The existence of only two states or truth values (e.g. true and false):principle of bivalence...
Against both Epicurus and the Stoics, Carneades argued that no deterministic consequences follow from the principle of bivalence (the principle that for any statement P, either P is true or P is false).
So we may represent the Aristotelian solution as one which rejects the law of bivalence.
Against the Stoics he argued that a commitment to bivalence and the principle that every action has a cause does not entail that all actions are fated.