12 · Having established these distinctions we can now proceed to the sequel. If there are things capable both of being and of not being, there must be some [30] definite maximum time of their being and not being; a time, I mean, during which the thing can be and a time during which it can fail to be. And this is true in every category, whether the thing is, for example, a man, or white, or three cubits long, or whatever it may be. For if the time is not definite in quantity, but longer than any that can be suggested and shorter than none, then it will be possible for one and the [281b1] same thing to be for infinite time and not to be for another infinity. This, however, is impossible.
Let us take our start from this point. The impossible and the false have not the same significance. One use of ‘impossible’ and ‘possible’, and ‘false’ and ‘true’, is [5] hypothetical. It is impossible, for instance, on a certain hypothesis that the triangle should have its angles equal to two right angles, and on another the diagonal is commensurable. But there are also things possible and impossible, false and true, absolutely. Now it is one thing to be absolutely false, and another thing to be absolutely impossible. To say that you are standing when you are not standing is to [10] assert a falsehood, but not an impossibility. Similarly to say that a man who is playing the harp, but not singing, is singing, is to say what is false but not impossible. To say, however, that you are at once standing and sitting, or that the diagonal is commensurable, is to say what is not only false but also impossible. Thus it is not the same thing to make a false and to make an impossible hypothesis; and [15] from the impossible hypothesis impossible results follow. A man has, it is true, the capacity at once of sitting and of standing, because when he possesses the one he also possesses the other; but it does not follow that he can at the same time sit and stand, but at different times. But if a thing has for infinite time more than one capacity, another time is impossible and the times must coincide. Thus if anything [20] which exists for infinite time is destructible, it will have the capacity of not being. Now if it exists for infinite time let this capacity be actualized; and it will be in actuality at once existent and non-existent. Thus a false conclusion would follow because a false assumption was made; but if what was assumed had not been impossible its consequence would not have been impossible.
Anything then which always exists is absolutely imperishable. It is also [25] ungenerated, since if it was generated it will have the power for some time of not being. For as that which formerly was, but now is not, or is capable at some future time of not being, is destructible, so that which is capable of formerly not having been is generated. But in the case of that which always is, there is no time for such a capacity of not being, whether the supposed time is finite or infinite; for its capacity [30] of being must include the finite time since it covers infinite time.
It is therefore impossible that one and the same thing should be capable of always existing and of always not-existing. And not always existing, the contradictory, is also excluded. Thus it is impossible for a thing always to exist and yet to be destructible. Nor, similarly, can it be generated. For of two terms if the second [282a1] cannot be present without the first, and the first is impossible, so too is the second. What always is, then, since it is incapable of ever not being, cannot possibly be generated. But since the contradictory of ‘that which is always capable of being’ is [5] ‘that which is not always capable of being’; while ‘that which is always capable of not being’ is the contrary, whose contradictory in turn is ‘that which is not always capable of not being’, it is necessary that the contradictories of both terms should be predicable of one and the same thing, and thus that, intermediate between what always is and what always is not, there should be that to which being and not-being are both possible; for the contradictory of each will at times be true of it unless it [10] always exists. Hence that which not always is not will sometimes be and sometimes not be; and it is clear that this is true also of that which cannot always be but sometimes is and therefore sometimes is not. One thing, then, will have the power of being and of not being, and thus be intermediate between the other two.
Expressed universally our argument is as follows. Let there be two attributes, A and B, not capable of being present in any one thing together, while either A or C [15] and either B or D are capable of being present in everything. Then C and D must be predicated of everything of which neither A nor B is predicated. Let E lie between A and B; for that which is neither of two contraries is a mean between them. In E both C and D must be present; for either A or C is present everywhere and therefore in E. [20] Since then A is impossible, C must be present, and the same argument holds of D.
Neither that which always is, therefore, nor that which always is not is either generated or destructible. And clearly whatever is generated or destructible is not eternal. If it were, it would be at once capable of always being and capable of not always being; but it has already been shown that this is impossible. Surely then [25] whatever is ungenerated and in being must be eternal, and whatever is indestructible and in being must equally be so. (I use the words ‘ungenerated’ and ‘indestructible’ in their proper sense, ‘ungenerated’ for that which now is and could not at some previous time have been truly said not to be; ‘indestructible’ for that [30] which now is and cannot at any future time be truly said not to be.) If, again, the two terms follow one another, if the ungenerated is indestructible, and the indestructible ungenerated, then the eternal follows each of them: anything [282b1] ungenerated is eternal and anything indestructible is eternal. This is clear too from the definition of the terms. Whatever is destructible must be generated; for it is either ungenerated or generated, but, if ungenerated, it is by hypothesis indestructible. Whatever, further, is generated must be destructible. For it is either [5] destructible or indestructible, but, if indestructible, it is by hypothesis ungenerated.
If, however, ‘indestructible’ and ‘ungenerated’ do not follow one another, there is no necessity that either the ungenerated or the indestructible should be eternal. But they must follow one another, for the following reasons. The terms ‘generated’ and ‘destructible’ follow one another; this is obvious from our former remarks, since [10] between what always is and what always is not there is an intermediate which neither follows, and that intermediate is the generated and destructible. For whatever is either of these is capable both of being and of not being for a definite time: in either case, I mean, there is a certain period of time during which the thing is and another during which it is not. Anything therefore which is generated or [15] destructible must be intermediate. Now let A be that which always is and B that which always is not, C the generated, and D the destructible. Then C must be intermediate between A and B. For in their case there is no time in the direction of either limit, in which either A is not or B is. But for the generated there must be such [20] a time either actually or potentially, though not for A and B in either way. C then will be, and also not be, for a limited length of time, and this is true also of D. Therefore each is both generated and destructible. Therefore ‘generated’ and ‘destructible’ follow one another. Now let E stand for the ungenerated, F for the [25] generated, G for the indestructible, and H for the destructible. As for F and H, it has been shown that they follow one another. But when terms stand to one another as these do, F and H following, E and F never predicated of the same thing but one or other of everything, and G and H likewise, then E and G must follow one another. [30] For suppose that E does not follow G; then F will, since either E or F is predicable of everything. But of that of which F is predicated H will be predicable also. H will then follow G; but this we saw to be impossible. And the same argument shows that [283a1] G follows E.
Now the relation of the ungenerated (E) to the generated (F) is the same as that of the indestructible (G) to the destructible (H). To say then that there is no reason why anything should not be generated and yet indestructible or ungenerated [5] and yet destroyed, to imagine that in the one case
generation and in the other case destruction occurs once for all, is to destroy part of the data. For everything is capable of acting or being acted upon, of being or not being, either for an infinite, or for a definitely limited space of time; and the infinite time is only a possible alternative because it is after a fashion defined, as a length of time which cannot be [10] exceeded. But infinity in one direction is neither infinite nor defined. Further, why, after always existing, was the thing destroyed, why, after an infinity of not being, was it generated, at one moment rather than another? If there is no reason and the moments are infinite in number, it is clear that a generated or destructible thing existed for an infinite time. It has therefore for an infinite time the capacity of not being (since the capacity of being and the capacity of not being will be present together), if destructible, in the time before destruction, if generated, in the time [15] after generation. If then we assume the two capacities to be actualized, opposites will be present together. Further, this will be equally present at every moment, so that the thing will have for an infinite time the capacity both of being and of not being; but this has been shown to be impossible. Again, if the capacity is present [20] prior to the activity, it will be present for all time, even while the thing was as yet ungenerated and non-existent but capable of being generated. At the time, then, when it was not, at that same time it had the capacity of being, both of being then and of being thereafter, and therefore for an infinity of time.
It is clear also on other grounds that it is impossible that the destructible should not at some time be destroyed. For otherwise it will always be at once [25] destructible and in actuality indestructible, so that it will be at the same time capable of always existing and of not always existing. Thus the destructible is at some time actually destroyed. The generable, similarly, has been generated; for it is capable of having been generated and thus also of not always existing.
We may also see in the following way how impossible it is either for a thing which is generated to be thenceforward indestructible, or for a thing which is [30] ungenerated and has always hitherto existed to be destroyed. Nothing that is by chance can be indestructible or ungenerated, since the products of chance and fortune are opposed to what is, or comes to be, always or for the most part, while anything which exists for a time infinite either absolutely or from a certain point, is [283b1] in existence either always or for the most part. That which is by chance, then, is by nature such as to exist at one time and not at another. But in things of that character the contradictory states proceed from one and the same capacity, the matter of the thing being the cause equally of its existence and of its non-existence. Hence opposites would be present together in actuality. [5]
Further, it cannot truly be said of a thing now that it exists last year, nor could it be said last year that it exists now. It is therefore impossible for what once did not exist later to be eternal. For in its later state it will possess the capacity of not existing, only not of not existing at a time when it exists—since then it exists in actuality—but of not existing last year or in the past. Now suppose it to be in [10] actuality what it is capable of being. It will then be true to say now that it does not exist last year. But this is impossible. No capacity relates to being in the past, but always being in the present or future. It is the same with the notion of an eternity of existence followed later by non-existence. In the later state the capacity will be present for that which is not there in actuality. Actualize, then, the capacity. It will [15] be true to say now that this exists last year or in the past generally.
Considerations not general but proper to the subject also show it to be impossible that what was formerly eternal should later be destroyed or that what formerly was not should later be eternal. Whatever is destructible or generated is always alterable. Now alteration is due to contraries, and the things which compose [20] the natural body are the very same that destroy it.
BOOK II
1 · That the heaven as a whole neither came into being nor admits of destruction, as some assert, but is one and eternal, with no end or beginning of its total duration, containing and embracing in itself the infinity of time, we may [30] convince ourselves not only by the arguments already set forth but also by a consideration of the views of those who differ from us in providing for its generation. If our view is a possible one, and the manner of generation which they assert is [284a1] impossible, this fact will have great weight in convincing us of the immortality and eternity of the world. Hence it is well to persuade oneself of the truth of the ancient and truly traditional theories, that there is some immortal and divine thing which [5] possesses movement, but movement such as has no limit and is rather itself the limit of all other movement. A limit is a thing which contains; and this motion, being perfect, contains those imperfect motions which have a limit and a cessation, having itself no beginning or end, but unceasing through the infinity of time, and of other [10] movements, to some the cause of their beginning, of others receiving the cessation. The ancients gave to the Gods the heaven or upper place, as being alone immortal; and our present argument testifies that it is indestructible and ungenerated. Further, it is unaffected by any mortal discomfort, and, in addition, effortless; for it [15] needs no constraining necessity to keep it to its path, and prevent it from moving with some other movement more natural to itself. Such a constrained movement would necessarily involve effort—the more so, the more eternal it were—and would be inconsistent with perfection. Hence we must not believe the old tale which says [20] that the world needs some Atlas to keep it safe—a tale composed, it would seem, by men who, like later thinkers, conceived of all the upper bodies as earthy and endowed with weight, and therefore supported it in their fabulous way upon animate necessity. We must no more believe that than follow Empedocles when he says that the world, by being whirled round, received a movement quick enough to [25] overpower its own downward tendency, and thus has been kept from destruction all this time. Nor, again, is it possible that it should persist eternally by the necessitation of a soul. For a soul could not live in such conditions painlessly or [30] happily, since the movement involves constraint, being imposed on the first body, whose natural motion is different, and imposed continuously. It must therefore be uneasy and devoid of all rational satisfaction; for it could not even, like the soul of mortal animals, take recreation in the bodily relaxation of sleep. An Ixion’s lot must [284b1] needs possess it, without end or respite. If then, as we said, the view already stated of the first motion is a possible one, it is not only more appropriate so to conceive of its eternity, but also on this hypothesis alone are we able to advance a theory consistent [5] with our premonitions of divinity. But of this enough for the present.
2 · Since there are some who say that there is a right and a left in the heaven, with those who are known as Pythagoreans—to whom indeed the view really belongs—we must consider whether, if we are to apply these principles to the body [10] of the universe, we should follow their statement of the matter or find a better way. At the start we may say that, if right and left are applicable, there are prior principles which must first be applied. These principles have been analysed in the discussion of the movements of animals,9 for the reason that they are proper to animal nature. For in some animals we find all such distinctions of parts as this of [15] right and left clearly present, and in others some; but in plants we find only above and below. Now if we are to apply to the heaven such a distinction of parts, we must expect, as we have said, to find in it also that distinction which in animals is found first of them all. The distinctions are three, namely, above and below, front and its [20] opposite, right and left—all these three oppositions we expect to find in the perfect body—and each may be called a principle. Above is the principle of length, right of breadth, front of depth. Or again we may connect them with the various [25] movements, taking principle to mean that part, in a thing capable of movement, from which movement first begins. Growth starts from above, locomotion from the right
, sense-movement from in front (for front is simply the part to which the senses are directed). Hence we must not look for above and below, right and left, front and [30] back, in every kind of body, but only in those which, being animate, have a principle of movement within themselves. For in no inanimate thing do we observe a part from which movement originates. Some do not move at all, some move, but not indifferently in any direction; fire, for example, only upward, and earth only to the [285a1] centre. It is true that we speak of above and below, right and left, in these bodies relatively to ourselves. The reference may be to our own right hands, as with the diviner, or to some similarity to our own members, such as the parts of a statue possess; or we may take the contrary spatial order, calling right that which is to our [5] left, and left that which is to our right. We observe, however, in the things themselves none of these distinctions; indeed if they are turned round we proceed to speak of the opposite parts as right and left, above and below, front and back. Hence it is remarkable that the Pythagoreans should have spoken of these two principles, [10] right and left, only, to the exclusion of the other four, which have as good a title as they. There is no less difference between above and below or front and back in animals generally than between right and left. The difference is sometimes only one [15] of function, sometimes also one of shape; and while the distinction of above and below is characteristic of all animate things, whether plants or animals, that of right and left is not found in plants. Further, inasmuch as length is prior to breadth, if above is the principle of length, right of breadth, and if the principle of that which is [20] prior is itself prior, then above will be prior to right (for things are called in order of generation prior in several ways). If, in addition, above is the region from which movement originates, right the region in which it starts, front the region to which it is directed, then on this ground too above has the character of a principle as compared with the other forms of position. Thus they may fairly be criticized, first, [25] for omitting the more fundamental principles, and secondly, for thinking that the two they mentioned were attributable equally to everything.
The Complete Works of Aristotle Page 83