 All the ontological accounts of impossible worlds presented so far are in a broad sense realist. They all accept that sentences referring to or quantifying over impossible worlds can be literally true, and take the entailed ontological commitment at face value, although they disagree with each other about the metaphysical status of worlds. A deeply anti-realist alternative to modal metaphysics has also been developed:  modal fictionalism.  The view is fictionalist (or anti-realist) about worlds. Its key claim is that talk of and quantification over worlds ought to be understood as literally false: it is only true within a “worlds fiction”. We make-believe in the fiction because it delivers useful results in the explanation of modal notions. Modal fictionalism promises the theoretical benefits of modal realism without the ontological costs. We should not include worlds (other than the actual world) in our ontological catalogue. But talking as if there were worlds is useful. Gideon Rosen (1990), a major proponent of the view, takes Lewisian modal realism to be the relevant fiction. But it is relatively easy to extend such modal fictionalist accounts into fictional treatments of possible and impossible worlds, taking e.g. Yagisawa’s extended modal realism as the fiction which we make-believe. JC Beall (2008) proposes an approach to impossible worlds (see  section 5.1),  which can be motivated by the idea that these are worlds where “logical fictions” take place.