Science
in Christian PerspectiveScience
in Christian Perspective
Letter to the Editor
Dembski's Dogma Denied: Natural Causes Produce Information
David F. Siemens, Jr.
ASA Fellow
From PSCF 49 (December 1997): 287-288.
In "Intelligent Design as a Theory of Information" (Sept. 1997: 180ñ90), William A. Dembski gives four corollaries to what he terms the Law of Conservation of Information. Two of these are: (3) The CSI (Complex Specified Information) in a closed system of natural causes either has been in the system eternally or was at some point added exogenously. (4) Any closed system of natural causes that is also of finite duration received whatever CSI it contains before it became a closed system. If the genomes of living things are CSI, these claims are not true. While I cannot claim to show that CSI originates de novo through natural causes, I find that, given CSI in a genome, it can multiply.
It appears that the application of information theory to living things has not recognized a fundamental difference between them and what is normally discussed. There is no question that two copies of the Declaration of Independence do not carry more information than one. Further, some mischance that garbles the transmission of information does not thereby increase CSI. One reason for this is that natural languages contain words that vary in length from a single letter to dozens of letters, with only a few sequences forming words, let alone sentences. For example, if one takes a three-letter word and changes one letter while keeping the other two, relatively few of the variants will be words. For example, excluding proper names, out of 75 possible sequences derived from "and" by this process, only "add," "aid," "end," "ana," "ant," and "any" are English words, about one in ten. But not one is a conjunction, and so would probably destroy the grammatical structure by being substituted.
In contrast, either DNA or RNA consists of four nucleotides or "letters," rather than the 26 of English. All "words" or codons are three nucleotides long, giving a total of 64, every one of which codes for something, an amino acid, a starting point or a stopping place. Consequently, a change in a nucleotide in a gene, whether a substitution, a deletion or an addition, can almost always be read by the microsomes to encode a protein, although loss of a start codon may prevent this. Granted, many such changes will harm the organism. But one may note that the change in one of the genes for hemoglobin which produces sickle-cell anemia and the various thalassemias is, in the heterozygote, protective against malaria. This increases fitness where malaria is endemic, even though the homozygous condition is classed as a lethal. It has also been argued that "sloppy" copying of the genome in a retrovirus like HIV allows the production of so many different strains that the immune system is eventually overwhelmed. This is surely increased CSI.
Another factor allows the duplication of genes. While extra chromosomes usually give rise to problems (trisomy 21 or Down's syndrome is probably the best known), it appears that the results of unequal crossing over and the transfer of part of one chromosome to another is often benign. Were the insertion of genetic material not usually harmless, genetic engineering would be impossible.
While no one can absolutely prove that these processes have generated new information in genomes, there are observations which can best be interpreted this way. First, Drosophila has a single TATA box, a sequence of four genes with the distinctive series of nucleotides that gives it its name. These genes are activated sequentially to control specific steps in embryonic development. If my memory serves, the sequence is twice triggered at different stages. In Homo, there are four TATA boxes, all of them so similar to the Drosophila version and to each other, in sequence and in function, that the simplest explanation is that they have a common origin. But the human set are sufficiently different from each other that they are triggered at different times to control different aspects of development. Thus it seems that the human set picked up new information through natural causes. Someone knowledgeable in the area can probably fill in the information that I have missed about TATA boxes in other phyla and classes.
A second set of duplicated genes with new functions involves the visual pigments. It appears that the somatic blue-sensitive pigment is sufficiently similar to rhodopsin, the most common light-sensitive material, to have been derived from it by duplication and mutation. The single sex-linked visual pigment of the New World monkeys is very similar to the blue-sensitive pigment, but a few coding changes shift its peak absorption toward the longer wavelengths. The Old World apes have all these pigments and add another, to give trichromatic color vision. At least in some human beings, the gene for this last green-sensitive pigment, is duplicated or triplicated. Moving from simple sensitivity to light to special sensitivity to one, two and then three spectral areas surely involves an increase in information, most probably by natural causes. Consequently, Dembski's application of information theory to living creatures must be modified.