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

I say:
The answer is that we concede that duality can only be
imagined where there is a differentiation, and that in two
things, similar in every way, no difference can be imagined.
But your statement that this kind of composition is
impossible in the First Principle is a mere presumption, and
where is your proof of it?
Let us now treat this problem in detail. It belongs to their
well-known theories that the First Principle can as little be
analysed intellectually as divided quantitatively, and on this
fundamental truth, according to the philosophers, the
uniqueness of God must be based.
Ghazali does not know the mistake which is in this second proof, and
he begins to discuss with the philosophers the question to which they give
a negative answer, namely, if one may introduce a plurality into the
definition of the necessary existent. He wants to consider this problem in
detail, since the Ash’arites allow a plurality in God, regarding Him as an
essence with attributes. ‘ The mistake in this second proof is that two
different things can be essentially different and have nothing in common
but their name, in the case where they have no common genus, either
proximate or remote, for instance, the term ‘body’, attributed by the
philosophers to both the body of the heavens and the transitory body, and
the term ‘intellect’ attributed to the intellect of man and the separate
intellects, and the term ‘existent’ attributed to transitory things and to
eternal. Such terms must be regarded as equivocal rather than as
univocal, and therefore it does not follow that things which are
differentiated must be composite. And since Ghazali, in his answer to this
proof of the philosophers, limits himself in the way he has indicated, he
begins first by stating their theory of God’s unity and then tries to refute
the philosophers.
Ghazali, expounding the philosophical theory, says:
For the philosophers assert that God’s unity can only be
perfected by establishing the singleness of God’s essence in
every way, and by the denial of any possible plurality in Him.
Now plurality can belong to things in five ways. ‘
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