What's your opinion about complex systems?

[u/Complete_Necessary48]

The title. I have the impression that complex systems are controversial, as if it is really valid to apply physics tools and frameworks to understand emergent phenomena, not just physical in the traditional sense.

I'm referring to things like vote models based on the Ising model, modeling bird flocks and bacterium, the works.

I'm personally interested in the field, but sometimes I have the weird sensation that maybe it's bulls***t.

What do you think?

Edit: I should add that this is not an attack against this discipline and those who practice it. I myself do so, like for my thesis. This post was more like a 3:00 AM "what am I doing with my life" thought than "yo what's up with these bozos"

[u/TheMoonAloneSets]

what’s controversial about them? the math is rigorous, well-defined, and well-known

[u/Complete_Necessary48 → u/TheMoonAloneSets]

Well, my physics department it's full of this manchildish mentality with the likes of "your group's field of interest it's bullshit, they should fund me and my group!" I kinda want to know what people think out there

[u/warblingContinues]

Modeling things like bird flocks and bacteria is totally normal, but you cant model them using thermodynamics because the systems are not in equilibrium.  If you're interested, the appropriate search term is "active matter system."  You end up using tools from nonequilibrium statistical physics, which includes correlation functions, master equations, information theory, and approaches like agent based modeling.

[u/JGPTech → u/warblingContinues]

I'd argue their very existence proves equilibrium and we simply lack the tools to explain it. Like erubim said below in this thread. Its the ignore what doesnt i take exception to. The "don't try to take in all in at once". Please do try to take it all at once, and model the emergent properties while you're at it.

Edit - I don't understand why I am getting downvote. If someone wants to challenge me on this I will prove it right now by modeling a flock of birds using nothing but thermodynamic principles and I promise you it will make more sense than any reductionist approach you could counter with. I'm not being philosophical we can have a physics off math + coded model which one makes more physical sense back up by raw numbers. Just because my sundial is super accurate doesn't mean my hypothesis the sun is pulled by horses is correct. The sundial works despite my misunderstanding of the physics behind it, not because of it.

Edit - Just going to leave this here.

Fun/FlockMe at main · JGPTech/Fun

[u/david-1-1 → u/JGPTech]

You can't just claim to prove something, or promise something. If you believe you are right, do the math and point to your results. Then you will be upvoted for contributing to science instead of promising you can contribute to science.

Claims are usually the recourse of the undereducated.

[u/JGPTech → u/david-1-1]

oh I always back my shit up. I wasn't claiming anything I was daring someone to open their mouth. So bird flocks?

I'll run in on that Budapest/oxford line. The one they used to describe the leader-follower shit. Woulda been about 10-15 years ago now, lots of public data available. Also the PLOS ONE follow up. I am going use use my 7 observable operators of any complex system, cyclicity, recursion, fractality, regression, synergy, refraction, and outliers, to transform variables and do some time rescaling in a physically meaningful way. The end results will be the transformation of the leader follower relationship into a physically coherent equilibrium representation, then back to the current description of the leader follower relationship. My goal will be to show the empirical path measure obeys detailed balance and admits a Gibbs distribution over an effective free-energy landscape.

ill need like 4-5 hours on it. But I wouldn't mind more time. How long will you need for the NESS side of things? For the comparison?

[u/david-1-1 → u/JGPTech]

What's a NESS?

That sounds very ambitious. Don't have any expectations from Reddit. This is not a publication site, just a social discussion site. Your work is not likely to be seen by anyone in academia. But it does sound worth doing (it's outside of my field).

[u/JGPTech → u/david-1-1]

that last comment was the only honest thing you've said. your first comment was utter nonsense.

Fun/FlockMe at main · JGPTech/Fun

Edit - What pisses me off so much is not the utter nonsense, I expect that I do. Its the actual factual comment being massivly downvoted, while the nonsense gets upvoted. In a physics forum. I expect better, I do.

[u/david-1-1 → u/JGPTech]

I think it likely that not one of the people who downvoted your comment had any idea that you had actually thought about it, and did trial calculations. Nor are they familiar with Joe Poplett's framework.

Because of the volume of comments, and the low likelihood that a comment in a social physics forum is educated, and because of the ease of use of LLMs, readers tend to make snap judgements and downvote too easily. I didn't downvote you, but I did prejudge you.

The question remains as to whether your claims are supported by your logical framework, your programs, and their output. I did not see the usual Readme.md file containing these important pieces of evidence, so I cannot make any judgement myself. And as I said, this subject matter is outside of my expertise.

[u/david-1-1 → u/JGPTech]

My first comment was apt. It applied to you, and you rose to the challenge with evidence of your ideas. But you did not offer this evidence in your OP, and I cannot read information that is only in your mind.

I suggest, if you don't want to be downvoted, that you include more of your specific thinking and fewer generalized claims.

[u/chermi → u/JGPTech]

They're dissipative and active. At best some are NESS. That is, not equilibrium. Good luck finding the free energy.

Maybe you're conflating "using thermodynamic principles" with "proving equilibrium"? Thats my most generous interpretation.

[u/JGPTech → u/chermi]

That's such a cookie cutter response. Like you copy/pasted it from a script on hand. Did you read the paper? Did you run the code? The raw flock dynamics are a NESS. The point of EchoKey equilibriumization is that after a coordinate/time transformation, the empirical path measure satisfies detailed balance and admits a Gibbs distribution. I’ve posted the code and results: EP(raw)=2e−2 vs EP(rev)=~0, cycle affinity ≈ 0. That’s not conflating principles.

You looked at my claim and said, not possible this is why, then moved on without even thinking about anything. Why are you making comments on things you don't understand? What's your domain expertise? Snap judgements?

[u/chermi → u/JGPTech]

Thanks for the accusations. No script involved. Did you mean it was an equilibrium system or not? One last try at civility. Don't know why I'm trying.

[u/JGPTech → u/chermi]

I do not claim to prove the raw (r,v,t) dynamics are equilibrium; I prove existence of a coordinate/time representation that is.

Edit - I suspect the reason you try is because if you are incorrect, my response is warranted.

[u/david-1-1]

There is nothing misleading about emerging phenomena in complex systems! Temperature emerges from heat! Classical mechanics emerges from quantum mechanics! Human behavior emerges from interconnected neurons! Animals and plants emerge from the codes in DNA!

[u/Edgar_Brown]

“Complex systems” is mathematics, not physics. If the premises apply the conclusions apply, regardless of the field of application in which it’s being used.

[u/chermi]

It's vague enough that real bullshit can slip through. There are many good groups, but probably among the highest fraction of unqualified whack jobs in the sciences.

That is, there's really good work and there's really, really bad work. I think there's kind of a cargo cult effect of wanting your vague ideas to sound more scientific by being loosely quantitative. And since everything is "complex", it's hard to make real predictions. Therefore, people let bullshit pass because it's hard to show that a theory sucks when it makes vague, nearly unfalsifiable predictions.

To see the cargo cult effect, follow the citations of barabasi's work and see how poorly applied the results are in the social sciences.

Edit- collective/cooperative phenomena using voter and ising/potts models is among the good work. It's good partly because it doesn't proclaim to be some universal description like many complex systems people seem prone to. It' a predictive modeling with modest scope. See viscek, bialaek, sethna for example of excellent work applying simple theories to complex systems.

[u/erubim]

I believe this intuition of yours is correct: since we create models precisely to focus on what matters and ignore what doesn't, we will always have to deal with estimators (either on a micro or macro level). So ignoring parts of the system may fell like some form of bulls***t.

But that is also what makes the analysis of it possible by our brains.

So I believe that the dogma of complex systems analysis will always be around reducing complexity itself. We should never try to "take it all in at once" and prioritize. Every framework is either doing exactly that or has done it through some stage of development.

[u/kcl97]

It is real science because it is really hard to get funding for these fields compared to traditional big science where people just do mostly rinse and repeat They get scrutinized all the time just like what you have done calling their science bull-shit.

I sometimes think these people are insane trying to do interesting science in this world where money in king, they should just all go become crypto programmers and investment bankers. Why are they hurting themselves like this?

[u/kempff]

Um ... this is not a halfway house for people who have been watching pseudo-philosophical videos about life, the universe, and everything.

[u/Alphons-Terego → u/kempff]

I think they mean something I've seen myself in academia: There are people who studied physics applying phyaical models to gields outaide of physics like for example sociology. There's an entire movement in sociology that stems from physicists specialised in turbulence applying models for emergent behaviour in turbulence to sociological problems.

[u/TheMoonAloneSets → u/Alphons-Terego]

math is math; if a qualitative description based on causal relationships can be made, then a quantitative model based on physical principles can be constructed

the critiques I’ve seen of applying physical approaches to coarse-grained systems like biological, psychological, or sociological systems usually boil down to people arguing that the failure of the constructed models to accurately predict the dynamics is evidence that no such models can be constructed using physical principles; I would argue this says more about the critic’s dearth of understanding in how predictive models are constructed and in how causal relationships behave than it does about whether those systems are amenable to mathematical analysis

I would also point out that applying mathematical tools like those one might use in turbulence to other domains which contain many features analogous to those contained in the original field even if not fully isomorphic is an extremely fruitful endeavor that has historically often led to significant advances

[u/Alphons-Terego → u/TheMoonAloneSets]

I know. I never criticised it. I only pointed out that this isn't pseudoscience.