Last week I ran through some arguments that ought might be ambiguous between a deontological and an epistemic meaning. It turns out this issue has been the subject of some sustained research within formal semantics, and the best arguments seem to be on the side of there not being an ambiguity. See, for instance, Anna Papafragou’s paper Inference and word meaning: The case of modal auxiliaries. The most serious problems with the ambiguity theory are that (a) the alleged ambiguity is spread across so many words and languages that it needs explanation and none of the explanations provided seem to do the trick, and (b) it’s too easy to find uses where it is unclear which of the two meanings is meant, while it’s notoriously hard to do this with uncontroversially ambiguous words like bat and ball.

Last week I ran through some arguments that ought might be ambiguous between a deontological and an epistemic meaning. It turns out this issue has been the subject of some sustained research within formal semantics, and the best arguments seem to be on the side of there not being an ambiguity. See, for instance, Anna Papafragou’s paper Inference and word meaning: The case of modal auxiliaries. The most serious problems with the ambiguity theory are that (a) the alleged ambiguity is spread across so many words and languages that it needs explanation and none of the explanations provided seem to do the trick, and (b) it’s too easy to find uses where it is unclear which of the two meanings is meant, while it’s notoriously hard to do this with uncontroversially ambiguous words like bat and ball.