DEBUNKING ID

There's a nice little piece by a biologist in the New Yorker. Here are some highlights:

MASTER PLANNED
by H. ALLEN ORR
Why intelligent design isn’t.
Issue of 2005-05-30
Posted 2005-05-23


But biologists have shown that direct paths to irreducible complexity are possible, too. Suppose a part gets added to a system merely because the part improves the system’s performance; the part is not, at this stage, essential for function. But, because subsequent evolution builds on this addition, a part that was at first just advantageous might become essential. As this process is repeated through evolutionary time, more and more parts that were once merely beneficial become necessary. This idea was first set forth by H. J. Muller, the Nobel Prize-winning geneticist, in 1939, but it’s a familiar process in the development of human technologies. We add new parts like global-positioning systems to cars not because they’re necessary but because they’re nice. But no one would be surprised if, in fifty years, computers that rely on G.P.S. actually drove our cars. At that point, G.P.S. would no longer be an attractive option; it would be an essential piece of automotive technology. It’s important to see that this process is thoroughly Darwinian: each change might well be small and each represents an improvement.

Each gene in an organism’s genome encodes a particular protein. Occasionally, the stretch of DNA that makes up a particular gene will get accidentally copied, yielding a genome that includes two versions of the gene. Over many generations, one version of the gene will often keep its original function while the other one slowly changes by mutation and natural selection, picking up a new, though usually related, function. This process of “gene duplication” has given rise to entire families of proteins that have similar functions; they often act in the same biochemical pathway or sit in the same cellular structure. There’s no doubt that gene duplication plays an extremely important role in the evolution of biological complexity.


It’s true that when you confront biologists with a particular complex structure like the flagellum they sometimes have a hard time saying which part appeared before which other parts. But then it can be hard, with any complex historical process, to reconstruct the exact order in which events occurred, especially when, as in evolution, the addition of new parts encourages the modification of old ones. When you’re looking at a bustling urban street, for example, you probably can’t tell which shop went into business first. This is partly because many businesses now depend on each other and partly because new shops trigger changes in old ones (the new sushi place draws twenty-somethings who demand wireless Internet at the café next door). But it would be a little rash to conclude that all the shops must have begun business on the same day or that some Unseen Urban Planner had carefully determined just which business went where.
The most serious problem in Dembski’s account involves specified complexity. Organisms aren’t trying to match any “independently given pattern”: evolution has no goal, and the history of life isn’t trying to get anywhere. If building a sophisticated structure like an eye increases the number of children produced, evolution may well build an eye. But if destroying a sophisticated structure like the eye increases the number of children produced, evolution will just as happily destroy the eye. Species of fish and crustaceans that have moved into the total darkness of caves, where eyes are both unnecessary and costly, often have degenerate eyes, or eyes that begin to form only to be covered by skin—crazy contraptions that no intelligent agent would design. Despite all the loose talk about design and machines, organisms aren’t striving to realize some engineer’s blueprint; they’re striving (if they can be said to strive at all) only to have more offspring than the next fellow.
Another problem with Dembski’s arguments concerns the N.F.L. theorems. Recent work shows that these theorems don’t hold in the case of co-evolution, when two or more species evolve in response to one another. And most evolution is surely co-evolution. Organisms do not spend most of their time adapting to rocks; they are perpetually challenged by, and adapting to, a rapidly changing suite of viruses, parasites, predators, and prey. A theorem that doesn’t apply to these situations is a theorem whose relevance to biology is unclear. As it happens, David Wolpert, one of the authors of the N.F.L. theorems, recently denounced Dembski’s use of those theorems as “fatally informal and imprecise.” Dembski’s apparent response has been a tactical retreat. In 2002, Dembski triumphantly proclaimed, “The No Free Lunch theorems dash any hope of generating specified complexity via evolutionary algorithms.” Now he says, “I certainly never argued that the N.F.L. theorems provide a direct refutation of Darwinism.”

Of the five founding fathers of twentieth-century evolutionary biology—Ronald Fisher, Sewall Wright, J. B. S. Haldane, Ernst Mayr, and Theodosius Dobzhansky—one was a devout Anglican who preached sermons and published articles in church magazines, one a practicing Unitarian, one a dabbler in Eastern mysticism, one an apparent atheist, and one a member of the Russian Orthodox Church and the author of a book on religion and science. Pope John Paul II himself acknowledged, in a 1996 address to the Pontifical Academy of Sciences, that new research “leads to the recognition of the theory of evolution as more than a hypothesis.”