Abstract

This paper argues that the science of logic follows the theory of knowledge. The objects are ens rationis. It admits that we have two kind of logic: formal logic, which follows via rationis, named abstractio formalis; and real logic, which follows via rationis, named abstractio totius. In consequence, there are divers habits of logic, which permit the use of our different acts of understanding, which pertain to both uses of ratio. Each one of these different logics has different principles: the rational principle, the axioms of logic; the formal principle; the principle of generalisation