=221.= The doctrine of fate also seems to conflict with some of the commonest forms of speech. For if it is correct to say ‘Either this will happen, or it will not happen,’ it seems incorrect to say ‘it may happen’; and still more of the past, since we must admit of any event that ‘it has happened’ or ‘it has not happened,’ there seems no room for the statement ‘it might have happened.’ Chrysippus however maintains that the words ‘may’ and ‘might’ are correctly used, or (in other words) that we may assert that it is or was ‘possible’ for things to happen, whether or not they will happen or have happened. For example, the pearl here is breakable, and may be broken, though fate has ordained that it never will be broken. Cypselus might not have been tyrant of Corinth, though the oracle at Delphi declared a thousand years before the time that he would be[15]. This view had been sharply contested by Diodorus the Megarian; and the controversy was summed up in the ‘master argument.’ This is stated as follows: there are three propositions in conflict with one another in the sense that if any two of them are true, the third is false. They are these: (i) every past event is necessary; (ii) the impossible cannot follow on the possible; (iii) there are things possible that neither are nor will be true. Diodorus accepted the first two; he therefore drew the conclusion that there is nothing possible except that which is or will be true; or in other words he denied the existence of any category of ‘things possible’ distinct from that of facts past or future. Cleanthes and Antipater accepted the second and third propositions: Chrysippus accepted the first and third, but denied the second[16]; that is he admitted that the possible thing (e.g. the breaking of the pearl) might become the impossible because fate had decided to the contrary. The choice intimates much; it shows that the Stoics, however strongly they assert the rule of fate or necessity, intend so to interpret these terms as to reconcile them with the common use of words, that is, with the inherited belief in divine and human will, breaking through the chain of unending cause and effect[17]. [Sidenote: Definitions of fate.]