Full Idea
Chrysippus's accounts of possibility and fate are in conflict. If he is right that 'everything that permits of occurring even if it is not going to occur is possible', then many things are possible which are not according to fate.
Gist of Idea
Chrysippus is wrong to believe in non-occurring future possibilities if he is a fatalist
Source
comment on Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - 70: Stoic Self-contradictions 1055e
Book Reference
'The Stoics Reader', ed/tr. Inwood,B/Gerson,L.P. [Hackett 2008], p.104
A Reaction
A palpable hit, I think. Plutarch refers to Chrysippus's rejection of Diodorus Cronus's Master Argument. Fatalism seems to entail that the only future possibilities are the ones that actually occur.
Related Idea
Idea 20832 The Master Argument seems to prove that only what will happen is possible [Diod.Cronus, by Epictetus]