Divine Simplicity: Christ as the Crisis of Metaphysics by Paul R. Hinlicky (review)

Paul Hinlicky examines historic Christian theology’s teaching on the unity of God’s essence. “Divine simplicity” refers to the idea that God’s being is not compounded of different parts. Rather, in light of God’s aseity, God is identical with his distinct attributes and not compounded of pre-existent qualities that somehow merge together.

Hinlicky suggests that this doctrine has multiple versions. He distinguishes between strong doctrines of simplicity and weaker ones. The strong version originated among those philosophers known as “Pre-Socratics” (notably in Parmenides, among others). The tendency of the tradition of strong simplicity is to see any differentiation within God (or perhaps simply ultimate reality) as unreal. Multiplicity and distinction are a mark of temporality, and unbefitting for the unitary arche of being. In tandem with such a view of ultimate reality is an orientation toward an almost pure apophatism, wherein God is seen as transcending even the distinction between being and non-being (Plotinus, Pseudo-Dionysus, John Scotus Eriugena, etc.).

Although the Church Fathers appropriated the categories of Greek metaphysics as a means of translating the God of the gospel into the conceptual idioms of the wider Greco-Roman world, such modes of thinking always sat uneasily with the Christian account of God. Not only does the stronger doctrine of simplicity militate against God having positive attributes (such as wisdom and holiness), but it would seem to also eliminate the distinction between the persons of the Trinity. Moreover, for Hinlicky, the strong simplicity ultimately means that God’s being is to be understood according to a protological unity lying beyond the concrete manifestation of God’s being in time as Father, Son, and Holy Spirit. At this point, Hinlicky appears to be deeply indebted to Robert Jenson’s rejection of any definition of divinity the opens up a gap between God’s temporal manifestations and his eternal reality.

Hinlicky opts for what he describes a weak simplicity. This weak simplicity is a doctrinal rule whereby the Father, Son, and Holy Spirit are to be spoken of as one God. Such a rule is justified by the fact that the Trinity manifests a common agency by enacting a single coordinated plan in creation and redemption. Therefore, much like Jenson, Hinlicky suggests that God’s identity as one subsists in a narrative unity, not in a kind of substantial unity that implicitly removes all genuine distinctions.

In favor of this, Hinlicky proposes a form of social Trinitarianism, albeit a somewhat less extreme version than one might find in the work of Stanley Grenz, or Jürgen Moltmann. In order to find a precedent for social Trinitarianism within the larger Christian tradition, Hinlicky employs the common tactic of playing the Cappadocians off against Augustine, and re-asserting the validity of the de Régnon thesis. The late nineteenth-century Roman Catholic scholar Theodore de Régnon claimed that Latin and Greek Trinitarian theology are inherently different. Whereas Latin Trinitarian theology begins with the unity of the divine substance and works its way to the individuality of the persons, Greek Trinitarian theology begins with the distinct persons and works its way to the common divine substance. Hinlicky’s defense of this thesis is not very convincing in light of the work of Lewis Ayres, Sarah Coakley, and Michel Barnes. These scholars have shown this view of Trinitarian theology is based on a very selective reading of the Patristic data. While Hinlicky acknowledges criticism of the de Régnon thesis (by Ayres, but not the others), he does little to defend it on the grounds of historical data.

Although this work is very learned, it possesses a number of weaknesses. Hinlicky tends to give overly detailed summaries of the works of others. Second, in light of a direct study of the notion of simplicity in the primary sources, many (notably Richard Muller) have argued that simplicity merely refers to the apophatic assertion that God is not compounded. Such...