The Complete Aristotle (eng.)

is one as indivisible, nothing
will have quantity or quality, and so the one will not be infinite,
as Melissus says-nor, indeed, limited, as Parmenides says, for
though the limit is indivisible, the limited is not.
    But if (c) all things are one in the sense of having the same
definition, like ‘raiment’ and ‘dress’, then it turns out that they
are maintaining the Heraclitean doctrine, for it will be the same
thing ‘to be good’ and ‘to be bad’, and ‘to be good’ and ‘to be not
good’, and so the same thing will be ‘good’ and ‘not good’, and man
and horse; in fact, their view will be, not that all things are
one, but that they are nothing; and that ‘to be of such-and-such a
quality’ is the same as ‘to be of such-and-such a size’.
    Even the more recent of the ancient thinkers were in a pother
lest the same thing should turn out in their hands both one and
many. So some, like Lycophron, were led to omit ‘is’, others to
change the mode of expression and say ‘the man has been whitened’
instead of ‘is white’, and ‘walks’ instead of ‘is walking’, for
fear that if they added the word ‘is’ they should be making the one
to be many-as if ‘one’ and ‘being’ were always used in one and the
same sense. What ‘is’ may be many either in definition (for example
‘to be white’ is one thing, ‘to be musical’ another, yet the same
thing be both, so the one is many) or by division, as the whole and
its parts. On this point, indeed, they were already getting into
difficulties and admitted that the one was many-as if there was any
difficulty about the same thing being both one and many, provided
that these are not opposites; for ‘one’ may mean either
‘potentially one’ or ‘actually one’.
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3
    If, then, we approach the thesis in this way it seems impossible
for all things to be one. Further, the arguments they use to prove
their position are not difficult to expose. For both of them reason
contentiously-I mean both Melissus and Parmenides. [Their premisses
are false and their conclusions do not follow. Or rather the
argument of Melissus is gross and palpable and offers no difficulty
at all: admit one ridiculous proposition and the rest follows-a
simple enough proceeding.] The fallacy of Melissus is obvious. For
he supposes that the assumption ‘what has come into being always
has a beginning’ justifies the assumption ‘what has not come into
being has no beginning’. Then this also is absurd, that in every
case there should be a beginning of the thing-not of the time and
not only in the case of coming to be in the full sense but also in
the case of coming to have a quality-as if change never took place
suddenly. Again, does it follow that Being, if one, is motionless?
Why should it not move, the whole of it within itself, as parts of
it do which are unities, e.g. this water? Again, why is qualitative
change impossible? But, further, Being cannot be one in form,
though it may be in what it is made of. (Even some of the
physicists hold it to be one in the latter way, though not in the
former.) Man obviously differs from horse in form, and contraries
from each other.
    The same kind of argument holds good against Parmenides also,
besides any that may apply specially to his view: the answer to him
being that ‘this is not true’ and ‘that does not follow’. His
assumption that one is used in a single sense only is false,
because it is used in several. His conclusion does not follow,
because if we take only white things, and if ‘white’ has a single
meaning, none the less what is white will be many and not one. For
what is white will not be one either in the sense that it is
continuous or in the sense that it must be defined in only one way.
‘Whiteness’ will be different from ‘what has whiteness’. Nor does
this mean that there is anything that can exist separately, over
and above what is white. For ‘whiteness’ and ‘that which is white’
differ in definition, not in the sense that they are things which
can exist apart from each other. But Parmenides had not come in
sight of this distinction.
    It is necessary for him, then, to assume not only that ‘being’
has the same meaning, of whatever it is predicated, but further
that it means (1) what just is and (2) what is just one.
    It must be so, for (1) an attribute is predicated of some
subject, so that the subject to which ‘being’ is