Semantics in Tomás de Mercado's Logic

Abstract

This paper deals with an aspect of the semantic-theory of the scholastics, namely, the doctrine of suppositio, as it is presented by Tomás de Mercado, a logician of the 16th century in México. Suppositio was divided into (1) classes that are intensional and (2) classes that are extensional. A criterium to distinguish the extensional ones is the kind of ascensus/descensus that they are susceptible of. (Ascensus/descensus is a logical procedure akin to instantiation in modern logic.) In some scholastic authors the use of this criterion is subject to many changes and ambiguities. We try to show that the more simplified use of this procedure made by Mercado is consistent and clear enough.

[M.B.]