But the claim that what is contingent in itself has an essence upon which existence and nonexistence alternate, and that this essence may nevertheless be beginningless and necessary through another—as Ibn Sīnā and those who agree with him maintain—is false according to all rational people, earlier and later alike, even according to Ibn Sīnā himself, despite his self-contradiction.

[Objections to the foregoing on several grounds]

[The first objection]

His statement, “If consideration of its essence is coupled with a condition, it becomes impossible or necessary; if no condition is attached to it, the third alternative remains by virtue of its essence: contingency,” entails affirming an essence for this contingent being that is sometimes necessary and sometimes impossible. This entails that every contingent being has an essence distinct from its existence, and that this essence can be characterized by existence at one time and nonexistence at another. This is false, whether what is intended is the position of those among the Mu‘tazilah and others who regard the nonexistent as a thing, or the position of those philosophers who hold that the quiddities of species in external reality are distinct from existence in external reality. The invalidity of both positions has been discussed at length elsewhere.

He has offered no proof here that this is sound. The mere division he has presented does not demonstrate that the three categories exist in external reality. His argument therefore remains one whose premises have not been established.