As for the second approach adopted by the speculative theologians to establish the possibility of vision, it is the one chosen by Abū al-Ma'ālī in his book known as al-Irshād. It may be summarized as follows: the senses perceive only the essences of things. What distinguishes existing things from one another consists of states, not essences; the senses therefore do not perceive these states, but only essence. Essence is existence itself, which is common to all existing things. Thus, the senses perceive a thing only insofar as it exists.

All of this is utterly unsound. One of the clearest demonstrations of the falsity of this claim is that, if sight perceived things merely because they exist, it would not