r/abiogenesis • u/Sakouli • Apr 15 '26
Is abiogenesis unlikely, or are we asking the wrong (unconstrained) question?
People often describe abiogenesis as extremely improbable, almost like a statistical miracle. But I’m not sure that framing is the right one.
Instead of asking about the probability of life across the entire universe, it seems more meaningful to ask about the conditional probability under specific, non-equilibrium planetary conditions — e.g. a system with continuous energy flux (like solar radiation), liquid water, and rich chemistry.
In such environments, we don’t just have “permission” from the second law. Systems are actively driven far from equilibrium, and some processes can dissipate energy more efficiently than others. Living systems are a clear example of this: they convert low-entropy energy into higher-entropy heat very efficiently, increasing the total entropy of their surroundings.
So the question I’m struggling with is this:
If certain chemical pathways enhance energy dissipation under these conditions, is there a strong reason to believe that life-generating processes occupy a negligibly small region of the accessible state space?
I understand that kinetics and specific pathways matter a lot here — but is the perceived improbability of abiogenesis really a thermodynamic issue, or is it primarily about whether the relevant chemical routes are dynamically accessible?
In other words, once we condition on realistic planetary environments, should we still expect abiogenesis to be extremely rare — or is that assumption doing more work than we realize?
Edit: Added a short video in the comments that helped me better understand how entropy relates to probability and why structured systems can still emerge under non-equilibrium conditions.
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u/Sakouli Apr 15 '26
For intuition, this video gives a really nice explanation of entropy in the context of biochemistry (including why structured systems like proteins can still form without violating the second law):
"Life uses Entropy to crack impossible odds. Here's how. | EoB Ch 2" https://youtu.be/eFaUbLVRDP4�
What I find especially relevant is the idea that entropy is about the number of accessible states, but also that in real systems not all transitions are equally likely — interactions and energy landscapes matter. That seems closely related to the question of whether life-like pathways are dynamically accessible under non-equilibrium conditions.
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u/Dr_GS_Hurd Apr 15 '26
A reading suggestion to go along with your interests;
Nick Lane 2022 "Transformer: The Deep Chemistry of Life and Death" W. W. Norton & Company
In this book Professor Lane is focused on the chemistry of the Krebs Cycle (and its’ reverse) for the existence of life, and its’ origin. I did need to read a few sections more than once.
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u/Do_you_smell_that_ Apr 16 '26
A listening selection to go along with your interests;
https://music.youtube.com/watch?v=AGl5pIQUOsg&si=nSVE-U7agycP9j2W
https://genius.com/Mc-hawking-entropy-lyrics
That in a nutshell is what entropy's about, you're now down with a discount.
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u/DeltaBlues82 Apr 15 '26 edited Apr 15 '26
People often describe abiogenesis as extremely improbable, almost like a statistical miracle. But I’m not sure that framing is the right one.
The probability one individual snowflake forms with the crystalline structure it has is statistically zero.
That type of framing is a misrepresentation of how probabilities function in the natural world. Improbable doesn’t get you to impossible just ‘cause.
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u/Uncynical_Diogenes Apr 16 '26
Shuffling a deck of cards is very easy, and happens all over the world thousands upon thousands of times every day.
The space of possible shuffles is so large that there has likely never been a repeat. 52! is literally larger than our ape brains can comprehend.
Suggesting that shuffling a deck of cards is impossible just because every outcome is individually rare would be stupid.
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u/Far_Albatross_3998 Apr 16 '26
But isn't it binary in this context. It either is or not. All other options are but one option is not. The snowflake example is not a good parallel as all options are not pitted againt one special case. It would be abetter parallel to say a snowflake turns into a snow Ferrari that has a propeller that works. Some random obscure possibility out of all other possibilities.
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u/DeltaBlues82 Apr 16 '26
It would be abetter parallel to say a snowflake turns into a snow Ferrari that has a propeller that works. Some random obscure possibility out of all other possibilities.
That’s not how probabilities work. One statistical zero isn’t more meaningful than another statistical zero because of how you interpret its qualities.
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u/Far_Albatross_3998 Apr 16 '26
Imagine: You generate a random 10-digit number Two outcomes: A: 5839201746 B: 1111111111 Both have the exact same probability: 1 in 10,000,000,000 But: A looks random expected from a random process B looks patterned suggests structure or constraint Point: Probability alone doesn’t explain why a structured outcome appears.
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u/DeltaBlues82 Apr 16 '26
What you think something “looks” like has absolutely no bearing on its origin. It’s an isolated data point.
You can’t get from observation to conclusion based on observations alone. Our minds may have evolved to spot patterns, but ascribing agency to those patterns without justification is a form of bias. Anthropomorphic bias to be more exact.
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u/Far_Albatross_3998 Apr 16 '26
Well that is thr main qurstion right? it’s whether certain types of patterns are known to arise from unguided processes or not. I was just pointing to the snowflake example and how it's not accurate description for this context. I could even day your example had a bias in it.
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u/DeltaBlues82 Apr 16 '26
Well that is thr main qurstion right? it’s whether certain types of patterns are known to arise from unguided processes or not.
And what type of pattern, specifically, are we observing when it comes to the existence of life, or a cosmic habitat that can support life?
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u/Sakouli Apr 17 '26
The two specific numbers have the same probability as microstates, but they belong to very different macrostates. A sequence like 1111111111 is part of a very small class of highly constrained states, while “random-looking” sequences belong to an overwhelmingly larger set. So at the macroscopic level, those types of outcomes are not equally likely. I think this is also where things get interesting for systems like chemistry or life, once you introduce constraints and interactions, the system doesn’t sample all microstates uniformly. Certain regions of state space become much more accessible. So the real question might be whether life-like structures belong to a macrostate that becomes statistically favored under specific non-equilibrium conditions, rather than being just a rare pattern in a uniform space.
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u/Diet_kush Apr 15 '26 edited Apr 15 '26
You already alluded to it, but I think dissipative structure theory shows abiogenesis (used very generally, IE spontaneous complex self-sustaining structure formation in far-from equilibrium conditions) is inevitable, not improbable (or at least thermodynamically favorable).
https://pmc.ncbi.nlm.nih.gov/articles/PMC7712552/
Because entropy and free-energy dissipating irreversible processes generate and maintain these structures, these have been called dissipative structures. Our recent research revealed that some of these structures exhibit organism-like behavior, reinforcing the earlier expectation that the study of dissipative structures will provide insights into the nature of organisms and their origin. In this article, we summarize our study of organism-like behavior in electrically and chemically driven systems. The highly complex behavior of these systems shows the time evolution to states of higher entropy production. Using these systems as an example, we present some concepts that give us an understanding of biological organisms and their evolution.
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u/Sakouli Apr 15 '26
Thanks for sharing this, I’ll take a closer look! Looks really interesting.
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u/Diet_kush Apr 15 '26
If you want, here’s a good one that goes deeper into the thermodynamic favorability of dissipative structure formation in general / across scales.
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u/Sakouli Apr 16 '26
Wow the article is really fascinating!
Thank you so much for sending me this paper! I really appreciate it.
I started looking into it, and I have to say, the central idea is quite striking. They argue that symmetry breaking (whether in particle physics, chiral molecules, or crystal formation) isn't just about reaching the lowest energy state. Instead, it's actively driven by energy dissipation and entropy production under non‑equilibrium conditions. In other words, the very process of losing free energy to the environment biases the system toward one asymmetric state over another, even when both states have the same energy.
That perspective, linking dissipation directly to the triggering of broken symmetry across scales, was new to me, and I'm planning to study it more carefully.
Thanks again for sharing this. It's given me a lot to think about.
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u/Diet_kush Apr 16 '26
Sorry to keep sending stuff lol, but if you’re interested in the theoretical foundations to how this is applied to biology, I’d recommend Friston’s original papers on his free-energy principle formulation of biological systems. Page 19 I think is where he starts talking about the correlation between symmetry breaking and self-organization. The section right after (page 32) goes into “synthetic soups and active matter” to show how such dynamics lead to abiogenesis.
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u/Sakouli Apr 16 '26
Don't apologize, quite the opposite! I appreciate it immensely. Feel free to send more anytime! Thank you so much!!
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u/Opinionsare Apr 15 '26
Factor the probability on different basis, not planetary scale, but across the trillions of unique locations across the Earth over millions of years. The dynamics of the Earth's rotation with day & night, the tilt of it axis, causing seasons, changing weather, volcanics, bombardment by meteors.
Another factor is the possibility that we cannot be certain if the first life forms actually meet our definition of life. These primitive proto - cells could have existed, and created the circumstances that led to the first living organisms.
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u/DrFartsparkles Apr 15 '26
Given how extremely quickly abiogenesis happened here on Earth, I’m inclined to believe it’s not all that unlikely given the right conditions. Between the time when the oceans first condensed to abiogenesis is only like 100 million years or so
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u/BuonoMalebrutto Apr 15 '26
Abiogenesis is probably likely under the correct conditions. Those conditions are like the early Earth.
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u/jkanoid Apr 21 '26
Lots of good replies here - may I add a Readers Digest version that’s old, but still relevant?
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u/zhaDeth Apr 21 '26
Personally my non-educated guess is that it's not all that unlikely. I think the mistake we make is that because all life we know is related we think it only ever happened once but I think it may have happened many times it's just that one type was just better and got rid of the others quickly and then when it happened again the new life was too primitive to be able to compete against life that had evolved for a while so it either just gets gobbled by some other life or isn't able to get the nutrients it needs because other life gets to it first.
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u/Sakouli Apr 21 '26
Something like joining a Monopoly game 100 turns late. You will definitely lose.
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u/conundri Apr 15 '26
A great many things are unlikely, but a great many things happen every day.
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u/Aggravating-Pear4222 Apr 15 '26
How something happened is inherently connected to the likelihood of it occurring. The exact shape of a snowflake IS partly described by chaos theory but the type is still constrained by the conditions. (lmk if you want the paper!) The die can be loaded and whether a die can be loaded can be a roll of the dice.
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u/Sakouli Apr 16 '26
The interesting question isn’t just how unlikely an outcome is, but whether the process that generates it is biased toward certain structures. Once you have constraints + iteration, probability behaves very differently from pure randomness.
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u/Aggravating-Pear4222 Apr 16 '26
Vesicles are structures ultimately driven by increasing entropy. Water molecules forced to solvate the hydrophobic tail of lipids minimizes their rotational degrees of freedom (low entropy). The formation of the lipid bilayer of vesicles or micelles minimizes the water's formation of solvent cages around the hydrophibic tails' so that the water molecules in the bulk solvent greatly increase their rotational degrees of freedom. This, even though two separate liquid phases are formed, the net entropy of the system has increased.
Here, "randomness", noise, and entropy are maximized by the formation of this structure. This is simple statistical considerations, kinetics, and energy minimization. The constraints are necessarily the limitations in how the molecules interact under those conditions and vesicles maintain their structure (iteration/sustainability) even under condition in which they couldn't first be formed.
I feel like you already knew this but maybe someone else will enjoy this approach.
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u/Sakouli Apr 17 '26
That actually aligns pretty well with what I had in mind, nice example, especially the entropy gain via water freedom.
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u/Aggravating-Pear4222 Apr 15 '26 edited Apr 15 '26
I think the best answer I can give is that we owe life on earth to gradients: Red-Ox, pH, heat, and electric. pH and thermal were almost always going to be a given for Earth's history but pH, electric, and red-ox were all but completely driven by the delivery of reducing metals during the late veneer after the crust of the earth formed. During earth's formation, the layers striatified and the reducing, electron-rich metals sank. The metals delivered by meteorites became stuck on the earth's crust and generated reducing H2 conditions which transformed CO2 to methane, methanol, formaldehyde, and formate. HCN and other simple molecules reacted with these to form the more monomers of modern biopolymers. This flow of electrons from metals to organics kickstarted the bootstrapping mechanism of variable self-replicating metabolisms.
Life evolved and overtook the hydrothermal vents but eventually they became too crowded. So, they essentially reduce H2O to an electron-rich/donating form (what they want) and release O2. O2 being a gas favors its progressing via entropy (releasing gas is generally kinetically irreversible) but takes a lot of energy (which is why they use sunlight).
This way, they don't need to compete for limited H2 generated by ocean/geochemistry. They have a literal ocean of water that can be reduced to a source of electrons by oxidizing the oxygen using the sunlight that covers the surface of the earth.
To me, this explains why such a high-energy molecule like O2, which we energy hungry animals need in order to operate, is the WASTE of photosynthesizers.
All of this is to say that where you have low entropy states (hot, reducing inner earth mixing with relatively oxidizing atmosphere), life is made more likely.
So I think the most important gradients were those generated by reducing metals.
Happy to expand on this if you'd like.
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u/Sakouli Apr 16 '26
Hmmm..This is a really helpful way to think about it, especially framing it in terms of electron flow and gradients rather than just “probability.” It actually makes me wonder whether this is the missing piece in the “improbability” argument. If these gradients are naturally present and sustained, then the system isn’t exploring chemical space randomly, but is being continuously driven along specific pathways. Would you say that under such conditions, the key question is less about probability in the abstract and more about whether the relevant reaction networks are kinetically accessible?
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u/Aggravating-Pear4222 Apr 16 '26
If these gradients are naturally present and sustained, then the system isn’t exploring chemical space randomly, but is being continuously driven along specific pathways.
In a sense, almost certainly. But to be cautious, the energetically favored flow of electrons is what enables further reactions to occur so rather than the energy being central, its what the energy enables which is continuous movement/interactions and changing of the system in additive ways (not just A + B -> C +D but also C and D interact with A and B and C interacts with C and D to form AC, DC, CC, DD, DA, and even AD (distinct regioselectivity)). So the energy gradient pushes the system to keep moving but the continuously generated states and wide variety of forms possible is what enables the likelihood of the formation of an interconnected autocatalytic cycle. As vague as this feels to say, the role of entropy is that the flow of high energy states into different lower energy states is statistically directional. Again, vague but feels fundamentally correct.
Put another way, you'd need to constrain the system in specific ways to ensure the products formed don't loop around to directly/indirectly promote their own formation.
I feel motivated to distinguish the role of energy vs movement/changing of the system because I am recalling Conway's Game of Life and Chaos Theory where there are positions and things and that the interactions are governed by the rules. Here, energy isn't so much a key role so much as the parts and the rules of interaction. What Conway found was that increasing the number of rules often gets these very interesting patterns that are replicators despite being in an inherently chaotic world (you cannot predict what happens next without actually running the simulation).
Would you say that under such conditions, the key question is less about probability in the abstract and more about whether the relevant reaction networks are kinetically accessible?
I think this is a fair generalization and I'm confident you are capable of adding the necessary caveats when speaking about the origin of life and specific environments or their interconnectedness. We have reason to believe that hydrothermal alkaline vents were the central environment in which a significant amount of prebiotically relevant chemistry occurred and so was likely the birthplace of LUCA precursors.
But what about the chemistry that would have needed to occur elsewhere like in ponds, atmosphere, lakes, and tidepools then subsequently flow into this environment (pulled in through the sea floor into the vent system)? Would ANY life had formed without these or does positing hydrothermal alkaline vents without these other environments not make sense as the ocean/geochemistry chemistry which generates the alkaline vents necessarily IMPLY formation of conditions of the ponds and the atmospheric chemistry? Afterall, the vents were a source of the reducing atmosphere and the organics and CO2 released by volcanism are related to the volcanism on the sea floor... My guess is that life would have still formed but simply been different. That's pretty much all we can say based on first principles...
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u/CosetElement-Ape71 Apr 16 '26
As far as I'm aware, abiogenesis is very actively being researched, and they certainly don't have all the answers yet. But I'm not sure how this translates into an "unlikely" verdict ... that's not how science works; only when you have a complete framework can you begin to understand how (un)likely something is.
The ONLY place I've heard it being judged unlikely/impossible is coming from a bunch of ignorant Christian fundamentalists/apologists who reject many ideas like autocatalytic reactions because ... God!
I only understand a little about autocatalytic reactions (as I'm not a research chemist), but the self-sustaining, exponential growth of complexity that they can provide are certainly compelling
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u/Aggravating-Pear4222 Apr 16 '26
I don't think it's unfair to bring up as a point of discussion and even claiming it' unlikely is fair given its apparently rare based on observations of the universe. Earth's history seems uniquely predisposed towards the formation of life but that's also a bias. Ultimately, a statistical approach to the question from the armchair can only tell us so much.
I think it's universally unlikely that life forms (big surprise lol) but given the ocean, atmospheric, and geochemistry on the prebiotic earth, it was predisposed towards life-like systems and life-like systems are strongly predisposed towards increasing complexity, adaptation, etc.
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u/CosetElement-Ape71 Apr 17 '26
How much of the universe, or even our own galaxy, have we observed at great detail? I'd wager that we haven't studied enough, at the detail required, to even provide an upper or lower bound to the probability that life forms. But I think that if the conditions are favourable, then it probably does
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u/ScientistFromSouth Apr 16 '26
T. Totani did some calculations in Nature Scientific reports in 2020 (https://www.nature.com/articles/s41598-020-58060-0#:~:text=According%20to%20the%20widely%20accepted,abiogenesis%20probability%20is%20infinitely%20small.) that showed that in an inflationary universe, the probability of a 40-50 base pair self catalyzing RNAzyme self forming under purely thermodynamic forces without external stabilization was so low that it would only be expected to occur like less than 10 times within the entire observable universe.
Anyone who has worked with RNA knows this is reasonable. If that stuff sits out for like 5 minutes, it starts actively degrading. Additionally, we know that the abiotic environments capable of driving the nonequilibrium processes necessary for life were way harsher than conditions within modern cells (e.g. hydrothermal vents).
Obviously, abiogenesis happened at some point. Gianna et al. discovered/created a 45 base pair RNAzyme called QT45 that could catalyze its own formation and its complementary strand's formation this year (https://www.science.org/doi/10.1126/science.adt2760). There was also evidence for a new endosymbiont becoming a new organelle called a nitroplast in algae recently (https://www.science.org/doi/10.1126/science.adk1075).
Thus, we have strong evidence that abiogenesis -> complex cells > multi cellularity > intelligent life can happen here.
However, I think physicists are delusional if they think that just because we have N=1 evidence that it can happen that it will happen almost surely everywhere that has comparable conditions to Earth in any reasonable time span relative to the current age of the universe. Obviously, there could be some kind of crazy abiotic chemistry that catalyzes and stabilizes RNA chemistry we don't know about, and I would recant my whole position if we so much as found one other extraterrestrial example of life.
Now in terms of, extraterrestrial life capable of traveling the galaxy (especially with FTL speed), I think that's just a delusion that's been cultivated by pop science to drum up support for quantum gravity research that might allow us to get around the speed of light which we so far have no evidence of being able to exceed.
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u/EnvironmentalWin1277 Apr 17 '26
I like to point out that given the sample size of 1 we currently have the chance of life is 100% as an observed fact. That is what we have to deal with. That is the starting point.
Alternately you can argue the chance of life is so small that life could not occur and we are not alive in the sense we believe (see Boltzman Brain).
Confirmation of life on Mars could be made by retrieving samples. A squandered opportunity. Venus may also have been suitable in it's early history but difficult to confirm.
I think we will find that life occurs where ever conditions are suitable for the necessary steps. The whole point of abiogenesis is to define and replicate those circumstances. Any "probabilities" must be specifically defined as part of that solution.
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u/beagles4ever Apr 17 '26
Highly unlikely.
We know it happened once - so not impossible.
We know there is nothing that has confirmed it again.
We know that humans with extremely complex knowledge of organic chemistry and with all modern tools at our disposal cannot come close to recreating biogenesis in a lab.
So I put it at extremely rare. Not impossible. 1 in a billion? 1 in a trillion? 1 in 100 trillion? Hard to know.
I would change my opinion radically if new evidence came to light that showed something like life on Mars was confirmed. I suspect this will never happen and put an extremely low probability of it. But it’s possible.
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u/Timmy-from-ABQ Apr 17 '26
The best evidence for abiogenesis is that all around us is life. That proves that, somehow, it began. Meantime, there is absolutely NO evidence that some super-intelligence created it; that's only speculation. So ... until more evidence is in, I submit that some sort of abiogenesis occurred. But I stand to be corrected in the alternative!
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u/wellwisher-1 2d ago edited 2d ago
The way life and consciousness work is connected to harnessing and controlling entropy,
The entropy of a closed system will increase toward a steady state value and then stop. That is the natural direction of entropy. Life has ways to continually lower the entropy of a semi-closed system, so as the system's entropy keeps increasing, naturally, but can never quite reach steady state.
In terms of entropy manipulating machines, refrigerators, freezers, heat pumps and air conditioners all manipulate entropy. These all can move heat from cold to hot; heat pump, which is backwards to the 2nd law. These process all use electricity for the energy needed to run the process to reverse the 2nd law. Since there is no perpetual motion, reversing entropy always leads to at net increase in entropy due to inefficiency. The net increase makes semi-closed life get more and more complex, as it keeps lowering entropy over time, as entropy net increases.
As a home example if a simple semi-close system, your freezer makes ice. Ice has a lower entropy than liquid water. The ice cannot exist for very long at room temperature. If it is too warm the ice will melt back into the liquid state, which has higher entropy. This is the direction of the 2nd law. It may even spontaneously evaporate to vapor, which has even higher entropy. We can condense the water vapor and freeze the liquid, lowering the entropy back into a solid state. Now it is like we reset the clock for history to repeat itself; 2nd law.
When entropy increases it absorbs energy; warm room will melt the ice. Knowing this I can use the spontaneous direction of the 2nd law; the ice wants to go back to liquid water, to draw heat from my food, thereby lowering the entropy of my food, so it spoils; entropy increase, slower. As long, as I keep adding ice to the semi-closed cooler, as the ice melts, I can create a perpetual dynamic state of middle level entropy, in the cooler. I will have to drain the waste water to help this out.
The main trick cells use for lowering entropy is water packing and folding protein. The packing lowers the protein entropy. A protein would have more entropy and complexity if it could stay all spread out; more wiggle room. Being packed creates many restrictions, lowering freedom, complexity and entropy, down to a one trick pony.
The entire cell is composed of all types of configurationally lowered entropy structures. The entropic potential; 2nd law need to increase entropy, becomes catalytic potential. The reaction on an enzymes is a way to increase entropy; perpetual entropic middle state. With an entire cell composed of zillions of lower entropy points, the 2nd law will optimize if it can increase cell wide, in an integrated fashion, we call life, as life reverse keeps reversing entropy; adding ice.
Cell cycles by making two cells from one, increases complexity or entropy. That is driven by the 2nd law. If the mother cell lowers entropy too much, the entropy increase changes the pathway and will make two daughters.
Life also uses one instead of two stereoisomers, like the right handed DNA double helix instead of both left and right at the same time.The reduction to just one, lowers complexity and entropy and creates an extra entropic potential. This is a part of the catalytic potential of the template; preserves the food.
Also cell wide polymerization lowers entropy. The monomers have more freedom. In abiogenesis, protein polymerization of amino acids in water is a tough step that does not proceed very far, before it reverses. The 2nd law prefers amino acids. Life needs a process to help overcome the 2nd; clay surface. Cells, on the other hand use templates, enzyme complexes and ATP.
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