@CatDragon This is correct on the facts, but they may not know how narrowly.

It's reckoned by scientists that stable human groups can function reliably on consensus (barring special problems such as especially difficult people) up to around 150 people. (Known a Dunbar's Number, or informally as 'the Monkeysphere.) This is believed to be the average neurological limit of individual other persons most people can personally 'know' in a meaningful sense.

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@wesdym You can build larger societies by connecting the groups to build a larger network. Building consensus along larger networks take a lot of time though, so you'd expect people to spend much more time discussing collective projects than actually working on them, which means that such a society doesn't get very much work done and progresses very slowly.

Which is exactly what we need because by spending so much time at work, being awfully productive and building a rapidly progressing civilisation, we have brought the entire bloody biosphere to the brink of collapse. If we humans survive the #SixthExtinction we have triggered through the unintended side effects of our industrial economy, there won't be very many of us left, and the Industrial Age will simply be over, never to return.

Tribal societies work that way, connecting the individual hamlets and villages into a larger tribe through coming together to talk. And it needs shared rituals, of course, and a lot of singing and dancing and playing music and wearing fancy clothes. Anyway, we need to build new cultures that can survive the chaos of the coming tens of thousands of years, because it will take at least that long for this biosphere to be able to carry complex civilisations again, provided we manage to not only stop accelerating this ongoing mass extinction event immediately but also help the Earth heal by aiding local ecosystems. Which usually doesn't mean planting lots of trees in a short time, but it means to live on and with the land, to see where the local ecosystem wants to go and give it just a little aid. When you see a rare wild plant in some place, see if you can remove plants with which it doesn't get along and plant some that it likes. Some plants work together, others kill each other, and gardening doesn't mean ripping out everything wild and replace it with carefully manicured exotic plants from the other side of the world or weird mutant versions of local ones with giant blossoms in all kinds of weird colours, always killing everything that might eat those plants. Gardening means looking at everything that grows and all the ants and moles and toads and grubs and beetles, and doing what you can to help all those species thrive, to help the entire network of living things grow while at the same time gently pushing it towards an aesthetically pleasing look and feel, and of course you need a lot of herbs and fruit and vegetables in there as well since you are part of the ecosystem and you need to eat.

Our modern civilisation is ending. There isn't anything anybody can do about that. All we can do is decide in which direction we want to go from where we are. We missed our window for becoming sustainable, but that doesn't mean we need to stop trying--the more solar panels people install, the slower and more gentle the decline will be, with small decentralised local power grids taking over when the larger infrastructure becomes dysfunctional. The more bicycles people have, the more mobile they will be when car culture crumbles. Small to medium sized workshops can keep repairing and producing things when the large factory has closed down forever and the trucks don't come anymore.

Unfortunately for a big science fiction fan like me, we will never become space travellers. My favourite hypothesis is that the Big Filter, the reason why we haven't found any evidence for any interstellar civilisations, is that they don't exist because industrial civilisations collapse before even getting close to cracking the hard problems of trying to live outside their home planet's biosphere. And that is because their own biosphere will be so badly damaged by the unintended side effects of their technologies that their civilisation will come to an end before reaching the stars. Our future is not Star Trek, it is Always Coming Home by Ursula K LeGuin, I'm afraid.

@wesdym
@LordCaramac
The problem with "leftist" ideal societies is that they requires non greedy people.

The problem with "right" ideal societies is that they require non greedy rich people.

@arildsen Oh, that's easy. Just look at the last ten thousand years of human history.

The reality is, if you want large (> 150 ppl) groups of humans to function cohesively and in any organized, productive way, you need them to share a formal abstraction of some kind. Usually, this means some form of government, but not just ANY form. It must a form which is resistant to corruption which can too easily exploit that same abstraction. (That is the fatal weakness of communism.)