Aristotle, Proclus and Eustratius of Nicaea on the Platonic unhypothetical principle: Ontological and epistemological approaches to the Platonic Form of the Good

In Nicomachean Ethics I.6, Aristotle directs his criticism not only against the Platonic unhypothetical principle, the Platonic Form of the Good, but also against the notion of a universal Good. In this paper, I examine some of the most interesting aspects of his criticism of the Platonic Good and the universal Good in both the Nicomachean Ethics and the Eudemian Ethics. In my research, I also examine some crucial ontological and epistemological theses in relation to the Platonic Form of the Good as they are expressed by Proclus in his Commentary on Plato’s Republic and by Eustratius of Nicaea in his Commentary on Aristotle’s Nicomachean Ethics. In the Nicomachean Ethics, after a series of disputable ontological arguments, Aristotle’s criticism culminates in a strong ethical or rather practical and, at the same time, epistemological argument. This argument aims to show that we have to discover the dialectical stages between the ultimate End, i.e., the Good simpliciter or the absolute Good, and the relational goods until the last prakton agathon in which each praxis ends.