Aristotle's Metaphysics of Morals
“In Metaphysics 9, Aristotle offers a presumably complete means of articulating all the things that are through the correlative terms dynamis and energeia, potency and act, terms which are intended to be as universally applicable as the categories themselves. Chapter 2 begins by distinguishing two kinds of dynameis, rational and irrational[…]I will argue that the virtue is the dynamis for morally virtuous energeiai and show what sort of dynamis it is, and then briefly explain what sort of relation between virtue and happiness is implied when Aristotle asserts that eudaimonia is energeia kat'areten. By so doing, I will articulate a basic problem for Aristotle's metaphysics of morals: if virtue is correlative to both good action and to happiness, it cannot be comfortably classified as either a rational or an irrational dynamis, and that lack of fit between theoretical and practical science has profound consequences for a science concerned with good action.”
Garver, Eugene. "Aristotle's Metaphysics of Morals." Journal of the History of Philosophy 27, no. 1 (January 1989): 7-28. doi:10.1353/hph.1989.0016.