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

THE FIFTH DISCUSSION
TO SHOW THEIR INCAPACITY TO PROVE GOD’S UNITY
AND THE IMPOSSIBILITY OF TWO NECESSARY
EXISTENTS BOTH WITHOUT A CAUSE
Ghazali says:
The philosophers have two proofs of this. The first is to
say, ‘If there were two necessary existents, the species of
necessary existence would be attributed to them both. ‘ But
what is said to be a necessary existent must either be so
through itself, and cannot be imagined to be so through
another, or it must be so through a cause, and the essence
of the necessary existent will be an effect; and its cause then
determines its necessity of existence. ‘ ‘But’, say the
philosophers, ‘we understand by “necessary existent” only
an entity whose existence has no connexion with a cause. ‘
And the philosophers affirm that the species ‘man’ is
asserted of Zaid and of Amr and that Zaid is not a man
through himself-for in that case Amr would not be a man-but
through a cause which makes both him and Amr a man; and
the plurality of men arises from the plurality of matter in
which humanity inheres, and its inherence in matter is an
efficct which does not lie in the essence of humanity. The
same is the case with necessary existence in respect to the
necessary existent: if it is through itself a necessary existent,
it must possess this qualification exclusively, and if it exists
because of a cause, it is an effect and cannot be a
necessary existent. And from this it is clear that the
necessary existent must needs be one.
To this Ghazali objects and says:
We say: Your statement that the species of necessary
existence must belong to the necessary existent either
through the necessary existent itself or through a cause is a
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