person
Diodorus Cronus
also: Diodorus, Diodorum
Greek philosopher of the Megarian (Dialectical) school (d. c. 284 BC), famous for the Master Argument and his definition of the possible: only what is or will be true is possible, so the future is fixed. Cicero plays with this determinism in Fam. 9.4 (if Varro will come, his coming is necessary; if not, it is impossible).
Reading notes
- Ad Familiares 9.4 §1 I judge along the lines of Diodorus
Diodorus Cronus (d. c. 284 BC), of the Megarian/Dialectical school, defined the 'possible' strictly: only what is or will actually be true is possible, so the future is wholly fixed. The whole letter is a learned joke built on this technical debate about modal logic (peri dynaton, 'on possibles').
- Ad Familiares 9.4 §1 if you are going to come, you should know that it is necessary that you come; and if you are not, then your coming is of the class of impossibles
Cicero applies Diodorus's determinism to Varro's promised visit: on the Diodoran view, whatever will happen is necessary and whatever will not happen is impossible, so there is no real open possibility. He is teasing Varro that, logically, the visit is either inevitable or impossible --- there is no 'maybe.'
- On Fate §13 your great contest with Diodorus
Diodorus Cronus, the Megarian dialectician (d. c. 284 BC), held that only what is or will be true is possible, collapsing possibility into necessity (the 'Master Argument'). Chrysippus resisted this to preserve contingency.