Luke Muehlhauser just put up an interview transcript under the heading What I Think of the New Atheists, where among other things he brings up the complaint that “who made God?” is a bad response to theistic arguments, because things cited in explanations don’t themselves need to be explanations for the explanation to be a good one. In the past, Luke has devoted a whole post to this. In a sense I agree, but I think Luke’s hammering of this point is misguided because in the context of actual debates about the existence of God, it’s a perfectly good point.
I think most people who’ve gotten into debates with believers have run into the following pattern: the believer demands an explanation for X. If the atheist can’t provide one, this is proof that God exists and that atheism, not theism, is the irrational, faith-based belief. But if the atheist rattles off a known scientific explanation, the believer then demands an explanation for some thing that is cited in the scientific explanation, and the process repeats until the atheist admits lacking an explanation for something, which is then proof that God exists and that atheism, not theism, is the irrational, faith-based belief.
Rarely will this strategy be explicit, though I did once read a defense of intelligent design that argued that intelligent design will be a successful scientific movement in the long run because no matter how many things evolutionists explain, there will always be something else to interpret as intelligently designed. More often, the conversation will proceed more or less as I just described, so that the strategy, while not initially explicit, quickly becomes obvious. And occasionally, you will meet someone like William Lane Craig, who at first seems too smart to make such mistakes but falls into them eventually. I gave a number of examples of this in my comments on Craig’s presentation of the fine-tuning argument, as in his demands to know where the multiverse, if it exists, comes from, and his claim that if allegedly fine-tuned features of the universe are required by some physical laws, then we’d have to explain those physical laws.
By the way, making the cosmological argument intuitively appealing to the uninitiated generally requires a barrage of “why” questions. Of course if the believer is smart, he’ll have an ready-made reason why the “why” barrage doesn’t apply to God, but lots of the believers who go around picking arguments with atheists don’t seem to understand the need for that. Even when they do have an official answer as to “why doesn’t God need a cause/explanation,” believers will often press atheists with silly questions like “why is there something rather than nothing?” which turn out to be irrelevant on the believer’s official view.
It’s often said that no theist has ever been stupid enough to say things like “everything requires an explanation” or “everything has a cause.” Maybe no theist has ever said either of those things explicitly, but it’s hard to know how else to interpret many demands for explanation made in God debates. Even if you look at William Lane Craig, in his discussions of cosmological arguments he denies those things, but if all you knew about him were his discussions of the teleological argument you’d have reason to suspect he believes them. His teleological argument actually starts out with an undefended demand for explanation, and the closest he comes to defending that demand as far as I’ve seen is his claim that being a brute fact (something that has no explanation) is the same as something being the way it is by chance, but that’s an obvious mistake.
In short, the “who made God?” line would be a bad response to a hypothetical super-apologist who never used confused rhetoric about explanation. But it’s a perfectly reasonable thing to say in the context of most debates about the need for God as an explanation that most atheists have ever been in, and it’s a perfectly reasonable thing to say when generalizing about the arguments used in such debates.