 Although it has since become common in linguistic semantics to analyse content in terms of possible worlds, they are not always taken to be totally devoid of structure. As a case in point, Kratzer (2002) has argued that the verb know relates subjects to facts and thus its interpretation requires appeal to the mereology of worlds: facts are concrete parts worlds. Moreover, as in Kripke’s original approach, semantic theory frequently imposes some external structure on logical space. Thus, accessibility relations and distance measures between worlds are invoked to account for, respectively, propositional attitudes (along the lines of Hinitkka 1969) and counterfactual conditionals (following Lewis 1973). In a similar vein, the universe of individuals (or ‘entities’, in Montague’s parlance) nowadays gives way to a richer domain of structured objects, including substances and their parts, which may serve as extensions of mass nouns such as water (Pelletier &amp; Schubert 2003), as well as groups and their members, which are denoted by plural noun phrases (Link 1983). Also when properties (loving John) are considered as entities for which predicates may hold (Mary likes loving John), additional structure is needed: property theory gives the tools to incorporate them (Turner 1983).