I am skeptical that evolutionary processes can fully account for life’s origin, history, and design—and that often makes me feel like a fish out of water.
“Mainstream” scientists view biological evolution as the organizing principle in biology. In fact, Russian geneticist Theodosius Dobzhansky famously wrote, “Nothing in biology makes sense except in the light of evolution.”1 So, when I question evolutionary explanations, I become an outsider. I am outside the fish bowl, looking in. Because I’m a biochemist, my critics accuse me of being either dishonest or incompetent. Why else would I question the “fact” of evolution in the face of the overwhelming evidence for common descent? They claim that theological—not scientific motivations fuel my skepticism.
I would partially agree with that assessment. I find it hard to square certain features of the evolutionary framework with some of Christianity’s most important biblical and theological ideas. But, I also think that there are some very real scientific problems associated with the evolutionary paradigm. The deficiencies are best exposed by failed predictions.
From my perspective, the unpredicted pervasiveness of convergence justifies skepticism about evolution’s capacity to fully account for the history and diversity of life on Earth. Convergence stands as a failed prediction.
One of evolution’s failed predictions relates to the phenomenon known as convergence. This concept describes instances in which unrelated organisms possess nearly identical anatomical and physiological characteristics. Presumably, evolutionary pathways independently produced these identical (or near identical) features. Yet convergence doesn’t make much sense from an evolutionary perspective. Indeed, if evolution is responsible for the diversity of life, one would expect convergence to be extremely rare. As a I wrote in a previous blog post, the mechanism that drives the evolutionary process consists of an extended sequence of unpredictable, chance events. Given this mechanism, it seems improbable that disparate evolutionary pathways would ever lead to the same biological feature. To put it another way, examples of convergence should be rare.
The concept of historical contingency embodies the notion that evolution should be nonrepeatable, and is the theme of Stephen Jay Gould’s book Wonderful Life.2 To help clarify the concept of historical contingency, Gould used the metaphor of “replaying life’s tape.” If one were to push the rewind button, erase life’s history, and then let the tape run again, the results would be completely different each time.
Yet, biological convergence is widespread.3 Recently, researchers from the University of New South Wales (in Australia) added to the examples of convergence at an organismal level. From an evolutionary perspective, they showed that amphibious behavior in fish evolved 33 separate times among extant groups! In fact, in one family, fish adopted a terrestrial life style between 3 to 7 times.
This result was unexpected. One of the researchers involved with the study stated, “Because of the challenges fish face in being able to breathe and move and reproduce on land, it had been thought this was a rare occurrence.”4
Recently, another team of investigators from the University of Kansas identified another example of biochemical convergence. They showed that venom evolved, separately and independently, 18 times in fish that live in freshwater and marine environments. This result is all the more surprising because—as William Leo Smith, one of the study’s authors points out— “fish venoms are often super complicated, big molecules.”5
Does the Widespread Occurrence of Convergence Falsify Evolution?
From my perspective, the unpredicted pervasiveness of convergence justifies skepticism about evolution’s capacity to fully account for the history and diversity of life on Earth. It stands as a failed prediction. Yet many evolutionary biologists don’t see it that way. For example, the scientists from the University of New South Wales responded to their unexpected find this way: “Now we have shown this initial transition to land is quite common, it seems these challenges can be readily overcome.”6 However, their interpretation entails circular reasoning. Biologists thought that fish moving to land would be difficult given the immense challenges associated with this transition. But, when it was found to be a frequent occurrence, then they conclude it must be easy. But they have no reason to think it must be easy other than the widespread occurrence of this transition. I would contend that this circular reasoning reflects a deep-seated, a priori commitment to the evolutionary paradigm, in which evolution is accepted as fact, and no evidence can ever count against it.
Convergence and the Case for Intelligent Design
Though the idea of convergence fits awkwardly within the evolutionary framework, it makes perfect sense if a Creator is responsible for life. Instead of convergent features emerging through repeated evolutionary outcomes, they could be understood as reflecting the work of a Divine mind. The repeated origins of biological features equate to the repeated creations by an intelligent Agent who employs a common set of solutions to address a common set of problems facing unrelated organisms.
The Cell’s Design (book)