"'But who made God?' was the question of someone who had not yet emerged from the nursery."
Austin Farrer, Finite and infinite: a philosophical essay (Westminster: Dacre Press, 1959 ), 15.
Cf. McCabe: "what we mean by 'God' is just whatever answers the question ['Why anything instead of nothing?'']. Apart from knowing this, says Aquinas most insistently, all we can do is point, as systematically as we can, to several kinds or categories of things that the answer could not be. For one thing, whatever would answer our question could not itself be subject to the question--otherwise we are left as we are, with the same question still to answer. Whatever we mean by 'God' cannot be whatever it is that causes us to ask the question in the first place" (Herbert McCabe, O.P., "The involvement of God," God matters (London: Continuum, 2005 (1987)), 41).
Cf. Hart: "In truth, though, there could hardly be a weaker argument. To use a feeble analogy, it is rather like asserting that it is inadequate to say that light is the cause of illumination because one is then obliged to say what it is that illuminates the light, and so on ad infinitum."
"But such reasoning is also certainly not subject to the objection from infinite regress. It is not logically requisite for anyone, on observing that contingent reality must depend on absolute reality, to say then what the absolute depends on or, on asserting the participation of finite beings in infinite being, further to explain what it is that makes being to be. Other arguments are called for, as Hume knew. And only a complete failure to grasp the most basic philosophical terms of the conversation could prompt this strange inversion of logic, by which the argument from infinite regress--traditionally and correctly regarded as the most powerful objection to pure materialism--is now treated as an irrefutable argument against belief in God" (David Bentley Hart, "Believe it or not," First things (May 2010): 37-38.