Primitive modality and possible worlds

This paper sets out a number of reasons for thinking that the framework of possible worlds, even when construed non-reductively, does not provide an adequate basis for an explanation of modality. I first consider a non-reductive version of Lewis' modal realism, and then move on to consider the ersatzist approach of Plantinga et al. My main complaint is that the framework of possible worlds gets the semantics and metaphysics of ordinary modal discourse wrong. That is, possible worlds do not give us an adequate answer to the semantic question of what ordinary modal claims mean, nor do they give us an adequate answer to the metaphysical question of what makes such claims true