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Defenders 3: Excursus on Creation of Life and Biological Diversity (Part 33): Inadequacies of the Neo-Darwinian Mechanisms
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Welcome to Defenders, the teaching class of Dr. William Lane Craig.
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Today the Creation of Life and Biological Diversity, Part 33. For more information and resources from Dr.
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Craig, go to reasonablefaith.org We've been looking
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at the adequacy of the neo Darwinian mechanisms of random mutation and natural selection to draw the extraordinary extrapolation from local effects such as finch beaks and peppered moths to the evolution of all life on earth from a common ancestor. And we looked at the experience of both breeders as well as the peppered moth experiments and and then turned to the question of drug resistance in microorganisms as a result of random mutations. And you'll recall that Michael Behe looks at malaria as a counter example to this claim. Malaria mutates at a tremendously rapid rate and as a result it's been able to overcome every drug that, that we've developed against it. But the human respiratory system has also mutated and developed something that malaria has not been able to overcome, namely sickle hemoglobin. And the reason that malaria can overcome drugs and poisons is because in order to do so, relatively simple mutations need to occur. But according to Behe, in order to overcome sickle hemoglobin, you would need to have multiple mutations, either occurring simultaneously or blindly, step by step, and this is simply too improbable to happen. And therefore, despite trillions of cells and tens of thousands of generations, malaria has never been able to mutate enough to overcome sickle hemoglobin. Behe looks at HIV as another case study. HIV mutates 10,000 times faster than malaria. In the last 50 years alone, the AIDS virus has mutated as much as all the cells that have ever existed on this planet. In just 50 years, it has tried out every possible combination of up to six point simultaneous mutations and thus has become resistant to every drug that we've developed. But Behe says through all that, there have been no significant basic biochemical changes in the virus at all. On a functional biochemical level, the virus has been a complete stick in the mud. Behe concludes, and I quote, the studies of malaria and HIV provide by far the best direct evidence we have of what Darwinism can do. He says, and I quote, here we have genetic studies over thousands upon thousands of generations of trillions and trillions of organisms and little of biochemical significance to show for it. Our experience with HIV and malaria gives good reason, he says, to think that Darwinism doesn't do much, even with billions of years and all the cells in the world at its disposal. End quote. Finally, Behe claims that studies on the bacterium E. Coli carried out by Richard Lensky and his colleagues also support the same conclusion. Lenski published results of their research on 40,000 generations of E. Coli grown in the bacteria. I've read that it's over 65,000 generations today. And they discovered that while there were a couple score beneficial mutations that occurred in these E. Coli bacteria and nevertheless they were degradative or degenerative in nature, that is to say, they involved the loss of genetic information or the loss of protein function, there's no indication that these bacteria were on their way to building new complex systems. So Beh thinks that Lenski's work lines up well with the results of malarial and HIV studies. In a huge number of tries, one sees minor changes, some beneficial, but overwhelmingly degradative, with no new complex systems evolving. Malaria, HIV, and E. Coli represent three fundamentally different forms of life. A eukaryote that has a nucleus, a virus, and a prokaryote cell without a nucleus. And in each of these cases, the evidence for the efficacy of the neo Darwinian mechanisms is the same. It doesn't do very much. So I quote from Michael Behe's online blog. Instead of imagining what the power of random mutation and selection might do, we can look at the examples of what it has done. And when we look at the best, clearest examples, the results are, to say the least, quite modest. Time and again, we see that random mutations are incoherent and much more likely to degrade a genome than to add to it. And these are the positively selected beneficial random mutations. He says there is no evidence that Darwinian processes can take the multiple coherent steps needed to build new molecular machinery that fills the cell. End quote. Thus, the argument from the development of drug resistance in microorganism appears to completely backfire. Far from providing evidence of the power of the neo Darwinian mechanisms to produce grand evolutionary change, our experience with drug resistance in bacteria and viruses and microorganisms reveals the severe limits of those mechanisms. So again I ask, where is the evidence for the extraordinary extrapolation that neo Darwinism involves? Behe says, and I quote, the evidence for common descent seems compelling. But except at life's periphery, the evidence for a pivotal role for random mutations is terrible. Now, if he's wrong about this, then what is the evidence? I am genuinely open to it. Just tell me what it is. So when I as an objective, albeit lay observer, look at the evidence, it seems to me that we haven't been given any good reason to think that the neo Darwinian mechanisms are sufficient to to explain that extraordinary diversity of life that we see on this planet during the time available. Any comment or question about that point, George?
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Bill, sometimes you see comments in the popular press to the effect that evolution has designed us to be, for example, compassionate or empathetic. Or you'll see articles that say, for example, risky behavior by adolescents is something that evolution, you know, created and that all of these characteristics have some kind of popular thinking is survival benefit for the species, maybe not the individual, but the species. Based on what you're saying as you're discussing Behe, it seems like that's just magical thinking to think that evolution has designed these characteristics and nobody's ever identified the genetic basis for these characteristics, the expressions that we see or the so called evolutionary history that got us there.
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Yes, there's been a great deal of discussion whether altruism for example, can have an evolutionary basis because it seems the very opposite of having reproductive advantage if you're willing to sacrifice your life for someone who's not even a kinsman. And from what I've read, most of this does seem to just be hand waving that in fact it is largely conjectural as to whether or not our moral beliefs can be traced to some sort of genetic basis. But I want to say as a philosopher that even if they can, this is really irrelevant to the question of their objectivity. Because to think that that would undermine the objectivity of the moral values and duties we believe in is to commit the genetic fallacy. It's a textbook example of the genetic fallacy, which is the fallacy of trying to invalidate a viewpoint by explaining how the person came to hold it. And even if evolution is programmed into us belief in the noble morals and ideals that we have, that does absolutely nothing to prove that those are not objective and true.
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One more comment. It strikes me that Christians are often accused of magical thinking by believing in divine creation or the New Testament miracles. And it seems to me that she's on the other foot here.
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Okay, fair comment. Each person can make up his own mind. Yes, Bruce, along those same lines, a lot of times in the publications they
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ascribe cognitive qualities to evolution, that evolution
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knew this or decided this, which is
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completely contradictory, especially to naturalistic evolution.
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Yes, that doesn't invalidate the theory, but you're quite right Bruce, that often in sloppy presentations of it, anthropomorphic language will be used about natural selection thinking of what it will do and choosing to do this or that, and that is to misrepresent the theory. In their book the Anthropic Cosmological Principle, the physicists John Barrow and Frank Tipler List 10 steps in the course of human evolution, each of which. Each of which is so improbable that before it could occur, the sun would have ceased to be a main sequence star and incinerated the Earth. These include things like the development of a DNA based genetic code, the evolution of aerobic respiration, the evolution of glucose fermentation into pyruvic acid, the development of an endoskeleton, and so on and so forth. Ten steps in the evolution of Homo sapiens, each of which is so improbable that before it could happen, the sun would have gone through the course of its stellar evolution and become a red giant and incinerated the Earth as a result. Barrow and Tipler report, and I quote, There has developed a general consensus among evolutionists that the evolution of intelligent life comparable in information processing ability to that of Homo sapiens is so improbable that it is unlikely to have occurred on any other planet in the entire visible universe. But then the inevitable question arises. Why think in that case that it has evolved by means of these neo Darwinian mechanisms on this planet? Indeed, doesn't the evidence suggest just the opposite? In fact, Tipler himself now believes that the evolutionary process must have been guided in order to arrive at Homo sapiens. I mentioned earlier that during the 1970s within the evolutionary community, rumblings began to be felt about the inadequacy of the modern synthesis. Those rumblings have continued to grow, so that today it is widely recognized and that the neo Darwinian mechanisms are inadequate and so need to be supplemented by additional new mechanisms. In November of 2016, a conference of the Royal Society in London held a conference devoted to the theme of the problems in the modern synthesis. As you might expect, numerous new mechanisms were suggested, but no consensus emerged except that the standard picture needs major revision. Stephen Meyer was one of the attendees at this conference and among the competing alternatives presented were the following that he lists number one Evolutionary developmental biology. Evolutionary developmental biology, or this is sometimes affectionately called evo devo developmental biology, is the development of the embryo in utero. And many evolutionary developmental biologists will emphasize mutations in the genes that control the expression of other genes. And during the embryonic development of an organism, for example, a mutation in the so called Hox genes, which are master regulatory genes that affect the location, timing and expression of other genes, might have a disproportionately large effect on on development and thus it could play a significant role in modifying animal body plans. So evo devo advocates have thus broken with the modern synthesis regarding the notion of gradualism, the size or the increment of evolutionary change. It could occur in leaps through these embryonic developments. One challenge to this proposal, however, is that Hox genes in all animal forms are expressed well after the body plan is already established in utero. Earlier mutations that occur prove to be inevitably lethal to the organism. Alternative number two is self organization. Self organization Self organizational theorists try to explain the origin of order in living systems by reference to purely physical or chemical processes. They often point to simple geometric shapes or repetitive forms of order which arise from purely physical or chemical processes. For example crystals. Think of a snowflake, for example, in the beautiful order that that exhibits. Or vortices, that is to say, whirling whirlpools of water or convection currents brought on by temperature in the air. These all illustrated self organizational processes. Advocates see the embryological development of cells into the different cell types of distinct tissues like brain cells, heart cells, liver cells, and so forth to be due to epigenetic information, not genetic information. EPI is a Greek prefix meaning upon or in addition to, or over, over and above. And so epigenetic information will be information that is outside of the genetic structure. It's not part of the genome, and it specifies the position of the cell or the cell membrane, for example, relative to its context during embryological development. And advocates of the self organization thesis therefore reject the neo Darwinian assumption that animal development is determined entirely by genetic structure, and they deemphasize the role of random mutations in producing change. So on self organizational theories, you have a stronger emphasis on spontaneous order arising through epigenetic information. One challenge this theory faces, however, is that it doesn't explain the origin of the epigenetic information that governs cell differentiation. A third alternative is so called neutral evolution. Neutral evolution. Advocates of neutral evolution downplay natural selection in favor of neutral processes of mutation and genetic drift as the mechanisms responsible for evolution. Evolutionary biologists think that new forms of animal life originated in small populations that got separated from the larger populations. But advocates of neutral evolution argue that in these small populations, natural selection will have difficulty overcoming the effects of random genetic drift, meaning that the beneficial mutations are likely to be lost before they can become fixed in the population. So any evolution that takes place in the organisms of small populations is due almost completely to these neutral factors and is almost completely unaffected by natural selection. They just drift neutrally without respect to adaptive advantage. One problem for this view Is that there is apparently no experimental evidence that neutral processes like recombination, genetic drift and mutation can actually produce the genetic complexity required. Number four is Neo Lamarckianism. Neo Lamarckianism. You remember we talked earlier about Jean Baptiste Lamarck, the French biologist who preceded Darwin. Lamarck and Darwin both believed in fact that heredity was a matter of the use or disuse of certain organs by animals that then could be transmitted to their offspring through reproduction. With the identification of chromosomes as the entity responsible for the transmission of inheritance, however, Lamarckian theories fell out of favor. The gene now became the locus of all heritable change. After the discovery of DNA in 1953, biologists equated genes with specifically arranged nucleotide sequences on the DNA molecule. Recently, however, biologists have recognized that that some biological information, epigenetic information, resides in structures outside the DNA. And perhaps these non genetic sources of information influence the course of evolution. Changes in the non genetic structures of an organism could affect subsequent generations in the course of evolution. And I was fascinated to learn that Massimo Piliucci, whom I debated years ago at uga, is an advocate of Neo Lamarckianism, which I thought was rather charming. One problem that this view faces is that there is no case of induced epigenetic change which then persists permanently within a population, which is what Neo Lamarckianism says happens. Finally, number five, natural genetic engineering. Natural genetic engineering. Organisms on this view do not generate mutations randomly, but rather they can modify themselves in in response to environmental changes. On this view, organisms have a pre programmed adaptive capacity for engineered change where organisms respond intelligently to environmental influences, rearranging or mutating their genetic information in regulated ways in order to maintain viability. A problem for this view is that theorists do not explain where the programming that accounts for the pre programmed adaptive capacity of living organisms comes from in the first place. So in summary, I think you just get a feel here for the debate that is going on among evolutionary theorists today in an effort to provide adequate explanatory mechanisms for evolutionary change. When I was at a conference on the doctrine of creation three years ago, one of the speakers offered a critique of what he called Darwinism. During the Q and A. Afterwards, an evolutionary biologist from a major university stood to his feet and challenged him. Why do you keep talking about Darwinism? He said, Darwinism has been dead for over 100 years. The speaker replied, well then, Neo Darwinism. At which the biologist replied, neo Darwinism has been dead since the late 1960s. And the speaker didn't know what to say at that point now I was more than mildly surprised. Neo Darwinism is dead. Haven't we been taught from for years that it is an incontrovertible fact that those who challenge it are either religious kooks or ignoramuses on the level of flat earthers? The modern synthesis, which dominated 20th century biology for much of the century and which most of us learn in schools, is dead. I recall a remark in this connection by William Dembsky about mavericks who challenge a scientific paradigm. Dembski said, at first they are simply ignored. Ignore them and they'll go away. When they don't go away, then they are ridiculed and laughed at. As their critiques continue and can no longer be ignored, they are refuted by advocates of the established view. Next they may come to be tolerated, and finally the response to them is, well, we knew that all along. The contemporary state of the debate shows at least, I think, that the modern synthesis is inadequate to explain evolutionary change and so at least needs supplementation by additional mechanisms. Doubtless those mechanisms will include some of those that we have just briefly surveyed, such as the epigenetic information emphasized by evo devo theorists. But notice our original question remains unanswered. Are these mechanisms even taken collectively, adequate to explain the grand evolutionary story required by the thesis of common descent? I'm rather confident that the whole story has not yet been told and that even if the doctrine of common ancestry is true, these mechanisms are insufficient to explain the biological complexity of that we have today. Something more is at work. Any comments or questions on that point?
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If someone were to question taking something like E. Coli or HIV and looking at it going through a long series of mutations, the extrapolation of that to something much more complex like a human, what could we say to them?
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What could we say differently?
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What could we say in response to that? If they were saying, oh yes, that
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extrapolation needs to be justified? I mean, after all, the point that Behe makes in choosing these simple microorganisms is the rapidity with which they reproduce and mutate. They have mutation rates that are just fantastic compared to say, horses and elephants and other large scale animals. So he's picking organisms like bacteria, microorganisms and viruses that would be the best candidates for random mutation and natural selection to have a significant effect on their development. Brad, so if the mechanisms of evolution, evolutionary change and diversity are unknown, do we reject, can we reject common ancestry and the mechanisms of that? I mean, why do we keep talking about it and talking about evolution and all and common ancestry I think it's all. Yeah, you kind of got a fork in the road here, I think which. Well, there are two routes, right that you could take. One route would be to say that the thesis of common ancestry is true but that these mechanisms are inadequate to account for it. And that would allow you to be in line with the genetic data that has convinced most biologists that all forms are genetically related to each other, but that these mechanisms can't explain it. The other one would be to go back to the thesis of Khan ancestry and say well wait a minute, maybe these mechanisms do have a kind of limited effectiveness. They can produce small scale evolutionary changes, but not massive ones. And so maybe the thesis of common ancestry isn't true. And then you're going to need to explain the genetic evidence. You're going to need to provide some alternative for that. But that would be a different way of doing it.
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Yes Steve, concerning the epigenetic I read about that your DNA is not your destiny and then some other things. And the neo Lamarckianism they found it in Finland where if you when they had bumper crops because they had accurate histories of populations for centuries when you had bumper crops people tended to overeat and had short lifespans but when they didn't have a lot of grain they ate healthier greens. And it turns out that they now know the and what's odd, what I'm going to point to is that it seems like it's designed in there. If you eat a lot of greens, only healthy genes get expressed and it's by the methane bonding the closer it is it controls which genes get expressed. And so who put the design to have it's like God's trying to train us to try to take care of ourselves. You follow what I'm saying? And, and so there's a design in there where we have. It's not something new, it's only controlling the epigenetics controlling what's already in there to be expressed. It's already all that's designed. And then one of the later things they went on this is after the DNA it's not your destiny. They said at a zygote that even where the binding of the nucleus there's a films that attach to the cell wall. If you move any of those you change the outcome. They said everything, every bit of information organizational is used in epigenetics. There's four layers of programming of the DNA and the methane for meat and greens is just one of them.
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It's a lower one very interesting. I haven't heard about that specific case, but you're quite right in emphasizing things like even spatial orientation and location can affect this. I think we have time for one more question, Jim. If there are all these problems with the mechanisms of evolution that we've been discussing, how does this fit in? If one were to accept theistic evolution, that will be the question that we will take up next time. Okay. If you look at your outline, you will see now that we come to a point, point of theological synthesis where we try to say, okay, how should we understand this then as Christians? So we'll look at that when we meet again. Let's close with the benediction. Worthy art thou our Lord and God, to receive all glory and honor and power and blessing, for Thou hast created all things, and by Thy will they exist and were created. Amen.
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The copyright for the preceding material is held by Dr. William Lane Craig. For more, go to reasonablefaith.org.