The Answer to Chickens and Eggs
One regret I have regarding the demise of Uncommon Descent is being unable to continue discussion with Upright Biped, a regular at UD who believed he had an argument against the natural evolution of the genetic code, which I refer to as his “semiotic hypothesis”.
Whilst wrapped up in impenetrable jargon and idiosyncratic prose, it is/was quite a simple argument: that the first organisms could not evolve the genetic code without already having the metabolism in place and vice versa, an insoluble chicken-and-egg conundrum.
Upright Biped first publicized his idea in 2011, and it was the subject of an OP by Elizabeth Liddle (owner of this site) in October 2011.
I didn’t get involved much at the time, as discussion seemed to stick at the semiotics, whereas I thought Upright Biped’s best point was it would be impossible for a genetic storage system to evolve prior to metabolism and equally for heritable metabolic pathways to evolve without a genetic storage system. A classical chicken and egg issue.
In 2005, I encountered the late Robert Shapiro (over his alleged peer review of Mike Behe’s Darwin’s Black Box) who was a sceptic on RNA World, and he influenced me to adopt the same view. Anyway, Upright Biped continued sporadically to promote his idea at Uncommon Descent and elsewhere without much success, yet I thought the “which first, genetic code or metabolism” conundrum was a strong argument.
Not least due to the input from erstwhile TSZ regular, Allan Miller, I have since changed my mind about RNA World and now find it a plausible idea, and there is more and increasing evidentiary support for RNA World than I knew of in 2005 and 2011.
The brilliant thing about RNA World is that RNA can act as a gene, in that it can and does act as a template for replication and also RNA is capable of being a catalyst, a ribozyme, the RNA equivalent of a protein enzyme. Indeed, RNA is the catalytic heart of cellular metabolic “machinery” that synthesizes proteins, the ribosome. No chickens and no eggs, and critically, no genetic code needed.
I should put in a word for Nick Lane here, whose UCL research group have published many papers on the origin of life from a biochemical standpoint. I recently bought his book, Transformer: The Deep Chemistry of Life and Death, which I recommend as a good summary of the current state of play without being overly technical. There’s a good video of a recent talk here for a recent overview.
I’ve contributed a fair few comments to Uncommon Descent over the years, and been banned a few times, culminating in my disappearance under the pseudonym, Aurelio Smith, back in 2015, since when I’d been content to lurk until, last year I noticed Upright Biped addressing comments to an ID sceptic, JVL, promoting his semiotic argument again. JVL is a mathematician and Upright Biped seemed to have fixated on JVL to the extent of harassing him. So I registered under the pseudonym, Fred Hickson, and added my 2¢.
Unfortunately, force majeure has prevented the discussion with Upright Biped continuing so I hope he’ll consider joining us here.
If anyone has an idea how to get a heads-up to Upright Biped, I’d love to hear it.
This thread has the potential to generate some lively discussions so I hope it does get going.
I watched the video of Nick Lane’s talk with interest. He tells us that he has an open mind and his hypotheses could indeed turn out to be wrong. He stresses one major problem he sees with figuring out the origin of life. It’s the fact that we can speculate on ways by which the components needed to produce a functional growing and reproducing entity come into being, but building the separate components requires environmental conditions which are incompatible with each other. How can they ever be brought together?
I have a love/hate relationship with the way he compares the earth with a cell (see below). The earth and the cell, as above so below, the whole reflected in the parts. But he has the usual over-fondness of thinking about life in terms of mechanics. He sees both the earth and cells as batteries. According to him molecular machines are fundamental to life.
He seems to be open minded to any hypothesis on the origin of life as long as it begins with the assumption that life is obtained purely from one of the ways in which non-living matter happens to organize itself. Physics and chemistry are the root cause.
Those are just one or two quick points I from my initial look at the video. Let’s hope this thread generates some wider interest than has been the case here recently.
Alan,
I think that the whole field of abiogenesis research and the work of the likes of Nick Lane and Jack Szostak are fascinating. As I see it, they are addressing what was introduced to me by Tim Hunt as “the bootstrap problem”, viz:
Of course, the subsequent discovery that peptidyl transferase was a ribozyme helped enormously
It’s a really interesting problem, and not solved yet.
As I understood it (and I don’t really have the stomach to wade through Lizzie’s 4,000 words, UBP’s 4,000 word reply, and the other 5,000 words in that thread today) UBP had a different, far more ethereal, argument, viz:
He’s wrong, of course, but that’s a whole other ball of wax.
You know full well that entropy forbids abiogenesis. You also know your problems are compound and much more basic than this one.
Last I checked you were promoting a manufactured product – the virus – as argument for “evolution”. You’re sure about that?
To claim something is wrong you need a solid proof like a counter example or a logic chain. Do you have any such?
No one, and certainly not DNA Jock, knows any such thing, because it is simply not true: entropy does not forbid abiogenesis.
More precisely, “entropy forbids abiogenesis” is simply nonsense, and as such, it is neither true nor false.
I found this by Upright Biped in the Uncommon Descent archive. The comment links are lost but the page link still works. I quote:
The exchange of information [in protein synthesis] (from input to output) is facilitated by a set of special physical objects – the protocols – tRNA and its entourage of aminoacyl synthetase. Acting together they make it possible for the input to alter the output, and they do so by allowing them to remain separate. The tRNA physically bridges the gap between the input and the output, acting as a passive carrier of the physical protocol. It accomplishes this by being charged with the correct amino acid by the synthetases (the only molecules in biology which actually hold the rules to the genetic code).
The synthetases accomplish their tasks by being able to physically recognize both the tRNAs and the amino acids. They charge the tRNAs with their correct amino acids before they ever enter the ribosome. The actions of the synthetases are therefore completely isolated from both the input and output. In other words, the only molecules in biology that can set the rule that “this maps to that” are physically isolated from both the input and output, while the input and output remain isolated themselves.
This is a reasonable description of the role of aminoacyl tRNA synthetases in protein synthesis. And his argument that this system could not have evolved would be a strong one without the plausible precursor of RNA World.
How we get from RNA World to the present system is far from being resolved but RNA World is a plausible stepping stone.
I always thought saying a problem was unsolved meant that taking a strong position is a bit silly.
There are, of course, active researchers who pick a side and do everything in their power to test it. That’s reasonable.
Of course, I mean, by taking a side, choosing a scenario and exploring it.
If you download this index.html file and run it in a browser, you can see the comments in order, numbered properly, as they appeared at UD, but without the CSS formatting. This might be useful in this or future cases.
Alan, the comment you quoted from is 52.
aleta,
Thanks, Aleta. I’ll have another look when I have time. There’s a brass festival on in town this weekend and several friends and neighbours are performing.
In Nick Lane’s book, he mentions rivalry among research groups and individuals with some getting undue credit and others overlooked.
There’s good (biochemical and phylogenetic) evidence there was some sort of RNA world in which the translation system and genetic code evolved.
What the exact nature of this RNA world was, whether it was a cellular entity (probably), what sort of metabolic system it was embedded in if any, in what environment these entities lived, and so on, is all much less certain and basically almost completely unknown at this point.
There is basically zero evidence that directly connects this RNA-based organism (or whatever you want to call it) to some prebiotic environments. There’s a lot of research into hypothetical geochemical scenarios that could have somehow produced RNA, but we basically have no idea whether such environments as imagined, ever existed on Earth or anywhere else in the solar system.
I’m with Nick Lane in saying that I wouldn’t go to the stake claiming such an environment did not exist and didn’t produce RNA, but the mere fact that RNA exists seems a poor reason for positing it did in the first place.
As for the actual origin of life as we know it, there are basically two schools of thought:
1) Genes (either based on RNA or a more primitive digital genetic polymer) were the first adaptively evolving entities, they were more or less directly produced by the hypothetical environments imagined above, and these RNA-based entities
persisted for a long time in these environments and evolved the translation system and genetic code, possibly as part of some sort of protocellular entity, and these eventually evolved into cells as we know them.
2) Something more like an adaptively evolvable metabolism once existed that didn’t even have genes, and this system eventually evolved RNA and then later the translation system and the genetic code.
Though I can’t say there is any hard evidence that favors one scenario over the other, I’m slightly leaning towards 2 myself. I think it is a mistake to think evolution can only take place in digital polymer systems. As far as I am aware there are good reasons to think the space of possible systems in which evolution can take place is larger than the system we all know so well.
There’s a good recent paper on an alternative scenario (lipid-world) here:
Attractor dynamics drives self-reproduction in protobiological catalytic networks
https://www.cell.com/cell-reports-physical-science/fulltext/S2666-3864(23)00152-2
I’ve also been keenly interested in David Baum’s proposal that analog information preceded the digital in the origin of life:
Life’s Late Digital Revolution and Why It Matters for the Study of the Origins of Life
https://www.mdpi.com/2075-1729/7/3/34
Of course Nick Lane’s work is particularly interesting in that he’s not imagining a hypothetical environment because he feels the need to invent an explanation for how prebiotic chemistry could have produced copious amounts of RNA, but is instead going truly bottom-up and trying to work out how an actual known prebiotic environment could have produced putatively relevant biomolecules. What is much less certain about Nick Lane’s proposal, in my opinion, is to what extend these biomolecules could accumulate and undergo any sort of interesting evolution-like process that could ultimately result in living cells.
Nobody knows. We still know next to nothing about any of this. When it comes to creationism the only thing I think that needs to be said is it’s all just a giant argument from ignorance. We know too little to say what creationists want to say; that there is no way for life to originate. They like to think so, but they can never really articulate any good reasons that rationally compel that conclusion. And that includes proven bullshitter James Tour. He sure does blather a lot about purported reasons why life can’t originate, but they all eventually come down to “how did X?” and if you don’t know, then his adoring brainless fans complete the fallacious appeal to ignorance and conclude it’s not possible. Tour is usually smart enough to not come out and say it’s not possible, leaving his drooling sheep to make that inference themselves. I have never spoken to any of them that didn’t flail when pressed to explain how our current ignorance rationally entails that life’s origins is impossible.
For any Tour fan reading this: Come at me bro. Show me how it’s not possible.
On a related note, regardless of how RNA itself first arose(nobody knows), I think there’s good evidence the translation system and the genetic code evolved in this RNA world:
Here’s one possible scenario for the evolutionary origin of the system:
DNA_Jock,
We really don’t have a clue here on the OOL or the origins of distinct species on earth. If this is somehow understood who is working on the origin of matter? Is there any real likely yield to this research? Science does a good job building models of what we observe. The origin of what we observe maybe out of the prevue of science.
Another point. I think there’s a large difference between how life did originate and how life could originate. I think many RNA world researchers are pursuing models of the latter exactly because they are not really connecting their models for the origins of RNA to environments, and their subsequent geological development, known to have occurred on Earth or other places in the solar system.
That would be nothing new or different from SOP. Large chunks of life just suck.
I have a story about due credit that is unrelated to the topic, but responsive to your comment. I was attacked by an earworm this morning in the form of Puff the Magic Dragon.
I looked it up and found the original poem was written by Lenny Lipton while at Cornell. He read an Ogden Nash poem and thought he could do better. The nearest available typewriter belonged to Peter Yarrow, another student. He typed up the poem and quickly forgot about it. But Yarrow saw it and turned it into the song.
So you have a poem typed on someone else’s typewriter, forgotten and discarded.
Several years later, the record comes out, and Yarrow tracks down Lipton, because he has given him full credit for the lyrics. Lipton used the money to go into business. He invented the camera used for the rash of 3D movies in the 1980s, and the glasses sold for home 3D TVs.
This video from a series “long Story Short” sets out to debunk the RNA world hypothesis. They are promoted by the Discovery Institute, but, at the moment, I don’t know what the connection is between them.
The videos are informative in a simple and humorous way. In one of the videos it makes the point that the question usually asked is, “how did natural processes begin life?” Instead, a more open and honest question would be, “how did life begin?”
I think that’s a valid point. It is perfectly legitimate to research ways in which life could have evolved through natural physical and chemical processes. But it should be admitted that there are other options.
I have heard of promises that success will come in the future, but playing with physics and chemistry has not made much headway so far.
You need to think this through a bit more. Life either began by natural processes, or by magic. There is no known way to test for magic; the only method found so far is to chant “goddidit” endlessly. So your reformulation of the question, which looks honest, is in fact deceitful. It “honestly” phrases the question so as to allow religious claptrap to get a foot in the door. Life may have originated in a number of possible ways, so even showing that one is plausible doesn’t rule out another. But none of these are magic, all are natural.
We devoted an entire thread to your ignorance, and your unique way of counting microstates. The derp peaked around page 10.
I did point to CoVid-19 as something that we see evolving, and I reminded you that I had predicted the dominance of S: D614G, back when we were making fun of your ‘regression to the mean’ beliefs. So I am sure about that.
Why yes. Check out the snow-covered table.Of course, you won’t understand this if you cannot follow UBP’s argument and Lizzie’s dismantling of same. Given that you cannot count microstates consistently, I don’t hold out any hope here.
Fair enough. Minds are natural, thinking is a feature of nature. So positing that mind/s and/or thinking were involved in the origin of life is a legitimate proposition. Are you okay with that?
To be fair neither has faith in magically willing life to exist. Incidentally there are some scant clues that life’s origins owe to some sort of physical and chemical process. They are few and far between, but they have been found.
For example Nick Lane’s research group has shown there is a prebiotic, physic-chemical basis for why ATP(instead of the other nucleotide triphosphates) is used as a universal energy currency in life: https://discourse.peacefulscience.org/t/why-atp-abiotic-chemistry-provides-an-answer/14382
So there is a reason found in abiotic chemistry that explains a fundamental attribute of all known life. Under mild conditions that don’t destroy biomolecules, abiotic chemistry can only phosphorylate ADP to ATP, not the other nucleotides. No such reason exists on intelligent design.
And there is evidence that the first amino acids to be recruited into peptides, proteins, and into the genetic code, were probably those synthesized by abiotic physical and chemical processes:
Inferences of ancestral nodes in the phylogenetic trees of the oldest (most widely conserved) protein sequences increasingly mirror the abiotic distribution of amino acids produced by nonbiological chemical reactions, as we go further and further back in time. That’s evidence right there that the earliest proteins were synthesized from amino acids that were produced by nonbiological processes, and that the biosynthetic pathways for their synthesis subsequently evolved. The “modern” distribution of amino acids we see in extant proteins increasingly gives way to the nonbiological distribution the further back we go, and larger and more complex amino acids like Tryptophan become less frequent, while the simpler amino acids like glycine, alanine, valine and so on become more and more frequent. This trend increasingly mirrors the distribution expected from chemical thermodynamic calculations of the ease of their synthesis, the distribution observed in various carbonaceous chondrites, and mirrors the distribution also seen in various experiments in abiotic organic chemistry, such as simulated hydrothermal conditions, volcanic and atmospheric spark-discharge experiments, and so on.
See:
Higgs PG, Pudritz RE. A thermodynamic basis for prebiotic amino acid synthesis
and the nature of the first genetic code. Astrobiology. 2009 Jun;9(5):483-90.
DOI: 10.1089/ast.2008.0280
Brooks DJ, Fresco JR, Lesk AM, Singh M. Evolution of amino acid frequencies in
proteins over deep time: inferred order of introduction of amino acids into the
genetic code. Mol Biol Evol. 2002 Oct;19(10):1645-55. DOI: 10.1093/oxfordjournals.molbev.a003988
Jordan IK, Kondrashov FA, Adzhubei IA, Wolf YI, Koonin EV, Kondrashov AS,
Sunyaev S. A universal trend of amino acid gain and loss in protein evolution.
Nature. 2005 Feb 10;433(7026):633-8. Epub 2005 Jan 19. Erratum in: Nature. 2005
May 26;435(7041):528. DOI: 10.1038/nature03306
This ultimately chemical origin of the first proteins is clearly an outcome that is much more expected on the hypothesis that life began through some process of abiotic geochemistry and physics.
Ask yourself why should this trend be observed in amino acid gain and loss? Why would the frequency of nonbiologically produced amino acids increase the further we go back in time on a phylogenetic tree? If life originated by some sort of intelligent design, the designer could have made the first life to exist with basically any distribution of amino acids that the designer wanted. For example, the designer could have made the first life to exist with the exact same distribution of amino acids that we see in life that exists today on Earth in 2023.
No because minds are a product of evolution, and the origin of life is also the origin of the process that ultimately results in minds.
It’s sort of like saying black holes are natural and made of subatomic particles so it’s okay to use black holes to explain the existence of subatomic particles. Well no, that reverses the chronology. First we must explain the subatomic particles, and then we can explain how they collect to form black holes.
Rumraket,
Where are you if this assertion turns out to be false?
How is it “nonsense”? Ever increasing entropy is a fact in the universe. Facts have Consequences. Like “abiogenesis is impossible”. A phenomenon I have analyzed and described. Is that something you have also analyzed? If so, show your work as I do.
There’s a third school of thought. The most established, supported by the brightest minds in history, and the only one with any evidence. Why are you wilfully ignoring it? I refuse to believe you haven’t heard of it or you have disproven it in any way to justify ignoring it.
I have never seen you post something that wasn’t fantastically stupid. Welcome to ignore.
You have not found a fault back then. Nor will you ever. Meanwhile, “your problems are compound and much more basic than this one”, like I said.
As long as we include manufactured products, we also see the automobile evolve. And what do we learn from that? Oops, it’s a designed product. We then conclude that life is designed as well. Good work, comrade. Your prediction meanwhile had nothing to do with “evolution” as I pointed out and you certainly were trying unsuccessfully to shut down ‘regression to the mean’ which continues to be a fact of life.
I don’t have the time and interest to dig up the dead. Unless you make your case, I will take that as an admission that your claim was false.
And who the heck are you? One that doesn’t understand shit and cannot provide one single logic argument.
The basic problem with “RNA World” as with all other “abiogenesis” crazy schemes is that it ignores the difference between life and the inert. Life has agency while the inert doesn’t. The transition from life to the inert is unidirectional in real life contrary to fiction.
What is life?
Of course not. Might as well claim that math is responsible for mashed potatoes. You need to demonstrate cause and effect, not just wave your hands and mumble.
By golly, nonlin has been doing some serious introspection. I didn’t think he was capable of that.
Exactly.
Evolutionary processes allow us to explain why animals have the kinds of minds that they do, with the cognitive capacities and incapacities that are observed and posited, and also explains why human minds are different from the minds of nonhuman animals, to the extent that they are.
The best book I’ve yet read on evolutionary explanations for animal cognition generally is Complexity and the Function of Mind in Nature by Peter Godfrey-Smith. Godfrey-Smith argues that evolution by natural selection explains the role of coping with environmental complexity had in shaping cognitive evolution within the animal kingdom. Kim Sterelny, in Thought in a Hostile World and The Evolved Apprentice, builds on Godfrey-Smith to show how cumulative nice construction and increased phenotypic plasticity led to a distinct kind of animal mind within the hominid clade.
Whereas we have no reason to believe that are any minds that aren’t explainable in terms of cognitive neuroscience and shaped by evolutionary processes.
Whatever the explanation for abiogenesis turns out to be, minds had nothing to do with it.
CharlieM,
We know life based on what we observe requires high levels of organization to function. I agree a mind is the only known mechanism capable of this.
We don’t have a direct observation of how this happened but until recently we had no direct observation of atoms. No one has made a successful counter argument to this idea aside from labels and assertions.
Denial of this is essentially denial of inductive reasoning. Reasoning that is responsible for the fantastic technology that humans have built.
How about a watershed? High level of organization to function, highly complex. I suppose your god invented watersheds too, or did it just invent gravity and rain, and let them do the work? You know, kind of like letting evolution do the work of organizing life.
Entropy tends to increase in closed systems. And the universe as a whole is a closed system. That means that complexity cannot increase across the whole of the universe over time — the history of the universe is a history tending towards complete thermodynamic equilibrium.
It does not follow, of course, that therefore there cannot be local increases in organization at various places in the universe. Your claim that entropy forbids abiogenesis is sheer nonsense.
I am not denying that the chemistry necessary for life to exist has been a feature of the earthly environment from the beginning. It was ready and available to be used if the conditions were right and the required steps were followed to assemble and combine all the components required for the beginnings of physical life. Life depends on the properties of physical substances and the way they can interact chemically. The chemistry does not only permit physical life to appear, it allows life to thrive and diversify. But random tinkering with chemicals on a sterile earth, no matter how long it is left to bubble and boil, would have zero chance of leading to the complexities of the simplest living cell.
Here is a lecture James Tour gave entitled, “The Origin of Life: An Inside Story”. It is well worth watching and I’ll give the gist of the early part of it below.
The earliest living ‘simple’ cell would have been made up of carbohydrates, nucleic acids, lipids and proteins. No chemist understands how these four types of molecule combined to form the first physical living system. Living systems are built by bottom up with synthesis taking place at a phenomenal rate.
Didn’t Nick Lane mention that we use up around our own body weight in ATP every day. That is some turnover. Anyway, back to Tour’s lecture.
Scientists working in the field of synthetic organic chemistry target classes of molecules for specific functions and making progress is not easy. Training and experience is required to choose the right molecules for the right job. Nature has never seen the target, so how does it ‘choose’ which combinations to use to build life? It can’t pick and choose according to needs in the way that an organic chemist can.
There would be no life without the specific scrubber molecules which get rid off toxic waste products. But how did blind prebiotic nature achieve this if there was no target in mind? Organic chemists use a retro-synthetic approach. They know the target and so they no what to get rid off and what to keep. Blind nature does not have that luxury. It cares nothing for purification. For instance, why should it select for homochirality?
When Tour was working on building nano-cars and the like, quite often there would be unstable intermediates, but if these intermediates were not what was required then the path that followed would lead in the wrong direction. Only a few scientists with the experience to know what’s involved in building complex nano-systems from simpler molecules, and James Tour is one of them.
Below I’ve copied an image of the instructions for a qualified chemist to follow in just one step of the process in constructing a nano-motor. This demonstrates the careful precision needed in performing just one small part of a construction process when the goal is known in advance.
You can’t just say we’ll take a bit of this and try a bit of that and see what happens. That is not how biochemists work when they want to construct things, nothing would get made that way. But that is how abiotic processes would have to do it, because they are working blind. And that is assuming they had all the necessary ingredients readily available and the environmental conditions were such as to allow for construction to stay on the path leading to biological life.
That was a summary of about the first half hour of the lecture.
Even if the early earth was awash with adenosine molecules and fatty acids and amino acids and phosphates, then nothing resembling life would come from it, unless they could be brought together along with all the other necessary chemicals and somehow initiate metabolism. There are a host of reasons why the presence on earth of these chemicals alone would not be sufficient to initiate life.
That’s why nobody is positing the “random tinkering with boiling bubbling chemicals” as a model for the origin of life.
How do you know that?
This is where your collapse begins. Answer that “how do you know that?” question and notice how all your reasons collapse on further question. Try it. Go on, do it.
To all of Tour’s fans. All of you. Take the challenge. Answer my questions. Realize you’ve been duped when you can’t answer them. You’ve been fed a non-sequitur by a professional bullshitter and you didn’t even see it happen.
I will now demonstrate on CharlieM. And it will be easy.
After discussing some of the barriers against assembling the building blocks required for organic life Tour goes on:
Now he takes all that and transfers it to a limitlessly funded dream team of all our top scientists in all the relevant fields, with all of the ingredients and all of the facilities available.
James Tour dares to speak up against the dogmas of the establishment, and the good thing is that he is in a position to do so with authority even if it has cost him membership of some exclusive clubs.
How does Tour know what is the simplest possible living cell?
What are the building blocks required for organic life and how do you know?
Fair point. Let me rephrase it in a way the you might find more acceptable. The earliest living ‘simple’ cell would have been made up of a selectively permeable barrier to shield it from its environment and allow the relevant materials to be transferred in and out, the ability to replicate for sustained viability, a constant supply of material that allowed for structure and growth of form,
Any suggestions?
Of course the evolution of physical life as we know it, at some stage probably very close to its beginning, would have to have been made up of carbohydrates, nucleic acids, lipids and proteins.
Human technology has produced some very complex machines. But so far producing anything like a living cell is way beyond our capabilities. So that gives us some idea of the complexities involved.
Don’t you think experimenters would consider it an unparalleled achievement if they could produce anything like a living cell?
Indeed. But to some people, it is incomprehensible that the universe has laws that lead to the spontaneously self-organizing systems as long as there is a source of sufficient energy and a ready supply of interactable elements.
I see that you’re trying to get CharlieM to question Tour’s assumptions about how complex the very first cell must have been. I doubt you’ll succeed, but more credit it to you for trying.
Thank you, both for the concession of the point, and for providing a much more reasonable definition of what we could call the simplest living cell. By admitting to a lot more agnosticism about what is really required for any kind of cellular lifeform, it also becomes much more obvious how we can’t really claim to know that such a thing could not have formed in some primitive environment, nor can we claim to know that it needs this or that particular organic molecule known from present life.
Conceivably something even simpler than you described, possibly lacking some of the functions or structures, might not qualify for what we would want to characterize it as a lifeform, much less a cellular one, but that of course does not mean it could not be an intermediate in some hypothetical physical-chemical transition from non-life to life.
Somewhat ironically, a lot of the things Tour insist we are totally ignorant about actually also leaves much more space open for possibilities than he likes to emphasize in his talks. He likes to talk a lot about homochirality, for example, apparently in the belief that if we don’t have homochirality we can’t have a form of cellular life. But he doesn’t actually know this. It’s an assumption he makes.
The space wherein chemistry interacts with physics in unknown ways with unknown results is unimaginably vast, and anyone who insists we already know enough to say that life could not originate by a physical-chemical process is talking out of their rear end.
Reading the relevant literature on ool, they constantly mention monomers such as amino acids, nucleotides and lipids.
Whatever the simpler chemicals were, the beginnings of earthly life has resulted in the observable polymers that exist in extant life forms.
Right, but that doesn’t seem to answer my question.
I totally agree, but there’s a far cry from “this is used in extant life” to “it is necessary for any form of life.”
Of course the origin of life, if it is to explain how life as we know it came to be, must at some point involve the origin of the things we want explained, but that doesn’t mean those things are necessary for any form of life, and that there was not some stage in life’s evolution prior to life as we know it, where life lacked carbohydrates, amino acids, or what have you.
There are researchers pursuing a hypothesis that these things were there and were involved basically from the beginning even prior to cells(and trying to find out what kinds of chemistries could at least in principle produce those molecules), and others who are a lot more agnostic about what really is necessary for any kind of life, who are pursuing hypotheses that evolution-like processes could occur in much simpler systems or with much different forms of organic molecules than the ones we know from our kind of life.
I’m sure I’ve read an article somewhere on the emergence of homochirality in metabolism but can’t remember where. If half of the molecules are the wrong enantiomer, the other half are right and you just get a lower yield.
Not the paper I remember but covers the same ground.
What!? There are laws that ensure mere physics and chemistry will give rise to life and the ensuing consciousness we witness? 🙂
Well it must have been complex enough that it is beyond human capability to reproduce and doesn’t seem like it will be achieved any time soon.
But being a Professor of Chemistry, Professor of Materials Science and Nanoengineering, and Professor of Computer Science and a top researcher in his field what does Tour know. 🙂
Just as an illustrative mind game, I have proposed what I call the “biologist-50” index. The idea is, we take 1000 biologists, put them all in a big time machine, and go back to a time when they all agree there’s no life. Then move forward in time, say 100 years at a time, taking plenty of samples at every stop. Based on those samples, we ask our biologists if anything is alive in there. When we reach the time when 50% of the biologists agree something is alive, we are at the point when life originated.
It might also be interesting to determine when every one of the biologists agrees that life has truly started. And what it might look like in both the 50% and 100% cases. I seriously doubt it would look much like life today.
Not ensure, just allow. As far as we can tell, there is life here today, so clearly the laws of physics and chemistry permit life. And what is permitted is not prevented from starting.
I’m not about to say that anything theoretically possible is beyond human capacity to reproduce (we reproduce all the time!). Since life is clearly possible, we can’t rule out the possibility it might be created in a lab, though I don’t know what “soon” might be. Initially, the lab was the size of the whole planet and the time required was likely over a billion years. Presumably with current and future scientific knowledge we can speed that up, but I doubt it will happen in my lifetime.