Lorenzo Valla severely criticizes the medieval logic. But far from abolishing the logic, he elaborates a new dialectic, based on another conception of the furniture of the world, with a new table of the categories and of the transcendental terms. He distributes differently the relations between the arts of the language, with a broadened conception of grammar, and a different relation between dialectics and rhetoric ?What is the most important id the usage. Not only the common language but also the usage of the authors. Valla reaffirms the thickness of the language in all its dimensions