Necesidad lógica y lógica condicional

Abstract

In this paper we characterize Leibniz's idea of necessary truth with the aim of showing how, in the course of the development of logical theory, it has been weakened to the point of becoming just one of the many possible interpretations of the necessity operator. We show that this has happened not only in those classical modal logics with a Kripke semantics, but also in David Lewis' systems for counterfactual conditionals and in Carlos Alchourrón's logics for defeasible conditionals.