In Andy Egan & Brian Weatherson (eds.), Epistemic Modality
. Oxford University Press. pp. 108–130 (2011
The simplest story about modals—might, must, possibly, necessary, have to, can, ought to, presumably, likelier, and the rest—is also the canon: modals are context-dependent quantiﬁers over a domain of possibilities. Diﬀerent ﬂavors of modality correspond to quantiﬁcation over diﬀerent domains of possibilities. Logical modalities quantify over all the possibilities there are, physical modalities over possibilities compatible with the..