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

would have to exist by itself, and it needs an efficient cause to connect the
condition with it, since a thing cannot be the cause of the existence of the
condition of its own existence; but all these are common notions. And in
general one cannot imagine that it is possible to arrive by this method, as
applied to this problem, at something near evidence, because of the
equivocation in the term `existent necessary by itself’, and in the term
`possible by itself, necessary through another’, and the other preliminary
notions which are added to them.
Ghazali says:
The second proof of the philosophers is that they say that
the knowledge and the power in us do not enter the quiddity
of our essence, but are accidental, and when these
attributes are asserted of the First, they too do not enter the
quiddity of its essence, but are accidental in their relation to
it, even if they are lasting; for frequently an accident does not
separate itself from its quiddity and is a necessary attribute
of it, but still it does not therefore become a constituent of its
essence. And if it is an accident, it is consequent on the
essence and the essence is its cause, and it becomes an
effect, and how can it then be a necessary existent?’
Then Ghazali says, refuting this:
This proof is identical with the first, notwithstanding the
change of expression. For we say: If you mean by its being
consequent on the essence, and by the essence’s being its
cause, that the essence is its efficient cause, and that it is
the effect of the essence, this is not true, for this is not valid
of our knowledge in relation to our essence, since our
essence is not an efficient cause of our knowledge. If you
mean that the essence is a substratum and that the attribute
does not subsist by itself without being in a substratum, this
is conceded, and why should it be impossible? For if you call
this `consequent’ or `accident’ or `effect’ or whatever name
you want to give it, its meaning does not change, since its
meaning is nothing but `existing in the essence in the way
attributes exist in their subjects’. And it is by no means
265