- Hits: 3433 3433
I am delighted to find so robust a rebuttal of the Modern Synthesis from such eminent scholars in the field of evolution. Chapter by chapter they describe "machine tools" (in effect) by application of which living creatures are manufactured and through which they are able to adapt to changing circumstances. These machine tools, embedded in the genome, mask their complexity by offering to circumstances simple levers and buttons by which adaptation and evolution can be effected, as a car's brake and accelerator present to us extremely simple means of control of enormously complex machinery by which we can, with minimal attention, adapt to the changing conditions of the road and our own whims.
The subtitle of the book is "Resolving Darwin's Dilemma"--the continued operation of natural selection depends on the continued creation of suitable variation. The authors suggest the generation of suitable variation in living creatures is facilitated by systems of feedback built into genetic "machine tools," enabling them to present to development and adaptation dashboards of simple controls through which challenges from the environment or development can be automatically matched to appropriate outputs and outcomes.
The result is a clear definition of the conundrum evolution presents us with. We see living creatures becoming increasingly complex in the course of evolution. How can we phrase that conundrum most clearly? I think, in terms of what I like to refer to as the "engines of evolution"--how did such engines evolve? This vague term I can now illustrate by reference to the genetic "machine tools" described in this book. The conundrum posed by evolution can now be expressed as, how can we account for the evolution of these machine tools?
I joke, of course, when I say "The Plausibility of Life" is a rebuttal of Darwinism, because the authors are fervent believers in selection and, I assume, mutation. They believe they have contributed to Darwinism by showing how living creatures can respond to environmental and developmental challenges with finely adjusted responses, but they may merely have exchanged one problem for another: how evolution could generate machine tools with such finely crafted feedback mechanisms built into them?
The nub of the problem is, how can you generate machine tools for the manufacture of phenotypes only through selection of those phenotypes? Imagine doing something similar with cars. By constantly taking the more robust cars off the road and duplicating them with small variations in factories equipped with machine tools, how could that result in changes in the machine tools that manufacture those cars? Natural selection works in the moment to meet challenges, surely it will select for a capability to make more of something, quickly, to meet the current challenge, rather than for the generation of a system for adjusting the manufacture of that something over a range of values appropriate to a wide range of potential challenges over eons.
In their final chapters the authors take on creationism. Responding to doubts about evolution's capability to account for the "origin of complex structural and functional organization and design in organisms" they point to how their "machine tools" (as I'm calling them) facilitate variation through dashboards by which simple envirnomental inputs can trigger more complex and appropriate adaptations. But the authors appear blind to the question of how those machine tools evolved, and how "novelty" was achieved in their construction. And if these tools are so powerfully conserved, how did they evolve? To evolve through mutation they must have been less conserved. When did evolution know they were complete and should now be "conserved" (spared further mutation)? Note these issues summed up here: "The special nature of the complexity [of an organism] is at the heart of the capacity to generate variation. Ironically this complexity is dominated by conservation. Novelty itself has been deflated. Variation is facilitated largely because so much novelty is available in what is already possessed by the organism."
The authors' hypothesis confirms the Lamarckian position that evolution involves two distinct capabilities: creative construction of novel new capabilities (the authors' "machine tools"), followed by "adaptation" of creatures with these new capabilities to all available niches [environmental inputs operating the tools' dashboards). This may account for how species from successive stages in this process can coexist--the older ones are not less able to survive, they are merely overshadowed, as trucks overshadow cars but despite their greater heft do not drive lesser vehicles off the road. The mechanism of evolution involves not so much selection as a creation and conservation of novelty. The authors fail to account for that.