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

or non-eternity of the world, and whether the world has an agent or not, is
based on these fundamental propositions. The theologians and those who
believe in a temporal creation of the world are at one extreme, the
materialists at the other, while the philosophers hold an intermediate
position.
If all this is once established, you will see that the proposition that the
man who allows the existence of an infinite series of causes cannot admit
a first cause is false, and that on the contrary the opposite is evident,
namely, that the man who does not acknowledge infinite causes cannot
prove the existence of an eternal first cause, since it is the existence of
infinite effects which demands the necessity of an eternal cause from
which the infinite causes acquire their existence; for if not, the genera, all
of whose individuals are temporal, would be necessarily finite. And in this
and no other way can the eternal become the cause of temporal existents,
and the existence of infinite temporal existents renders the existence of a
single eternal first principle necessary, and there is no God but He.
Ghazali, answering this objection in the name of the philosophers, says:
The philosophers might say: The circular movements and
the forms of the elements do not exist at the present
moment; there actually exists only one single form of them,
and what does not exist can be called neither finite nor
infinite, unless one supposes them to exist in the
imagination, and things which are only suppositions in the
mind cannot be regarded as impossible, even if certain of
these suppositions are supposed to be causes of other
suppositions;' for man assumes this only in his imagination,
and the discussion refers only to things in reality, not to
things in the mind. The only difficulty concerns the souls of
the dead and, indeed, some philosophers have arrived at the
theory that there is only one eternal soul before it is united
with bodies, and that after its separation from the bodies it
becomes one again, so that it has no numerical quantity and
can certainly not be called infinite. Other philosophers have
thought that the soul follows from the constitution of the
body, that death is nothing but the annihilation of the soul,
and that the soul cannot subsist by itself without the body. In
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