Abstract

The article outlines the main motivations for postulating impossible worlds as entities which are required for complete analysis of modality. It also presents various accounts of the metaphysics of these worlds. It discusses and compares three types of such accounts: (1) T. Yagisawa’s Extended Modal Realism (EMR), (2) D. Nolan's Ersatzism (EE), and (3) F. Berto’s Hybrid Modal Realism (HMR). The presentation of each of these accounts contains an analysis of arguments against them and possible replies. The outcome of these considerations is the thesis that if one takes impossible worlds as required for a complete theory of modalities, then ersatzism seems to be the most appropriate of all known solutions. Although it requires to take modal terms as primitive ones, it avoids serious problems of alternative theories. The connection of modal realism with impossible worlds leads to the theory which is patently question-begging. In particular, it seems that it does not solve the problem of impossibilities, but rather shifts it, so it can be reformulated within the framework of EMR. On the other hand, the hybrid theory, although ontologically parsimonious, seems to be not as effective as one could expect it from the theory of impossibilities. The main difficulty for HMR is the analysis of counterfactuals with necessary false antecedents.