Abstract

Possible-worlds semantics proved itself as a strong tool in analysing the statements of actuality, possibility, contingency and necessity. But impossible phenomena go beyond the expressive power of the apparatus. The proponents of possible-worlds apparatus thus owe us at least three stories. The first one is the story about ontological nature of possible worlds, the second one is the story about the theoretical role such entities play and the third one is the story about the impossible. Modal Realism (MR) provides us with a positive story regarding the first and the second, but denies impossible worlds. Extended Modal Realism (EMR) adds a positive story about the third point too. This book is an attempt to paraphrase extended modal realism in different metaphysical frameworks. In Chapter I, I outline the theory of modal realism, its systematic account of modality and its ontological commitments. I also motivate an impossible-worlds discourse as well as a systematic appeal of extending the picture beyond the possible. I then propose several definitions of the concept of ‘impossible world’ (or impossible possible world). Finally, I discuss a particular metaphysics behind the concept - extended modal realism. Chapter II considers the epistemological worry associated with (MR) and (EMR) and concludes that although the worry is justified, there can be epistemological justification of the theory. Next, I outline the so-called indispensability argument for the legitimacy of mathematical Platonism. Finally, I argue that the argument, if accepted, can be applied to metaphysics in general, to the existence of concrete possibilia (and impossibilia) in particular. Chapter III focuses on the analysis of (EMR). To be more precise, I present a so-called advanced modalizing problem which seems to be infecting every genuinely realistic theory of modality. In this chapter, I propose a way of treating extraordinary modal claims by means of plurality of logical spaces. The next three chapters provide different ways of understanding (EMR). Namely, Chapter IV develops and defends Extended Modal Dimensionalism (EMD). (EMD) is realism about spaces, times and worlds—metaphysical indices that make objects spatial, temporal and modal, respectively. Metaphysical indices play the role of alethic relativisers, i.e. items to which matters of truth are relativized. The chapter examines several arguments against modal dimensionalism and shows that it offers a feasible way to understand (EMR). Chapter V offers a structural approach to possible and impossible worlds: Extended Modal Structuralism (EMS). In particular, I consider whether it makes sense to think of logical models in isolation from the concrete world but without their being divorced from all spatiotemporal totalities. The metaphysics of structure developed in this chapter assumes that structural properties of possible and impossible worlds are primitive and objective. However, I provide some characterisations of their logical and metaphysical behaviour, as well as guidelines for talking about them. Finally, Chapter VI proposes yet another metaphysical framework of hybrid modal realism. I present theories of (MR), (EMR) and modal fictionalism respectively, their advantages and drawbacks. Finally, I propose a so-called hybrid view. Roughly, the view is that one might be a modal realist when it comes to possibilia, but turn into fictionalism regarding impossibilia. The approach is dubbed Extended Modal Fictionalism (EMF) a version of fictionalism according to which claims made within a certain discourse are better to be understood as a sort of ‘fiction’, rather than as a literal truth.