Sextus Empiricus: Physics 379
and arrive at other harbours very far away from where they started? And
how will he who abolishes motion leave from and return to his house?
These considerations are perfectly unopposable. For this reason, when
one of the Cynics [Diogenes] had an argument against motion put to
him, he did not answer but rather got up and walked around, and so by
deed and because of the obviousness of it all, averred that motion can exist.
Thus, these men attempt to put to shame those who hold the opposite
position. 67. But those who abolish the existence of motion attempt to
use these arguments. If something is moved, either it is moved by itself
or by another. But if it is moved by another, since that which moves is
active, and that which is active is moved, the mover will be in need of
another mover, and the second in need of a third, until infinity, so that
motion would be without an origin, which is absurd. Therefore, it is not
the case that everything that is moved is moved by another. But neither
is it moved by itself. 68. For that which is said to be moved by itself
will either be moved causelessly or by some cause.
nothing is moved causelessly; and if it is moved by some cause, the cause
by which it is moved will become its mover, whereby one falls into an
infinite regress, according to the criticism made a short while ago;^42 now,
since everything that moves moves either by pushing or pulling or lifting
or dragging down, that which moves itself will have to move itself accord-
ing to one of the above-mentioned ways. 69. But if it moves itself by
pushing, it will be behind itself; if it moves itself by pulling it will be in
front of itself; if it moves itself by lifting it will be under itself; and if it
moves by dragging down, it will be above itself. But it is impossible for
something to be above, in front of, under, or behind itself. Therefore,
it is impossible for something to be moved by itself. And if something
is neither moved by itself nor by something else, then nothing is moved.
- If someone should take refuge in [the notions of] impulse and
choice, one ought to remind him of the disagreement regarding the phrase
'in our power' and that the matter remains undecided, since a criterion
of the truth has up until now not been discovered by us. - Further, this should be said. If something is moved, either it is
moved in the place in which it is or it is moved in the place in which it
is not. But it is not moved in the place in which it is. For if it is in a
place in which it is, it remains where it is. But it is not moved in the
place in which it is not either. For wherever something is not, it cannot
there do or suffer anything. Therefore, it is not the case that something is
moved. This is the argument ofDiodorus Cronos, which has encountered
many opposing arguments, only the most powerful of which we shall set - III-44 (24).