#873 Identity and the Doctrine of Divine Simplicity
February 04, 2024Dear Dr Craig,
In your question of the week # 866, you explained that the ancients didn't understand or know the modern, logical relation of identity and how it affects the case for unitarianism and its identity claims.
I was wondering whether the same problem affects, directly or indirectly, the ancients' view about divine simplicity.
When the Church Fathers, Anselm and others wrote that God is simple and that all of His attributes are identical, and at the same time predicated a lot of properties in God or recognized and defended that God is three distinct, not identical, persons (Trinity), perhaps their lack of grasping of the modern conception of the identity relation, somehow, caused some confusion in their minds regarding the radical and apparently problematic implications of God's simplicity to issues like the modal collapse (which perhaps never was fully realized or understood by them), the Trinity (which seems obviously incompatible with simplicity, since it implies an *intrinsic* distinction in God), the incarnation (which implies the Second Person adquiring an human nature) and the overall ancient and medieval discourse about God's attributes like for example eternality (atemporality, in the ancients' view) which is obviously not identical to omnipotence or omniscience.
In short, do you see any relation between the ancients' case for divine simplicity and their lack of grasping of the modern, logical relation of identity?
Thank you.
Marco
United States
Dr. craig’s response
A
I think you’re really onto something, Marco! Although contemporary philosophical theologians tend to ignore the problem of the coherence of divine simplicity with the doctrine of the Trinity, it is noteworthy—as well as sobering—that historically some of the most prominent proponents of divine simplicity, including Arian, Muslim, and Jewish thinkers, rejected the doctrine of the Trinity precisely on the basis of divine simplicity. Eunomius, ibn Sīnā, and Maimonides all repudiated the doctrine of the Trinity as obviously incompatible with a strong doctrine of divine simplicity.
The best discussion of this issue comes from Christopher Hughes, On a Complex Theory of a Simple God: An Investigation in Aquinas’ Philosophical Theology, Cornell Studies in the Philosophy of Religion (Ithaca, NY: Cornell University Press, 1989), Pt. II. Hughes argues that Aquinas’ attempt to have a God who is at once Triune and free from composition is “fundamentally incoherent” (p. 188) because in order to maintain divine simplicity he has to deny that if x=z and y=z, then x=y, which is entailed by the modern relation of identity.[1] Otherwise Aquinas yields the palm of victory to the Arians, Muslims, and Jews. Aquinas is aware of this and actually advocates rejecting the (modern) identity relation in order to maintain divine simplicity along with the Trinity. In short, Hughes concludes, “The full strength account of divine simplicity describes a God who could not possibly be Triune” (p. 240).
Hughes proposes a model of the Trinity that does not imply divine simplicity. His model anticipates William Hasker’s view that the persons of the Trinity are consubstantial in the sense that the divine persons are all constituted by the unique divine substance, just as a statue and a pillar can be distinct objects made out of the same marble. Hughes arrives at a model much like this, according to which there are three Trinitarian persons who all have God as their substance. This relation of “ensubstancement” neither is nor implies strict identity. Unlike the identity relation, it is irreflexive, asymmetric, and non-Euclidean. Hughes even suggests that this relation “in certain ways resembles the relation holding between ‘multiple centers of consciousness’ and a human person with a divided mind.”[2] Such a model, if successful, secures divine unicity, but not divine simplicity, since there are in God three non-identical persons and thus complexity.
[1] Aquinas differentiates between identity according to reality (secundum rem) and identity according to our understanding (secundum ratione). In order to maintain both divine simplicity and the doctrine of the Trinity, Aquinas is forced to deny the logical properties of identity secundum rem. “Aquinas denies that identity secundum rem is Euclidean because (as he sees it) such a move is the only one available to block an argument from premisses knowable by natural reason (concerning God’s simplicity) to the falsity of the orthodox doctrine of the Trinity” (Hughes, Complex Theory of a Simple God, p. 238). Aquinas’ escape route is, however, untenable, since the relation Aquinas calls identity secundum rem is just the modern relation of identity, and identity is a Euclidean relation. Hughes puts the point another way: if each of two things is really the same as a third thing, those two things cannot really be different things from each other. “The moral is that Aquinas’ theory of the Trinity is logically flawed at the core” (p. 238).
[2] Christopher Hughes, “Defending the Consistency of the Doctrine of the Trinity,” in Philosophical and Theological Essays on the Trinity, ed. Thomas McCall and Michael C. Rea (Oxford: Oxford University Press, 2009), p. 313; cf. pp. 310-12.
- William Lane Craig