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

God as pure unity, and by exposing their inconsistency in attributing to
Him definite qualities and regarding Him as the source of the world of
variety and plurality.
The infinite variety and plurality of the world does not derive directly from
God according to the philosophers in Islam, who combine Aristotle’s
astronomical view of animate planets circling round in their spheres with
the Neoplatonic theory of emanation, and introduce into the Aristotelian
framework Proclus’ conception of a triadic process, but through a series of
immaterial mediators. From God’s single act-for they with Aristotle regard
God as the First Agent-only a single effect follows, but this single effect,
the supramundane Intellect, develops in itself a threefoldness through
which it can exercise a threefold action. Ghazali objects in a long
discussion that if God’s eternal action is unique and constant, only one
single effect in which no plurality can be admitted will follow (a similar
objection can be directed against Aristotle, who cannot explain how the
plurality and variety of transitory movements can follow from one single
constant movement). The plurality of the world according to Ghazali
cannot be explained through a series of mediators. Averroës, who
sometimes does not seem very sure of the validity of mediate emanation,
is rather evasive in his answer on this point.
In a series of rather intricate discussions which I have tried to elucidate
in my notes, Ghazali endeavours to show that the proofs of the
philosophers for God’s uniqueness, for their denial of His attributes, for
their claims that nothing can share with Him His genus and species, that
He is pure existence which stands in no relation to an essence, and that
He is incorporeal, are all vain. The leading idea of the philosophers that
all plurality needs a prior joining principle, Ghazali rejects, while Averroës
defends it. Why-so Ghazali asks, for instance-since the essence in
temporal things is not the cause of their existence, should this not be the
case in the Eternal? Or why should body, although it is composite
according to the philosophers, not be the First Cause, especially as they
assume an eternal body, since it is not impossible to suppose a
compound without a composing principle? From the incorporeality of God,
the First Principle, Avicenna had tried to infer, through the disjunction that
everything is either matter or intellect, that He is intellect (since the
philosophers in Islam hold with Aristotle and in opposition to Plotinus that
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