Paley's watch

Over the last few days a creationist has been commenting on the Sandwalk blog linked to from my blogroll bar. Mostly he (?) has been rude and childish, but he also made a wearily familiar argument:

John Harsh-manure
What should be the reward for misplacing one's logic or brain?
I will give you an example, that Larry can understand. So, I would like to build a doghouse. I already have all the materials and tools to speed-up the self-shiting process. I have the power and all the materials. How long would it take for evolution=accidents to build this pretty simple structure? My Italian neighbor says it would take him 45 minutes. How about the mathematically calculated shit-ific calcu-shitions?
Would 4.2 billion yours suffice or you need a new brain to evolve to think straight? Well, no shit-ist can think like that so you may need some help...hihihi

To the degree that this is coherent (and admittedly that degree is not high), this is basically the argument from design, well known from William Paley's watchmaker analogy:

In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there; I might possibly answer, that, for anything I knew to the contrary, it had lain there forever: nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place; I should hardly think of the answer I had before given, that for anything I knew, the watch might have always been there. (...) There must have existed, at some time, and at some place or other, an artificer or artificers, who formed [the watch] for the purpose which we find it actually to answer; who comprehended its construction, and designed its use. (...) Every indication of contrivance, every manifestation of design, which existed in the watch, exists in the works of nature; with the difference, on the side of nature, of being greater or more, and that in a degree which exceeds all computation.

(Update: I should mention that I copied this quotation from Wikipedia, ellipses and all, because I do not have the book.) Really the only differences are that the watch is exchanged for a doghouse and that Paley was a better writer. And in fact all creationism or "intelligent design" ultimately reduces to this argument.

The problem is, of course, that the argument is a false analogy, a fact that would have been painfully clear even when Paley advanced it (and others even before him). But while it is immediately clear to most observers that that is so, it is often less easy to articulate the precise problem, which is why I write this. There are at least two very important differences between the analogy and the structures the creationist considers it analogous to, i.e. living organisms:

1. In the case of a watch or doghouse, we know the creator, or if not the specific individual then at least we know that such creators exist as a class of beings. We know from experience that there are other humans and that they sometimes develop the desire to construct a watch or, for that matter, a doghouse, and that they have the capabilities to act on this desire. In the case of life, we do not know that such a creator exists. In fact the argument from design is meant to demonstrate the existence of the creator, making it a case of begging the question or circular reasoning. (Because, in case clarification is necessary, the analogy only becomes valid if what it is supposed to demonstrate, the existence of a creator, is smuggled into it from the start.)
2. In the case of the watch or doghouse, we know the process by which they were created by their creators. Again, this is not so for life. Depending on the superstition one is thinking of, the best suggestions for a creator's mechanism of action are somewhere between "the ways of the LORD are mysterious" and "the gods shaped some clay and breathed life into it". That is why engineering is a science and creationism is not*.

Finally, yes, if piles of wood and nails would reproduce with slightly modified offspring, and if that offspring had a higher likelihood of surviving to produce more offspring if it looked more like a doghouse, then a couple of million years would certainly result in the evolution of doghouses. Again, a failed analogy, but only because piles of wood and nails do not actually reproduce and because this specific selective pressure does not appear to exist.

Footnotes

*) Admittedly I am more generous in this regard than others. I can imagine intelligent design with an unspecified, mysterious creator to be a reasonable scientific conclusion under certain circumstances. Imagine we found an extraterrestrial planet with complex life where there was no fossil record until 500,000 years ago, no phylogenetic or biogeographic structure to the organisms, and population genetics indicate that all organisms apparently started to evolve** around 500,000 years ago with remarkable genetic uniformity but no deleterious alleles. Under those circumstances, terraforming and subsequent bioengineering of life forms by an unknown extraterrestrial intelligence would constitute a valid preliminary scientific conclusion. Clearly that extraterrestrial intelligence would still have been the product of evolution itself, skyhooks vs. cranes and all that, but that is not the point here.

**) Of course, once you have things that mutate and reproduce evolution is not a question of evidence any more but one of logical necessity, but that is not what creationists are really concerned about.