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

And Ghazali’s words:
and an absolute non-entity has no cause and it cannot be
said to exist either by its own essence or not by its own
essence form a statement which is not true either. For there
are two kinds of negation, the negation of a particular quality,
proper to something (and this kind of negation must be
understood in respect of the words ‘by its own essence’ used
in this statement), and the negation of a quality, not
particular to something (and this kind of negation must be
understood here in respect of the term ‘cause’). ‘
Ghazali affirms that this disjunction is not even true of positive qualities
and therefore certainly not of negative and he objects to thus disjunction
by giving as ati example black acid colouredness. And lie means that now
we say of black that it is a colour, either because of its essence or through
a cause, neither alternative can be true, send both are false. For it black
were a cause, because of its essence, red could not he a colour. just as if
Amr were a man because of his essence, Khalid could not be cc man; on
the other hand, if black were a colour through a cause, colour would have
to be an addition to its essence, and an essence which receives an
addition can be represented without this addition, and therefore this
assumption would imply that black could be represented without
colouredness, and this is absurd. But this argument, Ghazali is erroneous
and sophistical, because of the equivocation in the terms ‘essence’ and
‘cause’. For if by ‘by its essence’ is understood the opposite of ‘by
accident’, our statement that black is a colour because of its essence is
true, and at the same time it is not impossible that other things, red for
instance, should be colours. And if by ‘cause’, in the expression that black
is a colour through a cause, is understood something additional to its
essence, i. e. that it is a colour through a cause external to black, it does
not follow that black can be represented without colouredness. For the
genus is an addition to the specific quality and the species, and the
species or the specific quality cannot be represented without the genus,
and only an accidental additional quality-not the essential additional
quality-can be represented without the genus. And therefore our statement
that black is a colour either because of its essence or through a cause is a
disjunction of which, indeed, one of the alternatives must be true, i. e.
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