it is impossible. The cause that brings a possible entity into existence is its most indispensable concomitant and its foremost condition. It makes no difference whether the entity is posited together with the absence of its necessary concomitant or without that concomitant’s presence: in either case, it is impossible unless the concomitant is present, for a thing cannot exist without its necessary concomitant. Thus, whatever is posited in external reality is either necessary in itself or through something else, or impossible in itself or owing to something else.

If it is said:

“Considered in itself, it is neither necessary nor impossible,”

the reply is:

“There is nothing in external reality that is neither necessary nor impossible. Rather, such a thing is posited in the mind: one conceives an entity that may either exist or not exist.”

Yet you were not speaking of what is posited in minds. Rather, you said, “Every existent,” thereby applying the division to things existing in external reality. These exist either through themselves or through something else. None of them can be considered while nonexistent unless it is in the mind—yet even there it has mental existence.

[The Fifth Argument]

His statement that, if a condition is conjoined with it, it is necessary or impossible considered in itself, whereas if no condition is conjoined with it—neither the presence of a cause nor its absence—there remains for it, by virtue of