Why certainly, how kind of you to ask. :-)

Pretend for a moment that you didn't like anything about modern civilization and you wanted to go back to a neolithic existence. This isn't a stable state though: after thousands of years people would forget about how bad things were and start civilization over again. Put another way, it happened once, so what would prevent it from happening again?

So we can't just set the clock back to an earlier idealized age. (Not least because it would imply the deaths of billions of people who are today dependent on the existing system.) Somebody somewhere would eventually rediscover steam power and the feedback loop would begin all over again.

So we are stuck with it, and by "it" I mean technology. At the level I'm talking about the details of the civilization hardly matter, it's the technology that defines our ability to even contemplate living not-in-harmony with Nature.

The Neolithic hunter-gatherer has a pretty sophisticated science and technology for dwelling in the way they do: it is becoming more and more widely recognized that such folk affect and adapt their habitat over time, in effect gardening their world.

But they don't build skyscrapers, they don't launch rockets.

What is the essential difference between the technology of long-term ecologically sustainable hunter-gatherer societies and the modern technology we take for granted today?

Two things: Power, and motive.

Power, capacity to do work, I don't need to define. We burn trees, fresh or as petrol, and eventually we harness the atom. Power is an unqualified good. It has to be used wisely. (Ask the Aral Sea what happens if you fail.)

Motive on the other hand can be good or bad. The "motive" of the neolithic society is to carry on in an eternal fashion, part of Nature, and so timeless.

The "motive" of current society, in contrast, is consciously or unconsciously a movement from "the past" to "the future" which by definition is different than now, and better.

Now, obviously, you can't maintain "progress", as it's called, forever. For society to last it has to attain some sort of stable state (even if that "state" is more of a dynamic "strange attractor", like the rise and fall of empires.) On the individual level the psychology of being future-fixated runs counter to the sanity of peace which implies contentment in the here-and-now.

But we do not want to forgo science, nor the obvious benefits that accrue to industrial, scientific technology. (Rockets, computers, materials, medicine, etc.) I don't imagine a world of navel-gazers in stasis.

SO, a Minimum Viable Civilization has to contain the core of our technical know-how, it has to allow for continuation of scientific investigation, and it has to look superficially like a combination of neolithic hunter-gatherers and Jeffersonian agrarian republic (economically if not politically) together in a stable mode: The farmers can't take new land without they leave the old to the wilderness. And the wilderness is actually high-touch horticulture over much of its area, although true wild lands would be set aside (for the spirits and whatnot.)

You would still have your Large Hadron Collider but no plastic in the oceans.

The rest of this is an excerpt from a bit I wrote in 2013, in the context of a "Future History" fictional projection. (I was very encouraged when I saw E. O. Wilson's "Half Earth"!)

In the future the surface of the Earth has been divided into two kinds of zones or areas: "Inside" and "Outside".

Inside: Artificial, Safe, Immortal

There is a single city but it's discontinuous, not connected. It's like islands and archipelagos of built area embedded in a "sea" of wild land and water. The city is ultra-tech, nano and beyond. People there do not age, or age and rejuvenate as they please. All the transhumanist techno-utopian dreams are come to fruition within the City. Barring accidents you live as long as you want and it is Christmas every single day.

Outside: Real, Dangerous, Reproductive

The rest of the world is one giant Nature reserve. All of the oceans and the great majority of the land masses are kept in a Natural state and evolution is permitted to continue without interference from our human institutions within the City. People live Outside too, in tribes and homesteads, and although there is first aid and basic medicine and surgery, they voluntarily endure the "slings and barbs of outrageous fortune". Transhuman modifications and forms are not "worn" Outside. This is also where all new people are conceived, gestated, and born. If you want to have a baby and raise a child you have to go Outside.

This is Humanity's grand compromise with our technology. In order to maintain a normative baseline, a "control group", for our wild forays into the Transhuman realms Inside we have to permit our own natural evolution to proceed Outside.

Graduation

I hadn't figured out what form it would take (it's an ongoing story idea I'm still playing with) but there would be some sort of "intake" or "graduation" process for bringing new humans into the City for the first time. I have no idea, I'm just mentioning it. ^_^