  As noted, the focus of the present article is on the metaphysics of  possible worlds rather than applications. Of course, the semantics of modal languages is itself an application, but one that is of singular importance, both for historical reasons and because most applications are in fact themselves applications of (often extended or modified  versions of) the semantical apparatus. Two particularly important  examples are the analysis of intensions and a concomitant explication of the de re/de dicto   distinction.[10] 