Thomas Merton, Journals, vol. 5, p. 183, entry of 25 December 1964:
St Maximus [the Confessor] says that he who "has sanctified his senses by looking with purity at all things" becomes like God. This is, I think, what the Zen masters tried to do. A letter from John Wu spoke of running into [D. T.] Suzuki at Honolulu last summer. They talked of my meeting with him in New York. Suzuki was going to ask me a question but didn't. "If God created the world, who created the Creator?' A good koan.
Nice try, Tom, but surely that old chestnut, sophomoric as it is, is not a good koan. Or at least it is not a good koan for one who is intellectually sophisticated. And this for the reason that it is easily 'solved.' A koan is an intellectual knot that cannot be untied by discursive means, by remaining on the plane of ordinary mind; a koan is a sort of mental bind or cramp the resolute wrangling with which is supposed, on an auspicious occasion, to precipitate a break-through to non-dual awareness.
God is the Absolute. The Absolute, by its very nature, is not possibly such as to be relativized by anything external to it. In particular, qua absolute, God does not depend on anything else for his existence or nature or modal status. It follows straightaway that he cannot have a cause. If to create is to cause to exist, then God quite obviously cannot have a creator. Since God cannot have a creator, one cannot sensibly ask: Who or what created God? Or at least one cannot ask this question in expectation of an answer that cites some entity other than God.
Classically, God is said to be causa sui. This is is to be read privatively, not positively. Or so I maintain. It means that God is not caused by another. It does not mean that God causes himself to exist. Nothing can cause itself to exist. If something could cause itself to exist, then it would have already (logically speaking) to exist in order to bring itself into existence. Which is absurd.
Equivalently, God is ens necessarium. In my book, that means that he is THE, not A, necessary being. He enjoys a unique mode of necessity unlike 'ordinary' necessary beings such as the set of natural numbers. Arguably, there is a nondenumerable infinity of necessary beings; but there is only one necessary being that has its necessity from itself (i.e., not from another) and this all men call God.
Accordingly, to ask who created God is to presuppose that God is a contingent being. Given that the presupposition is false, the question can be dismissed as predicated on misunderstanding. This is why the question is not a good koan. It is easily solved or dissolved on the discursive plane. Nothing counts as a koan unless it is insoluble on the discursive plane.
"But if God doesn't need a cause, why does the world need a cause?" The short answer is: because the world is contingent. We must regress from the world to God, but then that at God we must stop. No vicious infinite regress.
A Much Better Christian Koan: The Riddle of Divine Simplicity
I have just demonstrated to my own satisfaction that the old chestnut from John Stuart Mill is no good as a koan. But suppose we dig deeper. It is not wrong to unpack the divine necessity by saying that God exists in all metaphysically possible worlds. But it is superficial. For this is true of all necessary beings. What is the ground of the divine necessity?
I would argue that the divine necessity rests on the divine simplicity according to which there are no real distinctions in God. See my Stanford Encyclopedia of Philosophy entry for details. This implies, among other things, that God does not instantiate his attributes; rather he is (identical to) them. God has omniscience by being omniscience, for example. As St Augustine says, "God is what he has." The same goes for the other attributes as well. If you think about it you will soon realize that the logical upshot is that every attribute is identical to every other one.
God's being the Absolute implies that he is unique, but uniquely so. God is uniquely unique: he is not one of a kind, but so radically One that he transcends the distinction between kind and instance. God is not the unique instance of the divine kind: he is (identically!) his kind. That is why I say that God is uniquely unique: he is unique in his mode of uniqueness.
But surely, or rather arguably, this makes no discursive sense which is why very astute philosophical theologians such as A. Plantinga reject the simplicity doctrine. although he doesn't put it quite like that. (See his animadversions in Does God Have a Nature?) Almost all evangelical Christians follow him (or at least agree with him) on this. (Dolezal is an exception.) How could anything be identical to its attributes? To put it negatively, how could anything be such that there is no distinction between it and its attributes?
We are beginning to bite into a real koan: a problem that arises and its formulable on the discursive place, but is insoluble on the discursive plane.
On the one hand, God as absolute must be ontologically simple. No God worth his salt could be a being among beings, pace my evangelical friends such as Dale Tuggy. On the other hand, we cannot understand how anything could be ontologically simple. There are no good solutions to this within the discursive framework. There are solutions, of course, and dogmatic heads will plump for this one or that one all the while contradicting each other. But I claim that there is no ultimately satisfactory solution to the problem. Note that this is also a problem for the divine necessity since it rest on the divine simplicity.
My suggestion, then, is that here we have a candidate for a good koan within Christian metaphysics.
The Ultimate Christian Koan
This, I have long held, is the crucified God-Man. It is arguably absurd (logically contradictory) as Kiekegaard held that God become a man while remaining God. It is the height of absurdity that this God-Man, the most perfect of all men, should die the worst death the brutal Romans could devise, crucifixion.
If to accept this is to accept the crucifixion of the intellect, then here we have the ultimate Christian koan.