Luke (over at Common Sense Atheism) after writing a couple of posts attempting to refute Richard Dawkins (which I responded to here and here) has now written a post trying to refute a very similar rhetorical atheistic question. When a theist tries to argue for God he will often point to things (like the human eye or bacterial flagellum) which appear to be designed. Atheists often reply to ths in the following way: "Yeah, it could be designed, but then who designed the designer? Was God designed by a SuperGod™? Was SuperGod™ designed by an UltraGod™?" Here are some of Luke's thoughts on that reply:
“God did it” is generally a terrible, horrible, no good, very bad “explanation” for complexity or, well, pretty much anything. “God did it” does generally fail as an explanation.
But it does not fail merely because the theist has no explanation for his explanation (God)...
Let us ask ourselves what would happen if we required that a successful explanation must itself be explained.
This would lead immediately to an infinite regress of explanations. We would need to have an explanation of the explanation, and an explanation of the explanation of the explanation, and an explanation of the explanation of the explanation of the explanation… on into infinity. And thus, we would never be able to explain anything.
Moreover, this is not how science works. Examples from physics are the most obvious. In order to explain certain quantum phenomena, scientists have posited the existence of dozens of invisible particles with very particular properties that yield predictable results. These have been some of the most successful explanations in all of scientific history, yielding the most accurate experimental results we have ever achieved. And yet we have no explanations whatsoever for the particles that we have offered as explanations for the quantum phenomena.
I'm basically in agreement with Luke: I do not believe that people have to explain explanations. However, I think that some atheists, when they ask the question "Who designed the designer?" have something a bit different in mind that Luke isn't understanding. When someone asks "Who designed the designer?" what they have in mind is that the theist is getting to postulate a highly specific and complex entity with no justification whatsoever. The argument from design itself seeks to take some highly specific and complex entity (the eye, the flagellum, etc.) and explain it with God. But if the theist is allowed to postulate a highly specific and complex entity with no justification, then why can't the atheist simply postulate an eye or a wing without any justification or explanation?
Here's a good analogy to illuminate this further: Suppose that I win the lottery. Luke hears about this, and decides that he will explain my winning not as the result of chance, but as a result of conspiracy. He comes up with a theory about how I could have cheated and rigged the lottery in my favor. His theory explains nothing more than the theory that I won the lottery by chance. Furthermore, the initial probability or a priori probability that his theory is correct can be calculated, and the odds of it happening are one in a billion. The theory that I won the lottery by chance, however, has an a priori probability of one in a million. Now the question is: which theory should we prefer? Obviously, the chance hypothesis, because it is more probable. But let me ask this question: what if the conspiracy hypothesis and the chance hypothesis had the same a priori probability of being true (one in a million)? And what if Luke started a new blog, Common Sense Lottery Conspiracy, in which he tried to convince people of his conspiracy theory on the grounds that it was too improbable that I had won by chance?
Now suppose PZ Myers reads Luke's blog and comments: "Hey, if you get to postulate a highly improbable theory to account for Ryan's winnings, then why not just propose that he won by chance? Your argument gets us nowhere because the argument from improbability does not reveal to us why one theory should be preferred over another."
This analogy, I think, mirrors the situation with the design argument. Let me tell you what I mean: Most of us are familiar with the fine-tuning argument, that is, the argument that life cannot exist in the universe unless the physical constants have very specific values (out of all possible values, the majority of which will not support life) which are very improbable, and God explains that improbability: God intelligently designed the universe so it would allow life to exist.
For the sake of argument, let's pretend like it is has been conclusively proven that are form of life is the only kind that can exist, that our universe is the only one that exists, that only one extremely specific and improbable set of physical constants allows life even though many sets are possible (as far as we know). Let's suppose that the probability of a fine tuned universe occuring by chance comes out to 1 in 10^100. Now, would it be OK to infer God as the explanation of this phenomenon?
No. The chance explanation of the fine-tuning has an initial probability of 1 in 10^100, as we've said. But what is the initial probability of the existence of God? I'm inclined to think that it is very, very, very low. And if I am right then the fine-tuning argument for God cannot work because we cannot know whether or not the a priori probability of God is better than the a priori probability of a fine tuned universe coming about by chance, and so the argument from design cannot work. Here's an excerpt from an unpublished essay I've written which explains this:
"Consider the number of possible minds. Although I do not know the total number of possible minds, I think we can safely say that it is incredible high, based on the billions of unique human and animal minds that have existed and the possible minds of gods, spirits, and fictional characters that man has conceived of.
"Now, if we are considering positing a single spiritual mind as an inexplicable brute fact, what are the odds that this mind would be anything like the mind of God? I suggest that we apply the principle of indifference and assign each possible mind the same likelihood of existing uncaused. When we do this, it seems that the probability of God’s existence would be much less than one in ten billion (after all, there are six billion unique human minds in existence today, plus the minds of chimpanzees, gorillas, other intelligent animals, and fictional characters and invented gods that occupy the space of possible minds).
"There is another, more important worry: would this random, uncaused mind even be coherent and intelligent? I am very skeptical of the notion that it would be. I do not believe that coherency and/or intelligence is a feature of most possible minds. After all, the minds we observe around us are a very small subset of the total number of possible minds. Human and animal minds arise from brains that are non-randomly constructed from genetic material which has been fashioned by natural selection, which has surely tended to eliminate lack of intelligence and lack of coherency: the mentally disabled have a very low chance of passing on their genes. If you can imagine a mind that would result from a randomly constructed brain, you can understand my doubts about whether this mind would be coherent and intelligent. Of course, that is not an exact analogy, for a spiritual mind does not arise from a physical brain by definition. However, if you can imagine the mind that would result from a randomly constructed brain, if the mind in question was generated by a material medium like the brain, then my thought experiment should illustrate the same point.This leads us directly to the conclusion that the existence of God is a priori very improbable if it is admitted that God is a contingent and highly complex being."
Now, one could try to get rid of the improbability of God by defining him as necessary (I've talked a bit about that here). But then if you can simply assert that God is necessary or define him as necessary then why couldn't someone say the same thing about a life friendly universe?