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

things are two: matter and form, and that there is a third accidental
principle, privation, which is a condition of the occurrence of what
becomes, namely as preceding it: if a thing becomes, its privation
disappears, and if it suffers corruption, its privation arises.’
Ghazali says:
I say:
The second objection is that according to the
philosophers there are accidents which can become nonexistent
otherwise than through their contrary, for instance,
motion has no contrary, and the opposition between motion
and rest is, according to the philosophers, only the
opposition of possession and non-possession, i.e. the
opposition of being and not-being, not the opposition of one
being to another being,’ and the meaning of rest is the
absence of motion, and, when motion ceases, rest does not
supervene as its contrary, but is a pure non-existence.’ The
same is the case with those qualities which belong to the
class of entelechies, like the impression of the sensible
species on the vitreous humour of the eyes and still more the
impression of the forms of the intelligibles on the soul; they
become existent without the cessation of a contrary, and
their non-existence only means the cessation of their
existence without the subsequent occurrence of their
opposites, and their disappearance is an example of pure
nonexistence which arises. The occurrence of such a nonexistence
is an understandable fact, and that which can be
understood as occurring by itself, even if it is not a real
entity, can be understood as being related to the power of
the Omnipotent. Through this it is clear that, when one
imagines an event as occuring through the eternal Will, it is
unessential, whether the occurring event is a becoming or a
vanishing.
On the contrary, when non-existence is assumed to proceed from the
agent as existence proceeds from it, there is the greatest difference
between the two. But when existence is assumed as a primary fact and
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