“Nicholas of Cusa (1401-1464), for instance, spoke of God as the non aliud: the “not other” or “not something else.” For the Neoplatonist Plotinus (c. 204-270), the divine is that which is no particular thing, or even “no-thing.” The same is true for Christians such as John Scotus Eriugena (c. 815-c. 877) or Meister Eckhart (c. 1260-c. 1327). Angelus Silesius, precisely in order to affirm that God is the omnipotent creator of all things, described God as “ein lauter Nichts”—“a pure nothingness”—and even (a touch of neologistic panache here) “ein Übernichts.” If this all sounds either perilously blasphemous or preciously paradoxical, this is because language of this sort is meant to give us pause, or even offense, in order to remind us as forcefully as possible that, as the great Muslim philosopher Mulla Sadra (c. 1572-1640) insisted, God is not to be found within the realm of beings, for he is the being of all realms. Or, as the Anglican E.L. Mascall put it, God is not “just one item, albeit the supreme one, in a class of beings” but is rather “the source from which their being is derived.””
David Bentley Hart, The Experience of God: Being, Bliss, Consciousness
I’m sympathetic more and more to understanding God as unpronounceable, as YAHWEH. The more imaginatively and humbly we do so, I think, the more we’ll see that the line dividing atheism and theism is thinner than we imagined.