Chapter 6
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Chapter 6 THE EVOLUTIONISTS RESPOND
The evidence for design in nature - both in living things and in non-living things - was not discovered by design theorists primarily, but by biologists and physicists of every philosophical outlook; but the metaphysical implications of those discoveries are what they are, and design theorists are using this evidence to press the case for treating design theory as science, despite its theological implications. But the three books relied upon most heavily in this essay were published in 1991, 1994 and 1996. Plenty of time has passed since then for the evolutionists to begin to respond. What have they said? I. Specified Complexity in the Cosmos. As far as the fine-tuning of the universe is concerned, they have not said much, except to acknowledge the theological implications. In 1982 Fred Hoyle concluded that "a superintellect has monkeyed with physics, as well as with chemistry and biology."1 Paul Davies moved from promoting atheism in 19832 to conceding in 1984 that "the laws [of physics] . . . seem themselves to be the product of exceedingly ingenious design"3 to testifying in his 1988 book The Cosmic Blueprint that there "is for me powerful evidence that there is something going on behind it all. The impression of design is overwhelming."4 Stephen Hawking notes that "The odds against a universe like ours emerging out of something like the Big Bang are enormous. I think there are clearly religious implications."5 Agnostic Robert Jastrow described his fellow astronomers as: scaling the mountains of ignorance . . . conquering the highest peak . . . pulling [themselves] over the final rock . . . [to be ] greeted by a band of theologians who have been sitting there for centuries.6 Hugh Ross comments: Words and phrases such as superintellect, monkeyed, exceedingly ingenious, supernatural Agency, Supreme Being and providentially crafted obviously can refer only to a person. But more than just establishing that the Creator is a person, the findings about design provide evidence of what that Person is like. One characteristic that stands out dramatically is his interest and care for living things and particularly for the human race. For example, the mass density of the universe determines how efficiently nuclear fusion operates in the cosmos. As table 4.4 indicates, if the mass density were too great, too much deuterium (a heavy isotope of hydrogen with one proton and one neutron in the nucleus) would be made in the first few minutes of the universe's existence. This extra deuterium will cause all the stars to burn much too quickly and erratically for any of them to support a planet with life upon it. On the other hand, if the mass density were too small, so little deuterium and helium would be made in the first few minutes that the heavier elements necessary for life would never form in the stars. What this means is that the approximately 100 billion trillion stars we observe in the universe, no more and no fewer, are needed for life to be possible in the universe. Evidently God cared so much for living creatures that he constructed 100 billion trillion stars and carefully crafted them throughout the age of the universe so that at this brief moment in the history of the cosmos humans could exist and have a pleasant place to live. Of all the gods of the various religions of the world, only the God of the Bible is revealed as investing this much (and more) in humanity.8 Behe's teaching, however, has attracted more critics. Notable among them is Kenneth Miller, a cell biologist at Brown University. Miller has published a book defending Darwinism entitled Finding Darwin's God - A Scientist's Search for Common Ground Between God and Evolution,9 and he and Behe are engaged in an open debate on the World Wide Web concerning Behe's interpretations of the findings of moleculur biochemistry. Miller's credentials and his determined undertaking to refute Behe make his work worth considering; what's more, his evident Catholicism precludes any suspicion of an anti-theistic bias. Miller's book contains many interesting observations. His most important claims, however, are not presented in a way that is accessible to the general reader, and his other claims are inconclusive. Moreover, the ensuing exchange between him and Behe on the Web appears to me to favor Behe; though I will try to set forth enough of that interchange to enable the reader to form his own conclusions. Anyone wishing to know more can easily find all the articles in full at the Websites of the Discovery Institute (www.discovery.org) and of Professor Miller (www.millerandlevine.com/km/evol/index.html) As noted above, Behe charges that nowhere in the professional literature are there to be found any articles proposing a plausible evolutionary pathway for an irreducibly complex biochemical system. Miller does not deny that as of the writing of Behe's book, the charge was valid, but he says that in 1998 - after the publication of Darwin's Black Box - Musser and Chan proposed an evolutionary pathway for the formation of an irreducibly complex system, namely the cytochrome c oxidase protein pump, which consists of six proteins. Miller does not describe the proposed pathway in nearly enough detail to enable anyone (whether the general reader or an expert) to form her own opinion as to whether Musser and Chan have met Behe's challenge. I obtained their article from the Journal of Evolutionary Biology 10 and quickly learned that it is accessible only to expert readers. I wrote Professor Miller and complained that under these circumstances he is essentially asking me to take his word for it, which is something I am unwilling to do. Miller himself notes that many evolutionists are hostile to theistic world views and that their very evident philosophical naturalism leads them to commit egregious mental errors - which is precisely why, long ago, I resolved to form my own conclusions, and not to blindly accept the pronouncements of those who merely say, "We are the experts, and you must believe whatever we tell you." Why should I treat Miller any differently when he tells me essentially the same thing? As mentioned, Miller does not provide a summary of the work of Musser and Chan useful to the general reader. Behe does, however, and needless to say, that gives Behe an advantage in the debate - or it does if you concede that the general reader constitutes an appropriate audience for that debate. I suggest it does. Behe describes the Musser and Chan study as follows. [T]he cytochrome c oxidase proton pump (Musser and Chan 1998) . . . is involved in electron transfer. In humans six proteins take part in the function; in some bacteria fewer proteins are involved. While quite interesting, the mechanism of the system is not known in enough detail to understand what's going on; it remains in large part a black box. Further, the function of electron transfer does not necessarily require multiple protein components, so it is not necessarily irreducibly complex. Finally, the study is not detailed enough to criticize, saying things such as "It makes evolutionary sense that the cytochrome bc1 and cytochrome c oxidase complexes arose from a primitive quinol terminal oxidase complex via a series of beneficial mutations." In order to judge whether natural selection could do the job, we have to know what the "series of beneficial mutations" is. Otherwise it's like saying that a five-part mousetrap arose from a one-part mousetrap by a series of beneficial mutations.11 One of my operating assumptions is that if evolution occurred, it ought to be possible for a reasonably intelligent, informed and unbiased non-scientist who is willing to make the effort (such as myself) to be satisfied that it occurred on the basis of his own investigation, not merely upon the say-so of experts. Frankly, I do not trust the experts because the naturalistic bias of too many of them is too obvious. Elsewhere you note that about half of Americans doubt that evolution occurred, and you attribute this to their perception that the scientific community is hostile to widely-held humane values. Perhaps it also is partly attributable to the scientific community's failure to grasp the fact that many do not subscribe to philosophical naturalism - in the absence of which the truth of evolution is not self-evident - and so can only be persuaded by evidence. Now, supposing that wider acceptance of the theory of evolution is considered important by the scientific community - and I would assume that it is, for several very good reasons - then it would seem that interpreting the technical details for a wider audience, no matter how difficult, ought to be a priority. I would submit, in fact, that if you can't convince someone who, like me, has enough interest in the subject to make a concerted effort to get to the bottom of it, then there is little hope of making inroads into the general public. According to Behe, the Melendez-Hevia paper works out a scheme for how the organic-chemical components of the tricarboxylic acid (TCA) cycle, a central metabolic pathway, may have arisen gradually. (Melendez-Hevia, et al. 1996) There are several points to make about it. First, the paper deals with the chemical interconversion of organic molecules, not the enzymes of the pathway or their regulation. As an analogy, suppose someone described how petroleum is refined step by step, beginning with crude oil, passing through intermediate grades, and ending with, say, gasoline. He shows that the chemistry of the processes is smooth and continuous, yet says nothing about the actual machinery of the refinery or its regulation, nothing about valves or switches. Clearly that is inadequate to show refining of petroleum developed step by step. Analogously, someone who is seriously interested in showing that a metabolic pathway could evolve by Darwinian means has to deal with the enzymic machinery and its regulation. The second and more important point is that, while the paper is very interesting, it doesn't address irreducible complexity. Either Miller hasn't read what I said in my book about metabolic pathways, or he is deliberately ignoring it. I clearly stated in Darwin's Black Box [that] metabolic pathways are not irreducibly complex (Behe 1996) (pp. 141-142; 150-151), because components can be gradually added to a previous pathway. Thus metabolic pathways simply aren't in the same category as the blood clotting cascade or the bacterial flagellum. Although Miller somehow misses the distinction, other scientists do not. In a recent paper Thornhill and Ussery write that something they call serial-direct-Darwinian-evolution "cannot generate irreducibly complex structures." But they think it may be able to generate a reducible structure, "such as the TCA cycle (Behe, 1996 a, b)." (Thornhill and Ussery 2000) In other words Thornhill and Ussery acknowledge the TCA cycle is not irreducibly complex, as I wrote in my book. Miller seems unable or unwilling to grasp that point.12 Behe responds with four observations, two of which are of questionable import, but two of which justify serious doubt about the importance of Hall's experiment.14 First, Behe notes that the mutations in question began with materials which were close at hand (the gene for another enzyme of the bacterium) and which were already nearly identical to the removed gene (13 out of 15 active sites on the two genes were identical). Miller rejoins that such minute improvements are precisely what the theory of natural selection would predict. Second, Behe argues that contrary to Miller's own criterion for "a true acid test," a multipart system was not "wiped out" - only one component of a multipart system was deleted. Miller acknowledges that although Hall removed a single gene, the result was that in order to again metabolize lactose the bacterium had to develop three components anew - a new galactosidase enzyme, a new lactose-sensitive control region (which keeps the enzyme from being activated until lactose is present, in order to conserve energy when it is not present), and a new way to switch on the lac permease gene (which is necessary in order for the lactose to be transported into the cell). Score another one for Miller. However, after removing the gene, Hall cultured the bacteria in a solution containing the artificial chemical inducer isopropylthiogalactoside (IPTG), which the bacteria could metabolize - just efficiently enough to enable the bacteria to survive long enough to pull off the mutations necessary to metabolize lactose. This is a contrived condition which would not have arisen naturally. "Thus the system was being artificially supported by intelligent intervention," says Behe. And though the system did produce a new enzyme through two separate mutations, IPTG supported the system while it made one mutation at a time. "The inclusion of IPTG was the result of the decision of an intelligent agent (Barry Hall) to deliberately alleviate the irreducibility of the system. In the absence of that intelligent action, Darwinian processes alone were ineffective. That is exactly what intelligent design theorists would expect."15 Finally, Hall's study is an example of "adaptive mutation." As Hall himself later wrote, Adaptive mutations are mutations that occur in nondividing or slowly dividing cells during prolonged nonlethal selection, and that appear to be specific to the challenge of the selection in the sense that the only mutations that arise are those that provide a growth advantage to the cell. The issue of the specificity has been controversial because it violates our most basic assumptions about the randomness of mutations with respect to their effect on the cell. (Hall 1997) The mechanism(s) of adaptive mutation are currently unknown. While they are being sorted out, it is misleading to cite results of processes which "violate our most basic assumptions about the randomness of mutations" to argue for Darwinian evolution, as Miller does. Leaving aside the still-murky area of adaptive mutation, the admirably-careful work of Hall involved a series of micromutations stitched together by intelligent intervention. He showed that the activity of a deleted enzyme could be replaced only by mutations to a second, homologous protein with a nearly- identical active site; and only if the second repressor already bound lactose; and only if the system were also artificially supported by inclusion of IPTG; and only if the system were also allowed to use a preexisting permease. Such results are exactly what one expects of irreducible complexity requiring intelligent intervention, and of limited capabilities for Darwinian processes.16 First, Miller points out that "other mammals and most vertebrates have clotting systems that are nearly identical to ours."17 And by way of explaining why so many different proteins are involved in clotting, he says: The striking thing about this particular Rube Goldberg machine is how similar most of its parts are. Nearly all of the regulatory molecules belong to a single class of protein-cutting enzymes known as "serine proteases," and that, as Russell Doolittle realized many years ago, is the clue to understanding the system's evolution beginning with organisms that lacked a protein-based clotting system.18 A series of ordinary gene duplications . . . copied some of these serine proteases. One of these duplicate genes was then mistargeted to the bloodstream, where its protein product would have remained inactive until exposed to an activating tissue protease - which would happen only when a blood vessel was broken. From that point on, each and every refinement of the mechanism would be favored by natural selection.19 Here we see that the only evidence which Miller cites for the proposition that natural selection produced, or even could have produced, the human blood clotting system, is evidence of the similarities among the proteins involved in that system and other proteins in other human and nonhuman biochemical systems. Aside from those similarities, Miller's claim is based entirely on speculation that natural selection is capable of bridging the gaps from one protein to another and from one clotting system to another. There is nothing about similarities among organisms or biochemical systems which makes personal causation a less likely, or natural selection a more likely explanation for life or for biological diversity. Similarities among organisms can be accounted for at least as well by personal causation as by natural selection. If a personal creator were to fill this planet with millions of species, it would be no surprise if he made them with many similarities; and this is especially to be expected, given the apparent decision to place them all in a biosphere already specified to the extent we have seen ours to be, which can be hospitable only to creatures whose life systems, like the biosphere itself, are heavily based on hydrogen, carbon, oxygen and nitrogen. Furthermore, the presence of DNA in both plants and animals is accounted for just as well by design theory as by natural selection theory; but only design theory accounts for DNA in plants or animals. The key here is that for Miller and others, similarity in the blood-clotting systems of two organisms is treated by itself as decisive against the personal causation hypothesis, and as a sufficient basis for taking the development of one from the other by natural selection as proved. In summary, Miller has taken Behe on and has drawn but little blood, if any. Each of the studies he cites as evidence for natural selection suffers from an important defect. One lacks essential detail. Another does not involve irreducible complexity at all. A third required intelligent intervention for its outcome. And Miller's analysis of the human blood clotting system, boiled down to its essence, makes a "leap of faith" that similar systems, simply because they are similar, developed one from another by the power of natural selection. If these are the most powerful refutations of Behe's thesis which the scientific establishment can muster in five years, we may feel justified in concluding that no facts have been overlooked that would detract from the significance of the evidence for design, and no hidden fallacies in inferring design from that evidence. With each passing year, the lack of a convincing refutation becomes progressively more embarrassing to those who hold to the orthodox view. ENDNOTES 1Hoyle, The Universe, p. 16. © 2000 Thomas O. Alderman |
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