Sunday, April 8, 2007

Hallelujah! Rocks are Designed by God!

Unlike many creationists I don't consider engineers to be scientists, so I don't always have a lot to contribute to the science/pseudoscience discussion. But every so often, the ID/Creationists stray over the line into my territory. Like when a doctor starts saying silly things about both science and engineering.

About a month or so back, a new star appeared in the Intelligent Design firmament: Michael Egnor, professor of neurosurgery at SUNY, and with an impressive record as a practicing physician. It started (more or less) with his post at the Discovery Institute blog on why evolution is useless in medical practice, which begat a flurry of rebuttals from medical bloggers like Orac. Additional fun and games ensued as Egnor replied to his critics, or issued fresh pronouncements, resulting in a blizzard of blog posts that I won't even try to select from (Google Is Your Friend). Along the way, Orac issued Dr. Egnor a challenge (summarized here):
  1. Explain, specifically, how the design inference is "of great value" in medicine.
  2. Explain, specifically, how the design inference has been of "enormous help in scientific research in general and medical research."
This week, Dr. Egnor replied to Orac's challenge. The gist of his reply is that Watson and Crick's discovery of the structure of DNA is an example of "reverse engineering":
To untangle the structure of DNA, they inferred design, not chance. They reversed-engineered DNA. They collected physical data about the structure of DNA (X-ray diffraction studies, Chargaff’s rules, the physical chemistry of nucleotides, etc), and then they designed a model of the molecule to understand its structure and function.
Egnor seems to base much of his argument on the following Wikipedia entry (bolding is Egnor's, red text is mine):
Reverse engineering... is the process of discovering the technological principles of a device or object or system through analysis of its structure, function and operation…Reverse engineering is essentially science, using the scientific method. Sciences such as biology and physics can be seen as reverse engineering of biological 'machines' and the physical world respectively.
The Wikipedia entry has since been edited to remove the text in red -- a change with which I heartily agree. Yes, there is a conceptual similarity between the work of reverse engineers and that of research scientists. Both groups start with a "black box" (the externally-observed behaviour of their study system), draw inferences about what might make it behave that way, and then find methods of literally or metaphorically "looking inside the box" to elucidate its inner workings. But, really, the resemblance ends there. To apply the term "reverse engineering" to both activities is to illegitimately impose a concrete term from the one domain on to the other, on the basis of an abstraction properly seen as underlying both.

However, it gets worse.
Apparently, doing this kind of "reverse engineering" of the natural world implicitly invokes the concept of "design" (presumably by You Know Who):
Much of modern biological research, and most research in molecular biology, is reverse engineering. Some scientists infer design explicitly. Some use the design inference implicitly, even if they disagree with its philosophical implications. We can’t do modern biology, at least at the molecular level, without using reverse engineering, which is the inference to design.[emphasis mine]
This simply compounds misapplied terminology with confused logic. What on earth does Egnor mean here by "inference to design"? In reverse engineering, we know that the system under study is designed and built by humans -- it's not an inference, it's part of the background knowledge we start with. (As an aside, that piece information is often useful in the reverse engineering process: knowledge of human psychology and standard practices can inform our investigation into the study system. This stands in contrast to IDists, who claim that one can study design while knowing nothing about the nature of the designer(s)[1]). But in the case of natural-world research science, we don't know in advance that the object of study was designed -- that is the very "inference" the IDists want us to make. Egnor's attempt to impose "design inferences" on his historical example seems to rest on Watson and Crick's own words concerning the relation between the structure and function of DNA:
It is probably impossible to build this structure with a ribose sugar in place of the deoxyribose, as the extra oxygen atom would make too close a van der Waals contact.
It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.
As far as I can see, this is no more than to say that, because the molecule functions in a certain observed way, it must have a structure that allows for it to behave that way -- which says nothing about it having been designed (or not) by a concious agent.

But lets do a simple case study using Egnor's reasoning (insofar as I can decipher it):

Consider a rock -- a moderate-sized, hold-in-your-hand, ordinary rock. Doing an initial black-box analysis, I observe that it has a certain heft to it -- with some simple apparatus I could measure its volume and mass, and calculate its average density. What else? I tap it with a hammer, and observe that it doesn't shatter. From this I make an inference about the internal structure of my rock: it's not hollow (this cannot be taken for granted, as some rocks are). To confirm my hypothesis, I hit it really hard and smash it open. Sure enough, it's solid all the way through.

Now, does this internal part serve any function? Sure it does: it supports the outside, and contributes to the mass. In other words, it enables the "black box" behaviour, just as much as the specific constituents of DNA enable its observed behaviour. And if I'm entitled to make the "design inference" in the one case, I'm entitled to make it in the other. So I conclude: my rock is designed by an intelligent entity.

It should be noted, of course, that this is entirely consistent with traditional Christian theology, which holds that everything in heaven and earth is in some sense under the sovereign supervision of God. But for some reason, the IDists (despite almost all being Christians of some stripe) only think that some things are designed. Maybe they're heretics; I don't know :-).

1. See, for example: page 197 of Michael Behe Darwin's Black Box, Simon & Schuster 1996

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