`Ought' and resolution semantics (Q2869815)

This paper contributes to the semantic analysis of the deontic modality ``ought''. It is well-known that the standard view on this modality as a necessity operator subject to the principle of inheritance: If \(p\) entails \(q\), then ``ought \(p\)'' entails ``ought \(q\)''. This explains another principle, known as coarseness: \(\ulcorner S\) ought to \(\phi \urcorner\) can be true even though there are impermissible ways of \(\phi\)-ing. However, inheritance is liable to some serious difficulties, e.g., Ross Puzzle, Professor Procrastinate Puzzle, end some other. The paper under review presents a semantic construction called ``resolution semantics'' which violates inheritance but preserves coarseness. The author observes that the semantic value of an ought-sentence depends both on semantic features of its prejacent and on a set of external parameters. The latter is represented by some options (alternative courses of action available to the agent), an ordering (some way of ranking options), and the benchmark (a threshold in the ranking that distinguishes permissible options from impermissible ones). An action is said to be visible iff it perfectly divides the given set of options in two classes: those options that are ways of performing the action, and those that are not. Moreover, an action can be permissible (some option that is a way of performing an action meets or exceeds the benchmark), strongly permissible (every option that is a way of performing an action meets or exceeds the benchmark), optimal (all of the deontically ideal options are ways of performing an action). The key semantic clause for the ought-modality is then formulated as follows: \(\ulcorner S\) ought to \(\phi \urcorner\) is true (relative to a set of parameters) iff \(S\)'s \(\phi\)-ing is visible, optimal and strongly permissible (relative to those parameters). A formal account of the resolution semantics is developed, and some possible objections against it is thoroughly discussed.