Tahafut_al-Tahafut-transl-Engl-van-den-Bergh

I say:
There still remains the fact that the philosophers regard
this as impossible, because they ask why the will should
have distinguished just this body, whereas all other bodies
participate in bodiliness. But we have already explained that
it is of the nature of the eternal Will to differentiate one thing
from a similar one, and that the philosophers are forced to
admit such a quality for the determination of the direction of
the circular movement and for the determination of the place
of the poles and their points, and we shall not repeat this; but
our argument is, in short, that when they deny that a body
can be differentiated for the attachment of the will to it
without a distinctive attribute, this can be turned against
them in regard to this distinctive attribute, for we ask them:
‘Why is the body of heaven distinguished by this attribute,
which sets it apart from all other bodies, although all other
bodies are also bodies; and how can anything occur to it
which does not occur to other bodies? ‘ If this is caused by
another attribute, we must repeat the same question about
this other attribute, and in this way we should get an infinite
series, and they would be forced in the end to acknowledge
an arbitrary judgement of the will and the fact that in the
principles there is something that distinguishes one thing
from a similar one.
That a stone moves downwards through a quality which has been
created in it, and fire upwards, and that these qualities are opposed -this is
a self-evident fact, and to contradict it is pure folly. But it is still more
foolish to say that the eternal Will causes the movement in these things
everlastingly-without any act He deliberately choseIand that this
movement is not implanted in the nature of the thing, and that this is called
constraint; for if this were true, things would have no nature, no real
essence, no definition at all. For it is selfevident that the natures and
definitions of things only differ through the difference of their acts, just as it
is self-evident that every movement forced on a body comes from a body
outside it. And this argument has no sense whatever.
378