Gregory of Nyssa and quantum physics (about which I know almost nothing) agree: the rational mind cannot fully grasp the nature of light.
William Desmond might say that it is “overdetermined:” the problem is not that light manifests too little to our souls (mind, sense perception, imagination), but rather that it manifests too much. We cannot stare directly at the sun. Light is both wave and particle at the same time (which makes little sense rationally).
This “overdeterminedness,” Gregory argues, characterizes the Christian God who manifests himself (“godself” if you like) by revelation and who is apprehended by faith.
In Gregory’s words, in the context of his rainbow analogy for the Trinity,
… for just as in the case of things which appear to our eyes experience seems better than a theory of causation, so too in the case of dogmas which transcend our comprehension faith is better than apprehension through processes of reasoning, for faith teaches us to understand that which is separated in person [in the three persons of the Trinity], but at the same time united in substance. – St. Gregory of Nyssa, Epistula XXXVIII, quoted in Adrian Pabst, Metaphysics 71.
What is the relationship between nature and grace, between philosophy and theology, between reason and faith? Here we find a clue: faith apprehends that which overwhelms and transcends reason. Against virtually all modern thought beginning with late medieval nominalism, faith is more than reason, not less. Which is what John Milbank is trying to get at with his language of “intensities.”
Question: how does Desmond‘s “overdeterminedness” differ from Marion’s “saturated phenomenon?”