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

Ghazali denies. But if you have understood this, you will be able to solve
the problem Ghazali poses in this section.
If it is said: ‘It follows from this that there is no composition, either in
existence, necessary by itself, or in existence, necessary through another,’
we answer: As to what is necessary through another, the mind perceives
in it a composition through cause and effect; if it is a body , there must be
in it both a unity actually, and a plurality potentially; if it is, however,
incorporeal, the mind does not perceive a plurality either in act or in
potency . For this reason the philosophers call this kind of existent simple,
but they regard the cause as more simple than the effect and they hold
that the First is the most simple of them all, because it cannot be
understood as having any cause or effect at all. But composition can be
understood of the principles which come after the First; therefore,
according to the philosophers, the second principle is more simple than
the third, and it is in this way that their theory must be understood. The
meaning of ‘cause’ and ‘effect’ in these existents is that a potential
plurality (as it were) exists in them which shows itself in the effect, i.e.
there proceeds out of it a plurality of effects which it never contains
actually in any definite moments If the hearer has understood their theory
in this way and accepted it, he will see that they are not affected by the
objections of Ghazali. But one should not understand this theory in the
way Ghazali does, namely, that out of the second principle, because it
knows its own essence and knows its principle, and therefore possesses
two forms or a dual existence, there proceed two different things, for this is
a false theory. For this would mean that this second principle is composed
of more than one form and that therefore this form’ is one in its
substratum, many by its definition, as is the case with the soul. But the
theologians keep tenaciously to this false explanation in their statements
about the derivation of these principles from each other, as if they wanted
to understand the divine through an analogy with perceptible acts; indeed,
when metaphysics contains such theories, it becomes more conjectural
than jurisprudence. You will have seen from this that the conclusion
Ghazali wants the philosophers to draw concerning the plurality in the
necessary existent, because of the plurality which he considers must exist
in the possible existent, has no validity. For, if possibility were understood
as real possibility, it would indeed imply here a plurality, but since this is
impossible, according to what we have said and shall show later, nothing
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