throughout. But, [15] further, even if these passages, though they must contain bodies, are void, the same consequence will follow once more. And if they are too minute to admit any body, it is ridiculous to suppose there is a ‘minute’ void and yet to deny the existence of a big one of whatever size, or to imagine ‘the void’ means anything else than a body’s [20] place—whence it clearly follows that to every body there will correspond a void of equal bulk.
As a general criticism we must urge that to postulate pores is superfluous. For if the agent produces no effect by touching the patient, neither will it produce any by passing through its pores. On the other hand, if it acts by contact, then—even without pores—some things will suffer action and others will act, provided they are by nature adapted for reciprocal action and passion. Our arguments have shown [25] that it is either false or futile to advocate pores in the sense in which some thinkers conceive them. But since bodies are divisible through and through the postulate of pores is ridiculous; for, qua divisible, a body can fall into separate parts.
9 · Let us explain the way in which things possess the power of generating, [30] and of acting and suffering action; and let us start from the principle we have often enunciated. For, assuming, the distinction between that which is potentially and that which is actually such-and-such, it is the nature of the first, in so far as it is what it is, to suffer action through and through, not merely to be susceptible in some parts while insusceptible in others. But its susceptibility varies in degree, according as it is more or less such-and-such, and one would be more justified in speaking of pores in this connexion—just as in metals there are veins of susceptible stuff stretching continuously through the substance.
[327a1] So long, indeed, as any body is naturally coherent and one, it is insusceptible. So, too, bodies are insusceptible so long as they are not in contact either with one another or with other bodies which are by nature such as to act and suffer action. (To illustrate my meaning: Fire heats not only when in contact, but also from a [5] distance. For the fire heats the air, and the air—being by nature such as both to act and suffer action—heats the body.) But the supposition that a body suffers action in some parts, but not in others ἡis only possible for those who hold an erroneous view concerning the divisibility of magnitudes. For usά12 the following account results from the distinctions we established at the beginning. For if magnitudes are not divisible through and through—if, on the contrary, there are indivisible solids or planes—then indeed nothing would be susceptible through and through: but neither would anything be continuous. Since, however, this is false, i.e. since every body is [10] divisible, there is no difference between having been divided into parts which remain in contact and being divisible. For if a body can be separated at the contacts (as some say), then, even though it has not yet been divided, it will be in a state of dividedness—for it can be divided, since nothing impossible results. And in general it is absurd that passion should occur in this manner only, viz. by the bodies being [15] split. For this theory abolishes alteration; but we see the same body liquid at one time and solid at another, without losing its continuity. It has suffered this change not by division and composition, nor yet by ‘turning’ and ‘intercontact’ as Democritus asserts; for it has passed from the liquid to the solid state without any [20] reordering or transposition in its nature. Nor are there contained within it those hard (i.e. congealed) particles indivisible in their bulk; on the contrary, it is liquid—and again, solid and congealed—uniformly all through. This theory, it must be added, makes growth and diminution impossible also. For if there is to be apposition (instead of the growing thing having changed as a whole, either by the admixture of something or by its own transformation), increase of size will not have [25] resulted in any and every part.
So much, then, to establish that things generate and are generated, act and suffer action, reciprocally; and to distinguish the way in which these processes can occur from the (impossible) way in which some say they occur.
10 · But we have still to explain combination, for that was the third of the [30] subjects we originally proposed to discuss. Our explanation will proceed on the same method as before. We must inquire: What is combination, and what is that which can combine? Of what things, and under what conditions, is combination a property? And, further, does combination exist in fact, or is it false to assert its existence?
For, according to some thinkers, it is impossible for one thing to be combined with another. They argue that if the combined constituents continue to exist and [327b1] are unaltered, they are no more combined now than they were before, but are in the same condition; while if one has been destroyed, the constituents have not been combined—on the contrary, one constituent is and the other is not, whereas combination demands uniformity of condition in them both; and on the same principle even if both the combining constituents have been destroyed as the result [5] of their coalescence, they cannot be combined since they have no being at all.
What we have in this argument is, it would seem, a demand for the precise distinction of combination from coming-to-be and passing-away (for it is obvious that combination, if it exists, must differ from these processes) and for the precise distinction of the combinable from that which is such as to come-to-be and [10] pass-away. As soon, therefore, as these distinctions are clear, the difficulties raised by the argument would be solved.
Now we do not speak of the wood as combined with the fire, nor of its burning as a combining either of its particles with one another or of itself with the fire: what we say is that the fire is coming-to-be, but the wood is passing-away. Similarly, we [15] speak neither of the food as combining with the body, nor of the shape as combining with the wax and thus fashioning the lump. Nor can body combine with white, nor (to generalize) properties and states with things; for we see them persisting unaltered. But again white and knowledge cannot be combined either, nor anything else which is not separable. (Indeed, this is a blemish in the theory of those who [20] assert that once all things were together and combined. For not everything can combine with everything. On the contrary, both of the constituents that are combined must originally have existed in separation; but no property can have separate existence.)
Since, however, some things are potentially while others are actually, the constituents can be in a sense and yet not-be. The compound may be actually other [25] than the constituents from which it has resulted; nevertheless each of them may still be potentially what it was before they were combined, and both of them may survive undestroyed. (For this was the difficulty that emerged in the previous argument; and it is evident that the combining constituents not only coalesce, having formerly existed in separation, but also can again be separated out from the compound.) The constituents, therefore, neither persist actually, as body and white [30] persist; nor are they destroyed (either one of them or both), for their potentiality is preserved. Hence these difficulties may be dismissed; but the problem immediately connected with them—whether combination is something relative to perception—must be set out and discussed.
When the combining constituents have been divided into parts so small, and have been juxtaposed in such a manner, that perception fails to discriminate them one from another, have they then been combined? Or is it rather when any and [328a1] every part of one constituent is juxtaposed to a part of the other? The term, no doubt, is applied in the latter sense: we speak, e.g., of wheat having been combined with barley when each grain of the one is juxtaposed to a grain of the other. But every body is divisible and therefore, since body combined with body is uniform, any [5] and every part of each constituent ought to be juxtaposed to a part of the other.
No body, however, can be divided into its least parts; and composition is not identical with combination, but other than it. Thus it is clear that so long as the constituents are preserved in small particles, we must not speak of them as combined. (For this will be a composition instead of a blending or combination; nor will the part exhibit the same ratio between its constituents as the whole. But we [10] maintain that, if combination has taken place, the compound must be uniform—any part of such a compound being the same as the whole, just as any part of water is water; whereas, if combination is composition of the small particles, nothing of the kind will happen. On the contrary, the constituents will only be combined relatively to perception; and the same thing will be combined to one percipient, if his [15] sight is not sharp—while to the eye of Lynceus nothing will be combined.) Clearly too we must not speak of the constituents as combined in virtue of a division such that any and every part of each is juxtaposed to a part of the other; for it is impossible for them to be thus divided. Either, then, there is no combination, or we have still to explain the manner in which it can take place.
Now, as we maintain, some things are such as to act and others such as to suffer action from them. Moreover, some things—viz. those which have the same [20] matter—reciprocate, i.e. are such as to act upon one another and to suffer action from one another; while other things, viz. agents which have not the same matter as their patients, act without themselves suffering action. Such agents cannot combine—that is why neither the art of healing nor health produces health by combining with the bodies of the patients. Amongst those things, however, which are both active and passive, some are easily divisible. Now if a great quantity (or a large bulk) of one of these materials be brought together with a little (or with a [25] small piece) of another, the effect produced is not combination, but increase of the dominant; for the other material is transformed into the dominant. (That is why a drop of wine does not combine with ten thousand gallons of water; for its form is dissolved, and it is changed so as to merge in the total volume of water.) On the other hand, when there is a certain equilibrium between their powers, then each of them changes out of its own nature towards the dominant; yet neither becomes the [30] other, but both become an intermediate with properties common to both.
Thus it is clear that only those agents are combinable which involve a contrariety—for these are such as to suffer action reciprocally. And, further, they combine more freely if small pieces of each of them are juxtaposed. For in that condition they change one another more easily and more quickly; whereas this effect takes a long time when agent and patient are present in bulk.
Hence, amongst the divisible susceptible materials, those whose shape is [328b1] readily adaptable have a tendency to combine; for they are easily divided into small particles, since that is precisely what being readily adaptable in shape implies. For instance, liquids are the most combinable of all bodies—because, of all divisible materials, the liquid is most readily adaptable in shape, unless it be viscous. Viscous liquids, it is true, produce no effect except to increase the bulk. But when one of the [5] constituents is alone susceptible—or superlatively susceptible, the other being susceptible in a very slight degree—the compound resulting from their combination is either no greater in volume or only a little greater. This is what happens when tin is combined with bronze. For some things display a hesitating and ambiguous attitude towards one another—showing a slight tendency to combine and also an [10] inclination to behave as receptive matter and form. The behaviour of these metals is a case in point. For the tin almost vanishes, behaving as if it were an immaterial property of the bronze: having been combined, it disappears, leaving no trace except the colour it has imparted to the bronze. The same phenomenon occurs in other instances too.
It is clear, then, from the foregoing account, that combination occurs, what it [15] is, to what it is due, and what kind of thing is combinable. The phenomenon depends upon the fact that some things are such as to be reciprocally susceptible and readily adaptable in shape, i.e. easily divisible. For such things can be combined without its being necessary either that they should have been destroyed or that they should survive absolutely unaltered; and their combination need not be a composition, nor [20] merely relative to perception. On the contrary: anything is combinable which, being readily adaptable in shape, is such as to suffer action and to act; and it is combinable with another thing similarly characterized (for the combinable is relative to the combinable); and combination is unification of the combinables, resulting from their alteration.
1 · We have explained under what conditions combination, contact, and action and passion are attributable to the things which undergo natural change. Further, we have discussed unqualified coming-to-be and passing-away, and explained under what conditions they occur, in what subject, and owing to what [30] cause. Similarly, we have also discussed alteration, and explained what altering is and how it differs from coming-to-be and passing-away. But we have still to investigate the so-called elements of bodies.
For coming-to-be and passing-away occur in naturally constituted substances only given the existence of sensible bodies. But as to the matter which underlies these perceptible bodies, some maintain it is single, supposing it to be, e.g., Air or Fire, or an intermediate between these two (but still a body with a separate [329a1] existence). Others, on the contrary, postulate more than one—ascribing to their association and dissociation, or to their alteration, the coming-to-be and passing-away of things. (Some, for instance, postulate Fire and Earth; some add Air, making three; and some, like Empedocles, reckon Water as well, thus postulating four.)
[5] Now we may agree that the primary materials, whose change (whether it be association and dissociation or a process of another kind) results in coming-to-be and passing-away, are rightly described as principles or elements. But those thinkers are in error who postulate, beside the bodies we have mentioned, a single [10] matter—and that a corporeal and separable matter. For this body cannot possibly exist without a perceptible contrariety—this ‘Boundless’, which some thinkers identify with the principle, must be either light or heavy, either cold or hot. And what Plato has written in the Timaeus13 is not based on any precisely-articulated [15] conception. For he has not stated clearly whether his ‘Omnirecipient’ exists in separation from the elements; nor does he make any use of it. He says, indeed, that it is a substratum prior to the so-called elements—underlying them, as gold underlies the things that are fashioned of gold. (And yet this comparison, if thus expressed, is itself open to criticism. Things which come-to-be and pass-away [20] cannot be called by the name of the material out of which they have come-to-be: it is only the results of alteration which retain the name. However, he actually says that far the truest account is to affirm that each of them is gold.) Nevertheless he carries his analysis of the elements—solids though they are—back to planes, and it is impossible for ‘the Nurse’ (i.e. the primary matter) to be identical with the planes.
Our own doctrine is that although there is a matter of the perceptible bodies (a [25] matter out of which the so-called elements come-to-be), it has no separate existence, but is always bound up with a contrariety. A more precise account of this has been given in another work;14 we must, however, give a detailed explanation of the primary bodies as well, since they too are similarly derived from the matter. We must reckon as a principle and as primary the matter which underlies, though it is [30] inseparable from, the contrary qualities; for the hot is not matter for the cold nor the cold for the hot, but the substratum is matter for them both. Thus as principles we have firstly that which is potentially perceptible body, secondly the contrarieties (I mean, e.g., heat and cold), and thirdly Fire, Water, and the like. For these bodies change into one another (they are not immutable as Empedocles and other thinkers [329b1] assert, since alteration would then have been impossible), whereas the contrarieties do not change.
Nevertheless, even so the question remains: What sorts of contrarieties, and how many of them, are to be accounted principles of body? For all the other thinkers assume and use them without explaining why they are these or why they [5] are just so many.
2 · Since, then, we are looking for principles of perceptible body; and since perceptible is equivalent to tangible, and tangible is that of which the perception is touch, it is clear that not all the contrarieties constitute forms and principles of body, but only those which correspond to touch. For it is in accordance with a [10] contrariety—a contrariety, moreover, of tangible qualities—that the primary bodies are differentiated. That is why neither whiteness and blackness, nor sweetness and bitterness, nor similarly any of the other perceptible contrarieties either, constitutes an element. And yet vision is prior to touch, so that its object also is prior. The object of vision, however, is a quality of tangible body not qua tangible, [15] but qua something else—even if it is naturally prior.
Accordingly, we must segregate the tangible differences and contrarieties, and distinguish which amongst them are primary. Contrarieties correlative to touch are the following: hot-cold, dry-moist, heavy-light, hard-soft, viscous-brittle, rough-smooth, [20] coarse-fine. Of these heavy and light are neither active nor susceptible. Things are not called heavy and light because they act upon, or suffer action from, other things. But the elements must be reciprocally active and susceptible, since they combine and are transformed into one another. On the other hand, hot and cold, and dry and moist, are terms, of which the first pair implies power to act and [25] the second pair susceptibility. Hot is that which associates things of the same kind (for dissociating, which people attribute to Fire as its function, is associating things of the same class, since its effect is to eliminate what is foreign), while cold is that which brings together, i.e. associates, homogeneous and heterogeneous things alike. [30] And moist is that which, being readily adaptable in shape, is not determinable by any limit of its own; while dry is that which is readily determinable by its own limit, but not readily adaptable in shape.
From these are derived the fine and coarse, viscous and brittle, hard and soft, and the remaining differences. For since the moist has no determinate shape, but is readily adaptable and follows the outline of that which is in contact with it, it is [330a1] characteristic of it to be such as to fill up. Now the fine is such as to fill up. For the fine consists of subtle particles; but that which consists of small particles is such as to fill up, inasmuch as it is in contact whole with whole—and the fine exhibits this character in a superlative degree. Hence it is evident that the fine derives from the moist, while the coarse derives from the dry. Again the viscous derives from the [5] moist; for the viscous (e.g. oil) is a moist thing modified in a certain way. The brittle, on the other hand, derives from the dry; for brittle is that which is completely dry—so completely, that it has actually solidified due to failure of moisture. Further the soft derives from the moist. For soft is that which yields by retiring into itself, though it does change position, as the moist does—which [10] explains why the moist is not soft, although the soft derives from the moist. The hard, on the other hand, derives from the dry; for hard is that which is solidified, and the solidified is dry.
The terms ‘dry’ and ‘moist’ have more senses than one. For the damp, as well as the moist, is opposed to the dry: and again the solidified, as well as the dry, is [15] opposed to the moist. But all these derive from the dry and moist we mentioned first. For the dry is opposed to the damp; and the damp is that which has foreign moisture on its surface (sodden being that which is penetrated to its core), while dry is that which has lost foreign moisture. Hence it is evident that the damp will derive from the moist, and the dry which is opposed to it will derive from the primary dry. Again [20] the moist and the solidified derive in the same way from the primary pair. For moist is that which contains moisture of its own deep within it (sodden being that which contains foreign moisture), whereas solidified is that which has lost this inner moisture. Hence these too derive one from the dry and the other from the moist.
[25] It is clear, then, that all the other differences reduce to the first four, but that these admit of no further reduction. For the hot is not essentially moist or dry, nor the moist essentially hot or cold; nor are the cold and the dry derivative forms, either of one another or of the hot and the moist. Hence these must be four.
[30] 3 · The elements are four, and any four terms can be combined in six couples. Contraries, however, refuse to be coupled; for it is impossible for the same thing to be hot and cold, or moist and dry. Hence it is evident that the couplings of the elements will be four: hot with dry and moist with hot, and again cold with dry [330b1] and cold with moist. And these four couples have attached themselves to the apparently simple bodies (Fire, Air, Water, and Earth) in a manner consonant with theory. For Fire is hot and dry, whereas Air is hot and moist (Air being a sort of [5] vapour); and Water is cold and moist, while Earth is cold and dry. Thus the differences are reasonably distributed among the primary bodies, and the number of the latter is consonant with theory. For all who make the simple bodies elements postulate either one, or two, or three, or four. Now those who assert there is one only, and then generate everything else by condensation and rarefaction, are in [10] effect making their principles two, viz. the rare and the dense, or rather the hot and the cold; for it is these which are the moulding forces, while the one underlies them as matter. But those who postulate two from the start—as Parmenides postulated Fire and Earth—make the intermediates (e.g. Air and Water) blends of these. The [15] same course is followed by those who advocate three. (We may compare what Plato does in the divisions15; for he makes ‘the middle’ a blend.) Indeed, there is practically no difference between those who postulate two and those who postulate three, except that the former split the middle element into two, while the latter treat it as only one. But some advocate four from the start, e.g. Empedocles; yet he too [20] draws them together so as to reduce them to the two, for he opposes all the others to Fire.
In fact, however, fire and air, and each of the bodies we have mentioned, are not simple, but combined. The simple bodies are indeed similar in nature to them, but not identical with them. Thus the simple body corresponding to fire is fire-like, not fire; that which corresponds to air is air-like; and so on with the rest of them. But [25] fire is an excess of heat, just as ice is an excess of cold. For freezing and boiling are excesses of cold and heat respectively. Assuming, therefore, that ice is a freezing of moist and cold, fire analogously will be a boiling of dry and hot—a fact which explains why nothing comes-to-be either out of ice or out of fire. [30]
The simple bodies, since they are four, fall into two pairs which belong to the two regions, each to each; for Fire and Air are forms of the body moving towards the limit, while Earth and Water are forms of the body which moves towards the centre. Fire and Earth, moreover, are extremes and purest; Water and Air, on the contrary, are intermediates and more combined. And, further, the members of either pair are [331a1] contrary to those of the other, Water being contrary to Fire and Earth to Air; for they are constituted from contrary qualities. Nevertheless, since they are four, each of them is characterized simply by a single quality: Earth by dry rather than by cold, Water by cold rather than by moist, Air by moist rather than by hot, and Fire [5] by hot rather than by dry.
4 · It has been established before that the coming-to-be of the simple bodies is reciprocal. At the same time, it is manifest, on the evidence of perception, that they do come-to-be; for otherwise there would not have been alteration, since alteration is change in respect to the qualities of the objects of touch. Consequently, [10] we must explain what is the manner of their reciprocal transformation, and whether every one of them can come-to-be out of every one—or whether some can do so, but not others.
Now it is evident that all of them are by nature such as to change into one another; for coming-to-be is a change into contraries and out of contraries, and the elements all involve a contrariety in their mutual relations because their distinctive [15] qualities are contrary. For in some of them both qualities are contrary—e.g. in Fire and Water, the first of these being dry and hot, and the second moist and cold; while in others one of the qualities is contrary—e.g. in Air and Water, the first being [20] moist and hot, and the second moist and cold. It is evident, therefore, if we consider them in general, that every one is by nature such as to come-to-be out of every one; and when we come to consider them severally, it is not difficult to see the manner in which their transformation is effected. For, though all will result from all, both the speed and the facility of their conversion will differ in degree.
Thus the process of conversion will be quick between those which tally with one [25] another, but slow between those which do not. The reason is that it is easier for a single thing to change than for many. Air, e.g., will result from Fire if a single quality changes; for Fire, as we saw, is hot and dry while Air is hot and moist, so that there will be Air if the dry be overcome by the moist. Again, Water will result [30] from Air if the hot be overcome by the cold; for Air, as we saw, is hot and moist while Water is cold and moist, so that, if the hot changes, there will be Water. So too, in the same manner, Earth will result from Water and Fire from Earth, since both tally with both. For Water is moist and cold while Earth is cold and dry—so that, if the moist be overcome, there will be Earth; and again, since Fire is dry and [331b1] hot while Earth is cold and dry, Fire will result from Earth if the cold pass-away.
It is evident, therefore, that the coming-to-be of the simple bodies will be cyclical; and that this method of transformation is the easiest, because the consecutive elements tally. On the other hand the transformation of Fire into Water [5] and of Air into Earth, and again of Water and Earth into Fire and Air, though possible, is more difficult because it involves the change of more qualities. For if Fire is to result from Water, both the cold and the moist must pass-away; and again, both the cold and the dry must pass-away if Air is to result from Earth. So, too, if [10] Water and Earth are to result from Fire and Air—both must change.
This second method of coming-to-be, then, takes a longer time. But if one quality in each of two elements pass-away, the transformation, though easier, is not reciprocal. Still, from Fire and Water there will result Earth and Air, and from Air [15] and Earth Fire and Water. For there will be Air, when the cold of the Water and the dry of the Fire have passed-away (since the hot of the latter and the moist of the former are left); whereas, when the hot of the Fire and the moist of the Water have passed-away, there will be Earth, owing to the survival of the dry of the Fire and the cold of the Water. So, too, in the same way, Fire and Water will result from Air and [20] Earth. For there will be Water, when the hot of the Air and the dry of the Earth have passed-away (since the moist of the former and the cold of the latter are left); whereas, when the moist of the Air and the cold of the Earth have passed-away, there will be Fire, owing to the survival of the hot of the Air and the dry of the Earth—qualities constitutive of Fire. Moreover, this mode of Fire’s coming-to-be is [25] confirmed by perception. For flame is par excellence Fire; but flame is burning smoke, and smoke consists of Air and Earth.
No transformation, however, into any of the bodies can result from the passing-away of one quality in each of two elements when they are taken in their consecutive order, because either identical or contrary qualities are left—and from them no body can be formed. E.g. if the dry of Fire and the moist of Air were to [30] pass-away, the hot is left in both; and if the hot pass-away out of both, the contraries—dry and moist—are left. A similar result will occur in all the others too; for all the consecutive bodies contain one identical and one contrary quality. Hence, too, it clearly follows that, when one is transformed into one, the coming-to-be is [35] effected by the passing-away of a single quality; whereas, when two are transformed into a third, more than one quality must have passed-away.
5 · We have stated that all the bodies come-to-be out of any one of them; [332a1] and we have explained the manner in which their mutual conversion takes place. Let us nevertheless supplement our theory by the following speculations concerning them.
If Water, Air, and the like are a matter of which the natural bodies consist, as [5] some thinkers in fact believe, they must be either one, or two, or more. Now they cannot all of them be one—they cannot, e.g., all be Air or Water or Fire or Earth—because change is into contraries. For if they all were Air, then (assuming Air to persist) there will be alteration instead of coming-to-be. Besides, nobody supposes it to persist in such a way that it is Water as well as Air (or anything else) at the same time. So there will be a certain contrariety, i.e. a differentiating quality; [10] and the other member of this contrariety, e.g. heat, will belong to Fire. But Fire will certainly not be ‘hot Air’. For a change of that kind is alteration, and is not what is observed. Moreover if Air is again to result out of the Fire, it will do so by the conversion of the hot into its contrary; this contrary, therefore, will belong to Air, [15] and Air will be a cold something; hence it is impossible for Fire to be hot Air, since in that case the same thing will be simultaneously hot and cold. Both Fire and Air, therefore, will be something else which is the same; i.e. there will be some other matter common to both.
The same argument applies to all, proving that there is no single one of them out of which they all originate. But neither is there anything else beside these [20] four—something intermediate, e.g., between Air and Water (coarser than Air, but finer than Water), or between Air and Fire (coarser than Fire, but finer than Air). For the supposed intermediate will be Air and Fire when a pair of contrasted qualities is added to it; but, since one of every two contrary qualities is a privation, the intermediate never can exist—as some thinkers assert the ‘Boundless’ or the [25] ‘Environing’ exists—in isolation. It is, therefore, indifferently any one of them, or else it is nothing.
Since, then, there is nothing perceptible prior to these, they must be all. That being so, either they must always persist and not be transformable into one another; or they must undergo transformation—either all of them, or some only (as Plato wrote in the Timaeus)16 Now it has been proved before that they must undergo [30] reciprocal transformation, and that the speed with which they come-to-be one out of another is not uniform—since the process of reciprocal transformation is relatively quick between those that tally, but relatively slow between those which do not.
Assuming, then, that the contrariety, in respect to which they are transformed, is one, they must be two; for matter is the mean between the two contraries, and is [332b1] imperceptible and inseparable. Since, however, the elements are seen to be more than two, the contrarieties must at the least be two. But the contrarieties being two, the elements must be four (as they evidently are) and cannot be three; for the couplings are four, since, though six are possible, the two in which the qualities are contrary to one another cannot occur.
[5] These subjects have been discussed before; but the following arguments will make it clear that, since the elements are transformed into one another, it is impossible for any one of them—whether it be at the end or in the middle—to be a principle of the rest. There can be no such principle at the ends; for all of them would then be Fire or Earth, and this theory amounts to the assertion that all things [10] are made of Fire or Earth. Nor can a middle element be such a principle—as some thinkers suppose that Air is transformed both into Fire and into Water, and Water both into Air and into Earth, while the end elements are not further transformed into one another. For the process must come to a stop, and cannot continue ad infinitum in a straight line in either direction, since otherwise an infinite number of [15] contrarieties would attach to the single element. Let E stand for Earth, W for Water, A for Air, and F for Fire. Then since A is transformed into F and W, there will be a contrariety belonging to A and F. Let these contraries be whiteness and blackness. Again since A is transformed into W, there will be another contrariety; for W is not the same as F. Let this second contrariety be dryness and moistness, D [20] being dryness and M moistness. Now if the white persists, Water will be moist and white; but if it does not persist, Water will be black, since change is into contraries. Water, therefore, must be either white or black. Let it then be the first. On similar grounds, therefore, D (dryness) will also belong to F. Consequently F (Fire) as well [25] will be able to be transformed into Water; for it has qualities contrary to those of Water, since Fire was first taken to be black and then to be dry, while Water was moist and then showed itself white. Thus it is evident that all will be able to be transformed out of one another; and that, in the instances we have taken, E (Earth) also will contain the remaining two tallies, viz. the black and the moist (for these [30] have not yet been coupled).
We have dealt with this last topic before the thesis we set out to prove. That thesis—viz. that the process cannot continue ad infinitum—will be clear from the following considerations. If Fire (which is represented by F) is not to revert, but is to be transformed in turn into some other element (e.g. into Q), a new contrariety, other than those mentioned, will belong to Fire and Q; for it has been assumed that [333a1] Q is not the same as any of the four, E W A and F. Let K, then, belong to F and Y to Q. Then K will belong to all four, E W A and F; for they are transformed into one another. This last point, however, we may admit, has not yet been proved; but at any rate it is clear that if Q is to be transformed in turn into yet another element, yet [5] another contrariety will belong not only to Q but also to F (Fire). And, similarly, every addition of a new element will carry with it the attachment of a new contrariety to the preceding elements. Consequently, if the elements are infinitely many, there will also belong to the single element an infinite number of contrarieties. But if that be so, it will be impossible to define any element; impossible also for any to come-to-be. For if one is to result from another, it will have to pass through so many contrarieties—and then more. Consequently into [10] some elements transformation will never be effected—viz. if the intermediates are infinite in number, as they must be if the elements are infinitely many; further there will not even be a transformation of Air into Fire, if the contrarieties are infinitely many; moreover all the elements become one. For all the contrarieties of the elements above F must belong to those below F, and vice versa: hence they will all be [15] one.
6 · As for those who agree with Empedocles that the elements of body are more than one, so that they are not transformed into one another—one may well wonder in what sense it is open to them to maintain that the elements are comparable. Yet Empedocles says ‘For these are all equal…’17 [20]
If it is meant that they are comparable in their amount, all the comparables must possess an identical something whereby they are measured. If, e.g., one pint of Water yields ten of Air, both are measured by the same unit; and therefore both were from the first an identical something. On the other hand, suppose they are not comparable in their amount in the sense that so much of the one yields so much of the other, but comparable in power of action (a pint of Water, e.g., having a power [25] of cooling equal to that of ten pints of Air); even so, they are comparable in their amount, though not qua amount but qua having power. Instead of comparing their powers by the measure of their amount, they might be compared as terms in an analogy: e.g., ‘as x is hot, so y is white.’ But ‘as’, though it means equality in quantity, means similarity in quality. Thus it is manifestly absurd that the bodies, [30] though they are not transformable, are comparable not by analogy, but by a measure of their powers; i.e. that so much Fire is comparable with many times that amount of Air, as being equally or similarly hot. For the same thing, if it be greater in amount, will, since it belongs to the same kind, have its ratio correspondingly increased.
A further objection to the theory of Empedocles is that it makes growth impossible, unless it be increase by addition. For his Fire increases by Fire: ‘And [333b1] Earth increases its own frame and Ether increases Ether.’18 These, however, are cases of addition; but it is not by addition that growing things are believed to increase. And it is far more difficult for him to account for the coming-to-be which occurs in nature. For the things which come-to-be by natural process all do so either [5] always or for the most part in a given way; while any exceptions—any results which occur neither always nor for the most part—are products of chance and spontaneity. Then what is the cause determining that man comes-to-be from man, that wheat (instead of an olive) comes-to-be from wheat, either always or for the most part? Are we to say that bone comes-to-be if the elements be put together in such-and-such a manner? For, according to his own statements, nothing comes [10] to-be from their coming together as chance has it, but only from their coming together in a certain proportion. What, then, is the cause of this? Presumably not Fire or Earth. But neither is it Love and Strife; for the former is a cause of association only, and the latter only of dissociation. No: the cause in question is the substance of each thing—not merely (to quote his words) ‘a combining and a [15] divorce of what has been combined’. And chance, not proportion, ‘is the name given to these occurrences;’19 for things can be combined as chance has it.
The cause, therefore, of the things which exist by nature is that they are in such and such a condition; and it is this which constitutes the nature of each thing—a nature about which he says nothing. What he says, therefore, tells us nothing About Nature.20 Moreover, it is this which is both the excellence of each thing and its good; whereas he assigns the whole credit to the combining. (And yet [20] the elements at all events are dissociated not by Strife, but by Love; since the elements are by nature prior to god, and they too are gods.)
Again, his account of motion is too simple. For it is not an adequate explanation to say that Love and Strife set things moving, unless the essence of Love is a movement of this kind and the essence of Strife a movement of that kind. He [25] ought, then, either to have defined or to have postulated these characteristic movements, or to have demonstrated them—whether strictly or laxly or in some other fashion. Moreover, since the bodies are seen to move naturally as well as by compulsion, i.e. in a manner contrary to nature (fire, e.g., moves upwards without compulsion, though by compulsion downwards); and since what is natural is contrary to that which is due to compulsion, and movement by compulsion actually [30] occurs; it follows that natural movement also occurs. Is this, then, the movement that Love sets going? No: for, on the contrary, the natural movement moves Earth downwards and resembles dissociation, and Strife rather than Love is its cause—so that in general, too, Love rather than Strife would seem to be contrary to nature. And unless Love or Strife is actually setting them in motion, the bodies themselves have absolutely no movement or rest. But this is absurd; and what is more, they do [334a] in fact obviously move. For though Strife dissociated, it was not by Strife that the Ether was borne upwards. On the contrary, sometimes he attributes its movement to something like chance (‘For thus, as it ran, it happened to meet them then, though often otherwise’),21 while at other times he says it is the nature of Fire to be [5] borne upwards, but ‘the Ether’ (to quote his words) ‘sank down upon the Earth with long roots’.22 With such statements, too, he combines the assertion that the Order of the World is the same now, in the reign of Strife, as it was formerly in the reign of Love. What, then, is the first mover and the cause of motion? Presumably not Love and Strife: on the contrary, these are causes of a particular motion, if at least we assume that first mover to be a principle.
[10] An additional absurdity is that the soul should consist of the elements, or that it should be one of them. How are the soul’s alterations to take place? How, e.g., is the change from being musical to being unmusical, or how is memory or forgetting, to occur? For clearly, if the soul be Fire, only such properties will belong to it as characterize Fire qua Fire; while if it be compounded, only the corporeal modifications will occur in it. But the changes we have mentioned are none of them corporeal.
7 · The discussion of these difficulties, however, is a task appropriate to a [15] different investigation:23 let us return to the elements of which bodies are composed. The theories that there is something common to all the elements, and that they are reciprocally transformed, are so related that those who accept either are bound to accept the other as well. Those, on the other hand, who do not make their coming-to-be reciprocal—who refuse to suppose that any one of the ‘elements’ comes-to-be out of any other taken singly, except in the sense in which bricks come-to-be out of a wall—are faced with an absurdity. How, on their theory, are [20] flesh and bones or any of the other compounds to result from the elements?
Indeed, the point we have raised constitutes a problem even for those who generate the elements out of one another. In what manner does anything other than, and beside, the elements come-to-be out of them? Let me illustrate my meaning. Water can come-to-be out of Fire and Fire out of Water; for their substratum is something common to them both. But flesh too, presumably, and marrow [25] come-to-be out of them. How, then, do such things come-to-be? For how is the manner of their coming-to-be to be conceived by those who maintain a theory like that of Empedocles? They must conceive it as composition—just as a wall comes-to-be out of bricks and stones; and this mixture will be composed of the elements, these being preserved in it unaltered but with their small particles juxtaposed each to each. That will be the manner, presumably, in which flesh and [30] every other compound results from the elements. Consequently, it follows that Fire and Water do not come-to-be out of any and every part of flesh. For instance, although a sphere might come-to-be out of this part of a lump of wax and a pyramid out of some other part, it was nevertheless possible for either figure to have come-to-be out of either part indifferently: that is the manner of coming-to-be when both come-to-be out of any and every part of flesh. Those, however, who maintain the theory in question, are not at liberty to conceive things in that manner, but only as a stone and a brick both come-to-be out of a wall—viz. each out of a different [334b1] place or part. Similarly even for those who postulate a single matter of their elements there is a certain difficulty in explaining how anything is to result from two of them taken together—e.g. from cold and hot, or from Fire and Earth. For if flesh consists of both and is neither of them, nor again is a composition of them in [5] which they are preserved unaltered, what alternative is left except to identify the resultant of the two elements with their matter? For the passing-away of either element produces either the other or the matter.
Now since there are differences of degree in hot and cold, then although when either is actual without qualification, the other will exist potentially; yet, when [10] neither exists in the full completeness of its being, but both by combining destroy one another’s excesses so that there exist instead a hot which (for a hot) is cold and a cold which (for a cold) is hot; then there will exist neither their matter, nor either of the contraries in actuality without qualification, but rather an intermediate; and this intermediate, according as it is potentially more hot than cold or vice versa, will [15] in accordance with that proportion be potentially twice as hot or as cold—or three times or whatever. Thus all the other bodies will result from the contraries, or from the elements, in so far as these have been combined; while the elements will result from the contraries, in so far as these exist potentially in a special sense—not as matter exists potentially, but in the sense explained above. And when a thing [20] comes-to-be in this manner, the process is combination; whereas what comes-to-be in the other manner is matter. Moreover contraries also suffer action, in accordance with the definition established in the early part of this work.24 For the actually hot is potentially cold and the actually cold potentially hot; so that hot and cold, unless they are equally balanced, are transformed into one another (and all the other contraries behave in a similar way). It is thus, then, that in the first place the [25] elements are transformed; and that out of the elements there come-to-be flesh and bones and the like—the hot becoming cold and the cold becoming hot when they have been brought to the mean. For at the mean is neither hot nor cold. The mean, however, is of considerable extent and not indivisible. Similarly, it is in virtue of a mean condition that the dry and the moist and the rest produce flesh and bone and [30] the remaining compounds.
8 · All the compound bodies—all of which exist in the region belonging to the central body—are composed of all the simple bodies. For they all contain Earth because every simple body is to be found specially and most abundantly in its own place. And they all contain Water because the compound must possess a definite outline and Water, alone of the simple bodies, is readily adaptable in shape; [335a1] moreover Earth has no power of cohesion without the moist. On the contrary, the moist is what holds it together; for it would fall to pieces if the moist were eliminated from it completely.
They contain Earth and Water, then, for the reasons we have given; and they [5] contain Air and Fire, because these are contrary to Earth and Water (Earth being contrary to Air and Water to Fire, in so far as one Substance can be contrary to another). Now comings-to-be result from contraries, and one pair of the contrary extremes is present; hence the other pair must also be present, so that every compound will include all the simple bodies.
[10] Additional evidence seems to be furnished by the food each compound takes. For all of them are fed by what they are constituted from, and all of them are fed by more things than one. Indeed, even plants, though it might be thought they are fed by one thing only, viz. by Water, are fed by more than one; for Earth has been mixed with the Water. That is why farmers too endeavour to mix before watering. Although food is akin to the matter, that which is fed is the figure—i.e. the [15] form—taken along with the matter. Hence it is reasonable that, whereas all the simple bodies come-to-be out of one another, Fire is the only one of them which (as our predecessors also assert) is fed. For Fire alone—or more than all the rest—is akin to the form because it tends by nature to be borne towards the limit. Now each of them naturally tends to be borne towards its own place; but the figure—i.e. the [20] form—of them all is at the limits.
Thus we have explained that all bodies are composed of all the simple bodies.
9 · Since some things are such as to come-to-be and pass-away, and since coming-to-be in fact occurs in the region about the centre, we must explain the [25] number and the nature of the principles of all coming-to-be alike; for a grasp of any universal facilitates the understanding of its specific forms.
The principles, then, are equal in number to, and identical in kind with, those in the sphere of the eternal and primary things. For there is one in the sense of matter, and a second in the sense of form; and, in addition, the third must be present [30] as well. For the two are not sufficient to bring things into being, any more than they are adequate to account for the primary things.
Now cause, in the sense of matter, for the things which are such as to come-to-be is that which can be and not be; and this is identical with that which can come to be and pass away, since the latter, while it is at one time, at another time is not. (For whereas some things are of necessity, viz. the eternal things, others of necessity are not. And of these two sets of things, since they cannot diverge from the [335b1] necessity of their nature, it is impossible for the first not to be and impossible for the second to be. Other things, however, can both be and not be.) Hence coming-to-be and passing-away must occur within the field of that which can be and not be. This, therefore, is cause in the sense of matter for the things which are such as to [5] come-to-be; while cause, in the sense of their end, is their figure or form—and that is the formula expressing the substance of each of them.
But the third principle must be present as well—the cause vaguely dreamed of by all our predecessors, definitely stated by none of them. On the contrary some amongst them thought the nature of the Forms was adequate to account for coming-to-be. Thus Socrates in the Phaedo first blames everybody else for having [10] given no explanation;25 and then lays it down that some things are Forms, others participants in the Forms, and that while a thing is said to be in virtue of the Form, it is said to come-to-be qua sharing in, to pass-away qua losing, the Form. Hence he thinks that assuming the truth of these theses, the Forms must be causes both of [15] coming-to-be and of passing-away. On the other hand there were others who thought the matter was adequate by itself to account for coming-to-be, since the movement originates from the matter.
Neither of these theories, however, is sound. For if the Forms are causes, why is their generating activity intermittent instead of perpetual and continuous—since there always are participants as well as Forms? Besides, in some instances we see [20] that the cause is other than the Form. For it is the doctor who implants health and the man of science who implants science, although Health itself and Science itself are as well as the participants; and the same principle applies to everything else that is produced in accordance with a capacity. On the other hand to say that matter [25] generates owing to its movement would be, no doubt, more scientific than to make such statements as are made by the thinkers we have been criticizing. For what alters and transfigures plays a greater part in bringing things into being; and we are everywhere accustomed, in the products of nature and of art alike, to look upon that which can initiate movement as the producing cause. Nevertheless this second theory is not right either.
30 For, to begin, with, it is characteristic of matter to suffer action, i.e. to be moved; but to move, i.e. to act, belongs to a different power. This is obvious both in the things that come-to-be by art and in those that come-to-be by nature. Water does not of itself produce out of itself an animal; and it is the art, not the wood, that makes a bed. Nor is this their only error. They make a second mistake in omitting the more controlling cause; for they eliminate the essential nature, i.e. the form. [336a1] And what is more, since they remove the formal cause, they invest the forces they assign to the simple bodies—the forces which enable these bodies to bring things into being—with too instrumental a character. For since (as they say) it is the nature of the hot to dissociate, of the cold to bring together, and of each remaining [5] contrary either to act or to suffer action, it is out of such materials and by their agency (so they maintain) that everything else comes-to-be and passes-away. Yet it is evident that even Fire is itself moved, i.e. suffers action. Moreover their procedure is virtually the same as if one were to treat the saw (and the various instruments of [10] carpentry) as the cause of the things that come-to-be; for the wood must be divided if a man saws, must become smooth if he planes, and so on with the remaining tools. Hence, however true it may be that Fire is active, i.e. sets things moving, there is a further point they fail to observe—viz. that Fire is inferior to the tools or instruments in the manner in which it sets things moving.
10 · As to our own theory—we have given a general account of the causes in an earlier work,26 and we have now explained and distinguished the matter and the [15] form. Further, since the change which is motion has been proved to be eternal, the continuity of coming-to-be follows necessarily from what we have established; for the eternal motion, by causing the generator to approach and retire, will produce coming-to-be uninterruptedly. At the same time it is clear that we were also right when, in an earlier work,27 we called motion (not coming-to-be) the primary form of [20] change. For it is far more reasonable that what is should cause the coming-to-be of what is not, than that what is not should cause the being of what is. Now that which is being moved is, but that which is coming-to-be is not: hence motion is prior to coming-to-be.
We have assumed, and have proved, that coming-to-be and passing-away happen to things continuously; and we assert that motion causes coming-to-be. That [25] being so, it is evident that, if the motion be single, both processes cannot occur since they are contrary to one another; for nature by the same cause, provided it remain in the same condition, always produces the same effect, so that either coming-to-be or passing-away will always result. The movements must be more than one, and they [30] must be one another either by the sense of their motion or by its irregularity; for contrary effects demand contraries as their causes.
This explains why it is not the primary motion that causes coming-to-be and passing-away, but the motion along the inclined circle; for this motion not only possesses the necessary continuity, but includes a duality of movements as well. For if coming-to-be and passing-away are always to be continuous, there must be some [336b1] body always being moved (in order that these changes may not fail) and moved with a duality of movements (in order that both changes, not one only, may result). Now the continuity of this movement is caused by the motion of the whole; but the approaching and retreating of the moving body are caused by the inclination. For the consequence of the inclination is that the body becomes alternately remote and [5] near; and since its distance is thus unequal, its movement will be irregular. Therefore, if it generates by approaching and by its proximity, it—this very same body—destroys by retreating and becoming remote; and if it generates by many successive approaches, it also destroys by many successive retirements. For contrary effects demand contraries as their causes; and the natural processes of passing-away and coming-to-be occupy equal periods of time. Hence, too, the [10] times—i.e. the lives—of the several kinds of things have a number by which they are distinguished; for there is an order for all things, and every time (i.e. every life) is measured by a period. Not all of them, however, are measured by the same period, but some by a smaller and others by a greater one; for to some of them the period, which is their measure, is a year, while to some it is longer and to others [15] shorter.
And there are facts of observation in manifest agreement with our theories. Thus we see that coming-to-be occurs as the sun approaches and decay as it retreats; and we see that the two processes occupy equal times. For the durations of the natural processes of passing-away and coming-to-be are equal. Nevertheless it often happens that things pass-away in too short a time, because of their mutual [20] commingling. For their matter is irregular, i.e. is not everywhere the same; hence the processes by which they come-to-be must be irregular too, i.e. some too quick and others too slow. Consequently the phenomenon in question occurs, because the coming-to-be of these things is the passing-away of other things.
Coming-to-be and passing-away will, as we have said, always be continuous, [25] and will never fail owing to the cause we stated. And this continuity has a sufficient reason. For in all things, as we affirm, nature always strikes after the better. Now being (we have explained elsewhere the variety of meanings we recognize in this term) is better than not-being; but not all things can possess being, since they are [30] too far removed from the principle. God therefore adopted the remaining alternative, and fulfilled the perfection of the universe by making coming-to-be uninterrupted; for the greatest possible coherence would thus be secured to existence, because that coming-to-be should itself come-to-be perpetually is the closest approximation to eternal being.
[337a1] The cause of this as we have often said, is circular motion; for that is the only motion which is continuous. That, too, is why all the other things—the things, I mean, which are reciprocally transformed in virtue of their qualities and their powers, e.g. the simple bodies—imitate circular motion. For when Water is [5] transformed into Air, Air into Fire, and the Fire back into Water, we say the coming-to-be has completed the circle, because it reverts again to the beginning. Hence it is by imitating circular motion that rectilinear motion too is continuous.
These considerations serve at the same time to explain what is to some people a puzzle—viz. why the bodies, since each of them is travelling towards its own place, [10] have not become dissevered from one another in the infinite lapse of time. The reason is their reciprocal transformation. For, had each of them persisted in its own place instead of being transformed by its neighbour, they would have got dissevered long ago. They are transformed, however, owing to the motion with its dual character; and because they are transformed, none of them is able to persist in any [15] fixed place.
It is clear from what been said that coming-to-be and passing-away actually occur, what causes them, and what subject undergoes them. But if there is to be movement (as we have explained elsewhere, in an earlier work)28 there must be something which initiates it; if there is to be movement always, there must always be something which initiates it; if the movement is to be continuous, what initiates it [20] must be single, unmoved, ungenerated, and incapable of alteration; and if the circular movements are more than one, they must all of them, in spite of their plurality, be in some way subordinated to a single principle. Further since time is continuous, movement must be continuous, inasmuch as there can be no time without movement. Time, therefore, is a number of some continuous movement—a [25] number, therefore, of the circular movement, as was established in the discussions at the beginning.29 But is movement continuous because of the continuity of that which is moved, or because that in which the movement occurs (I mean, e.g., the place or the quality) is continuous? The answer must clearly be because that which is moved is continuous. (For how can the quality be continuous except in virtue of the continuity of the thing to which it belongs? But if the continuity of ‘that in [30] which’ makes the movement continuous, this is true only of the place in which; for that has magnitude.) But amongst bodies which are moved, only that which is moved in a circle is continuous in such a way that it always preserves its continuity with itself. The conclusion therefore is that this is what produces continuous movement, viz. the body which is being moved in a circle; and its movement makes time continuous.
11 · Wherever there is continuity in any process (coming-to-be or alteration [337b1] or any kind of change whatever) we observe consecutiveness, i.e. this coming-to-be after that in such a way that there is no cessation. Hence we must investigate whether there is anything which will necessarily exist, or whether everything may fail to come-to-be. For that some of them may fail to occur, is clear—and that is why ‘it will be’ and ‘it is going to be’ are different. For if it be true to say of something that it will be, it must at some time be true to say of it that it is; whereas, [5] though it be true to say of something now that it is going to be, it is quite possible for it not to come-to-be—thus a man might not go for a walk, though he is now going to go for a walk. And since in general amongst the things which are some are capable also of not being, it is clear that the same character will attach to them when they are coming-to-be: in other words, their coming-to-be will not be necessary.
Then are all the things that come-to-be of this character? Or, on the contrary, [10] is it absolutely necessary for some of them to come-to-be? Is there, in fact, a distinction in the field of coming-to-be corresponding to the distinction, within the field of being, between things that cannot possibly not be and things that can not be? For instance, is it necessary that solstices shall come-to-be, i.e. impossible that they should fail to be able to occur?
Assuming that what is prior must have come-to-be if what is posterior is to be (e.g. that foundations must have come-to-be if there is to be a house; clay, if there [15] are to be foundations), is the converse also true? If foundations have come-to-be, must a house come-to-be? It seems that this is not so, unless it is necessary absolutely for the latter to come-to-be. If that be the case, however, a house must come-to-be if foundations have come-to-be. For the prior was assumed to be so related to the posterior that, if the latter is to be, the prior must have come-to-be before it. If, therefore, it is necessary that the posterior should come-to-be, the prior [20] also must have come-to-be; and if the prior has come-to-be, then the posterior also must come-to-be—not, however, because of the prior, but because its future being was assumed as necessary. Hence, whenever the being of the posterior is necessary, the nexus is reciprocal—in other words, when the prior has come-to-be the posterior must always come-to-be too.
Now if the sequence of occurrences is to proceed ad infinitum downwards, the [25] coming-to-be of any determinate later member will not be absolutely, but only conditionally, necessary. For it will always be necessary that some other member shall have come-to-be beforehand, on account of which it is necessary that this should come-to-be: consequently, since what is infinite has no beginning, neither will there be any primary member which will make it necessary for the remaining members to come-to-be.
Nor again will it be possible to say with truth, even in regard to the members of [30] a limited sequence, that it is absolutely necessary for any one of them to come-to-be e.g. a house, when foundations have been laid; for (unless it is always necessary for a house to come-to-be) we should be faced with the consequence that, when foundations have been laid, a thing, which need not always be, must always be. No: if its coming-to-be is to be necessary, it must be always in its coming-to-be. For what is of necessity coincides with what is always, since that which must be cannot not be. Hence a thing is eternal if it is of [338a1] necessity; and if it is eternal, it is of necessity. And if, therefore, the coming-to-be of a thing is necessary, its coming-to-be is eternal; and if eternal, necessary.
It follows that the coming-to-be of anything, if it is absolutely necessary, must [5] be cyclical—i.e. must return upon itself. For coming-to-be must either be limited or not limited; and if not limited, it must be either rectilinear or cyclical. But the first of these last two alternatives is impossible if coming-to-be is to be eternal, because there could not be any beginning, whether the members be taken downwards (as future events) or upwards (as past events). Yet coming-to-be must have a beginning [10] ἡif it is to be necessary and therefore eternalά, nor can it be eternal if it is limited.30 Consequently it must be cyclical. Hence the nexus must be reciprocal. By this I mean that the necessary occurrence of this involves the necessary occurrence of something prior; and conversely that, given the prior, it is also necessary for the posterior to come-to-be. And this will hold continuously throughout the sequence; for it makes no difference whether we take two, or by many, members.
[15] It is in circular movement, therefore, and in cyclical coming-to-be that the absolutely necessary is to be found. In other words, if the coming-to-be of any things is cyclical, it is necessary that each of them is coming-to-be and has come-to-be; and if it is necessary, their coming-to-be is cyclical.
And this is reasonable; for circular motion, i.e. the revolution of the heavens, was seen on other grounds to be eternal since precisely those movements which [338b1] belong to, and depend upon this eternal revolution come-to-be of necessity, and of necessity will be. For since the revolving body is always setting something in motion, the movement of the things it moves must also be circular. Thus, since the upper movement is cyclical, the sun31 moves in this determinate manner; and since the sun moves thus, the seasons in consequence come-to-be in a cycle, i.e. return upon themselves; and since they come-to-be cyclically, so in their turn do the things [5] whose coming-to-be the seasons initiate.
Then why do some things manifestly come-to-be in this fashion (as, e.g., showers and air come-to-be cyclically, so that it must rain if there is to be a cloud and, conversely, there must be a cloud if it is to rain), while men and animals do not return upon themselves so that the same individual comes-to-be a second time (for [10] though your coming-to-be presupposes your father’s, his coming-to-be does not presuppose yours)? Why, on the contrary, does this coming-to-be seem to constitute a rectilinear sequence?
In discussing this, we must begin by inquiring whether all things return upon themselves in a uniform manner; or whether, on the contrary, though in some sequences what recurs is numerically the same, in other sequences it is the same only in species. Now it is evident that those things, whose substance—that which is undergoing the process—is imperishable, will be numerically the same; for the [15] character of the process is determined by the character of that which undergoes it. Those things, on the other hand, whose substance is perishable (not imperishable) must return upon themselves specifically, not numerically. That is why, when Water comes-to-be from Air and Air from Water, the Air is the same specifically, not numerically; and if these too recur numerically the same, at any rate this does not happen with things whose substance comes-to-be—whose substance is such that it is capable of not-being.