A new, peer reviewed scientific paper has been published that attempts to calculate an actual rate of abiogenesis on cosmic scales, “Emergence of Life in an Inflationary Universe” by Tomonori Totani, in Scientific Reports 10 (2020). It is pretty good, but has some fatal flaws you should be aware of before citing it uncritically (flaws the paper itself acknowledges, but not obviously enough to many lay readers). It’s worth writing an article on because usually this never happens—such proposed rates tend either to be speculations outside peer review, or complete nonsense some ignoramus just made up, or were not actual assertions of frequency but just some crude calculations to show why we need to do more work to find out what the actual frequency might be (which someone else—usually a Christian apologist—later tried to “pass off” as an actual assertion of cosmic frequency for abiogenesis). Plus, the flaws one might take issue with in this paper are not obvious, yet important to understand. So the following will hopefully be helpful.

Backstory

This is a subject I’m properly published in. My peer reviewed paper on abiogenesis frequency arguments appeared in Biology & Philosophy back in 2004: “The Argument from Biogenesis: Probabilities against a Natural Origin of Life.” I addressed the question of course not as a scientist (I rely on actual scientific sources for that) but as a philosopher, analyzing the use of these kinds of calculations to push particular ideological narratives, which I accomplished by diagramming the logic of such arguments and by researching who actually made them and on what grounds and what their original arguments actually were—plus also illustrating their obsolescence in many cases, since many past claims had since been refuted by subsequent science, as I also documented.

I’ve since written a few blog articles on the subject of abiogenesis as well, most recently summarizing the matter in my critique of videos pushing theism at PragerU, but more particularly in Why Life Must Be Complex (and Thus Probably Won’t Be on Mars) and Could Be a 38% Chance We Are the Only Civilization in the Known Universe. Throughout all this work, including under peer review, I find that all attempts to locate an actual expected frequency of spontaneous biogenesis in the universe are fatally flawed, and can be proved to grossly under-estimate that frequency. And most scientists agree. The consensus in the protobiology and exobiology community is pretty much that abiogenesis is probably relatively common cosmically, if rare galactically. Only the actual discovery of alien life (or some reliable way of actually observationally proving its galactic absence) is likely at this point to alter that assessment.

In my paper for B&P I found all previous claims of frequency suffered from one or more of several fatal flaws (and by “fatal” I mean: you can’t fix them; it’s not some trivial error that once fixed produces a usable result):

  1. Obsolete sources: Whatever frequency was being quoted was so old, subsequent science already refuted it or rendered it unusable.
  2. Omission of context: The numbers being quoted were not actually used to assert a frequency of biogenesis in the first place.
  3. The wrong math: Not correctly calculating a probability (many different mistakes are made here, some inexcusable).
  4. Confusing the winner with the players: Assuming that only exactly our life is possible (or that there is only one possible self-replicating molecule), when in fact many other kinds of life are possible (and there must be many different self-replicators that could start it off), which has to be correctly taken into account in the math.
  5. Begging the size of the protobiont: Not deriving a sound evidence-based estimate for how small (i.e. how structurally simple) a self-replicating molecule can be.
  6. Confusing evolved for spontaneous features: Bizarrely assuming the first replicator has to be a highly evolved organism, or have all the same features as one (and thus grossly over-estimating a first replicator’s size).
  7. Requiring more accident than physics actually suggests: Incorrectly assuming certain features like homochirality must be original rather than evolved (heterochiral self-replicators are actually possible and could have evolved into homochiral ones), and/or incorrectly assuming such features must be arrived at by random chance when many known conditions can produce them nonrandomly (e.g. stellar conditions can cause homochirality long before random assembly produces a first replicator; recombination on clay surfaces already produces homochirality; homochiral chains are more stable and thus more able to grow into lengths necessary for self-replication; etc.).

Totani’s paper appears to avoid all these errors except numbers 5 and 7, and even with those he does far better than most, his arguments all based on solid science, which is an achievement in itself. His only Class 5 error is ignoring pre-RNA worlds and over-estimating even the minimum RNA size based on some faulty logic. With respect to his Class 7 error, he does not make that common mistake about homochirality, but his math still ignores many known mechanisms for ordering molecules, and thus can only grossly under-estimate biogenesis frequency. As we’ll see shortly, Totani actually admits that in his own paper’s conclusion, and it’s important to examine why that’s more important than he lets on.

Nevertheless, even with those two errors, Totani’s conclusion is that we should expect random abiogenesis to occur several times in the probable volume of the universe, but average less than once per volume of cosmos equivalent to the universe currently visible. This is a far more pessimistic estimate of biogenesis than any living protobiology expert has ever proffered. Usually such extreme pessimism attaches only to the frequency of civilizations, not of simple life or mere origin events (most of which will never evolve even into complex life much less civilizations). And yet, Totani shows that the observable universe is such a minuscule fraction of the size the universe must have on current cosmological theories (e.g. given the flatness of spacetime which entails a universe far larger than the mere horizon of visible light) that spontaneous abiogenesis is still an inevitable event, even with his extraordinarily pessimistic assumptions. As he puts it, even his most conservative estimates entail “life would have emerged on countless planets in the whole inflationary universe in which we exist.”

And yet his assumptions are still overly pessimistic. Let’s take a look…

Class VII Error: Overrating Accident vs. Necessity

Totani only calculates for random assembly of an RNA molecule of 40 nucleotide length (at the smallest). He disregards homochirality (and correctly explains why we should) and allows a large number of such molecules the possibility being self-replicating (avoiding error number 4) and demonstrates why small variations in starting assumptions have little effect on his conclusions, which are logarithmic (so the effects of varying microparameters are too minuscule to matter). But though he mentions the likelihood of ordering forces that greatly increase the probability of spontaneous assembly, he includes none of them in his calculations—for the obvious reason that we don’t yet have experimental data on their efficiency. But that makes his calculation a fallacy of Argument from Ignorance. He rightly calls for more experimental work to fix this problem, but an inattentive reader might miss that and think his results are scientific fact when even Totani himself admits they are an underestimate owing to present scientific ignorance, not scientific knowledge.

For example, Totani adds in his conclusion:

A possibly important process is polymerization over multiple cycles. In polymerization on clay surfaces, inactive monomers and oligomers left from the previous cycle must be released from a clay surface for the next cycle to work, but a fraction of long oligomers may remain on the surface. Adding newly activated monomers to such oligomers over many cycles may be an efficient way to assemble a long polymer.

Meaning, his math only assumed random assembly from scratch, when we know for a fact many polymers will build on existing ones, so that long strings have higher probabilities than random chance alone would predict. And when we take that into account, he says, this would imply “a possibility that abiogenesis has occurred more than once inside the observable universe” and therefore “this possibility should not be overlooked.” Of course, his math overlooks it.

This is kind of like robbing Peter to pay Paul here. He admits we should not overlook this; after having just overlooked it. So to translate what just happened into colloquial English: he is here telling you, perhaps too obscurely, that his actual results are a gross under-estimate of how many spontaneous life-forming events there are likely to be in the universe. His excuse is simply that the effect of including such ordering forces is unknown, therefore his math does not account for them. But that amounts to admitting his results are actually, in fact, false. It’s like saying “if we disregard all the things that make life frequent, we get a result that life is infrequent.” Being practically a useless tautology, this isn’t a very meaningful scientific result.

But it’s at least a useful start.

What Totani is doing here is working out in a well-informed and responsible way what the odds would be “by the most conservative polymerization process, i.e., random Poissonian adding of monomers,” and then correctly admits that that’s not likely the actual way life arose, it’s just the one way we can empirically prove possible at the present time (because he is only using as premises processes well demonstrated to work empirically and widely documented to occur in nature; facts, rather than mere theories). And by admitting he is only running numbers for “the most conservative” process, he is in effect building an argument a fortiori: rather than saying life must be so rare as to occur not even once per visible universe (i.e. per “Hubble volume”), he is saying that even if life is so rare as this (i.e. even if life only arises from purely random processes, the mere “random Poissonian adding of monomers”), it will inevitably occur countless times per actual universe (since the visible universe is necessarily only a fraction of the whole, and current successful cosmological theory gives strong indications of the minimum size of the actual universe on present observations, e.g. the extreme flatness of spacetime entails the universe extends an extraordinary distance beyond the visible horizon).

So although an apologist could misquote Totani’s paper as arguing against natural biogenesis, his paper is actually making a strong argument for natural biogenesis. And explicitly so: that’s his thesis. But one could even responsibly and validly use it as an argument against divine creation of life, even though that isn’t Totani’s thesis, because the divine does not need such a vast cosmos and complex chemistry to get life, whereas every godless universe does, so observations exactly match expectation on atheism without any added suppositions, whereas this is not the case for theism. The Bayes’ factor thus always leans towards atheism here.

But we can go beyond Totani’s math to a sounder idea of how life might arise from world to world using his own qualifying statements. As Totani himself admits:

It should be noted, however, that the case of a high abiogenesis rate…cannot be excluded by this work, because we assumed that abiotic RNA polymerization occurs only by the random Poisson process of adding monomers. Potential roles of much more efficient processes [in] the origin of life, such as non-linear auto- or cross-catalytic reactions, have been studied theoretically [for example].

Totani also notes that direct detection of life on alien worlds would support the conclusion that some such processes do indeed operate in the origination of life, and that in fact his paper’s results would reinforce that conclusion (since it predicts a much lower frequency of life by random process alone, discovering a higher frequency would demonstrate random processes do not operate alone). Therefore “this possibility should not be excluded.” Instead, Totani makes clear, all that “is shown by this work is that such a hypothetical process is not necessary if we [require] abiogenesis events to occur somewhere in an inflationary universe.” In other words, a random process alone is indeed fully sufficient. No divine intervention required—once we take into account well-established cosmology (he rightly leaves open the question at the level of fine tuning universe parameters as “far beyond the scope of this work”).

I think Totani does give a false impression though of the status of autocatalytic chemistry in the origin of life, particularly in more rapidly generating and thus selecting for long nucleotide chains. So his not including this in his math is a much more serious oversight than he lets on. Accounting for autocatalysis would greatly improve the frequency of life formation; it would remain cosmically rare, but not as rare as Totani’s math suggests. Totani appears to say that autocatalysis is merely “theoretical,” but that’s not exactly true. It merely hasn’t been used to generate spontaneous self-replicators in the lab—because that would require millions of years. Otherwise the phenomenon is well demonstrated to be real and well documented in nature. Indeed it would be weird if this played no role in forming the long polymers essential to any abiogenesis event, since autocatalytic systems can be vastly simpler than the polymers they produce, and thus will arise spontaneously with a far higher frequency. I cite abundant research on this point in my article for B&P and more has come out since (e.g. Hordijk & Steel’s 2018 summary of research “Autocatalytic Networks at the Basis of Life’s Origin and Organization” in Life and Hordijk’s earlier, 2013, summary “Autocatalytic Sets: From the Origin of Life to the Economy” in BioScience).

Class V Error: Begging the Size of the Protobiont

Another problem with Totani’s paper is that he seems to be over-estimating the minimum size of a self-replicator. That helps his case insofar as it shores up his a fortiori argument: even with such a conservative estimate, life comes out to be inevitable. But if you want to understand the actual odds of life forming by chance, you need to get away from his overly conservative assumption here. Which is derived only by fallacy, when he makes two arguments for his claim that the smallest possible RNA self-replicator must be at least 40 amino acids (in the form of nucleotides) long.

First, Totani argues from “the lack of evidence for multiple abiogenesis events in the history of Earth or in laboratories,” but elsewhere in the paper he contradicts himself by giving an already known explanation for that: at biogenesis “a long RNA polymer assembled by the Poisson process would be rare and there would be no competitor or predator around it.” So he knows why we don’t observe more of them: any spontaneous self-replicator would be so rapidly digested or destroyed by the existing biosphere as to have no chance of evolving into more ordered life. So we could never hope to see a second biogenesis event on earth, even should that occur. At most we can say a self-replicator must be longer than would have been discovered in labs by now, but we really haven’t even come close to fully exploring every possible nucleotide sequence in the domain Totani excludes.

Still, I do agree two such events on earth would be highly unlikely. Yes, Totani grossly under-estimates its frequency; but I’m pretty sure any adjustment of his math toward a more realistic frequency still wouldn’t get us to even beyond “once per thousand solar systems” much less “once per moon or planet.” And most experts concur on that. Totani’s point is that his math finds a frequency of spontaneous assembly of self-replicators well above one per solar system if self-replicators can be as small as merely 21 amino acids long. In particular, Totani concludes, “The minimum RNA length must be” either “21, 27 and 32 to expect one abiogenesis event for a survey of a single star,” “galaxy,” or “the observable universe” respectively. Which means self-replicators can’t be so small or else we’d seen a bunch more of them by now.

That is, however, a non sequitur—not only because, for instance, a minimum length of even 27 would only entail an average of one biogenesis event per galaxy, and we cannot expect to have surveyed the whole galaxy for life already (and this is again only with his conservative assumptions regarding process, which we noted above are already far too conservative); but also because, even if the minimum size were below 21, allowing multiple events in our solar system, we still cannot expect to have seen this even if it were happening, so our not seeing it is unusable as data. So that is not a valid argument.

Totani’s second argument is more defensible, but still flawed: there are no currently known “RNA molecules shorter than 25 nucleotides” that exhibit “a specified function,” whereas “there is a reasonable hope to find a functioning replicase ribozyme longer than 40–60” nucleotides. In other words, we haven’t observed anything in nature so small that even has a function, much less the function of self-replicating, so if we stick with what’s been experimentally accomplished so far, the minimum we can argue for is 40 nucleotides. It’s unclear if every possibility has been explored—Totani’s sources state that one could assemble and test every possible combination of 25 nucleotides in the lab, but do not indicate anyone has ever done this. But I agree it’s reasonable to assume (even if not certain) that someone would have found one by now. The problem is that “must be larger than 25” does not get you to “must be at least 40.” The early earth had millions of years to randomly sequence molecules; scientists do not. So replicators of, say, 30 nucleotide length are beyond our ability to discover by merely random mixing. So we cannot actually rule them out—and indeed, as we’ll see in a moment, shouldn’t.

This is the one point where Totani overstates what his sources actually say. He only cites two: a 2012 paper by Robertson & Joyce that only has this to say on the point:

It is difficult to state with certainty the minimum possible size of an RNA replicase ribozyme. An RNA consisting of a single secondary structural element, that is, a small stem-loop containing 12–17 nucleotides, would not be expected to have replicase activity, whereas…[something] containing 40–60 nucleotides, offers a reasonable hope of functioning as a replicase ribozyme.

So Totani’s “40-60” number is actually just speculation. It is not any actual evidence-based argument for a minimum size. Granted, it’s well-founded speculation, and thus works a fortiori. But if you want to get at what’s true, not just a fortiori, this isn’t helpful. Totani’s only other source is an old, 1993 chapter by Szostak & Ellington that actually concludes the viable minimum range to be 30-60 nucleotides, not 40-60.

And this, mind you, is solely for an RNA-first scenario. It is now known RNA might actually be an evolved, not an original, feature of life. Which gets us to Totani’s biggest mistake: he only ever considers RNA protobionts. Nowhere in his paper does he account for PNA-first models of biogenesis (he gives only one oblique mention of it as something he won’t consider). Yet these are increasingly more likely (see Nelson et al. 2000, Nielson 2007, Sharma & Awasthi 2016). As I wrote for B&P all the way back in 2004:

Even a simple RNA system could itself be an evolved structure. Life might have begun with an even simpler and stronger peptide or PNA system (Travis 2000). We have created self-replicating peptides as small as 32 amino-acids [in monomer form] long (Lee 1996), demonstrating that the smallest possible chemical that could spark life may be much, much tinier than anything any[one] has assumed possible. McFadden calculates the odds against the Lee peptide arising by chance as 1 in 10 [to the power of] 41 (1996: 98), which is so far within the realm of cosmic possibility that it is already certain to have happened many times [even within the visible universe].

Totani, in other words, is reading the wrong literature. He is looking for the smallest self-replicating RNA molecule, when what we should be looking for is the smallest PNA molecule, because we have already experimentally proven that PNA self-replicators exist that are much simpler than anything we know from RNA. Indeed, if we apply Totani’s own highly conservative math to the smallest empirically known PNA self-replicator (which might not even be the smallest possible), then his own conclusion would be that life has already originated on average once per Hubble volume, not less than once. And again, his math is already overly conservative on that point, as I explained earlier.

So we can actually be sure life is more common than Totani concludes. It still must be extraordinarily rare; just not that rare.

Conclusion

Tomonori Totani’s mathematical study is still pretty good. It’s probably the best attempt at running such a calculation yet published, and its premises are all scientifically and mathematically sound from an a fortiori perspective: he admits he is being very conservative in his estimates, and still finds that life will spontaneously arise countless times in a single inflationary universe with properties like ours. But Totani’s conclusion becomes fallacious if taken as more than an argument a fortiorti. If one mistakenly quotes him as showing what is the case, rather than what would be the case even on false assumptions more conservative than the evidence warrants, you’d be misrepresenting what even Totani himself says. So be on your guard against Christian apologists pulling that trick.

Totani admits to this in several respects. For example, he knows his ignoring of known ordering processes (such as autocatalytic systems and successive assembly on clay surfaces) in calculating the number of long polymers that will arise by chance is logically invalid; he is merely sticking to what is most empirically certain to argue an a fortiori case for his conclusion—which is that life will commonly exist by accident in our universe (the opposite of what Christian apologists might claim). But Totani doesn’t even mention other important respects in which his conclusion is too conservative, such as that life is far more likely to originate with PNA than RNA, and self-replicating PNA molecules are already known to exist that are far simpler than Totani assumes.

Finally, there is one other way in which Totani’s paper could be misused by Creationists that is worth closing with. And it’s a point about math. What Totani calculates is not the probability of abiogenesis, but the frequency of it. In a sense those are the same things, but in an important sense they are not. Totani wants to know what the average rate of abiogenesis should be given four different volumes (solar system, galaxy, visible universe, actual universe). He finds it’s well above one for the last of those volumes (the only one that really matters), but well below one for the others (especially the first two), which would be bad news for scientists seeking life on other worlds (much less Mars!). We already saw this conclusion changes when we input the actually known smallest self-replicator, to an average of one event per visible universe (and lo and behold, here we are!).

But in actual fact, lots of things will happen in any given volume that deviate from average. This is a mathematically crucial point. So pay close attention here. Not only is the universe so unfathomably large that abiogenesis is inevitable even on Totani’s overly conservative assumptions, but it’s so large that extraordinarily unlikely events also happen in it. And this is why probability is more important to look at than frequency. Frequency tells you the average distribution of a thing (such as how many royal flushes we can expect to see across all poker games ever played), not the specific distribution of that thing (such as where or how often clusters of royal flushes will be observed).

Thus even if it were the case that the probability against life arising within our universe were 1 in 10^41, countless events of that improbability will occur in our universe. Even the creationist mathematician William Dembski admitted we can expect at least one event to happen in the visible universe to an improbability of 1 in 10^150! Now, this means events in general, not life specifically. But if events of that improbability can occur, that life should be one of them is no longer remarkable. After all, we will only ever find ourselves in a universe that wins that lottery, so that we observe ourselves in one isn’t remarkable; and as even Dembski pointed out, a universe can easily win that lottery by chance. Because it’s winning lotteries on that scale all the time.

Dembski would argue that, yes, that’s true, but life is such a remarkably specific way to win that lottery, shouldn’t we still consider it remarkable? And the answer is…no, not really. If even the visible universe will have won 10^109 such lotteries by now—as Dembski’s own math shows to be the case—is it really so remarkable that one of those wins should just by accident turn out to be “a self-replicating molecule”? Rather than, say, a supernova exactly shaped like Salma Hayek, or a solar system whose planets move in perfect synchronized circles exactly as Copernicus imagined, or any of the gazillion other things with odds of 1 in 10^41 that will inevitably happen across all cosmic space and time.

Objectively, there is nothing more remarkable about life being one of those things than the Salma Hayek nova would be. We are the only ones who think the one is more remarkable than the other, and that’s simply because by that very accident we’re able to think at all. But accident it remains. And that’s why a Salma Hayek nebula would no more prove God exists, than a similarly improbable terrestrial abiogenesis would. Both are equally unlikely—and equally inevitable. That’s how huge our universe is.

This is probably a much harder point to grasp. Creationists have a really hard time comprehending the likelihood of coincidence. So I wouldn’t spend much time arguing it with them. It’s much easier to argue a fortiori: Totani proved that even using unrealistically conservative assumptions as to the facts, we can expect life to have spontaneously arisen countless times in the whole volume of the actual universe we live in; and when we correct Totani’s error regarding the smallest known self-replicator—when we redo all his math with the Lee peptide as our model—we can expect life to have spontaneously arisen at least once even in the visible volume of our universe. Which is, so far, exactly what we observe.

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