THE "FATAL FLAWS" WITH RICHARD CARRIER'S "EVOLUTIONARY" HAND-WAVING TO THE ORIGIN OF LIFE
The "Fatal Flaws" with Richard Carrier's
"Evolutionary" Hand-Waving to the Origin of Life
(from Self-Replicators to Cellular Life)
This brings us to another "Fatal Flaw." Richard glosses over the rest. He jumps from A all the way to Z, invoking "evolution" to solve the rest. But that amounts to hand-waving, and won't cut it (Yes, I’ve read all his cited sources, and they do not change this conclusion. In fact, Richard seems unaware of all they leave out, and the huge gaps that still remain). As I've told him before, jumping from a single self-replicator to life is like saying, "Hitler failed his entrance exam for art school. One thing led to another. And the US dropped an atomic bomb on the sovereign nation of Japan." It leaves out most everything, and explains nothing.
Richard's minimalist “self-replication is the definition of life” betrays the crux of the problem: life as we know it is far too complex to spontaneously generate (Piette, B. M., & Heddle, J. G. (2020). A peptide–nucleic acid replicator origin for life. Trends in ecology & evolution, 35(5), 397-406.):
"Life as we understand it is cellular. The last universal common ancestor (LUCA) of all cells (not a single cell of course but a population) is understood in some detail; it possessed a cell membrane, DNA, the basic molecular machines for copying DNA (i.e., polymerase etc.), and a functional ribosome, among many more. From this highly truncated list alone it is clear that LUCA was far too complex to spontaneously assemble. It must have evolved from simpler systems, themselves able to self-replicate with some tolerance for error (otherwise they would not be able to evolve). Indeed, it is difficult to imagine that anything recognizably a cell could have spontaneous origins.” (emphasis added)
Of course we say evolution must be involved, because the spontaneous origin of life as we know it seems impossible. Richard has moved the goal posts to an ultra-minimalist position that locates the origin of life at the level of a single self-replicator, because that’s the only type of ‘abiogenesis’ he can ‘prove’—he doesn't believe life as we know it can spontaneously emerge either! And yet life as we know it is what most people think of when they hear the “origin of life”.
An explanation for life’s emergence requires explaining how we get to life as we know it.
Now Richard and I could argue in circles about the definition of "life", how simple "first life" can be, and other possible forms of life, but it doesn't change the fact that some way, somehow, whether by spontaneous origin, evolution, or a combination of both, we still have only a few hundred million years at most to go from inert chemicals to life as we know it and the Last Universal Common Ancestor (LUCA) by approximately 4.0-4.1 billion yrs; the latter, with an estimated 500-600 genes (Koonin, E.V. (2003). Comparative genomics, minimal gene-sets and the last universal common ancestor. Nature Reviews Microbiology, 1(2), 127-136); which is about 100 genes more than our smallest known minimal cell (See, e.g., Reuß et al.(2016). The blueprint of a minimal cell: MiniBacillus. Microbiology andMolecular Biology Reviews, 80(4), 955-987; Strychalski et al. (2016). Design and synthesis of a minimal bacterial genome, see, here for pdf). These minimal cells, however, are either obligate parasites or synthetic cells that cannot exist on their own in a natural environment. The smallest known free-living cell requires at least 1,000 genes and 1,000 proteins. But let's go with the conservative 400 hundred or so genes with 400 hundred or so proteins that empirical studies support for a minimal cell. And we need thousands of copies of each of these proteins and other molecules--an estimated 1 million molecules total crammed into a tiny 1 cubic micrometer or so volume in order to achieve the requisite 'molecular crowding' required for cellular processes.
This minimal cell must of course have at least three main functional components: (1) compartmentalization, (2) replication, and (3) metabolism. Richard mocked me the last time I said this, but there is actually widespread recognition of this; despite our lack of consensus definition for life. See, for example, Figure 2 in the article I cited above: Kitadai, N., & Maruyama, S. (2018). "Origins of building blocks of life: A review," and also p. 1118, wherein they write:
"Life is generally characterized by the following three functions: (1) compartmentalization: the ability to keep its components together and distinguish itself from the environment, (2) replication: the ability to process and transmit heritable information to progeny, and (3) metabolism: the ability to capture energy and material resources, staying away from thermodynamic equilibrium."
This minimal cell must of course have at least three main functional components: (1) compartmentalization, (2) replication, and (3) metabolism. Richard mocked me the last time. The Reuß et al. (2016). The blueprint of a minimal cell: MiniBacillus article includes a detailed description of the types of genes and proteins/enzymes needed to direct a wide range of cellular processes that fall under our three components (For a summary breakdown, see, Table 1).
This is the type of "minimal life" we have to get to from inert chemicals in a few hundred million years. If a "self-replicator" is A, then our minimal cell is Z. In my mind, we haven’t explained the emergence of life until we explain how to go from inert chemicals to life as we know it.
Now before Richard accuses me of committing "fatal flaws" of my own, let's acknowledge that evolution is involved in getting to this point, and let's also acknowledge that "first life" could be far simpler (Although, we don't have empirical evidence for that, it is a common assumption and I concede the theoretical possibility). But regardless, it still doesn't change the fact that we still need to get to this type of minimal life (400 or so genes), and then LUCA (500-600 genes) in a few hundred million years by about 4.0-4.1 billion years or earlier (See, e.g., Harrison, M., & Bell, E. A. (2020, December). A Plan For Detecting Evidence of Hadean Life. In AGU Fall Meeting Abstracts (Vol. 2020, pp. P030-03): "molecular clock predictions" suggest the last universal common ancestor (LUCA) of Eubacteria and Archaebacteria emerged between 4.2 and 4.4 Ga.").
Now everyone agrees evolution is obviously involved, but that doesn't mean we can simply invoke the word "evolution" to span the gulf between A and Z. That is not an explanation. That is a gloss. For one, biological evolution and "chemical evolution" are not equivalents. Biological evolution is more concretely defined, while chemical evolution is not. The latter has no consistent, recognized usage, and is employed indiscriminately to mean different things in different contexts. That, among other things, is why Richard can't just say, "all we need is a single self-replicating molecule" and then "evolution" will do the rest. "Evolution" in the context of the origin of life is nebulous in meaning, so you must define it and provide more explanation beyond the word itself. We can't just jump from A to Z with a wave of the "evolutionary" hand, and then claim "science has shown." We must empirically demonstrate how we go from inert prebiotic chemicals to a single, self-replicating molecule to something like the aforementioned "minimal" life we know we must get to by about 4.0-4.1 billion years without invoking a simple "evolutionary" hand-wave that on closer look doesn't really explain anything, and lacks true empirical grounding.
Now what astounds me in all this is that Richard seems to think we've already bridged the gap. Yet every investigator around recognizes--what for some baffling reason he does not and seems blinded to--that we don't have a complete, convincing, empirically established, unbroken chemical pathway to life, but have enormous gaps, obstacles and holes in our understanding. This is such a common knowledge fact that hardly requires documentation that it is astonishing that you deny it. But to cite a couple examples, take for instance Kitadai, N., & Maruyama, S. (2018), who with regard to their Figure 15 "overview of chemical evolution" state that “several steps, particularly at the later stages of chemical evolution, are still highly hypothetical,” and that there is a “huge gap…between the primitive protocell composed of fatty acid and RNA, and the modern DNA/RNA/protein system. Most seriously, the overview (Fig. 15) might not represent prebiotic processes that actually occurred on the primitive Earth; rather, it was depicted based on current scientific knowledge about the origin of life. Future research might discover new reaction mechanisms that improve yields and selectivity of life’s building blocks synthesized abiotically, or be able to link currently unconnectable reaction networks.” (p. 1142).
See, also, Sutherland J.D. (2017). Opinion: Studies on the origin of life—the end of the beginning. Nature Reviews Chemistry, 1(2), 1-7: "Figure 3; Transition to life: onwards and upwards,” and see where Sutherland puts the “Current state of the field” in relation to what he considers to be “Fully alive.”
Sutherland also states in the abstract that "We are not yet close to achieving this end [i.e., of demonstrating chemical evolution] "in the laboratory [to] show how life can start from the inanimate" (emphasis added). Indeed, in Figure 3, Sutherland barely puts us out of the gate. The enormous gulf science still has yet to bridge is no Rubicon, but more like trying to jump across the Grand Canyon. In this sense, Richard's analogy is flawed on two counts: First, we've observed people cross rivers, but we've never observed life spontaneously emerge from non-life (the old maxim still stands: Omne vivum ex vivo--"All life [is] from life"); and second, I never said we default to "angels," even in the face of the seemingly insurmountable. Modern science, by definition, can't go there. Science still assumes a naturalistic origin of life a priori. But there's a difference between assumption, and empirical demonstration, and the latter we simply haven't achieved yet. That's just being honest, and it's something that everyone else seems to recognize: that science assumes, but hasn't empirically demonstrated that life can come from non-life. Thus, Richard can't just gloss over everything from A to Z by invoking "evolution" and pretend that's equivalent to empirical demonstration.
That's not to say that we haven't made tremendous advances. We have and I appreciated the studies Richard cited in this regard. But they must be critically and carefully read to understand what is and isn't being claimed and the limitations and assumptions in any given study. For example, the "Uncovering the Genomic Origins of Life" article he cites is a fascinating study that breaks new ground and pushes the limits of phylogenetic analysis, but beyond what many think is possible (as the study notes), and is still constrained by starting assumptions and lack of direct physical evidence for the “OLD”. It’s still a valid contribution but by itself has little solid empirical grounding, and accordingly highlights the need to compare results with "biological proof of process experiments."
He also cite Deamer's excellent review of "The Role of Lipid Membranes in Life's Origin". It is fascinating work, and again highlights many advances in the field. No argument there. My point is simply that we need to put it in proper perspective in, for example, Sutherland's "current state of the field" diagram. We're still in the infant stages. Despite the progress tremendous gaps and problems remain in the quest to experimentally demonstrate abiogenesis. I hope it happens. But it would be inaccurate to say we're already achieved it, or that we're anywhere close. If Richard doesn't believe me, he should consult his own sources, which say as much. For example, Deamer speaks to an earlier point I made about, "How when one considers the fate of organic compounds delivered during accretion, only a small fraction would survive atmospheric entry. Furthermore, most of what did survive would fall into the ocean and dissolve to produce a very dilute solution. It follows that some sort of concentrating process would be required for life to begin" (p. 5). He notes as I have that "a source of mononucleotides is still debatable” (p. 10). Regarding membranes, he notes "a plausible mechanism for synthesis of peptide bonds and ester bonds on the prebiotic Earth continues to be a major gap in our understanding of the origin of life" (p. 10). He further notes that "Decomposition of Monomers, Polymers and Molecular Systems" remain, "An Unresolved Problem" (p. 12), and discusses the "undesired crosslinking reactions" I've mentioned (p. 13), and lists five questions for future research to address additional unsolved problems (p. 13-14). Like chemical "evolution," "prebiotically plausible" has no consistent usage, and there are no recognized standards for what qualifies an experiment or scenario as such. Thus, just because a study claims it's "prebiotically plausible" doesn't mean it actually is. Deamer similarly notes that:
"We often claim that the reactions investigated in the laboratory using purified water, buffered pH, and pure reagents could also occur in the prebiotic environment, but this confidence may be unwarranted. Hydrothermal fields are abundant in volcanic sites such as Kamchatka, Iceland, New Zealand, Hawaii and the volcanoes associated with subduction zones of the Pacific Rim. We should be bold enough to rise to the challenge and attempt to show that processes simulated in the laboratory actually work in such prebiotic analogue environments." (p. 14)
It is indisputable that s “Lee peptide” “self-replicator” can not bridge the A to Z gulf.
We need to demonstrably bridge the gulf from A to Z, but need not be so ambitious here, and can start more 'simply' with just getting from a "self-replicator" A to say B or C or D, and especially in relation to the "Lee peptide". Yes, I understand Richard's stance equates the origin of a self-replicator with biogenesis. No, not everyone agrees with that (and even some of his source citations indicate this!). And yes, I reject his stance, so we will have to agree to disagree on that (I've read the sources he cites to bridge the gulf, and see tremendous gaps and holes that they note themselves). But what has been indisputably demonstrated is that Richard's claim is false at least with respect to “Lee peptides”: the origin of a “Lee peptide” “self-replicator” is not equivalent to biogenesis, and, in fact, accomplishes nothing, because a “Lee peptide” “self-replicator” doesn’t actually do anything without 15aa & 17aa substrates to act on. Additionally, in the quest to bridge the A to Z gulf the “Lee peptide” presents some unique problems of its own, including but not limited to:
(1) As already discussed, Lee et al. (1996) report non-exponential, parabolic reaction kinetics for the “Lee peptide”. In other words, a “Lee peptide” is not “a self-sustaining chemical system capable of Darwinian evolution,” and, thus, is not equivalent to the origin of life.
(2) The “Lee peptide” is a polypeptide and as such falls under “Proteins First,” along with all the difficulties that entails, which I presume Richard is already familiar with. “Proteins First” has few proponents today. It suffers general problems that all single biopolymer scenarios do (e.g., doesn’t explain the origin of metabolism, compartmentalization), and encounters special difficulties when it comes to the origin of genetic informational like RNA and DNA (or even PNA). How does Richard derive these other informational molecules from his Lee peptide? (Assuming he wants to circumvent having to independently originate them, which, of course, would simply compound the already astronomical improbabilities). And even if we do somehow get to the "Protein-DNA/RNA" stage, how do we reverse-write the linear amino acid sequence information in the Lee peptide (or any protein derivatives) into nucleotide language into genetic informational biopolymers?
These are but a few initial problems that need to be solved, not with an “evolutionary” wave of the hand, nor with generalizations, but with real empirical demonstration that is detailed and specific to the “Lee peptide”.
To summarize: There are at least four "fatal flaws" with Richard's central claim that the probability of abiogenesis (based on spontaneous formation of a “Lee peptide”) is 1 in 10^41, and this make biogenesis 100% certain: (1) It fails to understand the nature of the “self-replicator”—even if a “Lee peptide” spontaneously forms it will do nothing without catalytic-specific substrates to act on (“Fatal Flaw #2”). (2) It confuses “toy model” chemistry with the real world—hundreds of thousands to millions of identical “self-replicator” copies are needed to initiate a chemical reaction (“Fatal Flaw #3). (3) It confuses lab results with the real world—just because a molecule can be produced in a lab doesn’t mean it can form in nature ("Fatal Flaw #4"). (4) It substitutes an "evolutionary" hand-wave to artificially span the 'Grand Canyon' A to Z gap between a single self-replicating molecule and the type of minimal cellular life we know we need to get to by about 4.0-4.1 billion years, instead of providing true empirical demonstration ("Fatal Flaw #5"). Correspondingly, this renders any "1 in 10^41" Lee peptide"-based argument about Totani's estimate being "too conservative" moot.
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