of them has its own essence and attributes, and they share nothing whatsoever that exists in external reality. Thus one may exist while the other does not, and vice versa; one may die while the other remains alive, and vice versa; and one may suffer while the other experiences pleasure, and vice versa.

[Al-Rāzī’s discussion in his commentary on al-Ishārāt (The Pointers)]

For this reason, commentators on his words, such as al-Rāzī, have said:

“A particular individual is either apprehended in such a way that the very apprehension of it precludes its being common to multiple individuals, or it is not.

In the first case, either that apprehension depends on the existence of the object apprehended in external reality, or it does not.

There are thus three categories:

The first is the apprehension in which both conditions are met: it precludes being common to multiple individuals and depends on the existence of the object apprehended in external reality. This is sensory apprehension. For when I see Zayd, the object seen cannot, by its very nature, be common to many individuals; and this act of seeing occurs only when the object apprehended exists in external reality.