When reading a philosopher who is supposed to have been an Aristotelian we have the choice between two different approaches: (1) we may look for the framework into which the author tends to fit, or (2) we may find the peculiarities that make him outstanding among the Peripatetic philosophers of his time. In some previous studies on scholasticism in the sixteenth through the nineteenth centuries, I mostly tried to establish the framework itself which helps to identify an Aristotelian author. For Catholic schools, the cursus philosophicus of the Jesuits was this framework, and Honoré Fabri too taught the standard course at a Jesuit college in Lyons twice between 1640 and 1646. 1 The aim of this paper is to show how Fabri distanced himself from the institutional framework by transforming his personal Aristotelianism into a claim for rational method.