is necessary through another—if they have no need of anything nonexistent, then something nonexistent, which is necessary neither in itself nor through another, can exist through something nonexistent?”

A contingent being has no existence from itself; rather, it exists only through another, whether one says that its nonexistence does not depend on a cause or that its nonexistence results from the absence of what would bring it into existence. Thus, the aggregate of contingent beings, containing nothing that exists through itself, can only be nonexistent. Each of them can exist only if its existence is through another, whether it is called an effect of another or the product of another’s action. How can they exist through something other than themselves?

The crux of this answer is that “contingent” means contingent in the sense applicable to beings whose existence depends on something distinct from them. It follows that neither they collectively nor any one of them can have existence in any respect except through something distinct from them.

As for the contingency attributed to the aggregate of existing beings, it means that this aggregate is necessary only because something within it is necessary. Some part of that aggregate is therefore necessary in itself, so the aggregate does not depend on anything distinct from itself.

[The Third Argument]

This becomes clear from the third argument:

We begin by saying that every existing being either exists through something distinct from itself or does not exist through something distinct from itself. Anything whose existence is through something distinct from itself can exist only if there exists something that