I’ve posted a new, much improved draft of an old paper at my academic webpage. Here is the abstract:
This paper discusses an important puzzle about the semantics of indicative conditionals and deontic necessity modals (should, ought, …): the Miner Puzzle (Parfit 1988; Kolodny & MacFarlane 2010). Rejecting modus ponens for indicative conditionals, as others propose, seems to solve a version of the puzzle, but it fails to solve a close variant of it. In fact, I prove that the puzzle arises for a variety of sophisticated analyses of the truth-conditions of indicative conditionals. A comprehensive solution requires rethinking the relationship between relevant information (what we know) and practical rankings of possibilities and actions (what to do). I argue that (i) relevant information determines whether considerations of value may be treated as reasons for actions that realize them, (ii) incorporating this normative fact requires a revision of the standard semantics for modals expressing weak deontic necessity (should, ought), but not for modals expressing strong deontic necessity (must, have to), (iii) an off-the-shelf treatment of weak deontic necessity, due in part to von Fintel & Iatridou (2008); Sloman (1970), which distinguishes “basic” and “higher-order” values, and interprets weak deontic necessity modals relative to both, is well-suited to this task. The prominence of normative considerations in our proposal suggests a more general methodological moral: semantic analysis of normative language demands that close attention be paid to the underlying normative phenomena.