Jugement de séparation et sujet de la métaphysique

With this second dialogue, Salviati wants to remove Simplicio’s difficulties on the actual distinction of essence and being as well as on the notion of the act of being (actus essendi). Feeling that he had skipped stages in their first dialogue, he suggests going back to the determination of the exact subject of metaphysics according to Thomas Aquinas. He will progress in two steps: the transition from «first perceived being» to «common being» or «being as being» by a judgment of separation, and then the definition of the subject of metaphysics as «being negatively or neutrally immaterial». With this conclusion, Salviati intends to lead Simplicio to understand the autonomy of the principles of metaphysics towards philosophy of nature. Simplicio remains curious but dubious. Is not the negatively immaterial being a simple dialectical notion that Salviati would take for a metaphysical one? Is the independence of metaphysics from physics therefore also ensured? And consequently, is there actually a difference between the first perceived being and the common being, subject of metaphysics? What is, actually, the subject of metaphysics?