Pseudoenzymes Illustrate Science’s Philosophical Commitments

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BY FAZALE RANA – DECEMBER 7, 2016

A few months ago, I had a serious accident while shooting a compound bow in my backyard. The arrow jammed in the guide, and in my attempt to free the arrow, I caused the bow string to derail. When that happened, the string struck my left eye with such force that it fractured my orbit in five places and damaged my retina. I am now legally blind in my left eye. Thankfully, I still have some peripheral vision, but I lost all the central vision in my injured eye. (To mothers everywhere: Yes, I wasn’t careful and I shot my eye out. I should have listened.)

Because of my injury, there is a blacked-out area in the center part of my field of vision which prevents me from focusing with my left eye. Sometimes, if something is on my left side, I can’t see it—even if it is in plain view.

Science’s Blind Spot

Over the years I have come to appreciate that, very often, the creation/intelligent design vs. evolution controversy has less to do with the evidence on hand, and more with how each side sees the evidence. As a case in point, when examining the features of biochemical systems, most creationists and intelligent design proponents readily see evidence of a Creator’s handiwork. Yet adherents to the evolutionary paradigm don’t see evidence for design at all. Instead, they see flawed designs. Why? Because they view biochemical systems as the outworking of an unguided evolutionary history. According to this view, evolution’s mechanisms have cobbled together biochemical systems by co-opting and repurposing existing systems to generate novel biochemical functions. As such, evolution produces kludge-job designs. Not the elegant, sophisticated systems expected if life stems from a Creator’s handiwork.

In part, the differing perspectives are shaped by philosophical commitments and the expectations that flow from them. To expound upon this point: the philosophical framework for contemporary science is methodological naturalism. Accordingly, scientific explanations for the universe and phenomena within the universe (such as the characteristics of biochemical systems) must have a mechanistic accounting—an explanation exclusively rooted in natural processes. Any explanation that appeals to the work of supernatural agency violates the tenets of methodological naturalism and is not even entertained as a possibility.

The consequences of methodological naturalism are far ranging for the creation/intelligent design vs. evolution controversy. The constraints of methodological naturalism exclude a priori any model that appeals to intelligent agency to explain, say, the design of biochemical systems. So although biochemical systems bear the appearance of design, the scientific community must explain the design as a product of evolutionary mechanisms. Why? Because they have no other option. If biochemical systems didn’t evolve, then they must have been created. But, the tenets of methodological naturalism forbid this explanation. Hence, biochemical systems must have evolved—by default.

If biochemical systems arise via evolutionary mechanisms, then they must be cobbled together. They must be poorly designed. Consequently, adherents of the evolutionary paradigm are conditioned to see biochemical systems as poorly designed—even if they aren’t—because of their commitment to methodological naturalism. Many can’t see the design that is in plain view for creationists and intelligent design adherents.

The recent discovery of pseudoenzymes helps illustrate this point.

Pseudoenzymes: Evidence for Evolution or Intelligent Design?

The existence of pseudoenzymes came to light about a decade ago when the human genome sequence was made available for researchers to study. It turns out that almost every enzyme family encoded by the human genome includes seemingly nonfunctioning members. (Enzymes are proteins that catalyze—or facilitate—chemical reactions in the cell.) Biochemists have dubbed these nonfunctioning enzymes pseudoenzymes. These proteins bear structural resemblances to other members of their enzyme families, yet they are unable to catalyze chemical reactions.

Because researchers have already detected pseudoenzymes within every known enzyme family, they expect that many more pseudoenzymes await discovery. In fact, analysis of thousands of genomes has identified pseudoenzymes throughout the biological realm. To put it another way: Pseudoenzymes seem to be pervasive in biochemical systems.

Evolutionary biologists view pseudoenzymes as a byproduct of life’s evolutionary history. Presumably, these noncatalytic enzymes arose when genes encoding their functional counterpart became duplicated. After this event, the duplicated genes experienced mutations that disabled the catalytic function of their protein products, generating pseudoenzymes.

For adherents of the evolutionary paradigm, the widespread occurrence of pseudoenzymes serves as a prima facie (based on first impression) challenge to intelligent design, and a compelling reason to think that biochemical systems are the product of an evolutionary history. In this framework, pseudoenzymes are vestiges of life’s evolutionary past; nonfunctional biochemical scars that impede cellular functions.

On the other hand, as a creationist and intelligent design proponent, I resist this conclusion. Why? Because I have a different set of presuppositions than most in the scientific community. I believe that life arose through a Creator’s direct intervention and that science has the tool kit to detect evidence of intelligent agency at work. Because of my precommitments, I would posit yet-to-be-discovered functions for pseudoenzymes and a rationale for why these enzymes bear structural similarity to catalytic counterparts within their enzyme family.

And this is exactly what biochemists have discovered—pseudoenzymes are, indeed, functional, and there are good reasons why these biomolecules resemble their catalytic analogs.

The Role and Rationale for Pseudoenzymes

In a recent primer written for the open access journal BMC Biology, two biochemists surveyed recent work on pseudoenzymes, concluding that this newly recognized class of biomolecules plays a key role in cellular signaling pathways.1

The authors reflect on the role the evolutionary paradigm played in delaying this insight. They state:

“Because of the prejudice that focused attention on the catalytic functions of enzymes in signalling pathways, for a long time pseudoenzymes were considered to be dead—and therefore evolutionary remnants or bystanders in cell signalling networks. Contrary to this view, however, pseudoenzymes have now emerged as crucial players operating with an impressive diversity of mechanisms that we are only beginning to understand.”2

In other words, the biases created by viewing pseudoenzymes as the byproduct of evolutionary processes hindered biochemists from identifying and characterizing the functional importance of pseudoenzymes.

But this flawed perspective of viewing pseudoenyzmes as junk is changing. To date, biochemists have identified at least four functional roles for pseudoenzymes:

  1. They serve as protein anchors, locating cell signaling enzymes to appropriate locations within the cell.
  2. They function as scaffolds bringing enzymes of the same signaling pathway into proximity with one another, allowing the enzymes to efficiently work in conjunction with one another.
  3. They modulate the function of cell signaling proteins by binding to them, exerting an allosteric-type effect.
  4. They compete with “catalytic” cell signaling enzymes by binding the substrate without transforming it, regulating substrate transformation.

In part, the functional significance of pseudoenzymes justifies viewing these biomolecules as the work of a Creator. But, if these biomolecules are designed, why would pseudoenzymes be so structurally like their catalytic cohorts? Evolutionary biologists maintain that these similarities reflect their evolutionary history. But, if there is reason for the structural similarities, it further justifies viewing pseudoenzymes as designed systems. As it turns out, a rationale does exist for the close similarity in structure between pseudoenzymes and other members of their enzyme family. As the authors of the survey note:

“Enzyme structures are predisposed to mediating interactions with protein or metabolite ligands and thus these folds are the ideal templates for nature to repurpose for entirely new functions.”3

In other words, for pseudoenzymes to influence cellular signaling pathways, they must bind substrates and interact with other proteins in the pathways with a high degree of specificity and with the identical specificity as their catalytic counterparts. Their close resemblance to their catalytic analogs allows these biomolecules to do just that.

In short, in fulfilling their vital role as regulators of cell signaling pathways, pseudoenzymes display elegance, sophistication, and ingenuity. As a creationist, this is the reason I view these systems as a Creator’s handiwork. Because the field of pseudoenzyme biochemistry is so young, I anticipate the evidence for design to dramatically expand as we learn more about these surprising biomolecules.

Yet, despite everything we have learned about pseudoenzymes, adherents to the evolutionary paradigm simply can’t see these biomolecules as anything other than the product of an evolutionary history.

Because of the blind spot created by their philosophical commitments, the design of these systems is occluded from their view—and that causes them to miss the mark.

Resources
The Cell’s Design: How Chemistry Reveals the Creator’s Artistry by Fazale Rana (book)
Pseudoenzymes Make Real Case for Intelligent Design” by Fazale Rana (article)
Q&A: Is Christianity a Science Showstopper?” by Fazale Rana (article)
Does the Evolutionary Paradigm Stymie Scientific Advance?” by Fazale Rana (article)
Q&A: Is Evolution Falsifiable?” by Fazale Rana (article)

Endnotes

  1. Patrick Eyers and James Murphy, “The Evolving World of Pseudoenzymes: Proteins, Prejudice, and Zombies,” BMC Biology 14 (November 2016): 98, doi:10.1186/s12915-016-0322-x.
  2. Ibid.
  3. Ibid.
Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2016/12/07/pseudoenzymes-illustrate-science’s-philosophical-commitments

Q&A: Is Evolution Falsifiable?

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BY FAZALE RANA – OCTOBER 5, 2016

I expected to get a reaction—and I did.

Last week I posted the below ‘meme’ on my Facebook page and Twitter account, claiming that the evolutionary paradigm is unfalsifiable because of the stranglehold that methodological naturalism has on the operation of science.

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And of course, it elicited a rather negative reaction by at least one atheist who listed a number of ways to falsify biological evolution, delineated by evolutionary biologist Jerry Coyne.

So, is biological evolution falsifiable? Was it unwarranted on my part to claim that biological evolution is unfalsifiable? Am I “full of it,” as this skeptic asserted?

My response: In principle, chemical and biological evolution are falsifiable, as are all scientific theories. But in reality, the evolutionary paradigm is unfalsifiable—because of the influence of methodological naturalism.

In effect, methodological naturalism restricts the available explanations for the universe and phenomena within the universe such as the origin and history of life. Certain explanations are off the table, a priori. As a consequence, intelligent design/creationism cannot be part of the construct of science.

The Effect of Methodological Naturalism on Scientific Inquiry

Methodological naturalism provides the philosophical framework for science. This concept is distinct, yet related to philosophical naturalism. According to philosophical naturalism, all that exists is the material, physical universe. There is no supernatural. There is no reality outside of the universe itself. There is no God. As the late astronomer Carl Sagan once quipped, “The cosmos is all that is, or ever was, or ever will be.”

In contradistinction to philosophical naturalism, methodological naturalism claims to be metaphysically neutral on the question of God’s existence. According to the tenets of methodological naturalism, when one engages in the scientific enterprise it is necessary to suspend belief in God, regardless of one’s personal convictions. The only allowed explanations for the universe and phenomena within the universe are natural process, mechanistic explanations. One cannot appeal to the supernatural. But that doesn’t mean the supernatural doesn’t exist. Simply put, the supernatural is not given a place in the scientific project.

In other words, if you believe that God exists, your views cannot influence the way in which you conduct science. Methodologically speaking, you must function as if God does not exist. Sometimes methodological naturalism is called provisional atheism or benchtop atheism. This restriction makes methodological naturalism functionally equivalent to philosophical naturalism, rendering science an inherently atheistic enterprise, though, again, its practitioners may well believe God exists.

In effect, methodological naturalism restricts the available explanations for the universe and phenomena within the universe such as the origin and history of life. Certain explanations are off the table, a priori. As a consequence, intelligent design/creationism cannot be part of the construct of science. Any explanation that states an intelligent agent is responsible for, say, the origin of life, is prohibited. As a result, chemical and biological evolution are the only available alternatives for someone who’s trying to scientifically account for the origin and history of life.

The net effect is this: Chemical and biological evolution are true by default, regardless of the evidence at hand. No matter how much evidence exists challenging the evolutionary paradigm, it cannot be supplanted because there is no other alternative explanation that is allowed.

A Failed Prediction for the Evolutionary Paradigm

As it turns out, discordant phylogenies plague evolutionary biologists. On this basis alone, one could conclude that the evolutionary paradigm has been falsified.

As an illustration of this point, consider one of the ways that Jerry Coyne thinks biological evolution can be falsified:

“Complete discordance between phylogenies based on morphology/fossils and on DNA. While individual genes can show discordance by lateral transfer—rotifers, for example, have incorporated into their genome from DNA from very unrelated organisms, and this is also common for bacteria. But lateral transfer of genes, as opposed to their direct descent from parent to offspring, is relatively uncommon. So, for example, if we sequenced the genome of a blue whale and found that on the whole the species was more closely related to fish than to mammals, we’d have a serious problem for the theory of evolution.”

Coyne’s prediction is similar to one made by the late evolutionary biologist Morris Goodman.According to Goodman, one of the founders of the discipline of molecular anthropology:

“If the biblical account of creation were true, then independent features of morphology, proteins, and DNA sequences would not be expected to be congruent with each other. Chaotic patterns, with different proteins and different DNA sequences failing to indicate any consistent set of species relationships, would contradict the theory of evolution.”1

As it turns out, discordant phylogenies plague evolutionary biologists. It is not uncommon for evolutionary trees built from morphological features to disagree with evolutionary trees built from DNA sequence data. Again, it is not uncommon for molecular phylogenies to disagree with one another when constructed using different regions of the genome. (For examples, see the articles listed below under Resources.) On this basis alone, one could conclude that the evolutionary paradigm has been falsified—or at minimum one would be justified to express skepticism about the capacity of the evolutionary paradigm to account for the origin, history, and design of life.

Again, these are not predictions made by intelligent design proponents or creationists. These are predictions made by evolutionary biologists, both of whom are (or were) skeptics. And on the basis of these predictions, the evolutionary paradigm has failed.

But Wait—Not So Fast

How do evolutionary biologists respond to the pervasive problem of discordant phylogenies?

By arguing that the discordance can be dismissed because morphological data is an unreliable indicator of evolutionary history. How do they know this is the case? Because morphological and molecular phylogenies disagree.

Or they claim that the discordance results from incomplete lineage sorting. How do they know incomplete lineage sorting has occurred? Because evolutionary trees built using different genes (or genomic regions) disagree.

Another way evolutionary biologists dismiss the discordant trees is to assert that some regions of the genomes are phylogenetically uninformative. That is, these regions of the genome don’t issue a phylogenetically reliable signal. How do evolutionary biologists know this to be the case? Because evolutionary trees built from certain regions of the genome don’t yield the expected results—and consequently, produce discordant phylogenies.

These responses are classical instances of circular reasoning. In effect, evolutionary biologists are using discordant evolutionary trees as a way to explain why discordant evolutionary trees result when they attempt to build phylogenies using different data sets.

Is Evolution Falsifiable?

Why the circular reasoning? Because if one adheres to methodological naturalism, the only valid scientific explanation for the origin and history of life is through some type of evolutionary process. Evolution must be true by default. Why? Because if the evolutionary paradigm is falsified, then the only other alternative is intelligent design/creationism. And this approach to biology is prohibited, a priori, because of philosophical commitments to a materialistic approach to the life sciences. This state of affairs can only lead to tautologies when failed predictions arise, though the tautologies are draped in scientific jargon.

So, is biological evolution falsifiable? Yes, in principle. But no, in reality.

I suspect that when evolutionary biologists list “if-they-are-true” observations that would disprove biological evolution, it doesn’t mean they are necessarily willing to consider another paradigm. Because if they were, they would readily see the evolutionary paradigm’s many shortcomings.

Resources

Origin of Complex Cells: A Big Event for Evolution or Creation?” by Fazale Rana (article)
DNA Sequences: More Is Not Better” by Fazale Rana (article)
Birds Terrorize Evolutionary Biologists” by Fazale Rana (article)

Endnotes

  1. Morris Goodman, “Reconstructing Human Evolution from Proteins,” chap. 8.4 in The Cambridge Encyclopedia of Human Evolution, Steve Jones et al., eds. (New York: Cambridge University Press, 1993), 307–13.
Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2016/10/05/q-a-is-evolution-falsifiable