The subtitle of Behe's book suggests that it will present a scientific challenge to "evolution", but like his previous books, Darwin Devolves consists largely of subjective, semantic, and philosophical arguments rather than rigorous and compelling scientific evidence. Despite Behe's often railing against "Darwin's Theory" and "Darwinism," one soon learns that he acccepts the reality of "descent with modification" as well as an Earth approx. 4.6 billion years old, and that is main objection is the widely accepted conclusion that natural selection is a major mechanism of evolutionary change.

As a supposed "alternate theory", Behe advocates the vaguely defined concept of "intelligent design". Evidently what he means by this (as he often hints, but never directly states) is that some sort of divine or supernatural genetic manipulations took place during Earth history, without explaining or offering evidence for how, or how often these events occurred, or by whom (though most assume that "designer" is his code word for God). In contrast, natural selection and other natural processes (such as genetic drift) have been studied in various ways, and confirmed as important mechanisms of biological evolution.

Despite repeatedly lambasting "Darwinism" Behe himself acknowledges that natural selection can produce evolutionary chances including new species, but insists that it never produces any beyond the family level. He then seems to contradict the above admissions by declaring that natural selection actually causes organisms to "devolve" because the random mutations on which natural selections acts always "break" functioning genes. This assertion, which is the major thesis of his book, seems quite misleading, since there is abundant evidence that a small portion of mutations can confer adaptive advantages to organisms as their environments change, thus making mutations and natural selection major factors in evolution, and in a positive way. Even many young Earth creationists (YECs) accept this; in fact, Answers in Genesis authors cite mutations and natural selection as having significant and roles in speciation and "rapid post-Flood diversification" (even though they also believe all major "kinds" of organisms were created directly and only about 6,000 years ago).

Extending his apparent "cognitive dissonance" Behe himself acknowledges in places that random mutations can sometimes be "useful" and help organisms survive (he even cites examples), yet he continues to insist (sometimes in the same sentence) that mutations consistently "break" or "degrade" genes, and therefore even when selected, they cause "devolution." However, this strikes me as just playing with words, since clearly would be objective and fair for Behe to use terms such as "change" and "adapt" rather than "break" and "devolve" (especially since he never even defines the latter term). After all, if mutations can be "useful" and help organsims adapt and form new species, genera, and families (as he allows), then calling the process "devolutionary" seems not only dubious, but downright backwards. As a rough analogy, it would be like saying that if you replaced your functioning car tires with newer, deeper-tread snow tires to deal with slick or muddy road conditions, you have somehow "broken" your car or caused it to "devolve."

At any rate, Behe repeatedly insists that natural selection cannot produce anything but "trivial" changes (which again, he generally considers any less than at the family level). As supposed support for this claim, he stresses that no changes beyond new species have been observed in modern times. However, that argument is illogical and unfair, since larger evolutionary changes normally require far larger spans of time than can be directly observed in the lab or field in human lifetimes (and yet are well documented in the fossil record). Moreover, most scientists would not consider changes at the family or even genus level to be "trivial", nor see any reason why natural selection would not operate beyond those levels.

Behe notes on p. 155 that no new phyla, orders, or classes of animals have evolved in the last 2 million years, then flippantly remarks: "Surely we would expect at least one crummy new phylum, class, or order to be conjured by Darwin's vaunted mechanism [in that time span]." He adds "But no, nothing." Nothing? First, during those 2 million years many new species, genera, and families evolved and diversified, which as noted before, is hardly trivial, let alone "nothing." Second, that higher taxonomic levels did not appear during the last couple million years does nothing to discount the evidence that many did arise by natural means over far longer time spans earlier in Earth history. Behe states that during the "Cambrian" explosion many higher groups appeared over about 10 million years, as if that supports his point that similar higher taxa should appear in the last 2 million years. Besides the fact that most paleontologists indicate that the Cambrian explosion lasted for at least 25 million years, Behe neglects the important point that during early Cambrian times, many more ecological niches were available fill than in later periods, especially the last two million years. Moreover the environmental conditions (chemistry, radiation levels, number of organisms, etc. could have further contributed to the origin of new and higher taxa). Third, Behe's use of the term "nothing" for that span seems ironic in that it covers the origin of human beings from hominid ancestors.

Indeed, considering that Behe later stresses how unique human beings and their minds are, and that even some laymen who accept evolution of most organisms are bothered by the idea of human evolution, it seems quite curious that Behe glosses over human evolution, and does not clarify whether he thinks it required divine interventions, even though many hominids are considered to be in the same family and even genus with modern humans. This again raises questions about how, when, and by whom or what he imagines "intelligent design" was imparted to living things, and how such questions can be tested.

As in previous writings, Behe does not even try to answer them, and instead focuses showing that "intelligent design" in general can be demonstrated. His favorite approach is to cite alleged examples of "irreducible complexity", which he defines as structures or systems composed of several or more parts too well integrated to have arisen through a series of natural steps. He contends that if one cannot remove a component of a system or structure without destroying its function, then it is Irreducible Complex, and by inference, intelligently designed.

To illustrate the concept of IC Behe uses the example of a spring-loaded mouse trap, but even if it or other man-made machines were truly IC (more on this later) it would not prove that any biological systems are IC, since they have key differences. For one thing, the latter are composed of more plastic and sub-divisional components, which can always be somewhat reduced or altered at lease on a molecular level, without destroying all function of the system or structure. In other words, if one cannot take away major parts, one can aways remove part of a part, or part of a partial part, etc., and if the system was built in a sub-part fashion, or using templates or parts no longer used (or once used for other purposes) what collapses is Behe's argument for IC.

Behe cites several supposed example of biological structures or systems that are IC (including the blood clotting system and the human immune system), but he focuses most on the bacteria flagellum, which he calls the "poster child" case for Irreducible Complexity (IC). However, this case and the few others Behe has cited (such as the human blood clotting system and human immune system) have been thoroughly addressed and well refuted by other workers, including biologist and fellow Christian Kenneth Miller (1998, 2007). Despite this, he does not even mention Miller except in passing and on another matter, without citing any of his writings. Ironically, if Behe's ID thesis were true, it should be easy to cite countless clear examples of IC. That all he can muster is a few widely disputed ones thus does more to undermine than support his thesis.

Granted, Behe's inability to cite lots of clear IC examples does not prove that none exist. After all, every time an example is refuted, Behe can propose another one, and so on, ad infinitum. However, this brings up another serious problem with Behe's claims, which is that unlike proper scientific theories, "intelligent design" is not falsifiable. There is no conceivable test that would demonstrate that there was no "design" or "intelligence" behind a particular biological structure, let alone all biological systems and structures.

Behe disagrees and asserts that Intelligent Design is readily falsifiable. He states, "all a scientist has to do to prove me wrong is take a bacterium without a flagellum, or knock out genes for the flagellum in a bacterium, go into his lab and grow a bug for a long time and see if it produces anything resembling a flagellum. If that happened, intelligent design, as I understand it, would be knocked out of the water. I certainly don't expect it to happen, but it's easily falsified by such experiment" But like his other challenges, this one is absurdly unreasonable and patently illogical. As Behe knows, the evolution of the flagellum would have taken many thousands to millions of years, and under specific environmental conditions difficult to known, let alone accurately (or even approximately) reproduce in a lab. As Ed Brayton notes, Behe's challenge is "like arguing that a solar system could not have come together on its own without divine intervention, and that you can easily falsify that claim by creating a solar system in your laboratory..." (Brayton, 2006) Moreover, Miller and others have already shown that the flagellum is not irreducibly complex for other reasons, making Behe's challenge moot. Even more fundamentally, falsifying any specific alleged example of IC does not prove that other examples do not exist, let alone that no "intelligent design" was involved in the origin and evolution of living things, regardless of whether any are IC. So anyway you slice it, "Intelligent Design" cannot be falsified even in principle, making it inherently unscientific.

Behe has complained that critics want it both ways--to say they have evidence against his claims, but that ID is not falsifiable. But again his logic is faulty, and he is using a "bait and switch" tactic. What Miller and other critics of Behe have done is refute specific IC claims, which are indeed falsifiable, not his general claim that all living things are "Intelligently Designed", which are not falsifiable, for reasons already explained. Moreover, even it were possible (which it is not) to show that no biological systems are irreducible complex, Behe could still claim that they could have been designed anyway. After all, just because something could have originated without divine intervention or guidance, doesn't necessarily mean it was.

On the other hand, if all living things were rife with IC structures and systems as Behe claims, then he should be able to readily document countless clear examples. That can only cite a few alleged and widely disputed ones therefore seems to do more to undermine than supports his thesis.

Moreover, Behe's IC claims suffer from an even more basic problem, which is that is his central assertion that an IC system cannot come about through a series of natural steps is demonstrably flawed. For example, a natural bridge could form at least two different ways (Fig. 1 and 2). Both are IC by Behe's definition, in that one cannot remove major part of either without collapsing them and destroying their function as bridges. By Behe's logic, this means they must have been intelligently designed, but obviously this does not follow. These examples also show why Behe's routine use of the term "purposeful arrangement" is biased and misleading. These natural structures serve the function of a bridge, just as many biological structures serve one or more functions, but as these examples show, one cannot assume that that something "functional" is necessarily "purposeful" in the sense Behe implies (that is, demonstrating an underlying intelligence). Moreover, these examples indicate that IC entities can arise even without the benefit of natural selection. Lest Behe claim that one could take away part of one of the slabs and still not destroy the bridge, one could likewise take away a part of one of his mousetrap parts (say, chip away part of the base, or make the spring smaller, etc. and still have it work. That's one reason it would be hard to claim any complex structure (organic or inorganic) is truly IC. That is, one can always alter or take away a part of a part, or a part of a partial part (at least on a molecular level) and still have the structure or system largely or somewhat function.

Figure 1. A natural arch serving as a foot bridge, formed in a series of natural steps. After a series of sedimentary strata are deposted over time (A), uplift and erosion could produce an arch-like structure (B). Over only the surface layer might be left (C), composed of multiple blocks, and serve as a fairly stable natural bridge (despite being IC by Behe's definition), without even having help from natural selection, let alone "intelligent design" or a pre-ordained "purpose."

Figure 2. A natural bridge formed in an alternate and even simpler way. Simiar bridges actually exist in nature (see photo below). Both figures © Glen J. Kuban, 2019

Figure 2. Natural Bridge, National Bridges National Momument, San Juan Co, Utah. Photo by S. Krieg

Moreover, the relevance of the example because especially clear in view of evidence that certain biological structures originally formed on frameworks or "scaffolds" that have since been reduced or lost, cause the current system to be irreducibly complex, without implying intelligent design. Likewise, Behe largely neglects the concepts of preadaptation and exaptation, whereby structures used for a certain function or functions can through natural selection be later used for other functions. This applies to Behe's IC claims, because as Behe's colleagues note, a structure can be presently IC even though it was naturally built from one that was not (Lang and Rice, 2019).

Behe makes other arguments in an attempt to support ID, but most are essentially appeals to intuition, instinct, and "common sense," which hardly constitute scientific or compelling evidence. He often stresses how difficult it is to imagine how certain biological structures or systems could come about naturally, implying they therefore must have been intelligently designed. However, these involve additional logical fallacies, termed the "argument from incredulity", the "argument from ignorance," and "God of the gaps" argument. They all entail the faulty logic that if we don't know how something happened, or can't imagine how it happened, then either it didn't happen, or God did it. Of course, the problem with this type of reasoning is that our imaginations are quite limited, and that scientific evidence and knowledge tends to expand with time (and be self-correcting), and thus is generally more reliable than intuition and subjective judgments.

Similarly, Behe repeatedly commits the fallacy of "assuming one's conclusion" by asserting that various biological structures must have been intelligently designed because they display "purposeful arrangement". The problem is, the concept of "purpose" is subjective, and already presupposes intelligent design. Indeed, if one substitutes the more neutral term "function" wherever Behe uses the loaded term "purpose," the biological facts remain the same, but his teological conclusions evaporate. As noted earlier, Behe uses similar semantic ploys by stating that all mutations (even if useful) "break" or "damage" a gene, instead of using more neutral terms such as "change" or "alter." Most of Behe's other arguments are likewise based more on semantics and/or dubious logic than substantive evidence. Many are essentially repetitions of the same well-refuted arguments from his previous books, such as Darwin's Black Box and Edge of Evolution).

For example, Behe repeatedly evokes William Paley's 1802 "Watchmaker" argument, which says that if something appears designed, then we can safely assume it was designed. However, this does nothing to counter the abundant evidence that natural selection and other natural processes acting over long time spans can produce structures and systems with the appearance of design. By Behe's argument, one would assume that the neck of the giraffe was "purposefully" and "intelligently" designed to reach tall branches. He actually intimates as much on p. 150. However, virtually all modern scientists, and even many YECs today, accept that the giraffe's neck and many other impressive biological features can arise through natural selection. In fact, the YEC group Answers in Genesis includes a short-necked giraffe-like animal to illustrate this.

Indeed, for these and other reasons Behe is not consistent with the Watchmaker argument. After all, he allows that natural selection can produce many changes in organisms, at least up to the family level. However, the features or organisms involved will often appear designed for a specific function (or in Behe's biased parlance, "a purpose"), even though being within the family level, they are within the capabilities of natural selection. In other words, the Watchmaker analogy as applied to living things and many of their features is unreliable even by Behe's own standards. Returning to the neck of the giraffe, Behe implies that neck was intelligently designed, even though giraffes are in the same family as the shorter-necked Okapi and some fossil giraffes. So again, by Behe's own standards, his inference that giraffe necks were intelligently designed is baseless and inconsistent.

Examples even outside of biology can further illustrate the principle that appearance of design does not prove actual or "intelligent" design. For example, under certain geologic conditions, iron pyrite crystals can form virtually perfect cubes. They certainly look like fabricated objects, even though they are clearly products of nature. Likewise, snowflakes come in all sorts of intricate and elaborate patterns, which also give the appearance of design, and even quite artistic design. Yet I am sure even Behe would not argue that God habitually manipulates frozen water droplets to create snowflakes. Naturally, one is free to believe that God or some higher power created the materials and physical laws involved in these phenomena, but such beliefs, like many of Behe's theological claims, are untestable and thus outside the realm of science.

On p. 87 Behe criticizes supposedly "dogmatic thinking" that "rejects the evidence of our uniform experience--that the purposeful arrangement of parts of a system reliably indicates design." However, not all our experiences are "uniform" and if he means everyday experiences in general, those too are often unreliable, especially when it comes to scientific issues. And again, if he had used the more objective term "functional arrangement" in place of the presumptive term "purposeful arrangement", his argument immediately fails.

Behe continues the same flawed reasoning by stating, "...whenever we see independent pieces ordered to each other to make a coherent whole, we should always suspect design..." But suspicions are not scientific evidence, and as been already shown, "ordered arrangements" of parts do not prove "purposeful design" in either living or nonliving systems. Perhaps sensing the weakness of his argument, Behe adds, "...the more pieces there are and the more "closely matched to the whole" [whatever that means], "the stronger our confidence in an intelligent design conclusion." However, this just an extension of the same flawed argument. To illustrate, if thousands of ice crystals formed an elaborate "design" on one's living room window, or numerous mineral crystals combined to formed a spectacular geode cathedral (as they sometimes do), neither would not constitute any more compelling cases for intelligent design than a single snowflake or single pyrite cube.

Behe's reference to "dogmatic thinking" also seems unfair to critics of Behe's claims. Many do not rule out the possibility of God or other religious beliefs --they just do not (unlike Behe) consider it within the realm of science to either confirm or disprove them. This includes Behe's own colleagues at Lehigh University (where he teaches biochemistry), who have renounced Behe's views, stating, "It is our collective position that intelligent design has no basis in science, has not been tested experimentally, and not should be regarded as scientific."

In short, while Behe repeatedly implies that major biological changes must be due to some sort of divine interventions or guidance, his arguments for this are weak and subjective at best, often relying on flawed logic or misleading semantics. He provides no positive evidence for ID beyond dubious examples of irreducible complexity, nor any explanations or evidence for what specific interventions took place, or how, when, or by whom they occurred.

In the final section of Darwin Devolves, entitled "Solution," you might expect some attempt to answer some of these questions, and perhaps to provide some evidentiary support. Instead, he returns to the simplistic "mind vs. accident" theme, and launches into a long treatise about the nature and mysteries of the "mind" --suggesting that only an intelligent first mind can explain the human mind (even though he does not even precisely define the term), and that this somehow constitutes an all-encompassing solution that answers, or eliminates the need to answer, the above questions.

However, not only does it fail to answer the specific questions noted above, but even as a general defense of the "design" view it falls flat. As with previous arguments, those in this section likewise rely on semantics, speculation, and philosophical arguments rather than scientific evidence. He ridicules others for holding that the "mind" is a natural product or manifestation of the brain, even though this is widely held by a majority of scientists and laymen alike. Indeed, many religious believers do not see this view of the mind as a threat to the religious concept of a human soul or spirit, as these are widely regarded as something beyond "mind" and beyond the domain of science.

Many other examples of dubious and misleading comments by Behe could be offered. For example, on p. 81 he suggests that scientists have no explanation for how a complex eye could evolve, other than pointing out (as Darwin did) that living creatures have a wide range of eye-like structures, from simple light-sensitive spots to intricate eyes of vertebrates. However, many scientific papers discuss fossil and anatomical evidence for the evolution of the eyes which go far beyond what Behe claims. Moreover, even the range of eyes documented, and the fact that in most cases, one can remove or alter some part of the eye, or a part of a part, and still have some measure of vision, demonstrating they are not irreducibly complex. Likewise, Behe claims in other writings that no one had published any details of how the human immune system or blood clotting system evolved or even could have evolved, and that it was because they were irreducibly complex. In fact, scores of scientific papers on each had been published, including ones showing that neither are "irreducibly complex."

In several places Behe remarks that "many scientists" reject or question "Darwinism", even stating that there is "widespread skepticism" on the issue. In fact, the vast majority of scientists (by all evidence over 99% in highly relevant fields such as biology and paleontology), including most theistic ones, accept biological evolution and the important role of natural selection. Any debates are largely over the relative role of various mechanisms and factors, and how to integrate new findings in genetics, population biology, and paleontology, not whether "intelligent design" is a more plausible explanation (even at higher levels of change) than natural mechanisms, or even a valid scientific theory.

Some young-earth creationists might misconstrue (if they did not read carefully) that Behe supports their view. However, even though both groups subscribe to the idea of "design", they differ greatly on how it came about. Whereas YECs believe that God created the entire universe and all basic "kinds" of living things only several thousand years ago, as noted earlier, Behe accepts a 4.6 billion year old Earth, and "descent with modification" (including human evolution), while evidently believing that major evolutionary changes came about through numerous episodes of divine genetic interventions over vast periods of time.

That said, to advocate their views, both Behe and many YECs often use flawed arguments and incomplete or misleading depictions of the evidence to advance their views. Both also often try to reduce the entire issue to "accident" vs. "preexisting mind" or "chance vs. God", which oversimplifies both the evidence and the views of many people. For example, natural selection is not a random process, but operates on random mutations. Likewise, many people (including some scientists) believe or allow that God could have worked in a transcendent or "behind the scenes" way through evolution, but do not claim this can be scientifically demonstrated, or that trying to do so is even within the realm of science.

Indeed, during court cases regarding the teaching of Intelligent Design in public schools, Behe's ID views were ruled to be inherently religious rather than scientific (Fampeople.com, 2019).

References

Behe, Michael J., 1996 (2nd Ed, 2006), Darwin's Black Box: The Biochemical Challenge to Evolution. New York: Free Press. ISBN 978-0-684-82754-4.

Behe, Michael J., 2007. Edge of Evolution. New Your: Free Press.

"Fampeople", 2019, Michael Behe: Biography. Web article at: https://fampeople.com/cat-michael-behe_2

Lang, Gregory L, and Amber M Rice, 2019. Evolution Unscathed: Darwin Devolves agues on weak reasoning that unguided evolution is a destructive force, incapable of innovation. Evolution 73-4, p. 862-868. Web version at: https://onlinelibrary.wiley.com/doi/full/10.1111/evo.13710

Miller, Kenneth A, 2007. Finding Darwin's God. Harper Perennial.

Miller, Kenneth A. 1996. Review of M. Behe's book: Darwin's Black Box. Published in Creation/Evolution, Vol. 16: pp, 36-40. Web version: http://www.millerandlevine.com/km/evol/behe-review/index.html