Friday, September 14, 2007


Egnor the 'Baffoon'

Unsatisfied with the damage he first did to one foot, Dr. Michael Egnor has taken careful aim at the other and loosed another barrage. Demonstrating an utter lack of comprehension of the saw that one should 'leave bad enough alone,' Egnor has compounded his previous error by again taking on Jeffrey Shallit at Recursivity (even committing typos in giving the title of Dr. Shallit's previous post). And, again, Dr. Shallit needs no help from me. But there is one attempted point of Egnor's that I think is worth commenting on: his illicit use of analogy.

As I have argued before:

Arguments by analogy or metaphor, when used correctly, are both valid and illuminating. For example, a crucial argument made by Charles Darwin in support of evolution was the analogy between 'artificial selection' by breeders and 'natural selection' by the environment. But such arguments must be internally valid and consistent, as well as carefully crafted so that the analogy truly corresponds to the points purportedly being made.
Egnor thinks he has struck some sort of unanswerable blow by blovating:

If the scientific discovery of a 'blueprint' would justify the design inference, then why is it unreasonable to infer that the genetic code was designed?
Because the genetic code is not a "blueprint," doctor, that's why. Blueprints (which, in the age of Computer Aided Design, have trod the path of the dodo) are drawings made by known agents that consist of manufactured products called "paper" and "ink" with a known source that have a known conscious purpose in a peculiarly human activity called "construction."

All you are missing to make your analogy perfect, doctor, is everything. We know, for example, that genes are "manufactured" by the ordinary processes of chemistry within the bodies of living things, the vast majority of which have, as far as we can tell, no conscious purpose at all, much less a conscious purpose to manufacture DNA. In other words, unlike blueprints, the production of DNA operates by natural law, independent of conscious intent and without conscious purpose on the part of the producer. Blueprints, unlike DNA, have never been known to be spontaneously produced by the chemistry of, say, bacteria. Nothing supports the appropriateness of the attempted analogy, except Dr. Egnor's preconceived biases.

To claim that DNA is purposefully designed for some conscious purpose by analogy to known human artifacts is simply to beg the question on the issue Egnor is trying to prove -- the existence of a designer. But I've been through that before too.

Oh, but wait ... that's all Intelligent Design Creationists have going for them in the first place ... smoke and mirrors ... isn't it? Never mind ...

I've struggled to find a good analogy for DNA. A 'blueprint' is clearly wrong, a 'recipe' is better, and a 'book of recipes' better still.

However my latest thoughts are 'a pattern library for a foundry'. The cell is, of course, the working foundry. The benefit of this analogy is that each section of DNA is a 'shape' on a shelf, and when a order triggers a requirement for a new DNA element, the shapes are used to make an anti shape copy pattern, which then goes into the foundry to be 'cast' into the relevant gene product. You can even have further analogies of pattern controlled/built milling and drilling processes to snip out unwanted bits from the copy product before it is cast (although this may be overloading the analogy).

You could extend the analogy further to include developmental expression of genes (start up foundry activities), methylation (shelves of patterns being marked as out of use), and the idea of the foundary library having all the necessary patterns to make a new foundry....

A million miles away from a mere blueprint.
My expertise on DNA is, to put it mildly, less than profound but that sounds much better than comparing it to a blueprint. Wilkins keeps threatening to tell us why the concept of "information" is inapplicable to DNA and life in general. When he does, perhaps we can determine the best of all possible analogies.
When I think of a blueprint, I think of something which has some resemblance to the intended product. It is a little image of the result. A recipe, on the other hand, has no resemblance to the product. But one feature of DNA which is forgotten in any of these analogies is that there is no "final product" of DNA, for DNA keeps on serving its function in the production of proteins even in the adult. It is a vital part of the living thing, not something which is useful only at the beginning.

But I should put a cautionary tag on this comment, for I am not a scientist.
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