The Trinitarian Vision of Jonathan Edwards and David Coffey By S ...

of Neoplatonism into Christian theology, which led unavoidably to the obsession with divine unity in the Western trinitarian tradition.⁴¹ In contrast to this assertion, the late fourth-century pro-Nicene theology of inseparable external operations was the decisive influence on Augustine’s doctrine of divine unity. That Augustine understood himself to be theologizing within a received confessional tradition is made clear by his comment, “Just as Father and Son and Holy Spirit are inseparable, so do they work inseparably. This is also my faith inasmuch as it is the Catholic faith.”⁴² According to the doctrine of inseparable external operations, in any act of a divine person of the Trinity, the three persons act inseparably. Because the divine persons operate inseparably, they have the same nature. Unity of operation infers unity of nature. The doctrine of inseparable operations is Augustine’s doctrine of divine unity over a long period of time and in diverse literary forms. For example, this doctrine is present in Epistle 11, Augustine’s earliest trinitarian writing (389); in Sermon 52 (410–412); in later writings such as Letter 187 (417) and Tractate 20 (418–419); and throughout De Trinitate.⁴³

Important to note is that Augustine used the mental triads to illustrate the doctrine of inseparable operations. The mental triads are not used, as social trinitarians maintain, to portray God as an undifferentiated essence but rather to show how one divine person can be named singly in a divine act without dividing the nature. For example, in the Incarnation, only the Son takes on flesh, yet in that event, the Father, the Son, and the Holy Spirit operate inseparably.⁴⁴ The triads are an attempt to solve the apparent tension between the confessional formula of inseparable operations and the biblical data that assign unique activities to the divine persons.

Augustine’s mental triad of memory, understanding, and will illustrates the temporal manifestations of the divine persons in the following way. Although the divine persons exist and act eternally as the inseparable Trinity, they can manifest themselves singly—for example, the Son in the Incarnation. Memory, understanding, and will typify the metaphysical inseparability of the Father, the Son, and the Holy Spirit and their single manifestation. They do so because memory, understanding,