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

be included in the definition. And this is what one must believe about this
problem.
As for Ghazali’s objection, that a man knows of his soul that it is in his
body although he cannot specify in which part-this indeed is true, for the
ancients had different opinions about its seat, but our knowledge that the
soul is in the body does not mean that we know that it receives its
existence through being in the body; this is not self-evident, and is a
question about which the philosophers ancient as well as modern differ,
for if the body serves as an instrument for the soul, the soul does not
receive its existence through the body; but if the body is like a substratum
for its accident; then the soul can only exist through the body.
Ghazali says:
The seventh proof. The philosophers say that the
faculties which perceive through the bodily organs become
tired through the long-continued performance of the act of
perception, since the continuation of their action destroys the
mixture of their elements and tires them, and in the same
way excessive stimulation of the perceptive faculties makes
them weak and often even corrupts them, so that afterwards
they are not able to perceive something lighter and more
delicate; so for instance a loud voice and a strong light
hinder or corrupt the perception of a low voice and delicate
objects of sight afterwards; and in fact the man who tastes
something extremely sweet does not afterwards taste
something less sweet. But the intellectual faculty behaves in
the opposite way; a long observation of intelligibles does not
tire it, and the perception of important necessary truths gives
it strength for the perception of easy observations and does
not weaken it, and if sometimes tiredness may befall it, this
happens because it makes use of and gets assistance from
the imaginative faculty, so that the organ of the imaginative
faculty becomes weary and no longer serves the intellect.
Our objection to this follows the same line as before, and
we say that it may well be that the bodily senses differ in
this; and what is true for some of them need not be true for
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