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

seeing are equivalent in the eye. Thus no one can claim that the opposite
directions are equivalent, although he may claim that the substratum for
both is indifferent, and that therefore out of both directions similar actions
result. And the same holds good for before and after: they are not
equivalent, in so far as this event is earlier and that event later; they can
only be claimed to be equivalent so far as their possibility of existence is
concerned. But the whole assumption is wrong: for essential opposites
also need essentially opposite substrata and a unique substratum giving
rise to opposite acts at one and the same time is an impossibility. The
philosophers do not believe that the possibilities of a thing’s existence and
of its non-existence are equivalent at one and the same time; no, the time
of the possibility of its existence is different from the time of the possibility
of its non-existence, time for them is the condition for the production of
what is produced, and for the corruption of what perishes. If the time for
the possibility of the existence of a thing and the time for the possibility of
its non-existence were the same, that is to say in its proximate matter, its
existence would be vitiated, because of the possibility of its non-existence,
and the possibility of its existence and of its non-existence would be
dependent only on the agent, not on the substratum.
Thus he who tries to prove the existence of an agent in this way gives
only persuasive, dialectical arguments, not apodictic proof. It is believed
that Farabi and Avicenna followed this line to establish that every act must
have an agent, but it is not a proof of the ancient philosophers, and both of
them merely took it over from the theologians of our religion. In relation,
however, to the temporal creation of the world-for him who believes in itbefore
and after cannot even be imagined, for before and after in time can
only be imagined in relation to the present moment, and as, according to
the theologians, there was before the creation of the world no time, how
could there be imagined something preceding the moment when the world
was created? A definite moment cannot be assigned for the creation of the
world, for either time did not exist before it, or there was an infinite time,
and in neither case could a definite time be fixed to which the Divine could
attach itself. Therefore it would be more suitable to call this book
‘Incoherence’ without qualification rather than ‘The Incoherence of the
Philosophers’, for the only profit it gives the reader is to make him
incoherent.
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