 On the basis of a note in Simplicius’s commentary on Aristotle’s Categories (407.6–13), it is argued that some Aristotelians also qualified the principle of bivalence. (For this and other ancient deviations from the principle, see Sorabji 1980: 92–93.) On the other hand, future contingent propositions were treated as true or false in Stoic logic. The Stoics took the universally valid principle of bivalence to imply the predetermination of all future events. (See Cicero, De fato, 20–21; Bobzien 1998: 59–86.) 