Retorica e logica nella critica di Lorenzo Valla del quadrato delle opposizioni

In this paper I discuss Lorenzo Valla9s criticism of the traditional Square of Opposition displayed in the second book of the Dialectica . I show that, according to Valla, the opposition rules of the propositions must take into account both common speeches and the correct use of Latin language, not the formal link occurring between the parts of propositions. In Valla9s perspective, this theoretical change is carried out through rhetoric and philology, and it involves a reassessment of the arts of the trivium . As regards this topic, I argue that Valla aims niether to reduce dialectic to rhetoric nor to replace the former with the latter, but rather to establish some rhetorical principles as a better-suited way to set the opposition rules, because they take into account the linguistic context in which these rules apply.