Works of Aristotle, Vol. 2 (Physics, On the Heavens, On Generation and Corruption)

whether a finite or an infinite plurality. So they too are
inquiring whether the principle or element is one or many.

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185ᵃ

Now to investigate whether Being is one and motionless
is not a contribution to the science of Nature. For just as
the geometer has nothing more to say to one who denies
the principles of his science—this being a question for
a different science or for one common to all—so a man
investigating principles cannot argue with one who denies
their existence. For if Being is just one, and one in the
way mentioned, there is a principle no longer, since a prin-
ciple must be the principle of some thing or things.

5

To inquire therefore whether Being is one in this sense
would be like arguing against any other position maintained
for the sake of argument (such as the Heraclitean thesis, or
such as a thesis as that Being is one man) or like refuting a
merely contentious argument—a description which applies
to the arguments both of Melissus and of Parmenides: their
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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: accept one ridiculous proposition
and the rest follows—a simple enough proceeding.

15

We physicists, on the other hand, must take for granted
that the things that exist by nature are, either all or some
of them, in motion—which is indeed made plain by in-
duction. Moreover, no man of science is bound to solve
every kind of difficulty that may be raised, but only as
many as are drawn falsely from the principles of the science:
it is not our business to refute those that do not arise in
this way: just as it is the duty of the geometer to refute
the squaring of the circle by means of segments, but it is
not his duty to refute Antiphon's proof. At the same