Physics   

(4) 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, (5) place is also 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.
Also (6) 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 (7) is it without reason that each should remain naturally in its
proper place. For this part has the same relation to its place, as a
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 it was necessary to refer to them: what has now been stated
obscurely will then be made more clear. If the matter and the
fulfilment are the same thing (for water is both, the one potentially,
the other completely), 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.
This concludes my account of place-both of its existence and of its
nature.
Part 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 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' denoted the same thing, though the
essence of the three is different.
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 current view 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 merely give an ingenious
demonstration 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 that there is an empty interval in
which there is no sensible body. They hold that everything which is in
body 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 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 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.
(1) They argue, for one thing, that change in place (i.e. locomotion
and increase) would not be. For it is maintained that motion would
seem not to exist, if there 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