Aristotle · a new plain-English translation from the original language
1| It is also rightly said that the number is the same — the number belonging to the sheep and to the dogs, if each group is equal — but the ten is not the same, nor are the ten things the same, just as the equilateral triangle and the scalene triangle are not the same triangles, even though the figure is indeed the same, because both are triangles. For a thing is called the same insofar as it does not differ by a differentia, not insofar as it does differ — for example, one triangle differs from another triangle by a differentia of triangle. Accordingly they are different triangles, but not different in figure; rather they fall within the same, single division. For one figure of this sort is a circle, another of this sort is a triangle, and of this latter, one of this sort is equilateral, another of this sort is scalene. The figure, then, is the same, and this is a triangle, but the triangle is not the same. And likewise the number is the same (for their number does not differ by a differentia of number), but the ten is not the same; for the things of which it is said differ — some are dogs, others are horses. So much, then, has been said about time itself and about the matters proper to its examination. Ε.
2| Everything that changes changes in one of the following ways: it may change accidentally, as when we say that the musical thing walks, because what walks is that to which being musical happens to belong; or it may change because something belonging to it changes, and is then said to change without qualification — as with the things said to change in respect of their parts (for the body is healed because the eye or the chest is healed, and these are parts of the whole body). But there is also something that is moved neither accidentally nor because something else belonging to it is moved, but because it itself is what is primarily moved. And this is what is movable in its own right — though it differs according to the kind of motion: one thing is alterable, and within alteration the healable and the heatable are different from each other. And it is the same too on the side of the mover: one thing moves accidentally, another moves in respect of a part because something belonging to it moves, and another moves in its own right, primarily — for example, the doctor heals, while the hand strikes. Now since there is something that is the primary mover, and something that is moved, and further that in which motion occurs, namely time, and besides these, that from which and that into which — for every motion is from something and into something (for the thing that is primarily moved is different from that into which it moves and from that out of which it moves; take wood, hot, and cold: of these, the wood is the thing moved, the hot is that into which it moves, the cold is that out of which it moves) — the motion, then, is clearly in the wood, not in the form; for neither does the form move nor is it moved, nor does the place, nor the quantity, but there is the mover, the thing moved, and that into which it moves. For the change is named more from that into which it moves than from that out of which it moves. That is why destruction, too, is a change into not-being, even though what is destroyed also changes from being; and coming-to-be is a change into being, even though it is also from not-being.
3| What motion is, then, has been said earlier. But the forms, the affections, and the place into which the things that are moved are moved, are themselves unmoved — for example, knowledge and heat. Yet one might raise a difficulty: if the affections are motions, and whiteness is an affection, then there will be a change into a motion. But perhaps whiteness is not a motion, but whitening is. And within these too there is the accidental, the partial, the by-reason-of-something-else, and the primary and not-by-reason-of-something-else: for example, the thing being whitened changes into the object of thought accidentally (for it is accidental to the color to be an object of thought), and it changes into color because white is a part of color (just as it changes into Europe because Athens is a part of Europe), but it changes into white, the color, in its own right. It is clear, then, in what way a thing is moved in its own right and in what way accidentally, and in what way by reason of something else and in what way by that very thing primarily — both in the case of the mover and of the thing moved — and that the motion is not in the form but in the thing moved and movable, in actuality. Let the accidental kind of change, then, be set aside; for it occurs in absolutely all things, always, and of all things. But the change that is not accidental does not occur in all things, but among contraries, and the things between them, and in contradiction; and the proof of this is from induction. A thing changes out of the intermediate, for it treats the intermediate as a contrary relative to each extreme; for in a way the intermediate is the extremes. That is why the intermediate is said, in a way, to be contrary to the extremes and they to it — for example, the middle note is high relative to the lowest and low relative to the highest, and gray is white relative to black and black relative to white.
4| Since every change is from something into something (the name itself indicates this too, for meta signifies something after something else, and one term shows the prior, the other the posterior), the thing that changes would change in four ways: either from a subject into a subject, or from a subject into a non-subject, or from a non-subject into a subject, or from a non-subject into a non-subject. By 'subject' I mean what is signified by an affirmation. So it is necessary, from what has been said, that there be three kinds of change: that from a subject into a subject, that from a subject into a non-subject, and that from a non-subject into a subject. For the change from a non-subject into a non-subject is not a change at all, because it does not involve an opposition — it is neither a case of contraries nor of contradiction. Now the change from a non-subject into a subject, being in accordance with contradiction, is coming-to-be — coming-to-be without qualification when it is simple, and the coming-to-be of a particular thing from a particular thing when it is qualified (for example, the change out of not-white into white is the coming-to-be of this thing, a qualified coming-to-be; while the coming-to-be, without qualification, of substance out of what is, without qualification, not-being, is coming-to-be without qualification — the kind by which we say something comes to be without qualification, and not that it comes to be some particular thing). And the change from a subject into what is not a subject is destruction: destruction without qualification is that from substance into not-being, while a qualified destruction is that into the opposed negation, just as was said. And the same holds for coming-to-be.
5| Now if not-being is spoken of in many ways, and neither what is not-being in the sense of combination or separation can be in motion, nor what is not-being in the sense of potentiality — as opposed to what is unqualifiedly in actuality (for what is not-white or not-good can nonetheless be in motion accidentally, since the not-white might be a man; but what is without qualification not-a-this cannot be in motion in any way) — it is impossible for not-being to be in motion. And if this is so, coming-to-be cannot be a motion either; for what comes to be is not-being. For even if it comes to be in the highest degree accidentally, it is nonetheless true to say that not-being belongs to what comes to be, without qualification — and likewise with being at rest. These, then, are the difficulties that follow, and also this: if everything that is moved is in place, but not-being is not in place — for then it would be somewhere. Nor, again, is destruction a motion; for what is contrary to a motion is either a motion or rest, but what is contrary to coming-to-be is destruction. Since every motion is a kind of change, and the changes stated are three, and of these the ones in respect of coming-to-be and destruction are not motions — these being the ones in accordance with contradiction — it is necessary that the change from a subject into a subject alone is motion. And the subjects are either contraries or intermediates (let privation too be counted as a contrary, and it is indicated by an affirmative expression — for example, naked, toothless, and black).
6| If, then, the categories are divided into substance, quality, place, relation, quantity, and acting or being acted on, it is necessary that there be three kinds of motion: that of quality, that of quantity, and that in respect of place.
7| There is no motion in respect of substance, because nothing among the things that are is contrary to a substance. Nor is there motion in respect of relation: for when one of two related things changes, it is possible for the other to be truly asserted and then not truly asserted, even though it has not changed at all — so that their motion is only accidental. Nor again is there motion in respect of acting and being acted on, or of the mover and the moved, because there is no motion of motion, no coming-to-be of coming-to-be, and in general no change of change. For in the first place, motion could be of motion in two ways: either as of a subject — as a man moves because he changes from white to black; is motion, then, in the same way heated or cooled, or does it change place, or increase or diminish? But that is impossible, for change is not an attribute of any of the underlying subjects — or by some other underlying thing changing, through a change, into another form, as a man changes from sickness to health. But this too is impossible except accidentally. For the motion itself is a change from one form to another — for instance a man's change from sickness to health — and coming-to-be and perishing are the same way, except that they are changes into opposites in one manner, and motion in another. So a thing changes at the same time from health into sickness, and from this very change into another. Clearly, once it has fallen sick, it will have changed into some state or other (for it might also come to rest), and moreover not always into just any state that happens along, but that further change too will be from something into something else — so that the opposite change would then be a recovery of health. But this holds only accidentally, as when something changes from remembering into forgetting, because the thing that has it changes at one time into knowledge, at another into ignorance.
8| It will proceed to infinity, if there is to be a change of change and
9| a coming-to-be of coming-to-be. And necessarily the earlier change too, if the later is to exist — for instance, if the simple coming-to-be once came to be, then what was coming to be was itself coming to be, so that what was simply coming to be did not yet exist, but rather something already coming to be that was itself coming to be; and again this too once came to be, so that at that time what was coming-to-be-coming-to-be did not yet exist. And since among infinites there is no first term, there will be no first stage here, and so no next one either. So nothing can come to be, or be moved, or change at all. Further, of the same thing there is a contrary motion (and also rest), and coming-to-be and perishing likewise; so that what is coming to be, once it has come to be coming-to-be, at that very point is perishing. For it is not perishing the moment it is coming to be, nor later — for what is perishing must already exist. Further, matter must underlie both what is coming to be and what is changing. What, then, will this be? Just as body or soul is what is alterable, so what will play that role for a motion or a coming-to-be that is itself coming to be? And again, what is it that they are being moved into? For there must be a motion or coming-to-be of this thing from this into this. And at the same time, how will it even come to be? For learning is not the coming-to-be of learning, so there is no coming-to-be of coming-to-be, nor of anything of anything. Further, if there are three species of motion, then both the underlying nature and that into which things move must be one of these — for example, that locomotion is altered, or is itself carried along. And in general, since everything is moved in three ways — either accidentally, or in virtue of a part, or in its own right — change could change only accidentally, as when someone recovering health runs or learns; but the accidental case we set aside long ago.
10| Since, then, there is motion neither in respect of substance, nor of relation, nor of acting and being acted on, it remains that there is motion only in respect of quality, quantity, and place; for in each of these there is a contrariety. Let motion in respect of quality, then, be called alteration, for this is the common name that has been attached to it. By quality I mean not that which is in the substance (for the differentia too is a quality) but the affective quality, in virtue of which a thing is said to be acted on or to be unaffected. Motion in respect of quantity has no common name, but by each direction it is growth and diminution — growth being motion toward the complete magnitude, diminution being motion away from it. Motion in respect of place has no name, either common or particular; let the common name for it be locomotion. Yet, properly speaking, only those things are said to be 'carried along' which do not have it in their own power to come to rest when they change place, and which do not move themselves locally. Change within the same species toward the more and the less is alteration: for it is a motion either from a contrary or into a contrary, either without qualification or in some respect. For when it goes toward the less, it will be said to change toward the contrary, and when toward the more, as if from the contrary toward the thing itself; for it makes no difference whether the change is in some respect or without qualification, except that in the qualified case the contraries need only be present in part. And the more and the less consist in the contrary's being present to a greater or lesser degree, or not.
11| That these are the only three kinds of motion, then, is clear from what has been said. A thing is called unmoved either because it is altogether incapable of being moved — just as sound cannot be seen — or because, though it is moved, it moves only with difficulty over a long time or begins slowly, which is called hard-to-move; or because, though it is naturally disposed to be moved and capable of it, it is not being moved at the time, in the place, and in the way that it is naturally disposed to be — and this alone, among unmoved things, I call being at rest. For rest is the contrary of motion, so it would be the privation of motion in what is receptive of it. What motion is, then, and what rest is, and how many changes and what kinds of motions there are, is clear from what has been said.
12| After this, let us say what 'together' and 'apart' are, and what 'touching' is, and what 'between' is, and what 'in succession' is, and what 'contiguous' and 'continuous' are, and to what kinds of things each of these naturally belongs. I call things 'together', in respect of place, when they are in one primary place; 'apart', when they are in different places; and 'touching', when their extremities are together. Since every change is between opposites, and opposites are either contraries or contradictories, and there is nothing between the two sides of a contradiction, it is clear that the 'between' will occur among contraries. The 'between' requires at least three terms: for the contrary is the limit of the change, and the 'between' is that which a changing thing naturally arrives at earlier than the limit into which it finally changes, when it changes continuously in accordance with its nature. A thing moves continuously when there is no gap, or the smallest possible gap, in the thing that changes — not in the time (for nothing prevents a gap in the time; indeed one can sound the lowest note immediately after the highest) but in the thing in which the change occurs. This is evident both in changes of place and in the other kinds of change. The contrary in respect of place is that which is farthest apart along a straight line; for the shortest distance is bounded, and what is bounded is a measure. A thing is 'in succession' when, coming after the starting point — in position, or in form, or as marked off in some other such way — there is nothing of the same kind between it and that to which it is in succession (I mean, for example, one line in succession to another line or lines, one unit to another unit or units, one house to a house; nothing prevents there being something of a different kind between them). For what is in succession is in succession to something, and is posterior to it: it is not the one that is in succession to the two, nor the first day of the month that is in succession to the second — rather, it is these that are in succession to those. And 'contiguous' is whatever, being in succession, touches that to which it is in succession.
13| The continuous is a kind of the contiguous. I call things continuous when the limit of each, at which they touch, becomes one and the same, and — as the name indicates — they are held together; and this cannot happen while the two extremities remain two. Given this distinction, it is clear that the continuous is found among those things out of which some one thing is naturally constituted by their joining. And in whatever way the connecting factor comes to be one, in that way the whole too will be one — whether by a peg, or by glue, or by contact, or by growing together. And it is clear also that
14| The first is being-in-succession: for what is in contact must be in succession, but not everything in succession is in contact (which is why, in things prior in account — for instance in numbers — being-in-succession applies, but touching does not). And if a thing is continuous, it must be in contact, but if it is in contact, it is not yet continuous — for it is not necessary that their extremities be one, if they are together, but if they are one, they must also be together. So growing-together is last in the order of coming to be: for the extremities must touch if they are to grow together, but not everything that touches has grown together; and where there is no touching, clearly there is no growing-together there either. So if there is a point and a unit of the sort said to be separate, it is not possible for a unit and a point to be the same thing: for touching belongs to points, but being-in-succession belongs to units; and for points it is possible for there to be something between them (for every line lies between points), while for units it is not necessary — for there is nothing between a dyad and a unit. What, then, together and apart are, and what touching is, and what between and being-in-succession are, and what contiguous and continuous are, and to what sorts of things each of these belongs, has been stated.
15| Motion is called one in many ways, for we speak of the one in many ways. In genus, then, motion is one according to the figures of the category (for locomotion is one in genus with every locomotion, but alteration is other in genus from locomotion); it is one in species when, being one in genus, it is also in an indivisible species. For instance, there are differentiae of color — hence blackening and whitening are different in species — but there are no longer differentiae of whiteness; that is why one whitening is one in species with every whitening. But if there are some things that are at once both genera and species, clearly it is possible that a motion will in a sense be one in species, but not one in species without qualification — for instance learning, if knowledge is a species of supposition but a genus of the sciences. One might raise the difficulty whether motion is one in species when the same thing changes from the same thing into the same thing — for instance, a single point moving from this place into that place, over and over again. But if this is so, circular locomotion will be the same as straight locomotion, and rolling the same as walking. Or has it been determined that, where that in which the motion occurs is different in species, the motion is different — and the circular is different in species from the straight?
16| Motion is one in genus and in species in this way, then, but motion is one without qualification when it is one in substance and in number. What sort of motion this is will be clear once we have drawn the distinctions. For there are three things, in number, with reference to which we speak of motion: what is moved, that in which it moves, and when. I mean that there must be something that is moved — for instance a man or gold — and this must move in something, for instance in place or in an affection, and at some time, for everything moves in time. Of these, being one in genus or in species belongs to the thing in which the motion occurs; being contiguous belongs to the time; and being one without qualification belongs to all of these together. For that in which the motion occurs must be one and indivisible — for instance the species; and the when — for instance the time — must be one and not intermittent; and the thing moved must be one, not accidentally (as the white thing becomes black, and Coriscus walks — Coriscus and white are one, but only accidentally) — nor merely one in a common way. For otherwise it would be possible for two men to be recovering health at the same time by the same recovery, for instance from an eye-disease — but this is not one, it is one in species. As for Socrates undergoing the same alteration in species, but at one time and then again at another — if it is possible for what has perished to become one again in number, this too would be one; but if not, it is the same, but not one.
17| A difficulty close to this one also arises over whether health, and states and affections generally, are one in substance in bodies — for the things that possess them appear to be in motion and in flux. If, then, the health of this morning and the health now are the same and one, why should it not also be the case, when a person, after an interval, recovers health again, that this health and that one are one in number? For the argument is the same. Except that they differ to this extent: if they are two, then for this very reason — as being two in number — the activities too must be two, for one activity in number belongs to one thing in number. But if the state is one, perhaps it would not yet seem to anyone that the activity too is one (for when a person stops walking, the walking no longer exists, but when he walks again, it will exist again). If, then, it is one and the same, it would be possible for the same and one thing to perish and to exist many times. These, then, are the difficulties that lie outside the
18| present inquiry. But since every motion is continuous, the motion that is one without qualification must also be continuous — since everything is divisible — and if continuous, then one. For not every motion could be continuous with every other, any more than any chance thing can be continuous with any chance thing, but only those whose extremities are one. Now for some things there are no extremities, while for others the extremities are different in species and only homonymous — for how could the extremity of a line and the extremity of walking touch, or become one? Now things that are not the same in species nor even in genus could still be contiguous (for a person might run and immediately be feverish), and, for instance, the torch-race is a locomotion contiguous by relay, but not continuous. For the continuous has been laid down as that whose extremities are one. So things are contiguous and in succession by the time's being continuous, and continuous by the motions' being so — and this occurs when the extremity of both becomes one. Hence the motion that is continuous and one without qualification must be the same in species, and of one thing, and in one time: in time, so that there may be no immobility in between (for in an interval it is necessary to be at rest; so where there is a rest in between, the motion is many and not one, so that if a motion is divided by a standstill, it is not one, nor continuous;
19| and it is so divided if there is a time in between). But in the case of a motion not one in species, even if there is no interval, the time is one, but the motion is different in species: for the motion that is one without qualification must also be one in species, but a motion that is one in species need not be one without qualification. So it has been stated what motion is one without qualification. Further, the complete motion too is called one, whether it is complete in genus, in species, or in substance, just as in other cases too the complete and whole belongs to the one. And there are times when, even if it is incomplete, a motion is called one, provided only that it is continuous. Further, it is called one in yet another way besides those mentioned
20| Uniform motion is one motion. For non-uniform motion is, in a way, thought not to be one, but rather the uniform is one, just as the straight line is; for the non-uniform is divisible. It seems to differ in the sense of the more and the less. Now uniformity or its absence belongs to every kind of motion: a thing could be altered uniformly, and could be carried along a uniform path, for instance a circle or a straight line, and the same holds for growth and decay likewise. Non-uniformity is a difference that lies, on the one hand, in that over which the thing is moved (for it is impossible for the motion to be uniform unless it takes place over a uniform magnitude, for example the motion over a bent line, or over a spiral, or over some other magnitude of which no chance part fits any other chance part); while the other kind lies neither in the what, nor in the when, nor in the into-what, but in the how. For motions are sometimes marked off by speed and slowness: the motion whose speed is the same throughout is uniform, the one whose speed is not the same is non-uniform. Hence speed and slowness are not species of motion, nor differentiae of it, because they attend all the motions that differ in species. So neither are heaviness and lightness toward the same place a species or differentia, for instance earth's motion toward itself, or fire's toward itself. Non-uniform motion, then, is one in virtue of being continuous, though less so, which is what happens with motion along a bent path, and this lesser unity is always an admixture of the contrary. But if it is possible for every motion that is one to be either uniform or not, then successive motions that are not the same in species could not themselves be one and continuous; for how could a motion composed out of alteration and locomotion be uniform? For its parts would need to fit together.
21| Next we must determine what kind of motion is contrary to what motion, and treat rest in the same way. First we must distinguish whether the contrary motion is the motion from the same state as opposed to the motion to the same state (for example, the motion from health as opposed to the motion to health, the way generation and destruction also seem to be contraries), or the motion from contraries (for example, the motion from health as opposed to the motion from disease), or the motion to contraries (for example, the motion to health as opposed to the motion to disease), or the motion from a contrary as opposed to the motion to a contrary (for example, the motion from health as opposed to the motion to disease), or the motion from a contrary to a contrary as opposed to the motion from a contrary to a contrary (for example, the motion from health to disease as opposed to the motion from disease to health). For it is necessary that it be one of these ways, or several of them; there is no other way to set them in opposition. Now the motion from a contrary is not contrary to the motion to a contrary, for example the motion from health to the motion to disease; for they are the same motion, and one. Their being, however, is not the same for both, just as changing from health is not the same as changing to disease. Nor is the motion from a contrary contrary to another motion from a contrary; for it happens at the same time to be both from a contrary and to a contrary, or to an intermediate — but we will speak about this later — rather, changing to a contrary would seem to be the cause of the contrariety more than changing from a contrary; for the one is a release from the contrary state, the other a taking-on of it. And each motion is named more from what it changes into than from what it changes out of, for example the change into health is called becoming-healthy, and the change into disease is called becoming-diseased.
22| What remains, then, is the motion to contraries, and the motion to contraries out of contraries. Now perhaps it turns out that the motions to contraries are also from contraries, but their being is presumably not the same — I mean, the being of the motion to health is not the same as that of the motion from disease, nor is that of the motion from health the same as that of the motion to disease. Since change differs from motion (for motion is the change from some underlying subject into some other underlying subject), the motion from a contrary to a contrary is contrary to the motion from a contrary to a contrary, for example the motion from health to disease is contrary to the motion from disease to health. And it is also clear from induction what sorts of things are thought to be contraries: falling ill is contrary to becoming healthy, and learning to being deceived — not in virtue of themselves alone (for they are toward contraries; for just as one can acquire knowledge, so too deception, both through oneself and through another), and upward locomotion is contrary to downward (for these are contraries in length), and motion to the right is contrary to motion to the left (for these are contraries in breadth), and motion forward is contrary to motion backward (for these too are contraries). But change to a contrary alone, not out of some definite thing, is not motion but change — for example, coming to be white, not out of anything in particular.
23| And in the case of things that have no contraries, the change from the thing is contrary to the change into it; hence coming-to-be is contrary to perishing, and loss is contrary to acquisition; but these are changes, not motions. As for motions to an intermediate, in the case of contraries that have an intermediate, these are to be posited as being, in a way, motions to the contraries, since the motion treats the intermediate as a contrary, whichever direction it changes toward — for example, the motion from grey to white is treated as from black, and from white to grey as to black, while from black to grey is treated as to white, the grey being taken as white; for the middle is, in a way, called each of the two extremes in relation to each, just as has been said before also. Motion, then, is contrary to motion in this way: the motion from a contrary to a contrary is contrary to the motion from a contrary to a contrary.
24| Since it seems that not only is motion contrary to motion, but rest is too, this must be determined. Without qualification, motion is contrary to motion; but rest too is opposed to it, for rest is a privation, and privation too is in a way called a contrary. And a rest of a given kind is opposed to a motion of that kind, for example rest in respect of place to motion in respect of place. But so far this has only been said without qualification; for is it the motion from here, or the motion to here, that is opposed to remaining here? It is clear, then, that since motion involves two underlying subjects, remaining in this place is opposed to the motion from this place to its contrary, while remaining in the contrary place is opposed to the motion from the contrary to this place. And at the same time these two rests are also contrary to each other; for it would be absurd if motions were contrary but the opposed states of rest were not. And they are contrary in the case of contraries — for example, rest in health is contrary to rest in disease (and to the motion from health to disease; for its being contrary to the motion from disease to health would be unreasonable — for the motion into that state in which the thing has come to rest is rather a coming-to-rest, or at least it happens to come about together with the motion — and it is necessary that it be contrary to one or the other of these); for rest in whiteness, at any rate, is not contrary to rest in health.
25| In the case of things that have no contraries, the change from the thing is opposed to the change into it, but this is not motion — for example, the change from being as opposed to the change into being — and there is no remaining, that is, no rest, in their case, but rather unchangingness. And if there were some underlying subject, unchangingness in being would be contrary to unchangingness in not-being. But if not-being is not some subject, one might raise the difficulty of what unchangingness in being is contrary to, and whether it is a kind of rest at all. And if it is, then either not every rest is contrary to motion, or coming-to-be and perishing are motion. It is clear, then, that it should not be called rest, unless these too are motions, but that it is something similar to rest; and it is contrary either to nothing, or to unchangingness in not-being, or to perishing — for perishing proceeds out of it, while coming-to-be proceeds into it. But one might raise the difficulty
26| Why is it that in change of place there are both restings and motions that are in accordance with nature and contrary to nature, but not in the other kinds of change? Is one alteration, for example, in accordance with nature and another contrary to nature? — yet recovering health is no more in accordance with nature than falling ill, nor is falling ill any more contrary to nature than recovering health, and the same holds for whitening and blackening. And it is the same way with growth and decrease: for these are not contrary to each other as though one were in accordance with nature and the other contrary to it, nor is one growth contrary to another growth. And the same account holds for coming-to-be and passing-away: coming-to-be is not in accordance with nature while passing-away is contrary to nature (since growing old is in accordance with nature), nor do we observe one coming-to-be as in accordance with nature and another as contrary to it. Or is it rather that, if what happens by force is contrary to nature, then a passing-away brought about by force would be contrary to a passing-away that occurs in accordance with nature, since the forced one, being contrary to nature, is opposed to the one that is in accordance with it? Are there, then, also some comings-to-be that are forced and not the product of fate, to which the ones in accordance with nature are contrary — and forced growths and decreases as well, for example the growth of those who mature quickly through soft living, and grain that ripens quickly without becoming firm? And how does it stand with alteration? Is it the same way? For there would be some alterations that are forced and others that are natural — for example, patients discharged not on the critical days, and those discharged on the critical days: the former have been altered contrary to nature, the latter in accordance with nature. There will, then, also be passings-away contrary to one another, and not contrary to comings-to-be. And indeed what prevents this from being so in a way? For one passing-away might be pleasant and another painful, so that it is not passing-away without qualification that is contrary to passing-away, but rather in the respect that one is of one sort and the other of another.
27| Speaking generally, then, contrary motions and restings are, in the
28| manner stated, for example the upward contrary to the downward — for these are the contrarieties of place. Fire travels upward by nature, and earth travels downward; and their motions are contrary. Fire moves upward by nature but downward contrary to nature; and its motion in accordance with nature is contrary to its motion contrary to nature. And restings are the same way: for resting above is contrary to the motion from above to below. For earth, that resting above is contrary to nature, while this motion downward is in accordance with nature. So a resting that is contrary to nature is contrary to a motion in accordance with nature belonging to the same thing; for the motion belonging to the same thing is contrary in just this way — one of the two, the upward or the downward, being in accordance with its nature, and the other contrary to nature. There is a puzzle whether there is a coming-to-be for every resting that is not everlasting, and whether this coming-to-be is the coming-to-rest. Then of what remains contrary to nature — for example, earth resting above — there would be a coming-to-be. So when it was being carried upward by force, it was coming to rest. But what is coming to rest always seems to travel faster as it nears its place, while what moves by force does the opposite. So it will be at rest without having come to be at rest. Further, coming to rest seems either to be, without qualification, the same as being carried to one's own place, or to coincide with it. There is a puzzle whether the resting here is contrary to the motion away from here: for whenever something moves away from a given point and leaves it behind, it still seems to possess what is being left behind, so that if this resting is contrary to the motion from here toward the contrary place, the contraries will hold at the same time. Or is it at rest in a certain respect, if it still remains there, while, taken generally, of the thing that is moving, part is there and part is at the point into which it is changing? This is why motion, too, is more properly contrary to motion than resting is. So it has been stated concerning motion and resting, how each of them is one, and which are contrary to which.