We are in for a series of revelations that will deeply alter the way we understand the microscopic intricacies that hold us upright and posting on internet forums.
Exciting things happening in the field!
https://www.cell.com/cell/fulltext/S0092-8674(21)00293-2
Even the cell membrane is fantastically complex. Keeping out the bad stuff and letting the good stuff in. While keeping the good stuff in and letting the bad stuff out.
Also, abstraction is an activity which often serves to make additional room for new emergent complexities.
You can't just decide the fact society is made of humans is an irrelevant detail and model them with little rational balls, or whatever you came up with. Because the balls wouldn't do what we do. And I completely disagree it doesn't matter what the human body does. The human body matters to society a great deal, actually. Say, pollution in cities is absorbed by your human body, and affects health, even mental health, and how long you live. This affects social dynamics immensely or doesn't it? We've had entire social movements based on our understanding of the human body, how we categorize in various ways the human body, and violence done against the human body, choices about the human body, how we treat it medically and so on and so on. Countless examples.
Of course you can successfully model specific narrow events, do a representative sample and try to approximately guess, say the outcome of elections. Doesn't always work, but in this very simple example, you can abstract things. But you need to still abstract with deep understanding of what is abstractable for that specific point in space and time.
This approach fails miserably if you need to predict how society will evolve over time, and more fine-grained detail. Say, just 2 years ago society was largely ignorant of the AI revolution bubbling up based on work by Google & subsequently OpenAI. This is something society did, irreducibly, based on the people in it, and their bodies and neurons. And no basic statistics model that abstract us away would have predicted this.
Nature solved this problem of radical open-ended exploration through evolution. It takes a lot of time but in a single run evolution created all species and life on earth. Evolutionary methods also created AlphaGo, AlphaTensor and AlphaFold - three AIs that surpass all humans put together in specific fields.
Basically learning from massive search and problem solving outcomes - that's how you solve hard problems. And if you think about it, that's how science works too - so many papers, many contradicting each other or trying completely different approaches adds up to evolution in the space of scientific ideas. Any one human alone can't do it, but all of us over a long enough time can do so much more, diversity and open-endedness are key.
Hope that helps!
You took it as...?
> More complex than the immune system?
Possibly. From 2016: https://www.nature.com/articles/nature17316
text in <> are mine.
> The research group behind the current study previously showed11 that NHEJ <non-homologous end-joining, an error-prone mechanism of double-strand DNA break (DSB) repair> is essential for NSPC <neural stem/progenitor cells> differentiation, which implies a role for NHEJ-mediated DSB repair during normal brain development. It is possible that subpopulations of cells in the brain display the same types of rearrangements, and that some are positively selected. Similar studies in vivo and in other tissues are needed to test this hypothesis.
From 2022: https://www.nature.com/articles/s41597-022-01508-x
> We show that genome-wide maps of endogenous DSBs are highly correlated between experimental replicates up to 10 kilobases (kb) resolution, and that DSBs are non-uniformly distributed along the genome, in all three cell differentiation stages analyzed.
...
> Our datasets and analytical tools represent a valuable resource for exploring genome fragility during human neurogenesis and investigating how this might contribute to the pathogenesis of NDDs. <neurodevelopmental disorders>
https://en.wikipedia.org/wiki/V(D)J_recombination is wild.
My money is on the immune system being more complicated.
this rabbit hole goes deep...
Arguably the totality of all lifeforms on earth, which are all physically connected to each other by their common genealogical graph (and by Earth as their environment), is more complex, because it contains all the brains.
Personally don't see how this follows.
"There is no larger circle than this ball bearing!"
"What about the wheel it's used in?"
"That's tautological!"
Just as one can abstract out the brain from the body and talk about the complexity of the body (less the brain). Such a comparison is fine by me.
But society and the terrestrial ecosystem don't exist without functioning brains in them. And a genealogical relationship doesn't exist at all as a physical object, just as a conceptualized object (such as a graph). And conceptualized objects, such as graphs, typically aren't that complex (though can probably get there if someone dedicates the computational resources to do so).
>But society and the terrestrial ecosystem don't exist without functioning brains in them.
1) Original reply didn't say anything about society, only life an it's physical interactions.
2) Sure it does. Plenty of life forms without brains exist, and their sum is more complex than the human brain. The human brain itself is a composite of brainless life.
>And a genealogical relationship doesn't exist at all as a physical object, just as a conceptualized object (such as a graph). And conceptualized objects, such as graphs, typically aren't that complex (though can probably get there if someone dedicates the computational resources to do so).
That isn't because of what conceptual objects are, it's because of how they are used. The purpose of most conceptual objects is simplification. One can produce arbitrarily complex conceptual objects, we just don't normally because... why?
We can even throw out all of these semantics if you want and go with a much narrower version of the original statement: "The brain is the most complex physical system", and even that isn't necessarily true. The bacterial ecosystems that compose the digestive system have more interacting cells, with less defined interactions, than the brain. Maybe you meant "most complex computational system"? That's potentially true, depending on your definition of complexity.
I'm not interested in discussing complexity, just the foundations of productive (and polite!) discussion and debate. So we'll go our separate ways here. I would probably agree with you with respect to the brain not being the most complex physical system.
Keep in mind the latter contains the former. So, tautological, unanswerable question yes? (No)
If you instead stated that a screw is the most complex tool humans make, then anyone who said "two screws! (in a smartphone)" as a counterpoint is not debating in good faith.