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A review by joshuahedlund
Darwin Devolves : The New Science About DNA That Challenges Evolution by Michael J. Behe
3.0
I gotta be pretty close to the target audience for this book. I share Behe's profound dissatisfaction with the vague and convenient claims about the abilities of standard evolutionary mechanisms to overcome obstacles and create extraordinarily complex and strikingly teleological wonders. I share Behe's habitance in the spectrum between extremes, persuaded by compelling evidence for deep time and yet quite suspecting that God must have had something to do with it. So I wondered what "new" things he might have to say in his third book. I was quite intrigued by Behe's scientific descriptions of genetic mutations that benefit organisms in changed environments by breaking things. I was less impressed by his somewhat hasty conclusions that this is the only viable evolutionary mechanism in town. And I remain as baffled as ever about what exactly Behe believes actually happened instead.
In the last decade or two, genome sequencing has exploded in availability and affordability. We are now learning about the molecular details behind biological differences at an exponential rate. Behe devotes a lot of time to a particularly fascinating and recurring pattern where mutations that break things can actually be beneficial, and thus selected, if the organism's environment has changed such that it can actually survive better or reproduce faster without that broken function. Darwin's famous finches apparently evolved shorter beaks to eat different things by breaking genes involved in beak growth. Polar bears got white by breaking the genes for coloration. And on and on. Behe argues that we should expect random mutations that cause such beneficial destructions to be far more common than random mutations that build new stuff, simply because any random mutation on an existing protein is far more likely to do the former than the latter. These variations may help species diverge a bit and adapt a bit to changing conditions, but like a generalist "stick" that molds into specific uses as a "hammer" or a "fishing rod," these broken genes lock species into specialized corners they can't back out of by further random mutation. I found the genetic examples interesting, and the principle is one I will keep in mind - for example, when reading claims about the repeated loss of flight in birds settling on islands with open niches. But is that really all evolution can do on its own?
After arguing for the inadequacy of random mutation and natural selection to explain life's complexity, Behe describes a variety of "alternative" mechanisms that have been put forward in recent years by various evolutionary defenders. He uses their very existence as supplementary evidence for his own claims while dismissing them as equally inadequate. Behe is perhaps least dismissive of James Shapiro's "natural engineering" tools, but argues that even if such tools could create new functions, that still doesn't explain where the tools came from in the first place, and he's not impressed by the evidential lack of such tool use in, say, the famous long-running E. coli experiment. To Behe, purposeful complex functions can only come from a mind, and taking the finches and a couple other examples as illustrative, he draws a somewhat arbitrary line at the level of biological "family" for what evolutionary mechanisms can change.
But Behe doesn't offer anything more specific than that, and therein lies my greatest disappointment with the book. Mind is not a mechanism. If anything, it's a category for grouping mechanisms. And twenty years and three books later, he still hasn't proposed any, really. I understand exactly the model proposed by the young-earth creationists, as well as the godless Darwinists. But what is Behe's model for life having common ancestry but not going about it "randomly"? Does he imagine God as some kind of scienctist-gardener, letting creatures adapt randomly in minor ways but every million years or so bringing creatures into his cosmic lab to add some fresh genes and spark some new biological families or orders? Could the angels be involved? Or does the cosmic mind just sort of disseminate quantum effects on dividing cells in some woo-woo way to tilt base pairs in just the right way at just the right time? I do not ask these things in jest. I genuinely want to know what Behe thinks happened, or even just one possibility of what might have happened, on a practical and specific level. Especially if he's going to dismiss "alternative" natural explanations for not being practical or specific enough. Is that too much to ask?
Unfortunately, Behe seems to think dismissing everyone else and saying "therefore, mind" is good enough. But I don't find that any more satisfying than his opponents, and I'm not sure he's thinking clearly in his rush to get to his conclusions. For example, if Shapiro's tools can create new functions, could a mind create those original tools, as Perry Marshall seems to believe, and let life use them to evolve new things at higher levels than mere random mutation? Some of Behe's metaphors are also a bit counterproductive, conflating the building of complex things with their design. Centuries past, you used to be able to argue that complex things must have been built by humans, and not unintelligent or undirected processes; but now we have factories that can churn out widgets without human labor, and we know that our own cells are constantly dividing and building incredibly complex machinery with nothing more than the right starting conditions, the right energy inputs, and the laws of physics. Now those factories themselves were still designed by intelligent minds, and so perhaps the cells were too, but you're muddying the waters when you argue by analogy that it's impossible "to explain how unintelligent processes could make a building out of bricks and wood and pipes and wiring". Even Behe's conflation of mind and intelligence in the final section could use a bit of clarity to distinguish between animal intelligence and our own, or now the existence of artificial "intelligence" that can indeed arrange things in purposeful orders without possessing any sort of "mind".
So I learned some interesting things, but I still don't understand how Behe thinks we all got here. Maybe one day he'll explain it all in book number four...
In the last decade or two, genome sequencing has exploded in availability and affordability. We are now learning about the molecular details behind biological differences at an exponential rate. Behe devotes a lot of time to a particularly fascinating and recurring pattern where mutations that break things can actually be beneficial, and thus selected, if the organism's environment has changed such that it can actually survive better or reproduce faster without that broken function. Darwin's famous finches apparently evolved shorter beaks to eat different things by breaking genes involved in beak growth. Polar bears got white by breaking the genes for coloration. And on and on. Behe argues that we should expect random mutations that cause such beneficial destructions to be far more common than random mutations that build new stuff, simply because any random mutation on an existing protein is far more likely to do the former than the latter. These variations may help species diverge a bit and adapt a bit to changing conditions, but like a generalist "stick" that molds into specific uses as a "hammer" or a "fishing rod," these broken genes lock species into specialized corners they can't back out of by further random mutation. I found the genetic examples interesting, and the principle is one I will keep in mind - for example, when reading claims about the repeated loss of flight in birds settling on islands with open niches. But is that really all evolution can do on its own?
After arguing for the inadequacy of random mutation and natural selection to explain life's complexity, Behe describes a variety of "alternative" mechanisms that have been put forward in recent years by various evolutionary defenders. He uses their very existence as supplementary evidence for his own claims while dismissing them as equally inadequate. Behe is perhaps least dismissive of James Shapiro's "natural engineering" tools, but argues that even if such tools could create new functions, that still doesn't explain where the tools came from in the first place, and he's not impressed by the evidential lack of such tool use in, say, the famous long-running E. coli experiment. To Behe, purposeful complex functions can only come from a mind, and taking the finches and a couple other examples as illustrative, he draws a somewhat arbitrary line at the level of biological "family" for what evolutionary mechanisms can change.
But Behe doesn't offer anything more specific than that, and therein lies my greatest disappointment with the book. Mind is not a mechanism. If anything, it's a category for grouping mechanisms. And twenty years and three books later, he still hasn't proposed any, really. I understand exactly the model proposed by the young-earth creationists, as well as the godless Darwinists. But what is Behe's model for life having common ancestry but not going about it "randomly"? Does he imagine God as some kind of scienctist-gardener, letting creatures adapt randomly in minor ways but every million years or so bringing creatures into his cosmic lab to add some fresh genes and spark some new biological families or orders? Could the angels be involved? Or does the cosmic mind just sort of disseminate quantum effects on dividing cells in some woo-woo way to tilt base pairs in just the right way at just the right time? I do not ask these things in jest. I genuinely want to know what Behe thinks happened, or even just one possibility of what might have happened, on a practical and specific level. Especially if he's going to dismiss "alternative" natural explanations for not being practical or specific enough. Is that too much to ask?
Unfortunately, Behe seems to think dismissing everyone else and saying "therefore, mind" is good enough. But I don't find that any more satisfying than his opponents, and I'm not sure he's thinking clearly in his rush to get to his conclusions. For example, if Shapiro's tools can create new functions, could a mind create those original tools, as Perry Marshall seems to believe, and let life use them to evolve new things at higher levels than mere random mutation? Some of Behe's metaphors are also a bit counterproductive, conflating the building of complex things with their design. Centuries past, you used to be able to argue that complex things must have been built by humans, and not unintelligent or undirected processes; but now we have factories that can churn out widgets without human labor, and we know that our own cells are constantly dividing and building incredibly complex machinery with nothing more than the right starting conditions, the right energy inputs, and the laws of physics. Now those factories themselves were still designed by intelligent minds, and so perhaps the cells were too, but you're muddying the waters when you argue by analogy that it's impossible "to explain how unintelligent processes could make a building out of bricks and wood and pipes and wiring". Even Behe's conflation of mind and intelligence in the final section could use a bit of clarity to distinguish between animal intelligence and our own, or now the existence of artificial "intelligence" that can indeed arrange things in purposeful orders without possessing any sort of "mind".
So I learned some interesting things, but I still don't understand how Behe thinks we all got here. Maybe one day he'll explain it all in book number four...