 While Abelard thought that the universal validity of the principle of bivalence was an Aristotelian view, thirteenth-century commentators argued for the traditional interpretation. Albert the Great and Thomas Aquinas took Aristotle to be arguing in De interpretatione 9 that if every contradictory pair divides truth and falsity in a determinate way and the members are consequently determinately true or false, all things must determinately be or not be. They thought that Aristotle then refuted the consequent by referring to various contingent things. It follows that the antecedent cannot be true and future contingent propositions are not determinately true or determinately false. They are true-or-false under disjunction (Albert the Great, Liber Perihermeneias, I.5.4–6, 418–422; Thomas Aquinas, In libros Perihermeneias, I.13, 170–172; I.15, 202–203). The same interpretation of Aristotle is found in Arabic commentators Abū Nasr al-Fārābī and Averroes. (See Al-Farabi’s Commentary and Short Treatise on Aristotle’s De interpretatione, trans. F. Zimmermann, lxviii, 75–76, 78–79, 91–92, 244–245, and Averroes’s  Middle Commentary on Aristotle’s De interpretatione, 82va.) Al-Fārābī’s own view was that future contingents are either true or false (94–96; Marmura 1985; Adamson 2006). The traditional interpretation of Aristotle’s view was put forward by many later Latin commentators such as John Duns Scotus, Quaestiones in libros Perihermenias Aristotelis, I.7–8 (179–181), trans. Buckner and Zupko; Walter Burley, Commentarius in librum Perihermeneias Aristotelis, 92, 95–96; William Ockham, Expositio in Librum Perihermenias Aristotelis I.6.15; Peter Auriol, Scriptum in I Sententiarum I.38.3, 817–828; Gregory of Rimini, Lectura super I Sententiarum I.38.1.1 (238–243); Peter of Ailly, Quaestiones super libros Sententiarum I.11.1A). In his Supercommentary on Averroes’s Commentary on Aristotle’s De interpretatione, the Jewish philosopher Levi ben Gerson (Gersonides, 1288–1344) states that positing a truth value for future contingents leads to absurdity (83r; Rudavsky 1985: 166). However, John Buridan read Aristotle in the same way as Abelard. All assertoric statements are true or false though those about future contingents are not determinately true or false (Questiones longe super librum Perihermeneias I.10). Since theologians usually thought that divine omniscience and prophecy presupposed unrestricted bivalence, the discussion of future contingents was divided into historical constructions of Aristotle’s view, mostly in accordance with the traditional interpretation, and the systematic discussions in theology that mostly refuted this for doctrinal reasons. Later examples of the traditional interpretation of Aristotle’s view include George of Brussels, Logica magistri Georgii inserto textu Bricoti, 51rv; Iodocus Trutfetter, Summulae totius logicae II.1 (LL3v–4v); Veteris artis…Perihermeneiasque expositio (g1r); see also Baudry 1989 (ed.), La querelle des futurs contingents (Louvain 1465–1475). Textes inédits, 206. (For medieval interpretations, see Weidemann 1994; Gaskin 1995; Knuuttila 2010.)