Physics   

means substance, it follows that 'being' has more than one meaning.
In particular, then, Being will not have magnitude, if it is
substance. For each of the two parts must he in a different sense.
(2) Substance is plainly divisible into other substances, if we
consider the mere nature of a definition. For instance, if 'man' is a
substance, 'animal' and 'biped' must also be substances. For if not
substances, they must be attributes-and if attributes, attributes
either of (a) man or of (b) some other subject. But neither is
possible.
(a) An attribute is either that which may or may not belong to the
subject or that in whose definition the subject of which it is an
attribute is involved. Thus 'sitting' is an example of a separable
attribute, while 'snubness' contains the definition of 'nose', to
which we attribute snubness. Further, the definition of the whole is
not contained in the definitions of the contents or elements of the
definitory formula; that of 'man' for instance in 'biped', or that of
'white man' in 'white'. If then this is so, and if 'biped' is supposed
to be an attribute of 'man', it must be either separable, so that
'man' might possibly not be 'biped', or the definition of 'man' must
come into the definition of 'biped'-which is impossible, as the
converse is the case.
(b) If, on the other hand, we suppose that 'biped' and 'animal' are
attributes not of man but of something else, and are not each of them
a substance, then 'man' too will be an attribute of something else.
But we must assume that substance is not the attribute of anything,
that the subject of which both 'biped' and 'animal' and each
separately are predicated is the subject also of the complex 'biped
animal'.
Are we then to say that the All is composed of indivisible substances?
Some thinkers did, in point of fact, give way to both arguments. To
the argument that all things are one if being means one thing, they
conceded that not-being is; to that from bisection, they yielded by
positing atomic magnitudes. But obviously it is not true that if being
means one thing, and cannot at the same time mean the contradictory of
this, there will be nothing which is not, for even if what is not
cannot be without qualification, there is no reason why it should not
be a particular not-being. To say that all things will be one, if
there is nothing besides Being itself, is absurd. For who understands
'being itself' to be anything but a particular substance? But if this
is so, there is nothing to prevent there being many beings, as has
been said.
It is, then, clearly impossible for Being to be one in this sense.
Part 4
The physicists on the other hand have two modes of explanation.
The first set make the underlying body one either one of the three or
something else which is denser than fire and rarer than air then
generate everything else from this, and obtain multiplicity by
condensation and rarefaction. Now these are contraries, which may be
generalized into 'excess and defect'. (Compare Plato's 'Great and
Small'-except that he make these his matter, the one his form, while
the others treat the one which underlies as matter and the contraries
as differentiae, i.e. forms).
The second set assert that the contrarieties are contained in the one
and emerge from it by segregation, for example Anaximander and also
all those who assert that 'what is' is one and many, like Empedocles
and Anaxagoras; for they too produce other things from their mixture
by segregation. These differ, however, from each other in that the
former imagines a cycle of such changes, the latter a single series.
Anaxagoras again made both his 'homceomerous' substances and his
contraries infinite in multitude, whereas Empedocles posits only the
so-called elements.
The theory of Anaxagoras that the principles are infinite in multitude
was probably due to his acceptance of the common opinion of the
physicists that nothing comes into being from not-being. For this is