Why Darwin Matters_ The Case Against Intelligent Design - Michael Shermer [36]
Dembski’s Law of Conservation of Information is purposely constructed to resemble such physical laws as the conservation of momentum or the laws of thermodynamics. But these laws were based on copious empirical data and experimental results from the real world, not inferred from logical argument alone as Dembski’s law is. Further, no other recognized theory of information—such as that proposed by the mathematician and information pioneer Claude Shannon—includes a law or principle of conservation, and no one working in the information sciences today uses or recognizes Dembski’s law as scientifically useful, regardless of its design inference.
Even if Dembski’s LCI were validated, it is irrelevant to the theory of evolution, because it is abundantly clear that information in the natural world—through DNA, for example—is transferred and increased by natural processes. Microbiologist Lynn Margulis, for example, has demonstrated that complex eukaryote cells, such as those of which we are made, evolved from simpler prokaryote cells. The genomes of eukaryote cells increased in size—and thus in complex specified information—by incorporating simpler genomes of prokaryote cells.42 Intelligent Design theorists respond to this by saying the Intelligent Designer created complex eukaryote cells. If that is so, why does it appear that the Intelligent Designer cobbled these cells together out of parts lying around in the pre-Cambrian soup? In fact, complex eukaryote cells are a grab bag of goodies from the prokaryote world, including mitochondria, which contain their own genome. Ever heard of mitochondrial DNA (from which human lineages may be traced through females)? Our cells already have a nucleus containing a complete genome. What is another genome doing in our mitochondria? Evolution offers an answer: They are vestigial features of eukaryote cells that evolved from prokaryote cells. Intelligent Design, in contrast, offers nothing more than “then a miracle occurs.”
Richard Dawkins cogently answers the information challenge by reconstructing the evolution of hemoglobin—the oxygen-carrying protein in blood. Human hemoglobin contains four protein chains called globins that are similar to each other but not identical. The alpha globins each contain a chain of 141 amino acids coded by seven genes on Chromosome 11—four are pseudogenes that do not produce proteins, two produce adult hemoglobin, and one produces embryo hemoglobin. Similarly, beta globins each contain a chain of 146 amino acids coded by six genes on Chromosome 16, some of which are disabled and one used only in embryos. Letter-by-letter analysis of the genes coding for hemoglobin reveals that the two sets of genes on Chromosomes 11 and 16 are distantly related and share a common globin gene from a common ancestor five hundred million years ago. That gene duplicated, after which both copies were passed down for half a billion years, one evolving into the alpha cluster on Chromosome 11 and the other evolving into the beta cluster on Chromosome 16. Gene duplications led to the increase in complexity of the gene clusters, leading to the existence today of nonfunctional pseudogenes. Since this alpha-beta split happened five hundred million years ago we can predict that we should find the same alpha-beta split in all animals that evolved within the last half billion years. Sure enough, that is precisely what we find. As a final test, the jawless lamprey fish, the only surviving vertebrate predating the alpha-beta split, should lack this genetic divide. And sure enough, it does. Blood hemoglobin is explained by evolution, not Intelligent Design. Q.E.D.43
In general, DNA has the elements of historical contingency and evolutionary history, not design. DNA is information, and if the Law of Conservation of Information requires the input of