LECTURE 13 (216 a 27-216 b 20)

IT IS SHOWN FROM THE VOID ITSELF THAT THERE IS NO SEPARATED VOID

             541. He shows here that there is no void by means of arguments dealing with the void itself apart from any consideration of motion. He gives three arguments.

             He says first that it will be seen by one who considers a void in itself apart from motion that the word 'void' is well used by those who say that a void exists. For 'void' signifies something which is empty and which is not. And to say that a void exists is to say something which is empty and removed from reason and truth. He shows this as follows. If one places in water a cubic body (that is, a body having six square surfaces), it is necessary that the quantity of water which recedes from its place is equal to the quantity of the cube. And this is true of air as well as water, although it is not as evident, because water is more sensible than air. Therefore, for the same reason, whenever anything is placed in a body, which by nature can be moved in some direction, then it is necessary that that body be moved, unless the parts coalesce either by condensation or by one part entering into another. The body is moved either by yielding (when it has a free exit), for example, a heavy body like earth goes downwards, and a light body like fire goes upwards, and a body that is heavy in respect to one thing and light in respect to another goes in either direction, like air and water; or the body is moved by yielding under the conditions of an imposed body, as when the yielding body is impeded by an imposed body so that it cannot be moved according to its own exigency but according to the exigency of the imposed body. Nevertheless, it is universally true that a body into which another body is placed must yield, lest there be two bodies together.

             But it cannot be said that a void yields when a body is placed in it. For a void is not a body. But whatever is moved in any way is a body. Now if there is a void space, and if some body is placed in that space, then it is necessary that the imposed body passes through into that space which formerly was a void, that is, it exists together with it. It is as if water or air would not yield to a wooden cube, but rather these bodies would pass through the very body of the wooden cube, such that the air and water would penetrate into the body of the cube and would exist together with it.

             But it is impossible for a cubic, wooden body to exist together with a void space. For the cubic, wooden body has the same magnitude as the void, which is posited as a certain space having dimensions without a sensible body. And although the cubic, wooden body is either hot or cold, or heavy or light, nevertheless according to reason [ratio] that cubic, wooden body is other than all the sensible passions accidental to it--even though in the thing it is not separable from them. That which according to reason [ratio] is other than the passions is the very body of the wooden cube, that is, it is that which pertains to its corporeity. If, therefore, this body be separated from everything which is other than it according to reason [ratio], it follows that it contains or occupies a part of the void space equal to itself. And thus the body of the wooden cube will be in the same part of both a place and a void equal to itself.

             Granting this, it does not seem that there is any difference between the body of the cube and the dimensions of a place or a void. For just as place or void has dimensions without sensible qualities, so also the dimensions of the cubic body are other than passions of this kind, at least according to reason [ratio]. However two magnitudes of equal quantity cannot differ except in respect to site. For it is impossible to imagine that one line is different from another equal line unless we imagine each of them in a different site. Hence if two magnitudes are posited together, it does not seem that they differ. And thus if two equally dimensioned bodies exist together, whether they have sensible passions or not, it follows that the two bodies are one.

             Furthermore, if the cubic body and the space, which is a place or a void, would remain two and exist together, one cannot give any reason [ratio] why any other body cannot exist in the same place. And thus, just as the cubic body exists together with the space of a place or a void, likewise some third or even fourth body will be able to exist together with both of them. But this is impossible. For it cannot be said that another sensible body is unable because of matter to exist together with the cubic, wooden body. For place is not due a body by reason [ratio] of matter except insofar as matter is contained under dimensions. Hence the fact that two bodies cannot exist together is not due to the matter or to the sensible passions but only to the dimensions, in which there cannot be diversity, if they are equal, except in respect to site, as was said. Hence if there are dimensions in a void space as there are in a sensible body, then just as two sensible bodies cannot exist together, likewise neither can a sensible body and a void space exist together. This, therefore, is one inconsistency and impossibility that follows from the above position; namely, two bodies exist together.

             542. He gives the second argument where he says, 'It is also evident . . .' (216 b 12). He says that it is clear that the cube, which is moved and placed in a void space, has dimensions, which all bodies have. Therefore, if the dimensions of the cubic body do not differ according to reason [ratio] from the dimensions of place, and if place is nothing else than body without sensible passions, why is it necessary to assign some place for bodies outside their own bodies? For since such a body has its own dimensions, it seems in no way necessary to posit around it some other dimensions equal in space to its own dimensions. Therefore, if void or place is posited as a certain separated space, it follows that it is not necessary that bodies be in place.

             543. He gives the third argument where he says, 'Further, it ought to be . . .' (216 b 16). He says that, if a void is something, then this ought to be manifest in mobile things. But a void appears nowhere in the world. For that which is filled with air is not a void, although it seems to be. Air is something, even though it is not perceived by sight. If fish were made of iron and had an appearance similar to water, water could not be distinguished from them by sight. Nevertheless it would not follow that water or even fish do not exist. For not only sight but also touch distinguishes that which is touched. Thus it is clear that air is something. For hot and cold is perceived by touch.

             Therefore, from these arguments it appears that a void is not a separated space, neither within the world nor outside the world.