Likewise, when one of two identical times is singled out for an event to occur in it, this singles out one of two identical alternatives over the other. Such singling out gives it precedence over the other, and thus requires a determining cause that gives it that precedence.

Existence and nonexistence, however, are not identical in themselves. Although a contingent thing admits both existence and nonexistence, its existence is not identical to its nonexistence in the way that the two pans of a balance or two times are identical. Rather, both are possible for it, and it admits both.

The most that can be said is that, considered in itself, it is no more disposed toward one than toward the other. In this respect, the two are identical in relation to it, so making one prevail requires a determining cause. Upon closer examination, however, it becomes clear that they are not identical in relation to it, and that there are not two realities here, one of which is made to prevail over the other. Rather, it has no existence of its own at all; considered in itself, it warrants only nonexistence.

It should not be said that it warrants neither existence nor nonexistence. Rather, if we confine our consideration to the contingent thing in itself—which admits both existence and nonexistence—we know that it does not exist by virtue of itself.

We do not say that its essence entails nonexistence, such that its nonexistence is necessary and its existence impossible. That describes what is intrinsically impossible, not what is intrinsically contingent.

Rather, we say that, considered solely in itself, it is nonexistent, but its nonexistence is not necessary: it is a nonexistence that can give way to existence.