Discourses 2.19 ¶1 — Epictetus

Epictetus, Discourses 2.19 ¶1

The argument called the ruling argument (ὁ κυριεύων λόγος) appears to have been proposed from such principles as these. There is in fact a common contradiction between one another in these three propositions, each two being in contradiction to the third. The propositions are: that everything past must of necessity be true; that an impossibility does not follow a possibility; and that a thing is possible which neither is nor will be true. Diodorus, observing this contradiction, employed the probative force of the first two for the demonstration of this proposition: That nothing is possible which is not true and never will be. Now another will hold these two: That something is possible which is neither true nor ever will be, and, That an impossibility does not follow a possibility. But he will not allow that everything which is past is necessarily true, as the followers of Cleanthes seem to think, and Antipater copiously defended them. But others maintain the other two propositions: That a thing is possible which is neither true nor will be true, and, That everything which is past is necessarily true; but then they will maintain that an impossibility can follow a possibility. But it is impossible to maintain these three propositions, because of their common contradiction.