How many fascinating analogs exist for this problem?
"...the corrosion on the glass also forms millions of tiny pits. The authors think those pits could serve as tiny reaction chambers..."
In other words, the experimental conditions, as intended, were almost "too perfect." The simulation of reality requires some amount of unspecified noise with respect to CONDITIONS, in this case, corroded glass.
How many experiments, on the terminal or the bench, are run with noise in the underlying test conditions?
I'm not aware of any bench experiment that eliminates all noise (I think that would be physically impossible) but we can certainly isolate things from the external environment very well, and the physical results you get from those tend to be very "clean" (IE, if you're measuring a physical parameter which is required to be an integer, and computing a mean on your observed values, the mean will be near the integer and the variance will be tiny compared to the magnitude of the integer.
On the computer, many "experiments" (really simulations) are 100% deterministic and therefore have perfectly predictable noise characteristics. Most simulations are not deterministic for a wide range of engineering reasons (order of summation in a distributed environment, inability to specify random seed) but are nondeterministic in a statistically useful way (IE, you can run a few times and get a good idea of the real result).
> How many experiments, on the terminal or the bench, are run with noise in the underlying test conditions?
All of them, approximately. There are a few journals like http://www.orgsyn.org/ that consist entirely of rigorously vetted methods, but that is definitely an outlier. The significance of the noise will depend on the specifics, of course.
I'm fairly sure there have been a few high profile retractions of 'metal-free catalysis' that were ultimately traced to metal impurities in the reagents. There was also an incident with the DOE where in the process of refurbishing some of the nuclear arsenal they found that they couldn't reproduce one of the necessary ingredients due to some then unknown change. I am blanking on the (code)name of the material they were trying to reproduce though.
You're thinking of FOGBANK. Apparently they needed some of the impurities present in the original manufacturing runs to get the properties they wanted. Restarting FOGBANK production was problematic because a) the manufacturing process is in itself tricky and nasty and then b) once they restarted it they discovered the previously overlooked impurities.
So the new experiment has three flasks. One is borosilicate, the other two are teflon. One of the teflon flasks has pieces of borosilicate floating in it. Both the teflon flasks failed to reproduce the results of the original experiment.
Couldn't the takeaway here be that life is allergic to Teflon?
The takeaway is that the silica / silicate in the glass acted as the silica in the rocks and gave a more closer to real-life scenario, so it solidifies the original experiment even more, while noting that the original authors did not intend this.
what I mean is, how do they know that's what helped the reaction? The other two flasks were of a different material, but the same as each other. How do they know that material A aided the reaction as opposed to concluding that material B impeded it?
If Teflon impeded the reaction but borosilicate did not help it, then the two Teflon flasks would have had identical results. They didn’t have identical results, therefore logically one can conclude that borosilicate has a beneficial effect.
Yes, it would take more experiments to further explore the role of the vessel material.
This is how science works in general; someone gets an idea and runs a limited experiment and gets results. Then other people, seeing the results and understanding the limitations, get their own ideas and test those.
What I’m trying to say is that you’re not wrong to say there is more to test here. But, it’s not a fatal flaw to this experiment. All experiments have limits to what they can prove.
> This finding supports the authors' original hypothesis. Corrosion on the surface of the glass (due to the hot and caustic water circulating through it) plays a key role, since this releases silicon-dioxide molecules into the solution. This in turn acts as a catalyst to speed up the chemical reactions between the nitrogen, carbon, and hydrogen atoms that ultimately create organic molecules. In addition, they found that the corrosion on the glass also forms millions of tiny pits. The authors think those pits could serve as tiny reaction chambers, also speeding up the rate at which organic molecules form in the experiment.
1. It's known to be a catalyst in the chemical reaction
2. They believe that the tiny pits in the corroded glass also speed up the reaction. This could explain why the material of the flask matters.
That sounds like they had a hypothesis, did an experiment, the experiment matches their hypothesis, so they came up with a reasonable explanation why. But if noduerme had done the same experiment with the hypothesis "life can't form in the presence of Teflon" the experiment would have also confirmed his hypothesis, and he would have given you a reasonable explanation why that is.
It would have been more convincing/thorough if they had also tried e.g. a steel and a silicon carbide reaction flask.
If it is not the case that the Teflon + glass pieces run gave a result between the other two, perhaps the next step would be to run the experiment again in the glass vessels, but with pieces of Teflon in them. If Teflon is neutral, the results should match the glass-only run.
The Teflon flask with some borosilicate did have a lower ending PH than the flask with only Teflon. Assuming the authors ruled out other potential sources for that reduction, then one must conclude that borosilicate had an effect.
Yes, the pure borosilicate flask had a much greater effect, but there was also much greater surface area for the solution to work on.
An interesting experiment might be to see if the reduction in PH levels scaled with the amount of borosilicate added to the solution. They may have done that in the paper, but that'd settle the question you posed.
I might have missed something. says the teflon flasks produced less organic material, but I assumed it was only the teflon without borosilicate? my understanding was that borosilicate contributed to creation of organic materials.
Article Quote:
When Miller showed his results to Urey, the latter suggested a paper should be published as soon as possible. (Urey was senior but generously declined to be listed as co-author, lest this lead to Miller getting little to no credit for the work.)
As if Urey doesn't deserve enough respect, the story is better than described:
Sub-article Quote:
After Miller showed the impressive results to Urey, they decided to submit them to Science. Urey
declined Miller’s offer to coauthor the report because otherwise Miller would receive little or no credit. Knowing that a graduate student could have a difficult time getting a paper like this published, Urey contacted the Science editorial office to explain the importance of the work and ask that the paper be published as soon as possible. Urey kept mentioning the results in his lectures, drawing considerable attention from the news media.
The manuscript was sent to Science in early February of 1953. Several weeks went by with no news. Growing impatient, Urey wrote to Howard Meyerhoff, chairman of AAAS’s Editorial Board, on 27 February to complain about the lack of progress. Then, on 8 March 1953, the New York Times reported in a short article entitled, “Looking Back Two Billion Years” that W. M. MacNevin and his associates at Ohio State University had performed several experiments simulating the primitive Earth—including a discharge experiment with methane wherein “resinous solids too complex for analysis” were produced. The next day, Miller sent Urey a copy of the clipping with a note saying “I am not sure what should be done now, since their work is, in essence, my thesis. As of today, I have not received the proof from Science, and in the letter that was sent to you, Meyerhoff said that he had sent my note for review.”
Infuriated by this news, Urey had Miller withdraw the paper and submit it to the Journal of the American Chemical Society. Ironically, at the same time (11 March), Meyerhoff, evidently frustrated by Urey’s actions, wrote to Miller that he wanted to publish the manuscript as a lead article and that he wanted Miller—not Urey—to make the final decision about the manuscript. Miller immediately accepted Meyerhoff’s offer, the paper was withdrawn from the Journal of the American Chemical Society and returned to Science, and was published on 15 May 1953.
> Most ancient recipes call for whole small fatty fish to be layered between herbs and salt in concrete vats. Palacios’ team used large glass fermenting vessels.
There's a future where the art of charred oak barrel bourbon is lost and scientists try to recreate it in glass vessels....
Except, great irony, in TFA, it was the glass vessels and not the other ones which had bits of the walls going into solution and helping to make the other amino acids. Eventually perhaps giving rise to oak trees. Doesnt look like it to a lowly primate, but glass has a hallowed place in the cosmos, cherry oak is a fucking upstart
I don't know if people gloss over it, or it's just a good place to start. It's like if you were wondering how a giant Lego set came to be, you might start with the pieces.
I think an analogy would be we created some of the lego blocks in this experiment but a single cell would be akin to all the lego creations in the world.
TL;DR summary: The actual glass the lab flasks were made of mattered.
Miller's lab flasks were made of borosilicate glass and this caused more organic compounds to form than a more truly inert Teflon flask. But Earth's crust is over 90% silicates which could have similarly contributed to the formation of organic compounds in ancient pre-life earth.
I thought the more important fact was that the original experiment produced a bigger variety of aminos than previously thought, discovered by re-examining the original material with modern tech.
We have such a limited understanding of life that calling it “just” anything, at least with any degree of confidence, seems unfounded.
Our definitions are somewhat inadequate and full of edge cases and blurred lines. It doesn’t mean we should dismiss them out of hand, especially since the circumstances of life’s origin are so mistifying.
It s not mistifying that much if you look at the chemical timescale. Give me 2 bn years and see where I go. Try to imagine what that amount of time for random permutation can give in the entire space of the universe and you're bound to have a self reproducing machine popping up once.
This is a total non sequitur. The smallest organism we know of capable of independent self replication and Darwinian evolution has billions of atoms. The complexity gap from Miller-Urey style experiments to that is enormous, vastly overwhelming mere billions of years. Maybe there's some trick that evades this gap, but if so we don't know what it is, or how likely Origin of Life would be even with the trick.
Well this seems extremely specious. To presume the entire history of life must remain in existence on a heavily life-colonized world is bizarre reasoning. Any "simple self-replicator" would have long since been exterminated by it's more sophisticated next generation species, not to mention the multiple ages of radically different environmental pressures (i.e. the oxygen apocalypse) in the Earth's history.
You're essentially arguing that the absence today of simple replicating amino-acid organisms somehow implies that they must spontaneously form far far more complex systems to do so: yet the evidence says otherwise - we know for a fact and can observe the existence of purely RNA-based enzymatic systems (https://en.wikipedia.org/wiki/RNA_world) which are curiously involved in things like protein synthesis in our cells today.
You are now committing the other Origin of Life non sequitur that annoys the hell out of me: confusing the statement "the evidence does not require one to believe X" with the statement "the evidence requires on to believe not-X".
I'm not arguing that life must be rare. I'm not arguing that the smallest Darwinian replicator must have billions of atoms. I'm arguing against the PRESUMPTION that there must be a small replicator, and the inference (from that presumption) that life must be common. There is no evidence for such a small replicator (the RNA world work does not provide it). And understand that even if the smallest replicator were much smaller than this billions-of-atoms thing, it could still present a super-astronomical complexity gap.
The evidence for small replicators is that we now have large replicators. Whatever the absolute probabilities are, the relative probability of spontaneous emergence of small replicators is much, much larger than large replicators. Therefore, large replicators most likely evolved from small replicators.
Put another way: the most likely ancestor of all replicators was probably close to the smallest molecule that works.
Ah, this is the inference "we are here, therefore life must be common".
This is bogus, because it ignores Observer Selection. We are not at a randomly chosen planet in the universe (or in a larger multiverse), we are at a planet where there exists observers who could observe life exists. The more uncommon observers are, the more biased our position would be.
Ask yourself: if OoL were exponentially unlikely, requiring super-astronomical numbers of tries to get it to occur, far beyond the number of stars (or even atoms) in our visible universe, what exactly would we see that's different from what we do see? If there is no such thing, how could current evidence rule out that possibility?
I will totally agree that the mechanism by which life arose should be among the easiest routes to life. But this doesn't mean that process was likely in any absolute sense, just that it was among the least unlikely.
I'm not claiming life must be common. The strong anthropic theory explains why we can be having this conversation despite the probability of life emerging being arbitrarily low, so there's no reason to assume the probability of life must be high.
But no matter what that probability is, when there are 2 alternative pathways for a step, we should assume the more likely one. I merely claim that
inorganics -> small replicators -> large replicators
With people as insistently contrarian as you seem to be, I really wonder what alternatives, of how life came about, you are proposing?
Is it really just pure agnostic nihilism along the lines of "We know nothing!"? Or do you know of more reasonable alternative explanations, not investigated in experiments like this?
This is false (to some degree), if my memory is correct, life on earth emerged as soon as condition where favorable ~400m years after earth was formed, I am not saying it's aliens, aliens?
Another explanation for that would be that the conditions under which life could arise were only temporary: it had to arise then, or it wouldn't arise at all. For example, possibly life arose in one of a very large number of wet planetesimals that were still warm enough (due to decay of short lived isotopes like 26Al) for the water to be liquid. Or perhaps phosphides in infalling meteorites were necessary to provide some necessary form of chemical energy.
Such a fascinating point that I did not think about, it seems this is related to competing theories what world was first; RNA world vs Protein World (may be even both).
Another possibility would be that panspermia could be possible in densely packed newly forming star clusters, like the one our solar system was born in.
These clusters can be very dense (10,000 stars per cubic parsec, perhaps). With such closely spaced stars, and with residual gas around the stars, it might be much easier for material ejected from one system to be captured in another.
So, IF life arose very early in one such system, it might spread to all the others. The statistical weight of "early OoL" events would be amplified, vs. OoL events that occurred later after the cluster had spread out and dissipated. Observers would tend to derive from these prolific spreading events, just because they'd seed so many systems.
This is a nice scenario for science fiction, since it would allow thousands of life bearing systems in our galaxy (with compatible biosystems!), while evading much of the bite of the Fermi argument. In this scenario, SETI should look for stars with compositions very similar to the Sun, spread on an arc ahead/behind our system on its orbit around the center of the galaxy (the stars would have spread to about 180 degrees along this orbit since their formation).
Self-replicating machines already happened once, in many varieties. It's far from an assumption unless you want to appeal to the idea that they were intentionally created, but that really only pushes the problem further down the stack.
The philosophical name for this concept is panpsychism.
Personally, I’m a panentropist (my own creation) - I hold that the spectrum of life/consciousness varies depending on the level of entropy. So a flame has a higher level of consciousness than a piece of paper and oxygen molecules. But when you combine them they increase their level. It’s weird but it might be correct - doesn’t address issues of the hard problem of consciousness however
> The more possible states a system has, the more room for consciousness
That is one of the postulates of Integrated Information Theory, which aims to give an account of how consciousness can arise from physical substrates. (The idea seems closely related to the concept of entropy.)
That still doesn't rectify the conflict. The living being is reducing local entropy -- meaning it's less conscious than if it maximized local entropy per gp comment. Or put in real terms, lighting yourself on fire likely does not make you more alive/conscious even though it definitely increases your entropy.
If anything, it seems like the reversal of entropy would be a better description of life. To make paper and oxygen from fire would have higher consciousness than a fire itself
I didn't say it wasn't useful. My comment is in terms of physics rather than biology or chemistry. i.e. in physics, there is little difference but complexity between a rock and a human.
I don't think that many physicists would agree. There's this whole idea if entropy in physics, which is basically a valuation of information in a system, and humans would be much more complex when looking at that than a rock. There's also a lot more interesting stuff going on inside a human body than there is for a rock.
This is also, best strategy to search of extra terrestrial life, the concept of entropy for living systems deeply fascinates me, because how simple everything becomes (conceptually); life is entropy maximization systems in universe, looking at human kind it most efficient too.
What does complexity mean, exactly? How does it demark the line between living and not, is there a threshold, and what is the threshold?
There’s also a lot more interesting stuff going on inside a car, a computer, or the planet earth that is made of rocks, than there is for an individual rock. Our solar system is extremely complex, yet is not alive. So complexity doesn’t seem to mark the line between living and non-living things at all.
Saying life is “complexity” seems reductionist and almost information-free, it doesn’t really explain or even shed any useful light on the difference between living things and non-living things, since there are plenty of examples of high complexity, low-entropy inorganic objects & systems. We can synthesize complexity all day, but we don’t know how to synthesize life yet.
Since the beginning of time, things merge. Subatomic "particles" into atoms into molecules into bigger molecules, all directed by physics. Biochemistry, is just chemistry, is just physics.
That ignores emergent features, and that it's impossible for us to describe chemistry or biology only in terms of physics. Reproduction is one of the emergent features of biology.
That doesn't sound right to me[1]. Surely physics + enough detail is biology? Maybe it's not a level of detail we actually understand with contemporary science -- hence the addition of higher level abstractions like biology which are derived "top down" rather than "bottom up" (i.e., empirically) -- but "emergent systems" != "magic".
We should distinguish the field of physics, which is a human study, from the world, which it attempts to map or model on a fundamental level. We can say biology and chemistry are made up of the fundamental stuff of the world which physics seeks to understand, but that's different from saying chemistry and biology are just the science of physics. We have different domains for a reason. How that cashes out in the world itself are metaphysical questions of ontology, emergence, reductionism, mereology and Platonism/universals. Also the status of causality and laws of nature.
But then again, philosophy is also a domain of human inquiry. The world is just whatever it is, however we think it best to describe. Problem is that our different domains of descriptions and questions don't always fit easily with one another. So to say it's all just the domain of physics is to mistake one map for the territory.
From one perspective, mathematics is the study of the methods of reasoning on abstract concepts. Theorems follow from any set of axioms that do not lead to any contradiction. In physics, one is usually only interested in results relating to the current universe we live in. In that sense, mathematics can be viewed as more general.
The commenter is likely referring to complexity from simplicity, best shown in Stephen Wolfram's Rule 30. I'll be talking about this topic, and its implications, at length in an upcoming video on https://recursion.is/youtube.
That's a really profound sounding way of saying that life is complex and we don't understand it. Or are you saying that we do understand it? If so I'm sure you're in high demand right now.
this experiment only reduces the uncertaintly that the building blocks are widely available. The big problem wiht this experiment is that it misestimated the nature of the early atmosphere and os they basically simulated another planet. We don't know if any other planets have life, so simulating another planet isn't useful to illuminate anything about life on earth.
Huh? We know whatever the early conditions of earth were they were clearly amenable to the formation of these organic compounds since life arose here. It's absolutely also interesting to know that in certain known conditions this can also arise, even if those conditions are not the only conditions capable of creating the phenomenon.
That's circular reasoning. We're here so it must have happened in this specific way therefore it happened.
Sure, an expertly guided experiment in a glass tube can make some basic amino acids but they had to be removed from the experiment immediately before the the product was ruined by further reactions. It was a guided process which we've got no further in accounting for in the wild.
We've made no progress since these experiments to answering the questions posted by the theory of abiogenesis.
We've got no concrete answers, only suppositions.
This is not a popular thing to talk about but the fact remains that we are absolutely nowhere close to solving this in the manner in which we are proceeding in OoL studies. The track record for uncondendable conjecture is abysmal.
This is an example of why analogies and metaphors make clear thinking difficult. They're easy to think up - anyone can find some abstract similarity between X and absurd thing Y - but there is no substance there since the two things being compared are actually very different beyond that abstraction.
Or like saying "look, the monkey can sometimes make small words appear when it bangs on the keys of this typewriter. This tells us something about the origins of novels."
studying the behaviour of a monkey when introduced to a typewriter doesn't. Studying the formation of a few molecules in a controlled environment hardly explains how living forms came to exist.
we made substantial progress in biology before we understood molecules. this is because it's not necessary to be entirely reductive to understand larger systems.
It would seem that the next logical experiment is to take Miller-Urey as a given, throw a perfect blend of polymer chains into the "soup," and see if they can start forming RNA chains. I thought I had read about such an experiment, but I can't find a reference to it now. Anything coming up in Google for me is being obfuscated by this recent study, and mRNA COVID vaccine stuff.
I think what the naysayers are missing is that if this experiment had failed to generate any of the sort of organic molecules strongly associated with life, that would have shaken things up - or would you have been just as eager to dismiss this experiment in that case?
I think this is the fallacy of arguing the middle usually deployed against science.
There's a great example of Futurama, where the evolutionary naysayer demands an intermediate form, and Farnsworth shows him one... then he demands another, and Farnsworth shows THAT form... and this cycle repeats hundreds of times until Farnsworth has no intermediate form and the naysayer declares victory.
There is just enormous amounts of shoddy thinking out there from people on the subject of Origin of Life. I'm particularly annoyed by the non sequitur "the universe is large, so there must (with high probability) be life elsewhere." (If anyone reading this thinks that's a valid argument, go look in a mirror and slap yourself.)
Would you like to say a bit more about why that's not a valid argument. To be clear, I'm not saying it is (I don't know enough about the subject to do so) but it doesn't seem that far-fetched to me. Isn't similar probabilistic reasoning used to explain why evolution by natural selection gives rise to various complex life forms? If so, do you also think that that reasoning is shoddy?
Let N be the number of places life could arise, and p the probability that life arises in one of those places.
That argument is basically "there is a value of N such that for any p > 0, N p is much greater than 1."
But that's obviously wrong. For any N, there are values of p > 0 that make the product N p arbitrarily close to 0.
The dim intution behind the argument was that p can't be "too small". But given our current understanding of OoL, that's not a justified assumption. p could be exponentially small, if OoL requires some extremely unlikely step.
Natural selection is great once the system's reproductive fidelity is good enough to support it. The problem is bridging the gap from small molecules to that system. The smallest system we know of that can independently support Darwinian evolution has billions of atoms.
In this formulation, isn't p^N the probability that ALL places where life is possible, actually has life? It makes sense for that to approach zero.
What we want is the probability for at least one other place other than ours to have life. This would be 1 - (1-p)^N, which does tend to 1 as N gets arbitrarily large.
To get that formula: (1-p) is the probability that life does not exist in a place, so (1-p)^N is the probability that ALL places where life is possible, has no life. Therefore, 1-(1-p)^N is the probability of the opposite of that (where at least one place has life).
For a random variable X taking on non-negative integer values (here, the number of occurrences of life elsewhere in the universe), by Markov's inequality the probability that X = 0 is >= 1 - E[X]. Here, E[X] = Np, so if Np is very close to 0, the probability that X = 0 will be very close to 1.
That the probability goes to 1 as N goes to infinity FOR FIXED p is just another example of assuming p can't be "too small". The probability also goes to zero as p goes to zero. Why are you fixing p and not N? Why are you assuming p is large enough that N is in that asymptotic range where the probability has approached 1?
That seems right, but from a scientific point of view (as opposed to, say, a certain sort of theological view), two occurrences is not much more than one (even though one is so much more than zero.)
Two occurrences would actually be much more than one! Our own existence is useless due to observer selection, but discovery of even a single other independent OoL event nearby would allow us to infer OoL cannot be too uncommon.
Observer selection does not eliminate us as evidence for the proposition that life can exist. As for whether it is rare, you added the qualification 'nearby', and while it is true that it is most likely that any extraterrestrial life we detect will be nearby, the post I was replying to was arguing about the universal probability of life coming into existence, not about whether it will be discovered by us.
Furthermore, proponents of an extraterrestrial origin of life on Earth will doubtless argue that nearby life may have had a common origin.
Observer selection means p > 0 (ie the inequality is strict) but it can't tell us any more. Bayesian reasoning from our own solar system can put a reasonable upper limit on p but that isn't very helpful.
However, if we found life on Mars that same Bayesian reasoning would imply a meaningful lower limit on p as well, since life on Mars is independent of our existence to observe it.
If we found life on Mars that was independent of life on Earth it would imply a meaningful lower bound. Even finding a fundamentally different biosystem on Earth (life that didn't use nucleic acids, say) would be informative.
Just finding life on Mars that's the same kind of life as on Earth would not tell us much, as it could be explained by panspermia. There are Mars rocks on Earth, so transfer of life in those rocks should have happened constantly. If early Mars were habitable it almost certainly had life, due to this transfer.
This explains why it may not be a sound argument, not a demonstration of its invalidity. The distinction matters, because while invalid hypotheses can be summarily rejected, valid ones might turn out to be right.
Of course, if some people don't understand that this one is not an established fact, and that annoys you, I can't say you are wrong.
Yes. Of course, I was not arguing that life must be rare, I was arguing that the evidence we have does not compel one to believe life must exist elsewhere in the universe. The opposite of belief is not belief in the opposite.
There are rare instances where people say that life exists elsewhere, other just state that there is a possibility > 0.
I agree that it is arbitrary that the dimension of the exponent of n has to be larger than the negative one of p. That probably stems from the assumption that the universe is endless.
> p could be exponentially small, if OoL requires some extremely unlikely step.
"exponentially" is not a measure of size, nor is it a measure of relative size. If you think this anything base on "exponentially small" is a valid argument, go look in a mirror and slap yourself.
"Exponentially small" here means "the probability could be ~ e^-n" where n is a number proportional to the complexity of the minimal evolving system. This would happen if there's some gap that has to be bridged by random chance before we get a system capable of sustaining natural selection.
The point here is that this could easily be vastly smaller than 1/N, where N is (say) the number of atoms in the universe x age of the universe x rate at which atoms might interact to form such systems.
I think you could have easily understood this point if you had made an effort to do so, without me having to spoonfeed it to you here.
The problem there is we don't know the "world" of possibilities from which our existence was drawn. It might be the universe (which I read "observable universe"), or it might be out of a large number of causally disconnected universes, or even other branches of a universal wave function (in a Many Worlds interpretation). The "N" there is not the same as the "N" of "our universe".
We know approximately the lower bound of N, which is the approximate number of stars in the observable universe multiplied by an informed estimate of the expected number of planets within the goldilocks zone. That's usually what people mean when they discuss N. N could be that, or it could be much much larger, but I think it's fine to limit the discussion to the lower bound, we still have a huge N to work with.
Also I think you missed my point which is about Bayesian estimation of p, not of N.
I ignored the comment about Bayesian estimation because I couldn't turn that comment into something that made any sense. Perhaps you could explain in detail what you meant?
Your statements in this thread have assumed we have no info to work with (as far as estimating p goes) because we have no understanding of the mechanisms behind how life came to be. But this ignores the evidence that we are here, which is info that can be used in a Bayesian framework to estimate p. The fact we exist, as well as information about how many billions of years it took for us to evolve, contains significant information about p.
I still don't understand. We have no useful lower bound on the probability that life arises, so how does Bayesian reasoning bootstrap to any meaningful lower bound?
Who said anything about a lower bound of p? I was talking about a lower bound on N, not a lower bound on p.
Bayesian reasoning (by using the fact that we exist rather than don't exist, as well as other info about our existence, such as how long it took us to evolve) helps us estimate a probability distribution of p, as well as a central tendency estimate.
But selection can happen with autocatalysts as well. I agree that you can't say life /has/ to exist elsewhere, but I think the trend in research has shown that life seems likelier and likelier to arise the more it is studied.
"Trend in research"? How could that possibly work? Research will tend to clear the low hanging fruit early, which means the easy steps. This tells us nothing about how difficult the difficult steps (if any) might be.
The analogy I like here is those "collect the letters" games you see at fast food outlets and grocery stores. Buy a Happy Meal, get a scratch off ticket. If you collect all the letters in some phrase you win $N million. When you start the game, the trend is great. Letters are arriving and the phrase is filling in. But try as you might, that last letter never shows up. The game ends and you've won nothing. Of course, the way the game was designed was that last letter controls how many winners there could be. All the rest were distractions.
It does however tell us that the "easy" steps are easy, which was never a foregone conclusion. The other steps will remain what they are. It doesn't mean the trend will continue.
I find it weird to use a deliberately rigged game as an example. If one of the previous letters was wrong, the last letter being right means you don't win either.
It's like saying the difficult steps are going to be extra difficult because other steps were found easier than expected.
The point is that if you have N independent boolean random variables X1 ... Xn, establishing a lower bound on the probability that some proper subset of the Xi are true doesn't provide any useful lower bound on the probability they all are true.
Sure, my point was only that if the lower bound on the subset is higher than anyone expected, that will increase the probability of them all being true compared to your prior belief. And it will also increase the probability that life is more common.
You could argue that the priors were garbage I suppose. I'm not arguing for any particular probability.
The McDonalds example does not have independent variables as X1..Xn-1 are deliberately increased as Xn is decreased.
I'd also argue that origin of life doesn't have independent variables. If chemistry turns out to be more or less powerful in one setting, it should do something for our assessment of other settings, especially when it's similar processes.
It's not up to me to show that, since I'm not claiming life is rare. It's up to the person making the strong statement that life is (not just could be) common to convince me that there is no sufficiently difficult step. All I need to do is plausibly argue there could be a difficult step. Pointing out the complexity of all known self contained systems capable of Darwinian evolution is sufficient for that.
It's kind of ironic that both in cosmology and biology we know an incredible amount, but yet we still don't how the universe or life on earth began. Sure, we have educated guesses, but until we can unify QM and GR or produce a cell from simple elements, they remain guesses.
There are numerous possibilities for how life began, and whatever process was involved probably took a minimum of millions of years to lead to something self-replicating and stable enough to start adapting. This makes abiogenesis theories likely impossible to directly test over human time scales.
Not that we shouldn't try... it's possible that certain conditions can give rise to self-replicating molecular systems that can adapt very quickly. This doesn't prove that these conditions were the exact ones responsible on primordial Earth, but it does prove that the phenomenon of abiogenesis is categorically possible under plausible early Earth conditions.
There are lots of other phenomena in nature that may be impossible to directly test. Biological evolution for instance is somewhat testable, but only on a small scale in both time and organismal complexity:
We can also run computer evolution experiments that validate some of the theoretical assumptions underlying biological evolution in a very abstract way, but these can't validate specific biological hypotheses about physical systems.
That's how lots of science works. Especially science involving the past, or science very far away.
Even if we do create a "cell" (whatever that means), it will only give us a possible explanation of how it happened on Earth. It will shrink the possible probabilities of all other methods, such as Aliens engineering us, but we cannot reduce all probabilities to zero... without a time machine.
Unfortunately we live in a world where even 100% definite in-your-face proof will not convince a frighteningly large %age of humanity.
IMHO claiming everything is "still a guess" shows a lack of understanding of science. I'm not judging, because I can't tell what you do and don't know from just three sentences. But it kinda sounds like it.
> In addition, they found that the corrosion on the glass also forms millions of tiny pits. The authors think those pits could serve as tiny reaction chambers, also speeding up the rate at which organic molecules form in the experiment.
In my mind STEM topics exist on a scale that has math at one end, then there's a slight pause/discontinuity (as in point 2 in the underpants gnome business plan) before it continues with physics, chemistry, biology and onwards to god knows what. As you move along this axis stuff feels more and more complex, messy and hard to nail down definitively. More practical. More prone to get tripped up by silly mistakes and things you never imagined you had to think about.
The new compounds they discovered in the old samples kind of illustrates how much hard work is required to get good answers. You can't just suck on your pipe, scratch your quill on some parchment and exert yourself mentally, you have to scrape gunk out of test-tubes and be really careful and thorough in a highly practical sense. The world is imprecise and gnarly and you kind of have to hope for the best.
I really admire people who are capable of wringing results out of goo and specks of dust using gadgets that require calibration that has to be able to distinguish actual good signal from residues of the danish you had for breakfast.
(Example not entirely random since one of our engineers eating a danish for lunch in his office made the electrochemical sensors he was working on go absolutely apeshit. Kind of good to know before you evacuate a whole industrial site and send in the people in yellow hazmat suits)
I try to keep this in mind when reviewing predictions, speculation, and fiction about artificial intelligences that get super intelligent. There’s more to knowledge than just calculating faster. Hypotheses need to be tested by experimentation; theories must be supported by evidence. (This is not my original idea, I read it in an essay from an AI researcher.)
This is also why there is more to science than statistical analysis. Stats help us understand evidence we have collected. But at some point a new idea needs a new test in order to know if it is useful or correct.
I've been lucky enough to work with a few highly skilled organic chemists, and I know enough chemistry to know that I could never, ever join them as such. It's such a niche, specialised, and important and yet under-recognised set of skills.
A few examples. The order in which you add nominally unimportant reagents to a reaction can significantly matter – the enthalpy of mixing is non-zero, and so if you dissolve A and then B in solvent C before letting it reflux for five hours (say), it will be a different initial condition to adding B, then A. Many (most?) chemists weigh vials before adding a mass of x g/mg of a compound, in the process of adding that, and then again when they have removed "x" grams. Lids are pared with volumetric flasks. Tiny variations matter. Room humidity, temperature, and the history of the use of the equipment involved may change the answers. I had one graduate student (who came top in her year in chemistry) make an isotopically labelled molecule for me, with a ~70% yield and a ~100% labelling purity. A few years later, a biochemist following the "recipe" she developed (and beautifully illustrated!) was unable to get above 10% yield and about 80% purity. I never really was able to work out why. Any "debugging" conversation starts with "tell me exactly -- what did you do?". Things occasionally don't go "as well" when certain contaminants are (not) present. The debugger for reality sucks.
And still, despite all the fiddly nature of the work, it's downright dangerous. Organic chemists, as a species, live less long. They get blown up and gassed. I've been in a building when a "small scale" reaction has exploded and you feel the vibrations of it – nobody was seriously injured because the fume hood's shock sensors detected the azide derivatives decomposing rapidly and, within microseconds, dumped a load of cold CO2 down the front of the hood, stopping combustion and redirecting/reducing the blast. Another acquaintance of mine managed to have the building evacuated after ordering a 10 ml bottle of a compound he distilled from a hops extract and identified via GC-MSMS and MS^n spectrometry as part of a project trying to understand beer foam (and make better non-alcoholic beers; this is in about 2000 or 1999, before "good" alcoholfrei bier was available) – he naïvely opened the lid to see what it smelt like outside of the fume hood, and immediately uncontrollably vomited. So did his neighbours. Then the rest of the room. Then the floor. They closed it over a weekend, opened all the doors and windows, put in industrial fans, and it still stank for months.
Chemists do important, undervalued work. They make drugs, materials, batteries. They do everything from quantum mechanics to what I still consider to be not far removed from alchemy. Some of them are slightly odd people, but they are usually very fun to share a drink with...
Another anecdote (because it's Friday): We hired a chemist from a big rocket company into our computer company. He designed organic flammable compounds (rocket fuel) that got made in a clean room in vats and packed into tubes by technicians. They scraped the rapidly-hardening stuff with paddles and smeared it into the tubes. If they left any, the vat was toast and had to be replaced.
So they would try really hard to get it all, scraping the sides and sometimes jamming the paddle down on recalcitrant bits to get them unstuck.
My friend was very nervous about this, and so looked for another job, which was how I met him.
Not long after he was working with us, he got a call and turned white. He explained: the fellow hired in after him was standing behind a technician when the batch went up, turning them both into crackly bits of toast. That could have been him.
Anyway, no I'm not cut out to be an organic chemist.
Thank you for sharing this story. It's easy to think the well-educated/professional/R&D/STEM-academia fields are devoid of danger - they are for the most part - but survival and safety is not a solved problem in many niches of these domains.
I walk through a high-tech, massive industrial factory most days I go into the office. I find it harder to remember to look for wires and forklifts than I did when I was in roles closer to the danger. It's clearly a "natural" risk-analysis response, but risk doesn't go to zero, nor should the individual ever completely export their risk management to confidence in systems, processes, and organizations.
The key-cards and clean rooms and smart people can lead us to forget these things.
Stories like this are what make me so frustrated with the "anti-science" rhetoric you hear in politics coming from the same people that carry a miniature computer in their pocket that's the result of (wild guess) millions of man hours of research in physics, chemistry, and many forms of engineering.
The people that do this work are ACTUALLY making the world a better place.
tertiary amines, man. That's the reason I couldn't be an organic chemist. If you don't like the smell of decaying fish, it's tough.
Also pretty much everything in OC ends up being a yucky resin at the bottom of a flask you can't remove.
When I visited my grad school for the first time, there were ambulances and firetrucks outside the building. I went to the main office and there were EMTs everywhere and firemen. Turns out, they were doing spring cleaning of a fume hook and accidentally touched a bottle of ether. The ether had formed free radicals over time, and just touching the bottle caused it to expose, popping all the windows out 20 feet away. The chemist's face was permanently scarred (although his life was safed by the safety glass). That was later my office, although I did mostly computational work.
speaking of dicey chemistry, I'm sure you have already read the book, but to anyone else who hasn't: "Ignition!: An informal history of liquid rocket propellants" by John Drury Clark (https://www.goodreads.com/book/show/677285.Ignition_) made me realize two things: 1) I'm glad I didn't pursue a career in chemistry as I would doubtless have been drawn to things that are "interesting", 2) people who do "interesting" things in chemistry have the best stories.
We didn't have fancy fume hoods like that back in the day. Do you have a link to the device used in that fume hood? I only found this [1] but it doesn't sound like the device you're talking about.
I mean. I am not trying to underscore the work. But I feel you are making it sound magical. This is not much different than cooking, is it? Try making bread or beer by adding things out of order.
I feel so much of this mysticism is driven by over reliance on associative and distributive laws for elementary math. And it is super annoying because I know I do the same thing.
I think I was just sticking on the gp's "In my mind STEM topics exist on a scale that has math at one end..."
Especially with the first supporting evidence being that order matters on how you mix things. Only in very elementary math, it seems, is that not the case. Yet, we stick on that heavily.
That is, I wasn't trying to counter the point. I intend my point to be a further exploration on why that makes things feel more complicated. Near mystical, in that we can't always explain why an order is important. Sometimes we can, of course.
I track your point, though I might add that in advanced mathematics, things can often be reasoned in multiple directions, or sometimes proved via multiple methods. Often things are demonstrated irrespective of changing parameters, or otherwise the parameters are well understood to define the problem.
This isn't true for many orgo chemicals, based on the OP. The scale of sensitivity to initial and intermediate (!) conditions is un-intuitively high.
Makes sense. I think it is from a definition perspective, though. Statically, it is easy to define things independent of the process that governs them. Such that it is a middle college class that really covers dynamic systems for structural analysis. With most earlier classes being static analysis.
Even electrical classes started on analog circuits and power transmission later in courses. Early circuits are centered around ready dc connections. Or steady state ac ones.
I see it as a sensitivity to initial conditions. If anything, beginner cooks are more likely to overestimate this sensitivity (afraid to sub ingredients,
Your examples of bread or beer avoid this, but then consider whether brewing beer is a good, differentiating counter-example to organic chemistry. ;)
Yeah, I confess I picked baking and brewing specifically. Was also thinking cheeses making.
And agreed that for many processes, it is initial conditions. I also consider scaffolding for things like keystone arches. The final result being something that is only doable with items that are no longer there.
> In my mind STEM topics exist on a scale that has math at one end, then there's a slight pause/discontinuity (as in point 2 in the underpants gnome business plan) before it continues with physics, chemistry, biology and onwards to god knows what.
Whether or not it is a joke probably depends on how you label the axis along which you distribute these topics. :)
Observe that as you move from one side to the other (math to biology and onwards), you are essentially dragging along a good portion of the stuff as prerequisites you have to know a bit about.
By the time you reach something like immunobiology you can pretty much build a house out of the textbooks and go live in it. :)
The joke as I heard it in the 80's -- and I have no reason to think it was new then -- went something like: Physics is just applied math, chemistry is applied physics, etc...
I've always liked the view that Physics is just experimental discovery of the axioms "chosen" for our universe. Physics without experimentation just being a specific subset of math.
> In my mind STEM topics exist on a scale that has math at one end, then there's a slight pause/discontinuity (as in point 2 in the underpants gnome business plan) before it continues with physics, chemistry, biology and onwards to god knows what.
"Now one speculative [i.e., theoretical] science is said to be nobler than another, either by reason of its greater certitude, or by reason of the higher worth of its subject-matter...Of the practical sciences, that one is nobler which is ordained to a further purpose, as political science is nobler than military science; for the good of the army is directed to the good of the State."
So does this mean that any planet with a reduced atmosphere, electrical storms, silicate-rich rocky surfaces, and liquid water would have a good chance of developing life, at some point?
you can't conclude anything from these experiments like that.
we can conclude that many planets are likely to have rich organic soups, but nobody has made plausible link from organic soups to true living information processing systems.
Reminds me how they eye was seen as counter argument against evolution because its complexity couldn't have developed naturally. But today we pretty much know how it evolved from a photosensitive spot to the complex mechanism we see (huh!) today.
yes, but apparently through some irreducible complexity (arguable), and most of the original history of we got from "a soup" to "life" has been erased.
the original article was used in my graduate program as a list of all the things biologists shouldn't do when working on origin of life. Like, "they got the basic details of the atmosphere wrong". https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Evolution_...
Carl Sagan made amino acids with a similar experiment, I remember my dad telling me about it back in the 80s. It looks like he joined the scene a little later though, and that Urey (who only won a Nobel prize for discovering deuterium) was his mentor:
Then there is a mystory of how environment with high availability of phosphates, which are responsible for energy transfer in all life cells cells, came to be: https://shkrobius.livejournal.com/401292.html
While there is much that is unknown yet, there is much less mystery about phosphates than many people think.
In the modern oceans, there is a very high abundance of calcium and magnesium ions.
This keeps the phosphate concentration in the water low, because when there is much phosphate, it precipitates with the calcium ions, making apatite rocks.
However the oceans at the time when life appeared had a composition different than today.
The oceans have formed by the condensation of the volcanic gases, which are made of water and of acidic substances (mainly oxides of carbon and sulfur and hydracids of halogens and sulfur).
So the initial oceans were very acid. After formation they began to dissolve the more easily soluble rocks, e.g. carbonates and phosphates and then also the easier soluble of the silicates, starting with the alkaline silicates.
So the concentration of phosphate in the initial oceans was much higher than today, due to the very low pH of the water and due to the lack of calcium and magnesium ions in appreciable quantities.
In time the pH of the oceans increased tending towards the neutral value (today the oceans are slightly alkaline, but that changes with the increase of carbon dioxide in atmosphere, which makes them more and more acid), while the concentration of sodium and potassium increased, neutralizing a part of the acids.
Because the rocks with calcium and magnesium dissolve much slower than those with sodium and potassium, the concentration of calcium and magnesium in the sea water remained low for a longer time and it probably reached the current levels much later, after the apparition of life.
Only then the concentration of phosphate diminished to the current values.
So a much higher initial availability of phosphate in solution, in the sea water, is expected, it is not mysterious.
This reminds me of the chemist who's beard was so long and dirty it led to his experiments crystallising with high frequency due to the amount of matter falling off the hairs into solution.
The Miller-Urey experiment isn't relevant to me after learning more about the hydrothermal vent theory for abiogenesis. "The Vital Question" by Nick Lane is a great read for anyone interested in the topic
This makes me think, maybe the most important thing in the universe is silicon, and also, we're silicon life, computers Are our babies. I am yo neighbor.
>Julia Child and the OSS Recipe for Shark Repellent
>“The answer to the threat of man-eating sharks, the scavengers which infest all tropical waters of the world, was announced here today…” (quote from draft OSS/ERE Press Release on the development of a shark repellent; April 13, 1943)
And she showed how to bone a chicken on Saturday Night Live:
The National Air and Space Museum used to show this delightful video in its "Life in The Universe" exhibit, in which Julia Child recreates Stanley Miller's famous experiment, cooking up a delicious hot batch of Primordial Soup!
>Scientists don't yet know how life began here on Earth. Mineralogist Bob Hazen, who is profiled in the October issue of Smithsonian, thinks that rocks were key to the development of life. Reporter Helen Fields wrote:
>It’s the complexity of the hydrothermal vent environment—gushing hot water mixing with cold water near rocks, and ore deposits providing hard surfaces where newly formed amino acids could congregate—that makes it such a good candidate as a cradle of life. “Organic chemists have long used test tubes,” he says, “but the origin of life uses rocks, it uses water, it uses atmosphere. Once life gets a foothold, the fact that the environment is so variable is what drives evolution."
>The Miller–Urey experiment (or Miller experiment) was a chemical experiment that simulated the conditions thought at the time (1952) to be present on the early Earth and tested the chemical origin of life under those conditions. The experiment at the time supported Alexander Oparin's and J. B. S. Haldane's hypothesis that putative conditions on the primitive Earth favoured chemical reactions that synthesized more complex organic compounds from simpler inorganic precursors. Considered to be the classic experiment investigating abiogenesis, it was conducted in 1952 by Stanley Miller, with assistance from Harold Urey, at the University of Chicago and later the University of California, San Diego and published the following year.
In other words, the experimental conditions, as intended, were almost "too perfect." The simulation of reality requires some amount of unspecified noise with respect to CONDITIONS, in this case, corroded glass.
How many experiments, on the terminal or the bench, are run with noise in the underlying test conditions?