—both as a matter of rational necessity and by the consensus of rational people. A particular originated thing cannot be beginningless, for that would combine two contradictories. The dispute concerns the perpetual continuation of the type of temporal events, not the beginninglessness of any particular temporal event.

In sum (1), if it is maintained that temporal events may continue perpetually and that their type is beginningless (2), this is not to say that their type came into being (3) after not existing; for whatever may be beginningless cannot be nonexistent (4).

What is meant here is possibility in external reality, not merely conceptual possibility, which amounts to not knowing that something is impossible. The latter does not establish the beginninglessness of anything, unlike the former, which is knowledge that its beginninglessness is possible. For if its beginninglessness is possible, this can only be because it is necessary in itself or because it proceeds from the Necessary Existent (5). On either supposition, whatever is necessary in itself, or is a necessary concomitant of that which is necessary in itself, must be beginningless and cannot be nonexistent. For that which is necessary in itself must be beginningless and cannot be nonexistent; and that which entails a necessary concomitant cannot exist without that concomitant. Its necessary concomitants must therefore be beginningless and cannot be nonexistent.

When it is maintained (6) that temporal events may continue perpetually, the beginninglessness of their type is possible. Yet such beginninglessness is possible, [and the nonexistence of their type is impossible] (7), only if it has an eternal necessitating cause. In that case, the beginninglessness of their type is necessary (8 and the nonexistence of their type is impossible 8) (8). It does not follow that some part of the universe must be beginningless. Moreover, it is then the case that—