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Entropy and Life (wikipedia.org)
144 points by aluket on April 12, 2020 | hide | past | favorite | 61 comments


I’m currently working on a PhD in cryptography and I ran into this particular entry a few months ago while trying to wrap my head around entropy as an information theoretic concept. To be honest, it triggered a cascade of revelation that I had not felt since the last time I took psychedelics.

I read another article recently about the unexpectedly large role that randomness plays in embryonic development, and an idea clicked into place:

Life is about sustaining order amongst chaos, negentropy in a sea of entropy. But how does evolution lead to larger and larger pockets of negentropy that are capable of sustaining in increasingly hostile environments? How exactly does evolution lead to more and more “advanced” life forms?

Enter the magic of randomized algorithms. Randomized algorithms can often solve hard computational problems very efficiently, with the tradeoff that they have a small chance of failure. We can envision evolutionary leaps as computational problems, such as finding just the right folded protein to catalyze a particular cellular reaction. The magic of evolution is not just in building stable order, but also in harnessing randomness/entropy to solve environmental problems and then bootstrapping those solutions to solve higher level problems. Think about how just enough randomness is allowed into the process of meiosis to create perfectly functioning new humans that are wonderfully unique.

DNA and RNA are the non-volatile memory of the biological computer. Central nervous systems eventually reached a level of complexity that allowed them to persist memories, which opened up an even higher order problem solving mechanism. We humans have taken it even further with a cerebral cortex capable of abstraction, leading to complex language and the technology to record that language permanently.


My favorite take on life an entropy is that life is the most efficient way to burn energy, to increase entropy. Life is inevitable in the universe simply as a method of increasing overall entropy efficiently. A bunch of chemicals may eventually decompose into photons and electrons, but it's a lot faster if something eats them.


Entropy increase is a stochastic process though. The rules of nature do not result in a system that maximizes entropy at the maximum possible rate.


Entropy increase need not be chaotic. Stars generate entropy at a very reliable rate. We also do not know what a maximum rate, and I didn't state life was anything like a maximum rate, just faster than non-life in some circumstances.


But we don't know, or even think, that the rules of nature prefer a rate of entropy increase. We just know that it does increase, on average, in closed systems. If life as we know it creates entropy at a high rate compared to other natural processes, that is not a reason for life to be compulsory, or even preferred, by nature.


This take seems similar to inferring intentionality from evolution.


I would say inevitability rather than intention.


> I ran into this particular entry a few months ago while trying to wrap my head around entropy as an information theoretic concept. To be honest, it triggered a cascade of revelation that I had not felt since the last time I took psychedelics.

To be honest, I've tried to wrap my head around entropy a few times (both in information theory and physics), but I've never really understood it well. It's related to but not (completely) the same as a measure of chaos, and it is related to but not the same as the number of potential states- and so on.

Could people direct me to a good introduction/explanation to entropy in an information theory sense? I feel like I'd really enjoy biting into this topic, but I haven't found a good entry point yet


Have you read about Karl Friston's Free Energy Principle? Seems related:

Wiki: https://en.wikipedia.org/wiki/Free_energy_principle

HN Discussions: https://news.ycombinator.com/item?id=17529408


Also, just as our biological machinery is an engine of negentropy, carving out order from chaos, I think our brains continue that same work in the information theoretic sense of entropy. Humans are insatiably curious because we are alive, and to be alive is to be an engine of order among chaos.


> DNA and RNA are the non-volatile memory of the biological computer. Central nervous systems eventually reached a level of complexity that allowed them to persist memories, which opened up an even higher order problem solving mechanism. We humans have taken it even further with a cerebral cortex capable of abstraction, leading to complex language and the technology to record that language permanently.

Capitalism is to Natural Selection as the Brain is to the Genome. Capitalism is the same Darwinistic entropy engine as Natural Selection, just abstracted to the plane of higher thought rather than raw biochemistry.


I like where you’re going with this but I’m not sure the analogy is quite right. If you’ve read Dawkins, the genome is composed of genes which are basically the quanta of self-replication. He goes on to coin the term “meme” to refer to the analogous units of self-replication in mindspace. In other words, the brain is not analogous to the genome, rather the particular collection of abstractions (memes) which dominate how a particular brain processes and reacts to the world would be its cerebral “genome”.

I think we can say that natural selection operates across all levels of abstraction, because in the end the only objective reality is the biochemical one. Everything else is simulation. There is certainly a strong parallel between capitalism and Darwinian natural selection but I can’t immediately see a way to state that relationship in a clear analogy.


I'd argue that capitalism selects not only for certain types of brains (in a sort of accelerated natural selection geared towards intellectual ability), but for certain memes as well. It selects for "social memes" that determine corporate culture, which contributes largely to whether a company succeeds or not. It also selects for more "ideological memes" that serve as the basis for the company itself.

A company's success is the result of a meme (or set of memes) the founder created (or borrowed) and convinced others to buy into. Others only buy into the meme if they believe it would be beneficial to themselves as well. Thus the system as a whole selects for memes that provide high benefit to society.


My second LSD trip was all about this idea. The entirety of the universe heads in the direction of disorganization and life is the only process that does the opposite. Life is a tool by which the universe organizes itself. There's parallels of this idea everywhere (Father Sky, Mother Earth).

At least that's what I thought until I did a lot more reading over the next couple days after my trip and discarded the idea. Entropy and how life interacts with it turned out to be significantly more complicated than I thought.


You were not wrong, though. Life produces more entropy around it (it consumes energy) to lower its own entropy. Organisms are islands of lower entropy.

Paraphrased from what a physicist doing "systems biology" (more or less: biology from first principles) said to me. I have also had a few lectures about thermodynamics.


Well put


Life decreases entropy within its area of influence while increasing entropy outside its borders / cell walls / areas of influence.


You could call life an entropy pump.


If you have a glass of separated half coffee on the bottom and cream on the top, the complexity temporarily increases as the two halfs mix.

Then the complexity goes down again, as it becomes uniformly mixed.

Yet, the coffee and cream are not alive.


What are the chances of coffee and cream molecules being arranged in just that configuration without the intervention of life forms with caffeine addictions and ceramics factories?


what are the chances of an initial state of the universe with extremely low entropy?

the low entropy starting initial condition is the same in both cases, the glass is meant to be an analogy of the big bang.


> Then the complexity goes down again, as it becomes uniformly mixed.

This part is incorrect. It requires the intervention of energy by motivated life forms to to un-mix a mixture of coffee and cream, therefore it is very high entropy.


Granted, I am total noob in that topic, but how your example of cream and coffee mixing and reaching equilibrium different from a cell receiving an electrical spike pushing it to do its thing until it is done and settling at some equilibrium? Is cell is not alive?


“Disorder — A Cracked Crutch For Supporting Entropy Discussions”

http://entropysite.oxy.edu/cracked_crutch.html


In the appendix of the first Dune novel Frank Herbert has Liet Kynes say something along the lines of life being its own device for ever more efficiently making use of the energy available in a system, which in my opinion describes the relation between entropy and life quite nicely.


Also, the no-ship, no-chamber, "no-gene" vs prescience describes the battle between data and privacy. The desire to know and the desire to remain hidden.


Interesting paradox, how life seems to get more organized and contradict the 2nd law of thermodynamics. But of course like the article mentions, the 2nd law deals with closed systems and life on earth is an open system with a constant input of stupendous amounts of energy from the nuclear fusion furnace we orbit. A human in a closed system (airtight box?) would entrop-ize pretty quickly.


Ilya Prigogine won a Nobel prize working on that very issue!

https://en.m.wikipedia.org/wiki/Dissipative_system



I don't think I can ever forget the first time I read this short story by Ted Chiang on that topic: http://www.lightspeedmagazine.com/fiction/exhalation/


A human in a closed system would probably reduce their rate of entropy increase fairly quickly ;)


Entropy fuels all chemical reactions. Atoms wouldn't be able to recombine into molecules without the entropy. The Wiki article tries to build some higher abstractions but it is simple as that.

No entropy (absolute zero temperature) leads to the absence of Brownian motion which consequently leads to inability of atoms to recombine and form new matter. All chemical reactions would totally stop at 0 degrees.

Life would not be possible without chemical reactions. Entropy is invisible fuel that powers everything and makes things tick.


I have a theory about this. To me the relationship between entropy and life was a big realisation and left me wondering why it wasn’t of greater cultural or scientific interest. Here’s what I came up with:

All life is preoccupied with removing free energy in order to get greater predictability over the future, and that encompasses literally everything we do in one way or another. Therefore, the theory that life reduces local entropy is not in any way useful, because it doesn’t guide us to do anything differently than we are already doing. It’s a bit similar to the anthropic principle.

Example: let’s say you need to clean up your room. You’ll find that even doing a very quick straightening of debris on a table will make a space feel more orderly and produce some level of satisfaction. But if you’re not the type to do that regularly, you might not bother the next time because clutter is the norm and it’s more dependable.

Another example: tell a businessman that life is a process which reduces entropy locally. Ok, so he has to get greater predictability over his circumstances, how to do that? More money and power. That was already taking place.

Thus, this theory hasn’t really taken off for lack of utility.

When we have a magical entropy measuring device, then yes, we can use it for all sorts of things...


I had similar thought, which led me to believe that the closest thing to God is the irreducible quantum randomness in our molecules.

In fact, I believe that life is not exclusively about order, but rather about harnessing randomness (entropy by another name) and capturing its output to bootstrap solutions to environmental problems. Our entire manner of reproduction is about allowing just enough randomness to produce interesting new results while maintaining the integrity of the life-form.

I’m a cryptographer, by the way, so what got me thinking about this was how we put a nice box around randomness to produce cool stuff like encryption and signature schemes.


That sounds similar to what I arrived to when I became somewhat obsessed with the topic yet admittedly lacking much knowledge about it. Lookup hormesis (basically life needing some amount of chaos to keep it strong) or 10th man rule, there's some interesting correlates that I wrote about here [0]. It's all pretty interesting but being stubborn as I am, it took me a while to realize I'm better off leaving it to smarter people more versed in those topics. I eagerly await some very intelligent person who doesn't mind risking being seen as a quack to try to marry thermodynamic principles with human behavior and the like, even though it's more descriptive than prescriptive and may not tell us as much as we'd like to know. It also may be kind of existentially defeating to some as it'd necessarily prescribe deterministic views to life but some say quantum mechanics still leaves some philosophical wiggle-room for us there.

0: https://0134340.blogspot.com/2019/02/playing-tenth-man.html


Just read Carlo Ravelli's book The order of time, highly recommend. It argues that the change in entropy is the only equation of fundamental physics that knows any difference between past and future. It's the equation for time's arrow.


There are a few other asymmetries, such as the time asymmetry implied by CP violation in things like kaon decay.


Sorry my physics are lousy, but what about finding information on the quantum level? Can’t that also distinguish past from present?


Carlo Rovelli. Thanks. Just added to my goodreads list.


I recently discovered the work of Jeremy England [1] on this topic on a PBS Space Time YouTube video [2] dedicated to the origins of life. England's work dates back a few years (2012) and seems like it was an exciting advancement in the field but was also controversial. Does anyone here know the status of this line of research?

[1] https://aip.scitation.org/doi/10.1063/1.4818538

[2] https://www.youtube.com/watch?v=GcfLZSL7YGw


I worked for Jeremy. I still think his idea is really beautiful, and when it applies the math is airtight, but it hasn't matured into sharp predictions for real systems.

There were some simulations, but even then it was messy. For example, there were setups where energy was supplied by a driving force, and you could evolve "resonators". A naive application of Jeremy's ideas would predict a lot of structures in resonance with the drive, but in practice you often got less, because too good resonance actually made the structures break apart. So you couldn't get a sharp prediction about the final state even for a really simple system.

The issue is that thermodynamic notions are inherently "coarse", they only give you a high-level view of what's going on. Sometimes it's not powerful enough to say much useful unless you also know the detailed dynamics. This is also why, even if sharp and correct predictions were made for simulated systems, it's quite likely that biologists wouldn't view this as a true explanation for life. They would, perfectly legitimately, want to know about the detailed dynamics, the specific chains of chemical reactions that actually happened.

Now I'm in particle physics, so I'm not up to date, but the same dynamic happens here too. There are lots of beautiful ideas that come up, generate a flurry of excitement, and then get stuck for lack of sharp predictions, or feasible tests of those predictions. We file them away in the hopes that their time will come, possibly generations later. Science is hard!


I read an article about Jeremy England a few years ago, and have often thought back on it.

A New Physics Theory of Life - https://www.quantamagazine.org/a-new-thermodynamics-theory-o...

Here's his website with a list of recent publications: https://www.englandlab.com/publications.html

---

This one stands out for me:

Design of conditions for emergence of self-replicators - https://arxiv.org/pdf/1709.09191.pdf (2018, pdf)


I saw him give a talk some years ago and took a stab at understanding a couple of his papers. Frankly, I'm pretty sure I didn't get what he was driving at. It looks like he's left academia for the pharmaceutical industry, for whatever that's worth.


Life may not be the only process that works counter-entropy. There are two lines of thinking emerging that the principles we see so clearly in life may be more general and appear in abiotic processes as well... that physical systems "evolve" to transform available energy gradients into a localized increase in complexity. So evolution in a general sense is more fundamental than life, and inevitably eventually leads toward processes complex enough to be called "life".

One comes from the work of Jeremy England[1], who has published some excellent papers showing what he calls 'dissipation-driven adaptation', natural selection working on phsyical and pre-biological systems. Englands work is really eye-opening and I have feeling if he keeps it up he may be a likely candidate for a Nobel in physics or biology some day.

The other line comes from Adrian Bejan's formulation of what he calls the "constructal law"[2]. This describes some specific patterns according to which physical systems evolve to dissipate energy more efficiently. It seems to me that Bejan is a bit under-appreciated in academia, although apparently people have found quite a few practical applications of his ideas.

[1] https://en.wikipedia.org/wiki/Jeremy_England

[2] https://constructallaw.com/


Thanks. I've been wondering what's the correct word for 'evolution' in general. It's usually used to refer to evolution of life. However, similar process happens everywhere.

I think this mechanism actually explains why there is anything at all. Are there any theories about the evolution of physics itself? Or how could a universe be evolved out of randomness? Or if there's a 'base reality' which can support 'simulated reality' be evolved in it? I think something really simple could evolve into supporting simulated child-universes with more complex rules.


Into the Cool by Dorion Sagan and Eric Schneider is an excellent book on this subject, imo.


I made a short film on a related topic. Check it out https://youtu.be/Bv42PQ-Xxj8


I don't disagree with the proclamation here but can't say I agree with the result. The economy is tied to productivity and without productivity we're doomed to be stuck on an earth that will eventually stop existing, no matter how long we try to keep it habitable. I don't know what the best answer is but I don't think it should be to decrease productivity, at least not in the STEM sector.


This reminds me of some of the more interesting thoughts I had while learning about information theory and astrophysics. Apologies for the lack of rigorous terminology, this is all stuff I’ve just thought about and never discussed.

The speed of light is also the speed of causality. Information can be sent out at that speed. So information sources have a sphere of expanding influence. Information that one node sends can be taken in by another node, modified, then retransmitted. This is general enough that it could apply to many contexts, but I am interested in the most general context. Information that replicates itself: memes. Is our existence creating a meme sphere? Will our meme sphere(s) collide with other meme spheres? Is this all just an unnecessarily strange way to look at things? I wish I had a firmer grasp on interpretations of quantum mechanics, since that may inform some of my questions.


The more complex the encoding of information, the more time it takes to decode and retransmit it. Speed of light may be an upper bound on the speed of information, but anything on the order of memes require complex life forms to communicate and understand them.

> Will our meme sphere(s) collide with other meme spheres

Of course, "meme spheres" already collide all the time, but I think they are subject to too many intervening forces to be idealized as actual physical spheres like the propagation of light in a vacuum might be.


The meme spheres interact in a more complicated process than just a repeater. They can amplify each other by sending and returning the same (or similar) information.

Some ideas get retransmitted a lot more than others. I wonder if a universally retransmitted (maximum strength) meme is possible.


> Is our existence creating a meme sphere?

There’s one expanding into space right now at the speed of light representing the comment you just posted.


Entropy, energy and life was the topic of a very interesting book I read in the last two days: “why information grows” by Cesar Hidalgo. If you are interested on this topic it’s a must read!


Okay really weird to see this come up because just a few days ago I saw a video about reductionism in science and free will, I think it was a John Searle lecture.

I find the idea of life as an organizing force that locally reduces entropy and 'offloads' disorder on the environment deeply compelling, and what I wondered was, does this not put a pretty big nail into reductionist scientific worldviews that argue purely in terms of bottom-up physical explanations?

Is there some account of life at the level of particles that could ever give a reasonable description of the behavior we observe, or is the existence of living organisms evidence of some sort of genuine top-down causality?

The reason why I was looking into this was the TV show Devs that toys with the idea of determinism and the idea that even though someone could look at a prediction of their future, they could not change it, and to me this made sense if the world could be purely explained in terms of bottom-up physics, but I started to scratch my head if decision making could actually go top-down.

Anyway slightly rambly post but if someone has a book, or essay or some other reading recommendation on this I'd appreciate it.



>does this not put a pretty big nail into reductionist scientific worldviews

It's just generalized enough to be vaguely descriptive, not prescriptive, at least not yet. And I don't think it ever will because just as we have biologists, we still need medical professionals that can diagnose and understand more specifically the bottom layers.

Second question, someone mentioned Into The Cool, a book I'd like to also read that seems to take on this question.

Third question... to evoke the previous answer, why not both?


Universe was born pregnant with life, (C) mine, circa 2010.

I mean that with that huge size and so number of opportunities, "invention" of self-reproducible forms is inevitable. And so we can treat the life as yet another form of matter.

There are quite a lot of possible consequences of this axiom.


For a good piece of fiction that explores this idea, read the short story Exhalation by Ted Chiang.


The recent interview with David Silver on Lex Fridman's podcast touches on this towards the end - https://youtu.be/uPUEq8d73JI?t=6081


A chemical catalyst is an agent which lowers the activation energy for a reaction to proceed. A biochemistry professor of mine was fond of declaring life to be an entropic catalyst.


Thanks for sharing, its useful :)




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