(continued Subject: SWAA Lecture Date: 18 Jan 1993 16:25:42 GMT Darwinism's rules of reaso

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(continued From: philjohn@garnet.berkeley.edu (Phillip Johnson) Subject: SWAA Lecture Date: 18 Jan 1993 16:25:42 GMT ) Darwinism's rules of reasoning not only protect the cultural authority of Darwinists. They also permit Darwinist writers to take the mutation/selection mechanism for granted even when they are describing evidence which directly contradicts it. This feat of intellectual contortionism is strikingly illustrated by Stephen Jay Gould's book, Wonderful Life. Gould's bestseller adds a great deal to our knowledge of the "Cambrian explosion," meaning the sudden appearance of the invertebrate animal phyla, without visible ancestors, in the 600 million-year-old rocks of the Cambrian era. Unicellular life had existed for a long time, and some multicellular groups appear in the immediately Precambrian rocks, but there is nothing that can be established as ancestral to the Cambrian animals. As Richard Dawkins described the situation, "It is as though [the Cambrian phyla] were just planted there, without any evolutionary history." In recent years the mystery has deepened, because it appears (at least according to Gould) that the Cambrian animal groups were far more varied than had been imagined. The more distinct groups there were in the Cambrian, the more chains of ancestors there ought to have been in the Precambrian. Some remarkable Cambrian fossils found in a Canadian formation known as the Burgess Shale were originally classified in familiar groups. Gould explains that the discoverer of the Burgess Shale fossils, Charles Walcott, tried to "shoehorn" the odd creatures into familiar taxonomic categories because of his predisposition to avoid multiplying the difficulties of what is called the "artifact theory" of the Precambrian fossil record. As Gould explains the problem: Two different kinds of explanations for the absence of Precambrian ancestors have been debated for more than a century: the artifact theory (they did exist, but the fossil record hasn't preserved them), and the fast-transition theory (they really didn't exist, at least as complex invertebrates easily linked to their descendants, and the evolution of modern anatomical plans occurred with a rapidity that threatens our usual ideas about the stately pace of evolutionary change). The two drawings in the Appendix to this paper illustrate both the problem the Cambrian Explosion poses for any theory of evolution, and the way a museum exhibition attempts to control the damage. The Exhibition is titled "Life Through Time: The Evidence for Evolution," and it is at the California Academy of Sciences Museum in Golden Gate Park in San Francisco. The drawing on the right (not part of the museum exhibit) shows a realistic picture of the evidence itself, with the phyla appearing on parallel lines and absolutely no evidence of any common ancestors or transitional intermediates. The museum exhibit on the left -- labelled the "Hard Facts Wall" -- dresses up the evidence to force it into conformity with Darwinian ideology. The exhibit adds the hypothetical common ancestors and alters the vertical dimension representing the age of the fossils, in order to give the impression that the recalcitrant data constitute the required "evidence for evolution." At the intersection point where the common ancestors ought to be, the curators have placed magnifying glasses. Similar devices are used elsewhere in the exhibit to mark tiny animals or fossils. Unsophisticated museum visitors are apparently meant to get the impression that the invisible common ancestors are known to science, but just a little too small for the naked eye to see. By such means even a spectacular example of absence of evidence for evolution can be transformed into evidence for evolution, and even evidence for the creative power of natural selection. The museum exhibit illustrates the Cambrian Explosion with just a few well-known groups and thus understates the difficulty in reconciling the facts with any known theory of evolution. Reclassification of the Burgess Shale fossils has now established some 15 or 20 Cambrian species that cannot be related to any known group and therefore constitute distinct and previously unknown phyla. There are also many other species that can fit within an existing phylum but are still remarkably distinct from anything known to exist earlier or later. The general history of animal life is thus a burst of general body plans followed by extinction. Many species exist today which are absent from the rocks of the remote past, but they fit within general taxonomic categories present from the very beginning. Darwinian theory predicts a "cone of increasing diversity," as the first living organism, or first animal species, gradually and continually diversifies to create the various levels of the taxonomic order. The animal fossil record more resembles such a cone turned upside down, with the phyla present at the start and thereafter decreasing. In short, the more we learn about the Cambrian fossils, the more difficult it becomes to see them as the product of Darwinian evolution. Gould describes the reclassification of the Burgess fossils as the "death knell of the artifact theory," because it adds so many new groups that appear without Precambrian ancestors. If evolution could produce ten new Cambrian phyla and then wipe them out just as quickly, then what about the surviving Cambrian groups? Why should they have had a long and honorable Precambrian pedigree? Why should they not have originated just before the Cambrian, as the fossil record, read literally, seems to indicate, and as the fast-transition theory proposes? A mysterious process that produces dozens of complex animal groups directly from single-celled predecessors, with only some words like "fast-transition" in between, may be called "evolution" -- but the term is being used more in the sense of Grasse's heresy than of Dobzhansky's Darwinian orthodoxy. Each of those Cambrian animals contained a variety of immensely complicated organ systems. How can such innovations appear except by the gradual accumulation of micromutations, unless there was some supernatural intervention? It is not only that the Darwinian theory requires a very gradual line of descent from each Cambrian animal group back to its hypothetical single-celled ancestor. Because Darwinian evolution is a purposeless, chance- driven process, which would not proceed directly from a starting point to a destination, there should also be thick bushes of side branches in each line. As Darwin himself put it, if Darwinism is true the Precambrian world must have "swarmed with living creatures" many of which were ancestral to the Cambrian animals. If he really rejects the artifact theory of the Precambrian fossil record, Gould also rejects the Darwinian theory of evolution. (continued in next message...)


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