THE "FATAL FLAWS" WITH RICHARD CARRIER'S PROBABILITY CALCULUS FOR ABIOGENESIS
The "Fatal Flaws" with Richard Carrier's
Probability Calculus for Abiogenesis
"P(Lee)":
Source citation: Lee et al. (1996). A self-replicating peptide (Note: Richard's "P(Lee)" is linked to the wrong source. This is the correct one).
Summary: Richard's argument that the probability of abiogenesis is "logically necessarily a sum more probable than P(Lee) alone [i.e., 1 in 10^41]" (emphasis added) is entirely undermined by the fact that P(Lee) is not 1 in 10^41, but effectively P(Lee) = 0. A "Lee peptide" origin of life is statistically impossible. See, "The 'Fatal Flaw' with Richard Carrier's '1 in 10^41' Argument for Abiogenesis," and "Q's Open Challenge to Richard Carrier".
"+ P(any other PNA origin)":
Source citation: Liu et al. (2020). Spontaneous emergence of self-replicating molecules containing nucleobases and amino acids. Journal of the American Chemical Society, 142(9), 4184-4192.
Summary: Richard falsely implies that a "Lee peptide" is a PNA, and the article he cites for "any other PNA origin" actually has nothing at all to do with PNA, much less a "PNA origin." Ergo, Richard has not empirically demonstrated that life can originate by PNA.
Richard's "any other PNA origin," following as it does after "P(Lee)," implies the "Lee peptide" is a PNA. This only serves to highlight Richard's confused thinking. A "Lee peptide" is not a peptide nucleic acid (PNA). It is just a polypeptide string of amino acids. For more information, see, "Richard's First Mistake: a 'Lee peptide' is not a PNA."
The study that Richard cites is not empirical evidence of "any other PNA origin." In fact, the study is not about PNAs at all [Misrepresentation meter: 11]. This is a proof of concept/principle study that "chimeric amino acid/nucleobase self-replicating macrocycles capable of exponential growth" can exist in principle.
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| "Abstract." Liu et al. (2020). |
No claims of prebiotic plausibility are made. In fact, "the building blocks [used in the study] were not selected for prebiotic relevance," and were synthesized by "oxidation mediated by oxygen present in the air" (which is about as prebiotically implausible as you can get!). These molecules are not like DNA or RNA or PNA where information is 'stored' as linear sequenced nucleotides and 'copied'/replicated accordingly. They are cyclical disc-like molecules called macrocycles containing various random, non-specific combinations of amino acids and nucleobases that do not self-replicate in a biologically relevant way (i.e., there is no one-for-one duplication; identical copies of the macrocycles are not made).
Instead, the macrocycles ('discs') self-assemble by stacking on top of each other to form nanotube-like structures held together by weak attraction (i.e., non-covalent bonding) between the macrocycle 'discs' (i.e., they are not chemically linked together by covalent bonds). This produces a pseudo-linear sequencing of nucleobases simply by fact of the macrocycles containing nucleobases (it would be like saying discs of Life Saver® candy stacked on top of each other create a linear sequence of letters since there are letters embossed on each candy disc). There is no true linear informational sequencing of the kind we see in DNA, RNA, and PNA where linear sequenced nucleotides are linked together by covalent bonds. Nor is there even 'self-replication' of the pseudo-linear sequence of nucleobases. "Self-replication" occurs via "fiber-growth breakage" caused by "mechanical agitation." In simple terms, they 'shook/stirred' the solution causing the nanostructures to break in half, and then the halves elongated and 'grew' when more macrocylces were stacked on top of the ends. In other words, this was "self-replication" of a structure, not genetic information ("Self-replication" has more than one usage in science and does not always refer to the type of "self-replication" that Richard has in mind). The only connection to PNA in this study is that some of the macrocycles they engineered contained "peptide nucleic acid (PNA) building blocks [not PNA itself] in which nucleobases are already linked to amino acids from the start" (emphasis added).
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| "Scheme 1." Liu et al. (2020). |
"+ P(any TNA origin)":
Source citation: Marshall, M. (2012). Before DNA, before RNA: Life in the hodge-podge world. NewScientist.
Summary: This is not a separate way to originate life, but a "Pre-RNA World" type hypothesis that posits threose nucleic acid (TNA) as an RNA progenitor due to difficulties encountered by the "RNA World" hypothesis; effectively making "P(any TNA origin)" = 0.
Richard cites a news article, not a scientific study. It is also not a separate way to originate life but a variation of the "RNA-World" hypothesis, so there is no "P(any TNA origin)." [Misrepresentation meter: 12] Even the article states that there was “No TNA World,” and that researchers were not saying “TNA was the original genetic material.” The article also notes that TNA is “not found in nature”; that “there are problems with the hodge-podge world hypothesis,” including “there is no trace of TNA or its cousins in modern organisms,” and that “although TNA looks simpler than RNA, we can’t be sure it was easier to make some 4 billion years ago because no one has actually made it in the conditions that existed on earth before life began”; that “we still know very little about what TNA can do…The research…is just getting going”; and highlighted the overall speculative nature of the hypothesis with lines like "Take note, DNA and RNA: it's not all about you. Life on Earth may have begun with a splash of TNA—a different kind of genetic material altogether...the very first forms of life may have used a mix of genetic materials...it seems TNA might have been just as capable….,” and so on. (emphasis added).
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| Figure from Orgel (2000). "A Simpler Nucleic Acid." |
"+ P(any ANA origin)":
Source citation: Gandy, L. (2020). "Scientists have revised the recipe for the first gene and the origin of life." Massive Science.
Summary: This is not a separate way to originate life, but a variation of the "RNA World" that posits arabinonucleic acid (ANA) as "play[ing] an ancillary, supporting role in the 'RNA World'"; effectively making "P(any ANA origin)" = 0.
Richard links to another news article, not a scientific study. This is also not a separate way to originate life but a variation of the "RNA-World" hypothesis, so there is no "P(any ANA origin)." [Misrepresentation meter: 13] Even the article subtitle indicates that ANA—which is only different from RNA in the way one of its oxygen atoms points—is not a separate way to originate life, but a way to “accelerate RNA formation, making the RNA world hypothesis more plausible.” Szostak and his team found that RNA assembly was faster when both ANAs and RNAs were present; that strands of RNA and ANA that ended in ANA inhibited further growth; and that ANA strands could form bridges with RNA strands to help stabilize RNA. In these studies ANA is viewed as an RNA synthesis accelerator, regulator, and stabilizer, and plays an ancillary, supporting role in the "RNA World".
"+ P(any RNA origin)":
Source citation: "RNA World." Khan Academy.
Summary: This is about the "RNA World," not a separate RNA origin hypothesis.
This is a link to a Khan Academy article on the "RNA World," not a scientific study, and not a separate theory from the "RNA World." The "RNA World" itself has not even been conclusively demonstrated. [Misrepresentation meter: 14] The article says, "The RNA world hypothesis suggests that life on Earth began with a simple RNA molecule that could copy itself without help from other molecules." The article then talks about different types of RNA and their functions. I hope Richard is not suggesting that each of those types of RNA represent different ways that life can originate. No one thinks that. For example, no one thinks that life originated by "Grabber RNAs" that "grabbed onto other RNAs" for the simple reason that this would not account for the origin of the "other RNAs" that the grabber RNAs grab onto. Similarly, a "protein-directing RNA [that] may have helped organize proteins in a cell" does not account for the origin of the proteins that it helps organize. These are not separate ways to originate life, but variations of the same theme (i.e., the "RNA World Hypothesis"). The most instructive part of the Khan Academy article is the admission that "researchers have yet to create an RNA machine that can create whole nucleotides using ingredients that would have been available on primitive Earth.”
"+ P(any other origin)":
Source citation: "Hypothetical types of biochemistry." Wikipedia.
Summary: This is a Wikipedia article on "Hypothetical types of biochemistry." Yes, "hypothetical," as in "assumed," "supposed," "highly conjectural; not well supported by available evidence." [Misrepresentation meter: 15] The article states that "Hypothetical types of biochemistry are forms of biochemistry agreed to be scientifically viable but not proven to exist at this time.” (emphasis added). How Richard can mistake this as "empirical evidence" is baffling. (And he says I don't understand evidence!).
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