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

they are, according to the philosophers, interdependent
causes, so that the one cannot come into being by means of
the other without the intervention of another cause.
I say:
What he says here is that according to the philosophers the body of the
heavens is composed of matter, form, and soul, and that therefore there
must be in the second intellects from which the body of the heavens
proceeds, four entities, namely, one from which the form proceeds, one
from which the hyle proceeds-as both are interdependent, for matter is in
one way a cause of form and form in one way a cause of matterb-one
from which the soul proceeds, and one from which the mover of the
second sphere proceeds. But the view that the body of the heavens is
composed of form and matter like other bodies is falsely ascribed by
Avicenna to the Peripatetics. On the contrary, according to them the body
of the heavens is a simple body; if it were composite, it would, according
to them, suffer corruption, and therefore they say that it neither comes into
being nor perishes, and does not possess the potency for contraries. If it
were as Avicenna says, it would be composite like a living being, and if
this were true, quadruplicity would be a necessary consequence for the
man who asserted that from the one only one can proceed. And we have
already stated that the way these forms are causes for each other, for the
heavenly bodies, and for the sublunary world, and the way the First Cause
is a cause for all of them, is quite different from all this.
Ghazali says:
The second way is that the highest sphere has a definite
measure of size, and its determination by this special
measure taken from among all other measures is an addition
to the existence of its essence, since its essence might be
smaller or bigger than it is; therefore, it must have a
determinant for this measure, added to the simple entity
which causes its existence. The same necessity does not
exist for the existence of the intellect, which is pure
existence and not specified by any measure taken from
among other measures, and therefore may be said to need
only a simple cause.
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