The triad of essence, faculty, and activities

by Andrea Elizabeth

Energeia in the context of science according to Galen,

Galen thus recognizes a general distinction between the energeiai of bodily faculties or the soul, which we are in a position to know, and their ousiai, which we are not in a position to know. The triad consisting of a dunamis with its knowable energia and unknowable ousia is one that will later find wide application among the Neoplatonists and the Church Fathers. As the next section will demonstrate, the theological application of the triad had already been anticipated long before Galen by Philo of Alexandria. (Aristotle East and West, p. 59)