A relevance logic is motivated by the idea that the premises of a valid argument must be somehow “relevant” to its conclusion. The idea is motivated by the fact that…

The language sketched above is better referred to as first-order predicate calculus, as the language only quantifies over (first-order) individuals. A stronger language, second-order predicate calculus, can therefore be constructed…

Most non-classical logics are motivated by either philosophical considerations, such as the metaphysical status of the future, or technical concerns about the neutrality of the logical connectives or the notion…