Duns Scotus on Divine Substance and the Trinity
Cross, Richard (Oriel College, Oxford)
Medieval Philosophy and Theology 11 (2003)
Charting a course between modalism (the belief that there is just one divine person) and tritheism (the belief that there are three divine substances or Gods) has long been the major problem for Trinitarian theology. In what follows, I shall discuss part of the contribution made by Duns Scotus to this problem. I will argue that, with a few small modifications, Scotus presents a coherent account of the doctrine of three persons in one substance, and thus that this doctrine can be coherently defended against both modalism and tritheism. I do not intend to give a complete presentation of Scotus’s Trinitarian thought.
The background to the issue I am going to look at here can be found specifically in the condemnation, at Lateran IV, of Joachim of Fiore’s claim that the theory proposed by Peter Lombard—according to which, the divine essence is a thing (summa res)—is heretical. Joachim argued that the unity of the divine essence is no more than aggregative: God is a collection of three persons. This “social” sort of view of the Trinity was condemned at Lateran IV, which canonized instead Lombard’s view that the divine essence is one thing that “neither begets nor is begotten, and does not proceed.”