The Inseparable Operations of the Trinity: An Exposition and Defense of a Dogmatic Rule

Forthcoming, Eerdmans, 2019ish.

Book Synopsis

If you have been reading up on the doctrine of the Trinity, chances are you have encountered the so-called “axiom” omnia opera Trinitatis ad extra sunt indivisa. In English, all the works of the Trinity outside of Godself are indivisible. In the literature this is sometimes referred to as the doctrine of inseparable operations (DIO). The axiom was regarded to be analytic to the doctrine of the divine unity. It is both implied by the unity of divine essence, and it implies it.

But how should the rule be understood? Is it intelligible; conceptually defensible; does it cohere with other doctrinal claims? While a variety of articles tackle various aspects of DIO, there is no book-length treatment of this important rule. Hence this project. Below is a brief synopsis and rationale for it.

I am distinguishing between (a) hard inseparability, which holds that every action token (concrete, indexed action) attributed to one of the triune persons needs to be attributed to the other two persons as well; and (b) soft inseparability, which only requires that trinitarian persons share action types (not action tokens), their concrete actions being individuated. Hard inseparability, I am suggesting, was the all but unanimous consensus of the patristic tradition. Soft inseparability is a modern innovation, most at home in social trinitarianism. I will argue against the soft version, and in favor of hard inseparability. With many significant theologians, from Athanasius, to Basil the Great, to Gregory of Nyssa, Augustine, Maximus, and Hilary of Poitiers, I will argue that we must resist views of trinitarian agency which imagine the three cooperating through their individual actions. Rather, the triune persons act as a single agent in creation, redemption, glorification, yet every such inseparable operation exhibits a threefold modality: from the Father, through the Son, in the Holy Spirit. Such a modality coheres with the manner in which the divine persons share in the divine substance.

The hard version of DIO is not without its challenges. The first obstacle is the apparent differentiation between the actions of the triune persons, as they are narrated in Scripture. It will be shown, however, that Scripture is rather clear not only about the distinction between the persons, but on the inseparability of their actions. A second challenge is of the dogmatic order: if every action token must be assigned to each person, should one not assign the incarnation to the Father and the Holy Spirit also, with the absurd result that the Father too was incarnate? Or the crucifixion, with the problematic implication that the Father died on the cross? What about the cry of dereliction? Doesn’t Scripture require us to admit a separation between the Father and the Son, at least on the cross? A further differentiation between the respective agencies of the Son and Spirit is apparent in the ascension/Pentecost “exchange:” the Son must ascend, before the Spirit can come. Finally, how are we to understand the indwelling of the Holy Spirit from the perspective of DIO?

It is quite clear that a thorough defense of DIO requires addressing each of these tough questions. But the project is one that leads to deeper contemplation of God. It eventually will yield an account of trinitarian agency that is heavily informed by a doctrine of the missions of the Son and Spirit, which preserves divine transcendence, yet affirm his intimacy to creation. It will further need to incorporate a biblical hermeneutics of trinitarian agency; an account of divine action that is informed by both contemporary philosophy of action, as well as trinitarian metaphysics. A provisional outline of the book’s chapters will follow in a separate post.