Contra Eunomium was St Basil the Great’s first dogmatic treatise. It represents one of the most important pieces of fourth century reflection on the the doctrine of the Holy Trinity and the nature of theological language. Though Basil would subsequently refine his thinking, “the theological framework here constructed will remain the basis of his Trinitarian thought even as it develops through the years” (Stephen M. Hildebrand, The Trinitarian Theology of Basil of Caesarea, p. 45). Perhaps most importantly, Contra Eunomium decisively contributed to the establishment of the Nicene understanding of the Trinity. Mark DelCogliano and Andrew Radde-Gallwitz, the translators of the English version, describe the treatise as “a signal theological achievement. It contains the foundation for the Trinitarian theology that his brother Gregory of Nyssa (and to some extent Gregory of Nazianzus) later developed and clarified in the 380s and beyond, and that became the standard expression of pro-Nicene orthodoxy, sometimes called ‘the Cappadocian achievement'” (p. 34). Given its importance, it is surprising that the first English translation was only published two years ago.
A wide diversity of opinion existed in the fourth century Church on the trinitarian identity of God and the divinity of Jesus Christ. While the Council of Nicaea (325), with its dogmatic claim that the Son is “of one substance [homoousios] with the Father," has long been considered as a defining event in the life of the Church, it was not so understood by many Christians in the fourth century. It was but one of many councils. In the East the Nicene homoousion was viewed as unbiblical and problematic, too easily construed along Sabellian, or modalist, lines. The fact that Marcellus of Ancyra attended the council and subscribed to its creed made it especially suspect in the eyes of the Easterners. Multiple synods were held after Nicaea—each seeking to define the catholic faith. R. P. C. Hanson has gone so far as to describe the fourth century debates as a “search for orthodoxy, a search conducted by the method of trial and error” (The Search for the Christian Doctrine of God, pp. xix-xx). Michel Barnes suggests that Nicaea only became orthodoxy in 381, with the Second Ecumenical Council (“The Fourth Century as Trinitarian Canon,” in Christian Origins, pp. 61-62). “The West got the official language,” Barnes writes; “the East got the official interpretation.” Praying the apostolic faith was one thing, but actually finding the proper conceptuality and vocabulary by which to speak it was apparently a much more difficult matter.
Historians identify the competing theological factions that existed in the second half of the 4th century by Greek terms: the Homoousians (the Son is of the same substance as the Father), represented by Athanasius of Alexandria, Marcellus of Ancyra, Apollinaris of Laodicea, and many Western bishops; the Homoiousians (the Son is of like substance with the Father), represented by George of Laodicea, Basil of Ancyra, and Eustathius of Sebaste; the Homoians (the Son is like the Father), represented by Acacius of Caesarea, Eudoxius of Antioch, and a bunch of other guys I’ve never heard of; and the Heteroousians (the Son is unlike the Father in substance), represented by Aetius and Eunomius (also see M. C. Steenberg, “A World Full of Arians“). These are not hard and fast lines, however. Theological boundaries were dynamic and fluid in the fourth century.
Basil is usually located in the Homoiousian party—and he was most certainly influenced by Homoiousian theologians—yet by the time of Contra Eunomium we see him striving to articulate an understanding of God that would integrate the Eastern trinitarian paradigm with the language of Athanasius and other supporters of Nicaea. But his Contra Eunomium does not mention the Nicene Creed, and it employs the term homoousios only once—and there, as Lewis Ayres notes, “the term does not function as a point of departure for the argument” (Nicaea and its Legacy, p. 195).
Eunomius published his Apology in c. 360-361. Basil responded a few years later (c. 364-365). Why did Basil choose Eunomius as his target? Perhaps because, unlike the Homoians, Eunomius clearly and unequivocally denies the divinity of Christ. For Basil, Eunomianism is nothing less than blasphemy. As he states in the beginning of his treatise: “So, then, even though I have plenty of material to demonstrate in this treatise that Eunomius is lying, stupid, wanton, dissembling, and blasphemous, I will consider mentioning all these as secondary and focus on the blasphemy he has uttered regarding the grandeur of the glory of the Only-Begotten. After I have revealed the devices he uses to conceal his scheme, I will attempt to make his blasphemy as clear as day for all” (Eun. 1.1).
The Contra Eunomium, in other words, is not a dispassionate reflection on the doctrine of the Holy Trinity. It is a sophisticated polemical critique of a specific theological work that Basil regards as dangerous heresy. But it is precisely the heresy that brings forth from Basil his theological creativity, as well as a fair amount of invective. The translators explain:
The treatise is a point-by-point refutation of Eunomius’s Heteroousian theology and seeks to convince the reader that Eunomius has distorted the Christian faith and is a danger to believers. As the ancient genre of judicial oratory calls upon the audience to render a judgment in a court of law, Against Eunomius is best viewed as a Christian adaptation of the genre. Basil constructs his reader as a member of the jury. … And so, when reading Against Eunomius one must keep in mind that, in line with judicial oratory, Basil is concerned with furnishing incontrovertible proof of Eunomius’s impiety. He seeks to highlight Eunomius’s errors in logic or doctrine; prove that they are in fact dangerous, impious errors; and refute them. Basil is not primarily presenting his own theology of the Trinity, but developing a Trinitarian theology to disprove the validity of his opponent’s. (pp. 42-43)
How ironic that heresy can become the catalyst that leads the Church into a deeper apprehension and articulation of the Truth.