After briefly insisting that the confession of the Father, Son, and Holy Spirit does not undermine confession of the One God, St Basil returns to the divinity and mutual relationship of the Father and the Son. This return feels odd in the context of his homily On Not Three Gods, especially if Mark DelCogliano is correct that the attacks against Basil were advanced by the Pneumatomachian lobby. On my unscholarly reading the homily makes more sense if Basil’s opponents are followers of Eunomius. I can envision Heteroousians accusing Basil of polytheism because of his insistence that the Son and Spirit are equal in divinity to the Father. They probably claimed that their system avoids polytheism because it confesses the One Unbegotten God who might never have created the Son and Spirit (see “The ‘Biblical’ Monotheism of Eunomius”). Against Heteroousian critique, Basil affirms the eternal consubstantiality of Father and Son:
The perfect is neither decreased nor increased. There is one unbegotten God. There is one only-begotten of him, the Son and God. Just as there is not another co-unbegotten God with the one [unbegotten], so too there is not another co-begotten Son. Just as the Father is not the Father in name only, so too the Son is not the Son in name alone. The Father is God; the Son is God. The Father is perfect God; the Son is also perfect God. The Father is incorporeal; the Son is incorporeal, the representation of the incorporeal and the incorporeal image. (Trin. 3)
DelCogliano argues that the above passage is in fact a citation from an older unnamed source. Be that as it may, Basil has made it his own. His meaning is clear: the Son is to be numbered with the Father on the divine side of things. Why are there not therefore two Gods (assuming that it even makes sense to speak of two infinite, incorporeal beings)? Because the Only-Begotten is the divinely-generated image and representation of God. Basil elaborates on this point in his On the Holy Spirit:
We have never to this present day heard of a second God. We worship God from God, confessing the uniqueness of the persons, while maintaining the unity of the Monarchy. We do not divide divine knowledge and scatter the pieces to the winds; we behold one Form (so to speak) united to the invariableness of the Godhead, present in God the Father and God the Only-Begotten. The Son is in the Father and the Father in the Son; what the Father is, the Son is likewise and vice-versa—such is the unity. As unique Persons, they are one and one; as sharing a common nature, both are one. How does one and one not equal two Gods? Because we speak of the emperor, and the emperor’s image—but not two emperors. The power is not divided, nor the glory separated. One is the dominion and authority over us; we do not send up glories to God, but glory; the honor given the image passes to the prototype. The image of the emperor is an image by imitation, but the Son is a natural image; in works of art the likeness is dependent on its original form, and since the divine nature is not composed of parts, union of the persons is accomplished by partaking of the whole. (Spir. 45)
Basil answers the charge of ditheism (and by implication, tritheism) by invocation of the Monarchy of the Father and the mystery of divine generation. The Father is the foundational principle of the Godhead. It’s not as if there exists two (or three) foundational principles. The Son owes his existence and divinity to the unbegotten God. He is generated by the Father as the Image of the Father, not from nothing but from the substance of the Father. He is not external to the Godhead, as the sculptured image of a king is external to his person, for Christ partakes of the divine nature in its entirety.
And if the question is raised, what is this divine generation? Basil has an immediate reply:
Do you believe that he has been begotten? Do not inquire how. … Do not inquire about what cannot be discovered, since you will not find it. For if you inquire, from what can you learn it? From the earth? It did not exist. From the sea? There were no waters. From the sky? It was not raised up. From the sun and the moon and the stars? They were not fashioned. Perhaps from the ages? The Only-Begotten is before the ages. Do not examine what has not always existed to learn about what always exists. … Let the begetting of the Only-Begotten from the Father be revered in silence. For only the one who has begotten him and the one who has been begotten understand it. (Trin. 3-4)
By adoption and grace the baptized have been given to participate in the eternal life of the Holy Trinity; but we are given to comprehend neither the divine essence nor the originating relations between the Father, Son, and Spirit.