Nunc vide utra te [Greek:  krisis] magis delectet, [Greek:  Chrysippeia] ne, an haec; quam noster Diodorus [a Stoic who for a long time had lived in Cicero’s house] non concoquebat.”  This is quoted from a letter that Cicero wrote to Varro.  He sets forth more comprehensively the whole state of the question, in the little book De Fato.  I am going to quote a few pieces (Cic., De Fato, p. m. 65):  “Vigila, Chrysippe, ne tuam causam, in qua tibi cum Diodoro valente Dialectico magna luctatio est, deseras ... omne ergo quod falsum dicitur in futuro, id fieri non potest.  At hoc, Chrysippe, minime vis, maximeque tibi de hoc ipso cum Diodoro certamen est.  Ille enim id solum fieri posse dicit, quod aut sit verum, aut futurum sit verum; et quicquid futurum sit, id dicit fieri necesse esse; et quicquid non sit futurum, id negat fieri posse.  Tu etiam quae non sint futura, posse fieri dicis, ut frangi hanc gemmam, etiamsi id nunquam futurum sit:  neque necesse fuisse Cypselum regnare Corinthi, quamquam id millesimo ante anno Apollinis Oraculo editum esset....  Placet Diodoro, id solum fieri posse, quod aut verum sit, aut verum futurum sit:  qui locus attingit hanc quaestionem, nihil fieri, quod non necesse fuerit; et quicquid fieri possit, id aut esse jam, aut futurum esse:  nec magis commutari ex veris in falsa ea posse quae futura sunt, quam ea quae facta sunt:  sed in factis immutabilitatem apparere; in futuris quibusdam, quia non apparent, ne inesse quidem videri:  ut in eo qui mortifero morbo urgeatur, verum sit, hic morietur hoc morbo:  at hoc idem si vere dicatur in eo, in quo tanta vis morbi non appareat, nihilominus futurum sit.  Ita fit ut commutatio ex vero in falsum, ne in futuro quidem ulla fieri possit.”  Cicero makes it clear enough that Chrysippus often found himself in difficulties in this dispute, and that is no matter for astonishment:  for the course he had chosen was not bound up with his dogma of fate, and, if he had known how, or had dared, to reason consistently, he would readily have adopted the whole hypothesis of Diodorus.  We have seen already that the freedom he assigned to the soul, and his comparison of the cylinder, did not preclude the possibility that in reality all the acts of the human will were unavoidable consequences of fate.  Hence it follows that everything which does not happen is impossible, and that there is nothing possible but that which actually comes to pass.  Plutarch (De Stoicor.  Repugn., pp. 1053, 1054) discomfits him completely, on that point as well as on the dispute [232] with Diodorus, and maintains that his opinion on possibility is altogether contrary to the doctrine of fatum.  Observe that the most eminent Stoics had written on this matter without following the same path.  Arrian (in Epict., lib. 2, c. 29, p. m. 166) named four of them, who are Chrysippus, Cleanthes, Archidemus and Antipater.  He evinces great scorn for this dispute; and M. Menage need not have cited him as a