Did “might” make right? Epistemic modals in practical reasoning

Abstract

Many philosophers have argued that the orthodox analysis of epistemic-modal sentences, on which such sentences assert facts about what is compatible with some contextually given informational state, is fatally flawed. As an alternative, some have suggested a nonfactualist reading of such sentences. On this reading, utterances of epistemic-modal sentences do not assert propositions. Instead, they merely propose to keep possibilities in the common ground. In this paper, I pose a challenge for nonfactualism. I begin by noting that we often cite previously uttered epistemic-modal sentences as justifications for particular actions. Moreover, as I show, any utterance of an epistemic-modal sentence can, in principle, be later cited as justification for some action that was taken in light of it, even if the prejacent has since been revealed to be false. I then show that to justify action in this manner, utterances of epistemic-modal sentences must be construed as asserting propositions about what is compatible with the agent’s informational state at the time of assertion. This is incompatible with standard forms of nonfactualism about epistemic modals.