Pluralism Defined

AbstractLogical pluralism is a pluralism about logical consequence. Crudely put, a pluralist maintains that there is more than one relation of logical consequence. By way of illustrating the kind of claim involved in logical pluralism, a few analogies are considered in this chapter. According to the Generalised Tarski Thesis (GTT), an argument is valid if and only if, in every case in which the premises are true, so is the conclusion. Logical pluralism is the claim that at least two different instances of GTT provide admissible precisifications of logical consequence. Unlike the restricted Tarski Thesis, which admits only one instance of case (Tarski's models), the pluralist endorses at least two instances, giving rise to two different accounts of deductive logical consequence (for the same language), two different senses of ‘follows from’. There are at least two ways to not be a logical pluralist: reject the GTT or endorse exactly one instance.