Abstract

This study is an attempt to show that demonstration was conceived by medieval commentators as an instrument for advancing knowledge of the world. Although the theory of demonstration is not a “logic of discovery”, its specific aim would be to describe the characteristics that should have a discourse to be able to express the causal articulation of things belonging to the same genre. From the analysis of some texts by Thomas Aquinas on the distinction between knowledge propter quid and knowledge quia, it will be shown that the causal articulation represents the very novelty which is supposed to be acquired by a demonstrative syllogism. This conclusion will be confirmed by the analysis of some texts of the al-Ghazālī’s Logica which seem to reveal presuppositions of the writings of Latin commentators like Thomas Aquinas.