Yet if by “reality” one intends what the mind conceives—the mental quiddity, like the idea of a triangle imagined before it is instantiated outside—then the quiddity affirmed in minds is other than the reality that exists in concrete things. Accordingly, whoever says, as do the theologians who affirm the divine attributes, that the existence of every thing is identical with its quiddity is correct, provided he means that the existence established in the external realm is the very quiddity established there. Likewise, whoever says, following Abū Hāshim al-Jubbāʾī and the like, that the existence of every thing is other than its quiddity is also correct if he intends that the existence found outside the mind differs from the quiddity fixed within the mind. But if, as their school is reputed to hold, they mean that quiddities subsist externally—that is, that non-existent things somehow remain fixed in the state of non-existence and that existence is merely an attribute superadded to such a quiddity—this is a mistake.

More mistaken still are certain groups among the philosophers—such as Ibn Sīnā and his followers—who claim that for a contingent being its existence in the external world is something added to its quiddity, whereas for the Necessary Being His existence in the external world is identical with His quiddity. Their error is greater because it arises from two angles: first, they posit realities in the external realm that are other than the actually existing things found there; second, they treat the existence of the Necessary Being as an unqualified, absolute existence with no specific reality beyond sheer existence, alleging that He is distinguished from others only by negative or relational predicates—even though, in their own logic, they concede that negatives and relations do not differentiate between things that share in a universal positive attribute, and that real distinction is made only by positive predicates.