Friday, February 13, 2009

 

Mythbusters


In the category of excruciating irony, we have this title for a story by Pat Robertson's Christian Broadcasting Network: "On Darwin Day, Myths Parade as Fact." It may be ironic but it is certainly true because Pat's propagandists proceed to march out a whole phalanx of them delivered by, who else, that coterie of Discoveryless Institute talking ... um ... heads, Jonathan Wells, Stephen Meyer and John West.

About the only thing said in the piece that has any truth to it at all is that Darwin didn't present any evidence in the Origin for natural selection. The reason, of course, is that he didn't really need to. As the late Mike Majerus pointed out, natural selection is a logical result stemming from four observations, that had already been made as of Darwin's time, and three deductions from those observations:

Observation 1: Organisms produce far more offspring than give rise to mature individuals.

Observation 2: Yet, population sizes remain more or less constant.

Deduction 1: Therefore, there must be a high rate of mortality.

Observation 3: The individuals in a species show variation.

Deduction 2: Therefore, some variants will succeed better than others, and those with beneficial characteristics will be naturally selected to produce the next generation.

Observation 4: There is a hereditary resemblance between parents and offspring.

Deduction 3: Therefore, beneficial traits will be passed to future generations.

The observations were uncontroversial and the deductions follow from them in such a way that that virtually every creationist today will tell you that they accept "microevolution" by selection. Of course they then turn around and deny it again in the same breath, as in the concerted attack on Majerus' Peppered Moths work, but we're talking about creationists and can't expect even minimal consistency.

Also, since Darwin's time, we have had direct empiric evidence of natural selection at work, in the Peppered Moths and the studies of Darwin's finches in the Galapagos, among many others, so the implication that this is a grounds for rejecting evolution is, under the most charitable interpretation, disingenuous.

Of course, Darwin presented massive evidence for "macroevolution," more correctly called "common descent." So much so that, within a mere twenty years, virtually the entire scientific community had accepted the fact of evolution -- an amazing achievement -- though only a small minority of them had adopted Darwin's explanation of why and how it had come about. So, when Wells says:

"The myth is that Darwin provided all kinds of evidence for his theory in 'The Origin of Species.' Actually he didn't provide any at all or just about none at all," he said.

... he is simply lying through his teeth, either about Darwin's work or his expertise in the field. But beyond consistency, creationists, particularly the professional ones like Wells, also lack any sense of shame and they will spare no effort to mislead the flock.

Another myth peddled by this trio is from "scientist" Stephen Meyer (he's a philosopher/historian):

He makes a scientific argument that, "What we know from experience, our uniform and repeated experience which is the basis of all scientific reasoning is that those forms of technology and information technology, and informational coding, invariably arise from one and only one type of cause," Meyer said.

That is not a "scientific" argument, it's an attempt at an analogy. In fact, it is just William Paley's famous "watch analogy" posed in modern gabblespeak. Now, analogy can be part of a scientific argument -- Darwin's analogy of artificial breeding to natural selection is a good example -- but to qualify as a valid argument, it must first compare apples to apples. Both Hume and Kant had demolished the "analogy" of human technology to living organisms well before Paley wrote of it. And to make an analogy a scientific argument, it has to be empirically testable -- you have to be able to test if the analogy holds. In Darwin's case, you can test if nature acts similar to and gets similar results as breeders, since we know the means and motives of breeders. In ID's case, though, they refuse to pose the means of "design" or the motives of the "Designer." Even if we skip the obfuscation, and assume the "Designer" is God, there is nothing that God can't do and, as religionists are wont to say, his ways are mysterious. In the end, the ID formulation isn't even an analogy to human technology, since humans can't do what God can. It's simply pointing at things and saying "that sure looks designed to me!"

Then they trot out the business about the "tree of life" that has already been hashed out at length.

There is one other thing that's said in the article that is true:

Darwin is more widely accepted than ever, especially among scientists. But there are a growing number of critics.

It's just not true in the way they meant it. The theory of evolution (which is not coextensive with "Darwin") is certainly more widely accepted among scientists than ever. That means, however, that the supposedly "growing number of critics" can't be coming from the ranks of scientists.

In effect, they are admitting that ID is not science and its promoters are not acting as scientists when they foist it on a more-or-less unsuspecting public.

They got that part right.
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Comments:
I'm a little confused over your logical train of statements. Maybe I'm not reading it right, but I don't see how Deduction 2 follows from Observations 1, 2 and 3 and Deduction 1. Why can't the mortality be the same over all the variants? It seems to me that you need the statement that these different variations would show differential success before you come to that particular deduction, not as part of it.
 
Dave S. said...

I was the Anonymous in the previous post.

Sorry.
 
This was Majerus' formulation of it but, as I understand it, the logic of it is that, in a situation of high mortality, which we know is not completely random (there was much discussion already of the value of adaptation to survival), any variation in those adaptations must have some effect on survival. If, as Paley appealed to, the horse survives by being swift, the lion strong and brave, the eagle far-sighted, etc., any variation in those attributes would necessitate that some members of those species would be more swift, strong, brave, far-sighted, etc. than others and, therefore, would tend to survive better.
 
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