Recently, I visited the new website, faithandevolution.com, which was set up by the Discovery Institute to discuss religion and evolution. While I was there, I found a review of Francis Collins’ book “The Language of God” by creationist Jonathan Wells. Although the entire review is full of error and misrepresentation, I want to focus on a few key issues.
First, the issue of ‘junk’ DNA. Collins states that this nonfunctional DNA is evidence of common ancestry, since it is more similar between closely related species and less similar between more distantly related species. Collins also notes that it is possible that some small fraction of this junk DNA has some function. Wells counters this argument by pointing to studies which show that a small fraction of junk DNA has some function:
[I]n 2006 Japanese and American researchers discovered that “a large number of nonprotein-coding genomic regions are under strong selective constraint” – meaning that they have functions, otherwise selection would not affect them. The researchers wrote: “Transposable elements are usually regarded as genomic parasites, with their fixed, often inactivated copies considered to be ‘junk DNA’… [but many such] sequences have been under purifying selection and have a significant function that contributes to host viability.” In other words, the very “decapitated and utterly defunct” transposable elements that Collins considers his best evidence are turning out not to be functionless after all.
I’m willing to grant that ‘many’ (whatever such a vague word means) transposable elements have some function, on the condition that this does not show that all junk DNA is useful. In fact, one study, in which millions of nucleotides of junk DNA were deleted, showed that this junk really is junk: All of that missing junk DNA had no effect on the organisms tested.
Further in the review, I was struck by something that Jonathan Wells said: “[How does] Collins know what a Creator would do?” I had a profound realization when I read this. How do we know what a creator would do? We don’t. The only way we could is by making certain assumptions about the creator’s nature. And this is a problem for intelligent design: Unless they openly admit to making assumptions about the creator’s nature, they can’t make any predictions. IDers want to have it both ways: If we find lots of junk DNA that points to common ancestry, they say, “How do you know a creator wouldn’t put it there?” If we find that this junk DNA has a function, then that proves intelligent design because ID predicted it. Listen to what Stephen C. Meyer said when it was discovered that some junk DNA might have a function,
It is a confirmation of a natural empirical prediction or expectation of the theory of intelligent design, and it disconfirms the neo-Darwinian hypothesis. (Source)
Now why would that be? Is Meyer assuming that the creator has to create only functional things? But that’s exactly the presumption Wells just argued against. Sorry IDers, but you can’t have it both ways. I suspect that the conflict here comes because what Meyers really thinks is that God created life, and God wouldn't be expected to create junk, would he? And yet when its convenient IDers have no problem retreating from disconfirming evidence by feigning ignorance on the nature of the designer.
Tomorrow I'll write another post on Wells' review.
2 comments:
I see 3 arguments against ID’s “junk DNA” argument: (1) some DNA we know to have no function; (2) As noted above, ID has argued both sides of this proposition; (3) If junk DNA is the most important prediction ID has ever made, why have no IDers ever lifted one of their own fingers to verify it, or to suggest specific research to verify it?
Argument #1 has not been fully developed above. ID must argue that someday a use will be found for all junk DNA. But we know at this time that some of it is pseudogenes, inactivated ERVs, and failed transposons---that is broken pieces of something that once did have a function. So ID must explain why the designer has not tossed out this known junk, This attack on ID has another advantage. These junk items are not only useless, but they closely resemble “designs” from organisms that are related as predicted by evolution. So ID’s designer not only includes useless junk, but the structure of that junk is exactly what evolution predicts.
Even creationists try to have it both ways - if there is no junk DNA, that's because God can create a perfect genome; if there is junk DNA, that's because of the Fall. ;-)
It's like I said in a previous comment - you can't make predictions if you believe an intelligence had anything to do with life on Earth unless you know what that intelligence is capable of and what its intentions/motivations are.
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