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

white inhering in the white body, for every part of whiteness which inheres
in the individual body has one and the same definition as the whole of
whiteness in this body. ‘ Secondly, it may be meant that the attribute is
attached to the body without a specific shape, ‘ and this attribute again is
divided through the division of the body not in such a way that the
intension of the definition of the whole is identical with the intension of the
definition of every part-for instance, the faculty of sight which exists in one
who sees-but in such a way that it is subject to a difference in intensity
according to the greater and lesser receptivity of the substratum, and
therefore the power of sight is stronger in the healthy and the young than
in the sick and the old. What is common to those two classes is that they
are composed of individuals, i. e. that they are divided by quantity and not
by quiddity, i. e. that either the uniqueness of the definition and the
quiddity remains or that they are annulled. < Those which can be divided
quantitatively into any particular part are one by definition and quiddity and
those which cannot be divided into any individual part whatevers only
differ from the first class in a degree of intensity, for the action of the part
which has vanished is not identical with that of the part which remains,
since the action of the part which has vanished in weak sight does not act
in the same way as the weak sight. b Those two classes have it in
common that colour also cannot be divided by the division of its
substratum into any particular part whatever and keep its definition
absolutely intact, but the division terminates in a particular part in which
the colour, when it is distributed to it, disappears. ? The only thing which
keeps its distribution always intact is the nature of the continuous in so far
as it is continuous, i. e. the form of continuity.
When this premiss is assumed in this way, namely by holding that
everything which is divisible in either of these two classes has a body as
its substratum, it is self-evident, and the converse, that everything which is
in a body is divisible according to one of these two classes, is evident too;
and when this is verified, then the converse of its opposite is true also,
namely that what is not divisible according to one of these two classes
cannot be in a body. If to these premisses there is added further what is
evident in the case of the universal intelligibles, namely that they are not
divisible in either of the two ways, since they are not individual forms, it is
clear that there follows from this that neither is the substratum of these
intelligibles a body, nor is the faculty which has the power to produce them
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