THE physicist must have a knowledge of Place, too, as well as of the
infinite-namely, whether there is such a thing or not, and the
manner of its existence and what it is-both because all suppose that
things which exist are somewhere (the non-existent is nowhere--where
is the goat-stag or the sphinx?), and because "motion" in its most
general and primary sense is change of place, which we call
"locomotion".

    The question, what is place? presents many difficulties. An
examination of all the relevant facts seems to lead to divergent
conclusions. Moreover, we have inherited nothing from previous
thinkers, whether in the way of a statement of difficulties or of a
solution.

    The existence of place is held to be obvious from the fact of mutual
replacement. Where water now is, there in turn, when the water has
gone out as from a vessel, air is present. When therefore another body
occupies this same place, the place is thought to be different from
all the bodies which come to be in it and replace one another. What
now contains air formerly contained water, so that clearly the place
or space into which and out of which they passed was something
different from both.

    Further, the typical locomotions of the elementary natural
bodies-namely, fire, earth, and the like-show not only that place is
something, but also that it exerts a certain influence. Each is
carried to its own place, if it is not hindered, the one up, the other
down. Now these are regions or kinds of place-up and down and the rest
of the six directions. Nor do such distinctions (up and down and right
and left, &c.) hold only in relation to us. To us they are not
always the same but change with the direction in which we are
turned: that is why the same thing may be both right and left, up
and down, before and behind. But in nature each is distinct, taken
apart by itself. It is not every chance direction which is "up", but
where fire and what is light are carried; similarly, too, "down" is
not any chance direction but where what has weight and what is made of
earth are carried-the implication being that these places do not
differ merely in relative position, but also as possessing distinct
potencies. This is made plain also by the objects studied by
mathematics. Though they have no real place, they nevertheless, in
respect of their position relatively to us, have a right and left as
attributes ascribed to them only in consequence of their relative
position, not having by nature these various characteristics. Again,
the theory that the void exists involves the existence of place: for
one would define void as place bereft of body.

    These considerations then would lead us to suppose that place is
something distinct from bodies, and that every sensible body is in
place. Hesiod too might be held to have given a correct account of
it when he made chaos first. At least he says:

    "First of all things came chaos to being, then broad-breasted
earth,"
implying that things need to have space first, because he thought,
with most people, that everything is somewhere and in place. If this
is its nature, the potency of place must be a marvellous thing, and
take precedence of all other things. For that without which nothing
else can exist, while it can exist without the others, must needs be
first; for place does not pass out of existence when the things in
it are annihilated.

    True, but even if we suppose its existence settled, the question
of its nature presents difficulty-whether it is some sort of "bulk" of
body or some entity other than that, for we must first determine its
genus.

    (1) Now it has three dimensions, length, breadth, depth, the
dimensions by which all body also is bounded. But the place cannot
be body; for if it were there would be two bodies in the same place.

    (2) Further, if body has a place and space, clearly so too have
surface and the other limits of body; for the same statement will
apply to them: where the bounding planes of the water were, there in
turn will be those of the air. But when we come to a point we cannot
make a distinction between it and its place. Hence if the place of a
point is not different from the point, no more will that of any of the
others be different, and place will not be something different from
each of them.

    (3) What in the world then are we to suppose place to be? If it
has the sort of nature described, it cannot be an element or
composed of elements, whether these be corporeal or incorporeal: for
while it has size, it has not body. But the elements of sensible
bodies are bodies, while nothing that has size results from a
combination of intelligible elements.

    (4) Also we may ask: of what in things is space the cause? None of
the four modes of causation can be ascribed to it. It is neither in
the sense of the matter of existents (for nothing is composed of
it), nor as the form and definition of things, nor as end, nor does it
move existents.

    (5) Further, too, if it is itself an existent, where will it be?
Zeno's difficulty demands an explanation: for if everything that
exists has a place, place too will have a place, and so on ad
infinitum.

    (6) Again, just as every body is in place, so, too, every place
has a body in it. What then shall we say about growing things? It
follows from these premisses that their place must grow with them,
if their place is neither less nor greater than they are.

    By asking these questions, then, we must raise the whole problem
about place-not only as to what it is, but even whether there is
such a thing.