Future Contingents

Abstract

The philosophical debate concerning the truth-value of singular statements about future contingents derives from Chap. 9 of Aristotle’s treatise De Interpretatione. In his influential commentary, Boethius assumed that Aristotle qualified the validity of the principle of bivalence with respect to singular future contingent propositions – they only have the disjunctive truth-value “true or false.” Abelard believed that Aristotle assumed that future contingent statements were true or false, though not determinately true or false before the actuality of the things to which they refer. He retained the principle of bivalence for all assertoric statements but rejected the universal application of the stronger principle that every assertoric statement is determinately true or determinately false in the sense of having determinate truth-makers. As for interpreting Aristotle, later medieval thinkers were inclined to follow Boethius rather than Abelard. However, since theologians usually thought that divine omniscience presupposed bivalence, the discussion of future contingents was divided into historical constructions of Aristotle’s view and the systematic discussions in theology which usually followed the Abelardian lines. An influential formulation of this approach was put forward by William of Ockham. Boethius, Thomas Aquinas, and many others thought that God could know future contingents only because the flux of time was present to divine atemporal eternity. Peter Auriol argued that from God’s atemporal knowledge one could not conclude that future contingent propositions were true or false at all. This view found some supporters until it was damned by Pope Sixtus IV in 1474. Many late medieval thinkers defended God’s ability to foreknow free acts. This led to the famous middle knowledge theory of the counterfactuals of freedom which was put forward by Luis de Molina in the sixteenth century.