be capable of nonexistence under these circumstances, while its continued existence is necessary through something else. Thus, it is impossible for it to be capable of nonexistence under these circumstances, while its continued existence is necessary through something else.

Anything that can exist through something else and can persist cannot be nonexistent while it exists, nor can it exist while it is nonexistent. For if its existence does not persist, there must either be nothing that necessitates its existence, or something that necessitates its existence in one state but not another. Something whose existence is contingent becomes nonexistent only because that which necessitates its existence is absent. Perpetual nonexistence therefore involves the perpetual absence of that which necessitates existence, whereas newly occurring nonexistence involves its absence in that particular state.

What is meant is that the necessitating cause is not complete, not that every condition required for it to necessitate existence is absent. Rather, the absence of some conditions is sufficient for the thing not to exist. Yet the necessitating cause cannot be absent in one state but not another when the states are identical. Its perpetual absence would entail that the thing’s existence is perpetually impossible, whereas the assumption was that it could exist perpetually.

The substance of this argument overlaps with that of the argument they relied upon to establish the eternity of the world: that coming into existence without a cause for doing so is impossible, and that the existence of a complete necessitating cause in beginningless eternity entails the existence of what it necessitates. The underlying principle is that nothing newly occurs without a cause that necessitates its occurrence.

Their opponent among the speculative theologians—the Mu‘tazilites, the Ash‘arīs, and others—must therefore say either:

“Action in beginningless eternity is impossible,” as various groups among them have said;

or:

“It is possible, but that through which it would exist did not obtain, so its nonexistence was due to the absence of a condition of union.”

For the logically exhaustive division requires that one say:

Action in beginningless eternity is either possible or