Tense, propositions, and facts

There are two ways of incorporating temporal distinctions into a system of logic: tensed theories propose to expand standard logic with intensional tense operators; tenseless theories try to make do with the resources of extensional first-order logic, by using quantification over suitably chosen temporal entities, such as metaphysically basic time points or temporal parts. My concern in this paper is whether the adoption of a tensed theory of time also forces us to accept a particular view about propositions. Following Mark Richard (1981), say that a proposition is eternal if it always has the same truth value, and temporal if it is true at some times and false at others. Then my question is whether a tensed theory requires a commitment to temporal propositions. Prior thought that tense logic could do double duty as a linguistic theory of verb tense and as a metaphysical theory of the nature of time. However, it quickly became apparent that verb tenses in natural languages do not function like sentential tense operators. To mention just two familiar cases, sequences of tenses in English do not iterate like tense operators (Ogihara 1996), and verb tense often serves as a vehicle for establishing intersentential connections between the various components of a text, rather than shift the time of evaluation of a single sentence, as sentential tense operators do (Kamp and Reyle 1993: ch. 5). As James Higginbotham sums up the situation, “the modal theory of tenses is inadequate: there is no basic part of our language for which it is correct” (1999: 199). As far as applications of philosophical interest are concerned, this leaves us with the use of tense logic as a metaphysical theory; that is, as a theory of time that is formulated in terms of conceptually primitive tense operators. In Meyer (2013), I argued that such intensional theories of time are superior to their extensional rivals, but this is not an issue I want to revisit here. My thesis in the present paper is that the adoption of a tensed theory of the nature of time allows us to remain agnostic about whether there are any temporal propositions. What propositions we ought to accept, if any, depends on what we want to do with them. Since propositions are appealed to in many areas of philosophy, there are a number of different issues that need to be considered. Their primary employment of propositions is as the contents of assertions. Offhand, this might seem to