Dragos Andrei Giulea: Ousia and Physis in Eunomius’ Trinitarian Language of Apologia apologiae

Eunomius conceives of the notion of ousia in a consistent way as individual substance rather than essence or nature, in a Nicene way. In so doing, he carries on a pre-Nicene language which received its official confirmation at the Council of Antioch 268. That language was spread in the Eastern Roman Empire in the third and fourth centuries, particularly among the many kinds of anti-Nicene authors, from Arius to Asterius, to Eusebius of Nicomedia, to Eusebius of Caesarea, to the Homoiousians, to Aetius. Eunomius preserves certain theological elements from this Antiochene trajectory, such as the understanding of ousia and hypostasis as individual entity, and two of its main metaphysical consequences—the subordination of the Son, and the rejection of the Nicene homoousion.
On the contrary, the radical subordination of the Son to the point of
conceiving him as a creature without co-eternal existence with the Father
(without existence before his generation) and without ontological likeness with
the Father (excepting that of will and activity) definitely severed Eunomius
from the Antiochene trajectory and connected him with the theological visions proposed
by Arius, Asterius, and Aetius.Thus, the meanings of the terms ousia and physis are radically distinct, not synonymous or quasi-synonymous in Eunomius’ grammar. The notion of physis denotes the nature of a certain entity. However, Eunomius does not consider that Father, Son, and Holy Spirit share the same physis, in a Nicene way, but that each of them owns a distinct physis, a
doctrine previously professed by Arius and Asterius.