Abstract

Most, perhaps all, non-classical logics are a blend of classical logic with extralogical elements. Possibly this thesis has no general proof, and only a casuistic argument can be provided. I discuss a case of paraconsistency that results of applying a “filter” to two syllogistics. These syllogistics incorporate two ideas of Nikolai Vasiliev: the idea of a complete system of contrary judgements, and the idea of double judgements. I also show how these results can be extended to propositional logic, with the aid of the conjunctive and disjunctive normal forms. Despite the non-classical appearance, it is used, without exception, the classical notion of deductive validity: a conclusion cannot carry more information, but may carry less information than the information carried by the collection of the premisses.