Erich Rast

This text is a short introduction to logic that was primarily used for accompanying an introductory course in Logic for Linguists held at the New University of Lisbon (UNL) in fall 2010. The main idea of this course was to give students the formal background and skills in order to later assess literature in logic, semantics, and related fields and perhaps even use logic on their own for the purpose of doing truth-conditional semantics. This course in logic does not replace a proper introduction to semantics and is not intended as such, although parts of Chapter 1 and 4 could be used to supplement an introductory course in semantics. In contrast to other introductions it has a certain focus on ‘writing things down correctly.’ Proofs of metatheorems are omitted, though. This is work in progress. Please send suggestions and corrigenda to [email protected]. Have fun!

An account of non-existing objects called 'classical possibilism', according to which objects that don't actually exist do exist in various other ways, is implemented in a two-dimensional modal logic with non-traditional predication theory. This account is very similar to Priest's, but preserves bivalence and does not endorse dialethism. The power of classical possibilism is illustrated by giving some examples that makes use of a description theory of reference. However, the same effect could also be achieved in a more Millian fashion. It is argued that classical possibilism is ontologically more neutral than is commonly thought, because it allows for the formulation of various forms of reductionism within the object language.