Although confessional Lutherans affirm the ultimate authority of the Bible alone (sola Scriptura), various philosophical traditions have been legitimately utilized by Christians throughout history as instruments in service of the true faith. The pre-modern and early modern Church utilized thought-forms from Stoic, Platonic, and Aristotelian sources as means of explicating the central truths of the Christian faith to the post-biblical Gentile world. Although sometimes the use of philosophy obscured the truth of the Bible in the early Church, more often than not such thought-forms were used critically in light of the revealed realities of the faith. This can be supremely observed in the development of the distinct uses of the concepts of “substance,” “nature,” and “person” in the debates surrounding the Trinity and Person of Christ at Nicaea and Chalcedon.
Broadly speaking, most of the ancient metaphysical schemes utilized by Christians shared the common concept of “substance.” Although various ancient philosophical traditions defined substance differently (Stoic vs. Aristotelian, for example), broadly speaking substance ontology assumes two basic ideas: First, entities in a class or species share an objectively real common nature. For example, humans have a common nature with other humans. Secondly, that although certainly features of entities change, there is a core of identity or essence within them that persists over time. For example, despite physical changes I am the same person I was when I was a baby. It is easily observable that these aforementioned tenets of substance metaphysics imply linguistic realism and a correspondence theory of truth. That is, both claims assume that how humans typically use language to designate the identity of a given entity generally corresponds to the actual functioning of the world.
As should be clear from the description above, the ancient councils and creeds of the Church (particularly, those of Nicaea and Chalcedon) assumed the validity of substance metaphysics. For classic creedal orthodoxy, God is a single entity (ousia) with three real centers of identity (hypostasis) subsisting through their relations with one another. Likewise, Christ is a single center of identity (prosopon) whose integrity persists over time. He possesses two natures (physis), that is, he has a common nature with the other persons of the Trinity as well as the rest of humanity. From the great councils of the ancient Church, these thought-forms passed into the heritage of the Latin medieval church. From there were absorbed into the theology of the Magisterial Reformers of the sixteenth century with little comment.
Image from Marcellino D’Ambrosio, “Early Church Fathers Overview: Snapshot of the Fathers,” Crossroads Initiative, February 10, 2020, https://www.crossroadsinitiative.com/media/articles/early-church-fathers-overview-snapshot-of-the-fathers-of-the-church/.
