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

a plurality of existents without a cause, and let the plurality
follow from them! But if such a thing cannot be imagined,
because the necessary existent can be only one, and
anything added to it must be a possible, and the possible
needs a cause, then the following conclusion must be drawn
concerning the effect: if it is an existent necessary by itself,
then what the philosophers say is untrue, that there is only
one necessary existent; if it is a possible,’ then it needs a
cause; but it has no cause,’ and therefore it cannot know the
existence of its cause.
There is no special necessity for the first effect to have a
possible existence; this is necessary for any effect. However,
that the effect should know its cause is not necessary for its
existence, just as the knowledge of its effect is not
necessary for the existence of the cause; still, it seems more
plausible that the cause should know its effect than that the
effect should know its cause. Therefore the plurality which
would arise from its knowing its principle is impossible; there
is no principle for this knowledge and it is not a necessary
consequence of an effect that it should know its principle;
and out of this there is no issue.
I say:
This is a proof of one who affirms that the First Principle must, besides
knowing itself, know its effect; for, if not, its knowing itself would be
imperfect.
The meaning of Ghazali’s objection is that the knowledge the effect has
of its principle must either be based on a cause or be without a cause. In
the former case, there must be a cause in the First Principle, but there is
none; in the latter case, a plurality must follow from the First Principle,
even if it does not know it; if, however, a plurality follows from it, it cannot
be a necessary existent, for there can be only one necessary existent, and
that from which there proceeds more than one is only a possible existent;
but the possible existent needs a cause, and therefore their assertion that
the First Principle is a necessary existent is false, even if it does not know
its effect. He says also that if it is not a necessity of its existence that the
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