Many of them further restricted this to a particular form of rational inquiry: examining accidents and their inseparability from bodies, such that bodies cannot exist without them. They said:

“Whatever is never free of events that come into being, or does not precede such events, must itself have come into being.”

Some of them then believed this premise to be self-evident—indeed, necessarily known. They did not distinguish between a particular, bounded event and events considered as a kind, occurring continuously one after another, either because they thought the latter impossible or because it had never occurred to them. Yet even if it is said to be impossible, knowledge of its impossibility is not self-evident.

What is self-evident is only that an event with a definite beginning is like any other event that comes into being. As for events reckoned from a definite point in time, whatever does not precede them must itself have come into being. Whatever is never free of them does not precede them and must therefore have come into being. For if it does not precede them, it must exist either alongside them or after them. In either case, it must have come into being.

If, however, one supposes a perpetual succession of events, one after another, this must be said to be either possible or impossible. But knowledge of its impossibility requires proof. No known group of rational thinkers has said:

“Knowledge that this is impossible is self-evident and necessary, requiring no proof.”