Impossible Worlds

Francesco Berto and Mark Jago's book, Impossible Worlds (Oxford University Press) was published on 13 June 2019.

Berto and Jago start by considering what the concepts of meaning, information, knowledge, belief, fiction, conditionality, and counterfactual supposition have in common. They are all concepts which divide the world up more finely than logic does.

Logically equivalent sentences may carry different meanings and information and may differ in how they're believed. Fictions can be inconsistent yet meaningful. We can suppose impossible things without collapsing into total incoherence.

Yet for the leading philosophical theories of meaning, these phenomena are an unfathomable mystery. To understand these concepts, we need a metaphysical, logical, and conceptual grasp of situations that could not possibly exist: impossible worlds.

This book discusses the metaphysics of impossible worlds and applies the concept to a range of central topics and open issues in logic, semantics, and philosophy. It considers:

• problems in the logic of knowledge
• the meaning of alternative logics
• models of imagination and mental simulation
• the theory of information
• truth in fiction
• the meaning of conditional statements
• reasoning about the impossible.

In all these cases, impossible worlds have an essential role to play.