For much of the past century, theologians have busied themselves reconceiving the doctrine of the Trinity. Taking cues from Adolf von Harnack, some complain that the lively God of the Bible was domesticated by the fateful triumph of “classical theism,” which imprisoned the Triune God in the static, ahistorical, impersonal categories of Greek philosophy. Heidegger captured the mood: No one, he famously said, would want to pray, sacrifice, sing, or dance before Aristotle’s unmoved Mover.
Classical theists have been making a comeback of late, insisting that the tradition is better than detractors claim and that the supposed innovations have been unhelpful at best, heterodox at worst.
Both sides are half-wrong, or, more charitably, half-right. The classical theists are right about the tradition: Trinitarian theology isn’t an Athenian captivity of the Church. The innovators are right that the concepts and formulations of Trinitarian theology have been and can be refined.
It’s best to follow Robert Jenson here. Jenson says that the big story of Trinitarian theology has been “the evangelization of metaphysics.” A few vignettes from the history of theology will illustrate. This will get a little thick, so buckle up.
Vignette #1: The fourth-century heretic Arius denied that the Son is eternal God, saying, “There was when the Son was not.” Though the Son is very, very exalted, he is a creature.
Arius’s orthodox opponent, Athanasius, charged that Arius taught like a Greek. Athanasius was right. As Rowan Williams showed in his classic study, Arius accepted the widespread premise that the Absolute Being (God) must be free of all relations. A husband cannot be absolute because he’s defined, in his husband-ness, in relation to his wife. Nor is a father free to be a non-father, since he’s bound by his relation to his child(ren). On Arian reasoning, if God has an eternal Son, he cannot be absolute. Relation implies relativity, the opposite of absoluteness.
The orthodox party bit the bullet and confessed, against philosophical common sense, that the eternal, infinite God is a communion of divine Persons, each of whom is defined in relation to each of the others. With this confession, they upended metaphysics. “Absolute” has never meant quite the same thing since.
Vignette #2: Arianism was a theology of the cross, emphasizing that Jesus’s sufferings are essential to our salvation. Yet the Arians thought the high God was too pure to wade into the muck of the material world. Jesus couldn’t save if he were merely human, but anyone who sweats blood and shrieks from a cross can’t be fully divine either.
Astonishingly, the orthodox party bit that bullet, too, and said the unthinkable: God the Son, eternal God and Creator of heaven and earth, suffered and died in the flesh. That wasn’t a capitulation to Greek metaphysics. It was a revolution.
Vignette #3: Thomas Aquinas is a whipping boy for modern Trinitarian theologians. His theology can be made to sound like arid puzzle-mongering, but Jenson argues that Thomas revolutionized Aristotle as much as the church fathers did Plato and Plotinus.
According to Thomas, everything is a composite of an essence and the fact of existence. The essence of “dog” would exist even if my dog didn’t. My dog comes into being when doggy essence is combined with his particular existence.
God is the sole exception. He is not a composite of parts, whether physical, metaphysical, or conceptual. For God, essence and existence are identical. Typically, this is taken to mean that “existence” is inherent in God’s essence: He cannot not exist. Jenson turns that upside down, saying that the essence of God, the very definition of what it means to be God, is the infinite love and life of the Father, Son, and Spirit.
Ask, “What is God?” and the Christian answer isn’t, “A being with divine attributes.” God isn’t a mass of divine stuff. “What is God?” The Christian answer is, “Father, Son, and Spirit.” For Thomas, we must define “divine essence” as the abundant life of the Trinity.
Of course, not every new twist on the Trinity is true or consistent with the creed. But, do we have any reason to think that the evangelization of metaphysics ended in the thirteenth century? As Thomas would say, it would seem not.
And modern theologians have sometimes deepened our understanding of God in profound ways. One example will have to suffice: the ancient problem of God-and-time.
God is eternal, not bound by time. Yet, Christians believe, God the Son entered into human life without ceasing to be himself. How can we conceive an eternal God who can so fully experience created time?
Karl Barth resolved this problem by suggesting that “eternity” means Triune temporality. Because the Father begets the Son, there is a “beginning and ending” in God, but it is a beginning and ending without limitation. In the living relations of the divine persons, there is “a movement which does not signify the passing away of anything, a succession which in itself is also beginning and end.” It’s a divine mode of time and movement that involves neither progress nor regress, neither gain nor loss.
These brief notes support Jenson: The big story of Trinitarian theology isn’t “Hellenization” but the “evangelization of metaphysics.” Yet they also indicate that this evangelistic effort is, like every evangelistic effort, far from complete.
Peter J. Leithart is President of Theopolis Institute.