Job 33:6
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- Jun 15, 2017
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It seems that you are hearing something different than what I am saying. Since your response overcorrects by treating legitimate questions about sufficiency and scope as if they were denials of observation. No one here is claiming that gene duplication, divergence, co-option, or regulatory evolution are hypothetical or unreal. They are real, observed processes. The issue is not their existence, but what they have actually been shown to explain, and at what scale.
Take Hox gene duplication as an example. Comparative genomics clearly shows expansion and diversification of Hox clusters in vertebrates. What this demonstrates is elaboration and modulation of an already deeply constrained regulatory framework, not the origin of body-plan coordination itself. Hox genes only function within a pre-existing developmental architecture involving positional information, chromatin regulation, transcriptional control, and cell signaling networks. Duplication expands degrees of freedom within that framework; it does not explain how the framework originated or why partial disruptions are not catastrophically deleterious. That distinction matters.
Similarly, co-option and regulatory change are powerful concepts, but they often function as retrospective descriptions rather than forward-looking causal demonstrations. Saying that a gene or module was co-opted tells us that it now plays a new role, not how the intermediate stages avoided loss of fitness while transitioning between roles. In many systems, small regulatory changes are not benign—they are harmful. The fact that some regulatory tweaks produce innovation does not establish that such outcomes are common or that they adequately explain the rise of highly interdependent systems.
Experimental evolution is frequently cited here, but its limits are rarely acknowledged. Laboratory experiments overwhelmingly demonstrate optimization, loss, simplification, or repurposing of existing functions, usually over short evolutionary distances and within tightly controlled environments. Cases where enzymes acquire genuinely new catalytic roles almost always begin with promiscuous activity already present and proceed through incremental refinement. This is impressive—but it still presupposes a rich functional starting point. It does not show how systems requiring multiple coordinated novelties arise without guidance or prior structure.
So the disagreement is not about whether evolutionary mechanisms operate, nor whether they can produce novelty in some sense. It is about whether the observed instances of novelty scale to explain the emergence of tightly integrated biological systems, where function depends on multiple components being present together, correctly regulated, and mutually compatible. Demonstrating that mechanisms can tweak, expand, or repurpose existing systems is not the same as demonstrating that they generate such systems from less integrated precursors.
In short, these mechanisms are empirically real—but the question remains whether their demonstrated capacities are causally adequate for the explanatory work they are often asked to perform. Asking that question is not misrepresentation; it is how explanatory claims are properly evaluated in any historical science.
While you correctly acknowledge that gene duplication, divergence, co-option, and regulatory evolution are real, observed mechanisms, your critique sets an impossible standard of proof by demanding that every step in the evolution of complex, integrated systems be historically documented. Evolutionary biology, like all historical sciences, does not, and cannot, observe every intermediate state that occurred millions of years ago. Instead, it uses comparative genomics, developmental biology, and experimental evolution to infer plausible pathways. These mechanisms have been directly observed producing novel functions and integrating into existing systems, demonstrating that stepwise, selectable intermediates exist, even if we cannot witness every historical transition. Treating this inferential evidence as insufficient misrepresents how scientific explanation works in historical contexts.
Moreover, your argument conflates the origin of a framework with the refinement of a system built upon it. It is entirely expected that evolution builds complexity from pre-existing components; that is precisely how modularity, co-option, and duplication function. Experimental evolution repeatedly shows that partially functional intermediates can be refined into fully integrated systems. Comparative studies, such as Hox gene cluster diversification, illustrate how duplication and regulatory evolution expand functionality while preserving viability. Demanding proof of “origins from scratch” ignores the evidence that evolution works by modifying and integrating components, not by spontaneously generating fully formed systems. Your concern highlights philosophical incredulity, not a genuine failure of evolutionary mechanisms to explain complex, coordinated biological systems.
Much of your critique conflates evolution with abiogenesis, which creates a fundamental category error. Evolutionary theory explains how life changes and diversifies after self-replication already exists; it does not, and is not meant to, explain how the first functional molecules, regulatory frameworks, or cells arose from nonliving matter. Mechanisms like gene duplication, co-option, and regulatory evolution operate on pre-existing, partially functional components, and both comparative genomics and experimental evolution show how these mechanisms can generate new, integrated functions over time. Demanding that evolution demonstrate the origin of life itself or fully document every intermediate step sets an impossible standard and misrepresents the explanatory scope of the theory.
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