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

I say:
which doubles the whole of the others. These measurable
quantitative possibilities, of which some are longer than
others by a definite measure, have no other reality than time,
and those measurable quantities are not an attribute of the
essence of God, who is too exalted to possess measure,’
nor an attribute of the non-existence of the world, for nonexistence
is nothing and therefore cannot be measured with
different measures. Still, quantity is an attribute which
demands a substratum, and this is nothing other than
movement, and quantity is nothing but the time which
measures movement. Therefore also for you theologians
there existed before the world a substratum of differentiated
quantity, namely time, and according to you time existed
before the world.’
The summary of this argument is that, when we imagine a movement,
we find with it an extension which measures it, as if it were its
measurement, while reciprocally the movement measures the extension,
and we find that we can assume in this measure and this extension a
movement longer than the first supposed movement, and we affirm
through the corresponding and congruous units of this extension that the
one movement is longer than the other.’ If therefore for you theologians
the world has a certain extension from its beginning till now-let us
suppose, for instance, a thousand years and since God according to you
is able to create before this world another world, we may suppose that the
extension He can give it will be longer than the extension of the first world
by a certain definite quantity, and that He can likewise create a third world
before this second and that the existence of each of them must be
preceded by an extension through which its existence can be measured. If
this is true, and there is an infinite regress of this possibility of anterior
worlds, there is an extension which precedes all these worlds. And this
extension which measures all of them cannot be absolute nonexistence,
for non-existence cannot measure; it has, therefore, to be a quantity, for
what measures a quantity has to be quantity itself, and the measuring
quantity is that which we call time. And it is clear that this must precede in
existence anything we imagine to occur, just as the measure must
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