future contingents singular events or states of affairs that may come to pass, and also may not come to pass, in the future. There are three traditional problems involving future contingents: the question of universal validity of the principle of bivalence, the question of free will and determinism, and the question of foreknowledge.
The debate about future contingents in modern philosophical logic was revived by Lukasiewicz’s work on three-valued logic. He thought that in order to avoid fatalistic consequences, we must admit that the principle of bivalence (for any proposition, p, either p is true or not-p is true) does not hold good for propositions about future contingents. Many authors have considered this view confused. According to von Wright, e.g., when propositions are said to be true or false and ‘is’ in ‘it is true that’ is tenseless or atemporal, the illusion of determinism does not arise. It has its roots in a tacit oscillation between a temporal and an atemporal reading of the phrase ‘it is true’. In a temporalized reading, or in its tensed variants such as ‘it was/will be/is already true’, one can substitute, for ‘true’, other words like ‘certain’, ‘fixed’, or ‘necessary’. Applying this diachronic necessity to atemporal predications of truth yields the idea of logical determinism. In contemporary discussions of tense and modality, future contingents are often treated with the help of a model of time as a line that breaks up into branches as it moves from left to right (i.e., from past to future). Although the conception of truth at a moment has been found philosophically problematic, the model of historical modalities and branching time as such is much used in works on freedom and determination. Aristotle’s On Interpretation IX contains a classic discussion of future contingents with the famous example of tomorrow’s sea battle. Because of various ambiguities in the text and in Aristotle’s modal conceptions in general, the meaning of the passage is in dispute. In the Metaphysics VI.3 and in the Niocmachean Ethics III.5, Aristotle tries to show that not all things are predetermined. The Stoics represented a causally deterministic worldview; an ancient example of logical determinism is Diodorus Cronus’s famous master argument against contingency. Boethius thought that Aristotle’s view can be formulated as follows: the principle of bivalence is universally valid, but propositions about future contingents, unlike those about past and present things, do not obey the stronger principle according to which each proposition is either determinately true or determinately false. A proposition is indeterminately true as long as the conditions that make it true are not yet fixed. This was the standard Latin doctrine from Abelard to Aquinas. Similar discussions occurred in Arabic commentaries on On Interpretation. In the fourteenth century, many thinkers held that Aristotle abandoned bivalence for future contingent propositions. This restriction was usually refuted, but it found some adherents like Peter Aureoli. Duns Scotus and Ockham heavily criticized the Boethian-Thomistic view that God can know future contingents only because the flux of time is present to divine eternity. According to them, God contingently foreknows free acts. Explaining this proved to be a very cumbersome task. Luis de Molina (1535–1600) suggested that God knows what possible creatures would do in any possible situation. This ‘middle knowledge’ theory about counterfactuals of freedom has remained a living theme in philosophy of religion; analogous questions are treated in theories of subjunctive reasoning. See also ARISTOTLE , BOETHIUS , FREE WILL PROBLEM , MANY -VALUED LOGIC , TENSE LOGIC , VAGUENES. S.K.