Saturday, December 3, 2011

David Marshall: "Some Riddles of Evolution"

Today, I’ll blog about Chapter 4 of David Marshall’s The Truth Behind the New Atheism. This chapter is entitled “Some Riddles of Evolution”. Whereas, in Chapter 3, Marshall expresses some openness to evolution, in Chapter 4 he appears to question it, at least until the last few pages.

I’ll say before I write about Marshall’s questions that I do not know much about evolution, for science is not my field, and so I welcome correction. I will not, however, publish any comments that call me or anybody else stupid.

Now, on to Marshall. Several of his questions about evolution resemble the objections to it that I heard when I was growing up. First, Marshall expresses skepticism that something as complex as DNA (which was likely a prerequisite for the first life) could have emerged by chance. Second, in response to the evolutionist point that viruses and bacteria mutate to become resistant, he says that “I have seen none claim that in the relatively well-known recent history of these pathogens, any have in fact evolved into something strikingly new” (page 70). That reminds me of the the strands of creationism that are open to micro-evolution but not to macro-evolution. Third, Marshall says that helpful mutations (which are the basis of evolution) are rare. And fourth, he asks why we don’t see too many helpful mutations nowadays. His fourth point called to my mind a question that a relative of mine used to ask: “If evolution is true, why aren’t we still evolving?”

To his credit, Marshall interacts with new atheist arguments against Intelligent Design. ID advocate Michael Behe has argued that the eye is a problem for Darwinism, for the eye needs certain parts for it to work, and Behe cannot imagine animals surviving in a stage where they would have an eye without one of its important parts. The implication, for Behe, is probably that it makes more sense to say that God created the eye, than to say that the eye evolved through stages, some of which lacked the parts that were necessary for the eye to function. Richard Dawkins’ response is that even a deficient eye can work on some level, and so animals can survive with that. But Marshall retorts on page 74: “The question isn’t what happens when half the complete structure is missing. The question is what happens when half its parts are missing. What good is an eye without an optic nerve? Or an optic nerve that connects only halfway?”

Marshall also points out what he believes is a contradiction in Dawkins’ approach to Intelligent Design. Dawkins acknowledges that “genuinely irreducible complexity…would wreck Darwin’s theory,” and he quotes Darwin as saying that “If it could be demonstrated that any complex organ existed which could not possible have been formed by numerous, successive, slight modifications, my theory would absolutely break down.” And yet, Dawkins also says that “Searching for particular examples of irreducible complexity is a fundamentally unscientific way to proceed: a special case of argument from present ignorance.” According to Marshall, Dawkins challenges skeptics about evolution to look for irreducibly complex organs, and then he says that such a search would be unscientific!

Notwithstanding his questions, Marshall does appear to admit that there is evolution, for he states on page 77: “Species do not…change as gradually as Darwin anticipated—-something dramatically new appears, then remains much the same for long periods.” Marshall also asks if nature itself could be a design program, which may mean that God could have set natural selection into motion to bring about design.

A prominent theme in this chapter is how evolutionists have sought to censor and stigmatize any critique of evolution, even when it has been made by someone (say) with a doctorate from Cambridge. Marshall speaks favorably of an interaction between ID proponent Behe and evolutionist Kenneth Miller: “A better way to decide whether [irreducible complexity] can be disposed of at all (say, by positing intermediate uses for new organisms) is to read both sides of the debate” (page 75). And yet, at the end of the chapter, Marshall expresses discomfort with voices from both sides: “Both sides discredit themselves at times by forcing all science into a theological cage that depends on what great Christians thousands of years ago already saw as a naive reading of Genesis, and some atheists by ‘No Bleevurz Aloud’-type postings on the doorpost of Le Club Scientifique” (pages 76-77).

I won’t offer a thorough critique of this chapter, but I’ll say this: Evolution still does take place, as new species are developing. But I think that Marshall raises a good question when he asks why we have not seen it that much with humans. An evolutionist answer that I have read is that we survive as we are and thus are able to pass on our genes, and so the point here may be that we do not need to evolve, or that we haven’t been weeded out by natural selection (see my post on Jerry Coyne here). But that explanation does not satisfy me, for why can’t we survive and have helpful mutations? I doubt that helpful mutations came only on an “as needed” basis in the history of evolution, for fish were surviving quite well, but some of them still had a mutation that led them on the path to becoming something else. Why don’t we see this with humans, that often?

On the whole issue of whether the gaps in evolution should encourage scientists to throw in the towel and say “God did it”, or to have faith that there is a natural explanation out there and to search rigorously for it, I’d say that they should feel free to look for a natural explanation, and I question whether theists should root their belief in God so heavily in the existence of gaps.

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