Robert C. Koons, "A New Look at the Cosmological Argument," American Philosophical Quarterly 34 (April 1997): 193-211.
Robert Koons (Philosophy, University of Texas, Austin) has written a challenging reassessment of the cosmological argument, and develops a critique of what he calls the "junky cosmos" line of reasoning. "There is another serious drawback to the junky cosmos hypothesis: if employed globally, it has the consequence that any form of induction is demonstrably unreliable. If we embrace the junky cosmos hypothesis to explain away every appearance of orderedness in the universe, then we should assume that the simplicity and regularity of natural law is also an artifact of observer selection. Universes would be posited to exist with every possible set of natural laws, however complex or inductively ill-behaved. Now take any well-established scientific generalization. Among the universes that agree with all of our observations up to this point in time, the number that go on to break this generalization is far greater than the number that continue to respect it. The objective probability that every generalization we have observed extends no farther than our observations is infinitely close to one. Thus, relying on induction in such a universe is demonstrably futile. In short, the junky cosmos hypothesis is both the most flagrant possible violation of Occam's razor and a death sentence to all other uses of that principle. This hypothesis postulates an infinity of entities for which there is absolutely no positive evidence, simply in order to avoid the necessity of explaining the anthropic coincidences we have observed. This is the height of metaphysical irresponsibility, far worse than the most extravagant speculations of medieval angelology." return to top
Paul J. Morris, "Louis Agassiz's Arguments against Darwinism in His Additions to the French Translation of the Essay on Classification," Journal of the History of Biology 30 (1997): 121-134.
Louis Agassiz (1807-1873), the great Swiss-American fossil fish systematist, geologist, and, in Stephen Jay Gould's words, "America's leading biologist" of the mid-nineteenth century, never accepted Darwinian evolution. Many commentators have suggested that Agassiz's "species essentialism" motivated his resistance, yet Paul Morris (Biology, University of Massachusetts, Amherst) disagrees, arguing that "species were neither the core nor an important focus of Agassiz's arguments against Darwin."
Rather, as spelled out in a little-known 1869 publication, Agassiz develops "three main arguments; (1) Darwinism is an a priori doctrine that selectively interprets facts, rather than being induced from them. (2) Variation is a universal characteristic of organisms but has distinct limits: it exists only in individual peculiarities; never do species-level characters vary, nor do those characters that distinguish genera, families, orders, classes, or branches. (3) The fossil record is, in several ways, not consistent with the expectations of progressive evolutionary change expounded by Haeckel" (p. 126). Agassiz's arguments, Morris judges, are "clearly not the statement of an ambivalent scientist unwilling to take a stand on the issue of Darwinian evolution," but instead "the statement of a naturalist who was certain that the evidence of nature firmly supported his own worldview" (p. 133). Thus, in contrast to the usual picture of Agassiz as a religiously-motivated reactionary, Morris suggests "it should be abundantly clear that Agassiz's opposition to Darwinism was based in a cogent worldview, and that the core of his opposition lay in a literal, empirical interpretation of the natural world, especially the fossil record. Agassiz's arguments are clearly not a dogmatic argument based in religion, but are firmly based in the data of portions of the natural world that the Darwinian of the late 1800s was ill able to explain" (p. 133). return to top
Michel C. Milinkovitch, "Molecular phylogeny of cetaceans prompts revision of morphological transformations," Trends in Ecology and Evolution 10 (August 1995): 328-334.
Masami Hasegawa, Jun Adachi, Michel C. Milinkovitch, "Novel Phylogeny of Whales Supported by Total Molecular Evidence," Journal of Molecular Evolution 44 (Supplement 1, 1997): S117-S120.
That molecular evidence typically squares with morphological patterns is a view held by many biologists, but interestingly, by relatively few systematists. Most of the latter know that the two lines of evidence may often be incongruent. A recent case in point concerns the hypothesized evolution of whales. According to standard or "classical" classifications, all the toothed whales, the Odontoceti, share a more recent common ancestor than the baleen whales, the Mysticeti. But, in a provocative new theory advanced primarily by Michel Milinkovitch of the University of Brussels, anatomical evidence -- the teeth and single blow holes of toothed whales -- as well as behavioral evidence (echolation) is misleading. In fact, Milinkovitch writes, "evolutionary relationships among the major groups of cetaceans is more problematic since morphological and molecular analyses reach very different conclusions. Indeed, based on the conventional interpretation of the morphological and behavioral data set, the echolocating toothed whales (about 67 species) and the filter-feeding baleen whales (10 species) are considered as two distinct monophyletic groups. ...On the other hand, phylogenetic analysis of DNA ... and amino acid ... sequences contradict this long-accepted taxonomic division. One group of toothed whales, the sperm whales, appear to be more closely related to the morphologically highly divergent baleen whales than to other odontocetes." return to top
Emile Zuckerkandl, "Neutral and Nonneutral Mutations: The Creative Mix--Evolution of Complexity in Gene Interaction Systems,' Journal of Molecular Evolution 44 (1997): S2-S8.
Peter E. Warburton and David
Kipling, "Providing a little stability," Nature 386
(10 April 1997): 553-555.
Hubert Renauld and Susan M. Gasser, "Heterochromatin: a meiotic
matchmaker," Trends in Cell Biology 7 (May 1997): 201-205.
In one of his later books, written with his wife Ann Druyan (Shadows of Forgotten Ancestors, Ballantine, 1992), the late Carl Sagan argued that "genetic junk," the "redundancies, stutters, [and] untranscribable nonsense" in DNA, proved that there are "deep imperfections at the heart of life" (p. 128). Such comments are commonplace in the biological literature -- although perhaps less common than they were a few years ago. The reason? Geneticists are discovering functions for what used to be apparent genetic debris.
Take heterochromatin: the highly repetitive DNA coding for few, or no, proteins. "Despite its significant representation in the genome," Renauld and Gasser (Swiss Institute for Experimental Cancer Research) write, "(up to 15% in human cells and ~30% in flies), heterochromatin has often been considered as 'junk' DNA -- that is, DNA without utility to the cell" (p. 201). However, recent studies suggest that heterochromatin may play important functional roles; biologists have been looking at the wrong level. As Emile Zuckerkandl (Institute of Molecular Medical Sciences) observes,
Interestingly ... if one adds together nucleotides [DNA base pairs] that are individually nonfunctional, one may end up with a sum of nucleotides that are collectively functional. Nucleotides belonging to chromatin are an example. Despite all arguments made in the past in favor of considering heterochromatin as junk, many people active in the field no longer doubt that it plays functional roles. ...Just as, quite some time ago, populational thinking became a necessity in genetics, we need now to get used to populational thinking in regard to the function of nucleotides. They may individually be junk, and collectively, gold. (p. 53)
One such "collective" function may occur in meiotic pairing. Also, studies of artificial chromosomes have demonstrated other functions:
The minimal requirements for an artificial chromosome include sequences to allow for the maintenance of its ends (telomeres), replication of its DNA, and mitotic segregation to daughter cells (centromeres). ...The centromere is not simply a passive point at which the chromosome attaches to the microtubules of the mitotic spindle -- it actively participates in the segregation of chromosomes to daughter cells. The centromeric region contains at least one motor, which is involved in chromosome movement during cell division. The centromere also mediates a critical checkpoint that prevents completion of cell division until all chromosomes are properly attached to the mitotic spindle.
Copyright © 1997 Paul Nelson. All rights
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File Date: 1.1.98