by Aristotle
It will now be plain from these considerations what place is. There are just four [5] things of which place must be one—the shape, or the matter, or some sort of extension between the extremities, or the extremities (if there is no extension over and above the bulk of the body which comes to be in it).
[10] Three of these it obviously cannot be. The shape is supposed to be place because it surrounds, for the extremities of what contains and of what is contained are coincident. Both the shape and the place, it is true, are boundaries. But not the same thing: the form is the boundary of the thing, the place is the boundary of the body which contains it.
The extension between the extremities is thought to be something, because [15] what is contained and separate may often be changed while the container remains the same (as water may be poured from a vessel)—the assumption being that the extension is something over and above the body displaced. But there is no such extension. One of the bodies which change places and are naturally capable of being in contact with the container falls in—whichever it may chance to be.
If there were an extension which were such as to exist independently and be [20] permanent, there would be an infinity of places in the same thing. For when the water and the air change places, all the portions of the two together will play the same part in the whole which was previously played by all the water in the vessel; at the same time the place too will be undergoing change; so that there will be another place which is the place of the place, and many places will be coincident. There is [25] not a different place of the part, in which it is moved, when the whole vessel changes its place: it is always the same; for it is in the place where they are that the air and the water (or the parts of the water) succeed each other, not in that place in which they come to be, which is part of the place which is the place of the whole world.
[30] The matter, too, might seem to be place, at least if we consider it in what is at rest and is not separate but in continuity. For just as in change of quality there is something which was formerly black and is now white, or formerly soft and now hard—this is why we say that the matter exists—so place, because it presents a similar phenomenon, is thought to exist—only in the one case we say so because what was air is now water, in the other because where air formerly was there is now [212a1] water. But the matter, as we said before, is neither separable from the thing nor contains it, whereas place has both characteristics.
Well, then, if place is none of the three—neither the form nor the matter nor an extension which is always there, different from, and over and above, the [5] extension of the thing which is displaced—place necessarily is the one of the four which is left, namely, the boundary of the containing body at which it is in contact with the contained body. (By the contained body is meant what can be moved by way of locomotion.)
Place is thought to be something important and hard to grasp, both because the matter and the shape present themselves along with it, and because the [10] displacement of the body that is moved takes place in a stationary container, for its seems possible that there should be an interval which is other than the bodies which are moved. The air, too, which is thought to be incorporeal, contributes something to the belief: it is not only the boundaries of the vessel which seem to be place, but also what is between them, regarded as empty. Just, in fact, as the vessel is transportable place, so place is a non-portable vessel. So when what is within a thing [15] which is moved, is moved and changes, as a boat on a river, what contains plays the part of a vessel rather than that of place. Place on the other hand is rather what is motionless: so it is rather the whole river that is place, because as a whole it is motionless.
Hence the place of a thing is the innermost motionless boundary of what [20] contains it.
This explains why the middle of the world and the surface which faces us of the rotating system are held to be up and down in the strict and fullest sense for all men: for the one is always at rest, while the inner side of the rotating body remains always coincident with itself. Hence since the light is what is naturally carried up, and the [25] heavy what is carried down, the boundary which contains in the direction of the middle of the universe, and the middle itself, are down, and that which contains in the direction of the extremity, and the extremity itself, are up.
For this reason place is thought to be a kind of surface, and as it were a vessel, i.e. a container of the thing.
Further, place is coincident with the thing, for boundaries are coincident with [30] the bounded.
5 · If then a body has another body outside it and containing it, it is in place, and if not, not. That is why, even if there were to be water which had not a container, the parts of it will be moved (for one part is contained in another), while the whole will be moved in one sense, but not in another. For as a whole it does not simultaneously change its place, though it will be moved in a circle; for this place is [212b1] the place of its parts. And some parts are moved, not up and down, but in a circle; others up and down, such things namely as admit of condensation and rarefaction.
As was explained, some things are potentially in place, others actually. So, when you have a homogeneous substance which is continuous, the parts are [5] potentially in place: when the parts are separated, but in contact, like a heap, they are actually in place.
Again, some things are per se in place, namely every body which is movable either by way of locomotion or by way of increase is per se somewhere, but the world, as has been said, is not anywhere as a whole, nor in any place, if, that is, no body contains it. But the line on which it is moved provides a place for its parts; for [10] each is contiguous to the next.
Other things are in place accidentally, as the soul and the world. The latter is, in a way, in place, for all its parts are; for on the circle one part contains another. That is why the upper part is moved in a circle, while the universe is not anywhere. For what is somewhere is itself something, and there must be alongside it some [15] other thing wherein it is and which contains it. But alongside the universe or the Whole there is nothing outside the universe, and for this reason all things are in the world; for the world, we may say, is the universe. Yet their place is not the same as the world. It is part of it, the innermost part of it, which is in contact with the [20] movable body; and for this reason the earth is in water, and this in the air, and the air in the aether, and the aether in the world, but we cannot go on and say that the world is in anything else.
It is clear, too, from these considerations that all the problems which were raised about place will be solved when it is explained in this way.
There is no necessity that the place should grow with the body in it, nor that a [25] point should have a place; nor that two bodies should be in the same place; nor that place should be a corporeal interval (for what is between the boundaries of the place is any body which may chance to be there, not an interval in body).
Further, place is indeed somewhere, not in the sense of being in a place, but as the limit is in the limited; for not everything that is is in place, but only movable body.
[30] Also, it is reasonable that each kind of body should be carried to its own place. For a body which is next in the series and in contact (not by compulsion) is akin, and bodies which are united do not affect each other, while those which are in contact interact on each other.
Nor is it without reason that each should remain naturally in its proper place. For parts do, and that which is in a place has the same relation to its place as a [213a1] separable part to its whole, as when one moves a part of water or air: so, too, air is related to water, for the one is like matter, the other form—water is the matter of air, air as it were the actuality of water; for water is potentially air, while air is potentially water, though in another way.
These distinctions will be drawn more carefully later. On the present occasion [5] it was necessary to refer to them: what has now been stated obscurely will then be made more clear.28 If the matter and the fulfilment are the same t
hing (for water is both, the one potentially, the other in fulfilment), water will be related to air in a way as part to whole. That is why these have contact: it is organic union when both become actually one.
[10] This concludes my account of place—both of its existence and of its nature.
6 · The investigation of similar questions about the void, also, must be held to belong to the physicist—namely whether it exists or not, and how it exists or what it is—just as about place. The views taken of it involve arguments both for and [15] against, in much the same sort of way. For those who hold that the void exists regard it as a sort of place or vessel which is supposed to be full when it holds the bulk which it is capable of containing, void when it is deprived of that—as if void and full and place were the same thing, though the essence of the three is different.
[20] We must begin the inquiry by putting down the account given by those who say that it exists, then the account of those who say that it does not exist, and third the common opinions on these questions.
Those who try to show that the void does not exist do not disprove what people really mean by it, but only their erroneous way of speaking; this is true of Anaxagoras and of those who refute the existence of the void in this way. They show [25] that air is something—by straining wine-skins and showing the resistance of the air, and by cutting it off in clepsydras. But people really mean by void an interval in which there is no sensible body. They hold that everything which is is body and say that what has nothing in it at all is void (so what is full of air is void). It is not then [30] the existence of air that needs to be proved, but the non-existence of an interval, different from the bodies, either separable or actual—an interval which divides the whole body so as to break its continuity, as Democritus and Leucippus hold, and many other physicists—or even perhaps as something which is outside the whole [213b1] body, which remains continuous.
These people, then, have not reached even the threshold of the problem, but rather those who say that the void exists.
They argue, for one thing, that change in place (i.e. locomotion and increase) would not occur. For it is maintained that motion would seem not to exist, if there [5] were no void, since what is full cannot contain anything more. If it could, and there were two bodies in the same place, it would also be true that any number of bodies could be together; for it is impossible to draw a line of division beyond which the statement would become untrue. If this were possible, it would follow also that the smallest body would contain the greatest; for many small things make a large thing: [10] thus if many equal bodies can be in the same place, so also can many unequal bodies.
Melissus, indeed, actually argues from this that the universe is immovable; for if it were moved there must, he says, be void, but void is not among the things that exist.
This argument, then, is one way in which they show that there is a void. [15] They also reason from the fact that some things are observed to contract and be compressed, as people say that a cask will hold the wine along with the skins, which implies that the compressed body contracts into the voids present in it.
Again increase, too, is thought by everyone to take place by means of void; for nutriment is body, and it is impossible for two bodies to be together. Evidence of this [20] they find also in what happens to ashes, which absorb as much water as the empty vessel.
The Pythagoreans, too, held that void exists and that it enters the world from the infinite air, the world inhaling also the void which distinguishes the natures of [25] things, as if it were what separates and distinguishes the terms of a series. This holds primarily in the numbers; for the void distinguishes their nature.
These, then, and so many, are the main grounds on which people have argued for and against the existence of the void.
7 · As a step towards settling which view is true, we must determine the [30] meaning of the word.
The void is thought to be place with nothing in it. The reason for this is that people take what exists to be body, and hold that while every body is in place, void is place in which there is no body, so that where there is no body, there is nothing.
[214a1] Every body, again, they suppose to be tangible; and of this nature is whatever has weight or lightness. Hence, by deduction, what has nothing heavy or light in it, is void.
This result, then, as I have just said, is reached by deduction. It would be [5] absurd to suppose that the point is void; for the void must be place which has in it an interval in tangible body.
But at all events we observe then that in one way the void is described as what is not full of body perceptible to touch; and what has heaviness and lightness is perceptible to touch. So we would raise the question: what would they say of an [10] interval that has colour or sound—is it void or not? Clearly they would reply that if it could receive what is tangible it was void, and if not, not.
In another way void is that in which there is not ‘this’ or corporeal substance. So some say that the void is the matter of the body (they identify the place, too, with [15] this), and in this they speak incorrectly; for the matter is not separable from the things, but they are inquiring about the void as about something separable.
Since we have determined the nature of place, and void must, if it exists, be place deprived of body, and we have stated both in what sense it does not, it is plain that on this showing void does not exist, either unseparated or separated; for the [20] void is meant to be, not body but rather an interval in body. This is why the void is thought to be something, viz. because place is, and for the same reasons. For the fact of motion in respect of place comes to the aid both of those who maintain that place is something over and above the bodies that come to occupy it, and of those who maintain that the void is something. They state that the void is a cause of movement [25] in the sense of that in which movement takes place; and this would be the kind of thing that some say place is.
But there is no necessity for there being a void if there is movement. It is not in the least needed as a condition of movement in general, for a reason which escaped Melissus; viz. that the full can suffer qualitative change.
But not even movement in respect of place involves a void; for bodies may [30] simultaneously make room for one another, though there is no interval separate and apart from the bodies that are in movement. And this is plain even in the rotation of continuous things, as in that of liquids.
And things can also be compressed not into a void but because they squeeze out [214b1] what is contained in them (as, for instance, when water is compressed the air within it is squeezed out); and things can increase in size not only by the entrance of something but also by qualitative change; e.g. if water were to be transformed into air.
In general, both the argument about increase of size and that about the water [5] poured on to the ashes get in their own way. For either not any and every part of the body is increased, or bodies may be increased otherwise than by the addition of body, or there may be two bodies in the same place (in which case they are claiming to solve a general difficulty, but are not proving the existence of void), or the whole body must be void, if it is increased in every part and is increased by means of void. The same argument applies to the ashes.
It is evident, then, that it is easy to refute the arguments by which they prove [10] the existence of the void.
8 · Let us explain again that there is no void existing separately, as some maintain. If each of the simple bodies has a natural locomotion, e.g. fire upward and earth downward and towards the middle of the universe, it is clear that the void [15] cannot be a cause of locomotion. What, then, will the void be a cause of? It is thought to be a cause of movement in respect of place, and it is not a cause of this.
Again, if void is a sort of place deprived of body, when there is a void where will a body placed in it move to? It certainly cannot move into the whole of the void. The same argument applies as against those who think that place is something separate, [20] into which things are carri
ed; viz. how will what is placed in it move, or rest? The same argument will apply to the void as to the up and down in place, as is natural enough since those who maintain the existence of the void make it a place.
And in what way will things be present either in place or in the void? For the result does not take place when a body is placed as a whole in a place conceived of as [25] separate and permanent; for a part of it, unless it be placed apart, will not be in a place but in the whole. Further, if separate place does not exist, neither will void.
If people say that the void must exist, as being necessary if there is to be movement, what rather turns out to be the case, if one studies the matter, is the [30] opposite, that not a single thing can be moved if there is a void; for as with those who say the earth is at rest because of the uniformity, so, too, in the void things must be at rest; for there is no place to which things can move more or less than to another; since the void in so far as it is void admits no difference.
The second reason is this: all movement is either compulsory or according to [215a1] nature, and if there is compulsory movement there must also be natural (for compulsory movement is contrary to nature, and movement contrary to nature is posterior to that according to nature, so that if each of the natural bodies has not a natural movement, none of the other movements can exist); but how can there be [5] natural movement if there is no difference throughout the void or the infinite? For in so far as it is infinite, there will be no up or down or middle, and in so far as it is a void, up differs no whit from down; for as there is no difference in what is nothing, there is none in the void (for the void seems to be a non-existent and a privation); but [10] natural locomotion seems to be differentiated, so that the things that exist by nature must be differentiated. Either, then, nothing has a natural locomotion, or else there is no void.