The following discussion originally took place over WhatsApp and has been lightly cleaned up for spelling, punctuation, and readability. The substance and wording have otherwise been left essentially unchanged.
I discussed this with OP elsewhere before being asked to move the discussion here. Anything before RESPONSE is context.
Me:
I think the core issue all your arguments about future civilization and related things have is that you don’t grok the scale of things out there. Maybe intellectually, but definitely not emotionally or intuitively.
A central issue I feel you have is that you aren’t well versed in the plausible limits and capabilities of an advanced civilization, as they are implied by physics. And even if some things turn out to be wrong, that only distorts such a base model instead of breaking it.
In other words, your thoughts on advanced civilizations are foolish (if you forgive me the use of the term), because you don’t grasp the affordances and limitations of them.
You apply and use sophisticated extrapolations of the current state. But that will only ever get you to bigger cannons; a rocket is an idea beyond the horizon of your thought experiments. Never mind a relativistic beam rider.
Sorry if this comes across as harsh. I just noticed this and wanted to see how you would reply.
OP:
I guess this is a fundamental difference of views, because I don’t think limits set by physics have much to do with where social creatures’ endeavors end up going, aside from providing absolute upper bounds.
Like, I do just believe that endless expansionism is naive. Sometimes it serves, but always there is a master, and it’s not physics.
Me:
But again, I think you fail to appreciate the timescales involved for a civilization that actually survives long enough. Physics doesn’t merely provide abstract upper bounds; over sufficiently long timescales, those bounds increasingly become the practical limits of what someone will eventually try.
You don’t need endless expansionism to be a universal social value, or even a particularly common one. Given thousands, tens of thousands, or millions of years, immortals—or even sufficiently wealthy and leisurely mortals—produce enough Brownian motion in values, institutions, subcultures, ambitions, and experiments that eventually somebody explores almost every physically accessible niche.
That’s the asymmetry I’m pointing at. Expansionism doesn’t need to remain the master of civilization. It just needs to recur occasionally, somewhere, and be capable of propagating when it does. Preventing that indefinitely seems to require not merely that most societies stop expanding, but that civilization becomes extraordinarily effective at suppressing deviation and remains essentially steady-state over geological timescales.
So I think “there is always a master, and it isn’t physics” understates what a million years of social variation means. Masters change. Cultures change. Values drift. Dissidents appear. Physics doesn’t.
OP:
I get the timescale stuff, selection, and Brownian reasoning, yeah. I suspect the atom for me is that I don’t think a civilization that lasts for anything like those timescales remains capable of participating in its environment with the disposition that would lead to those outcomes, because inhering in such a posture is something fundamentally dangerous that, via those same sorts of in-the-limit/sampling considerations, ends it early.
Trying to sense into it, most of it seems to come from an intuition about metastability. Natural selection is shitty at crafting organisms to avoid undermining their substrates, but it still happens in some ways via indirect means. Plants don’t produce byproducts that are toxic to ~all life, e.g., despite it maybe being locally adaptive to do so. They don’t because they can’t; the process that made them plants isn’t able to access that part of the search space.
I think it’s this nature of confinement that cuts down the civilizational search space—the process that makes civilizations able to endure isn’t able to make them certain other ways.
I forgot a central bit here: intelligence, most abstractly, is about relevance realization, which is a force towards concern with externalities and awareness of substrate dependence directly. I think this radically empowers the mechanism above, since values, ethics, etc. are new axes that are fundamentally about externalities and are civilization-shaping ones.
At present we see lots of variance in those, but I don’t see why we should expect that to continue. There may be ideal basins that support civilization. Our search so far certainly wouldn’t have found them—we just started making variance in these available at scale within the last, like, 100 years.
My guess is, if there are stable long-term attractors, they tend pretty strongly towards externality mitigation.
Also, and totally unrelated, I’m a lot more bullish on physics changing. It seems naive also to believe in the constraints our current approximations have yielded. Though that’s not quite to your point, as I don’t think the way those might lax need be along axes we’d find legible at the moment.
RESPONSE
I think this clarifies where our disagreement actually is, because fundamentally, and somewhat ironically, I don’t disagree with you about civilization eventually accepting a boundary and becoming non-expansionist. I disagree about what it takes to get there, and what a civilization capable of remaining in your stable basin would actually have to do.
The first issue is another category error about the scale of the constraint.
You seem to be imagining a civilization with mature values becoming sufficiently opposed to expansionism that it simply stops undertaking civilization-scale projects analogous to Apollo. But under reasonable assumptions about self-replicators—which I would expect to be basic building blocks of any advanced civilization’s economy—and better models of interstellar flight, particularly beam-rider concepts, the actual constraint is much harder.
The problem is closer to preventing any individual or small group of actors from acquiring a ship capable of crossing the Atlantic and then doing so.
Assume a mature Dyson swarm containing billions of large power satellites. A beam-rider launch might require diverting a single dozens-of-gigawatts power satellite and keeping it on target for a few days. That’s not Apollo. That’s someone getting temporary control over one industrial installation among billions.
And relativistic self-replicating probes are only one of the more conspicuous ways to escape. Something like a hydrogen steamer stealth ship could intercept an interstellar asteroid and crawl out of Sol over centuries or millennia with a small colony civilization aboard. On the timescales we’re discussing, taking a thousand years to escape isn’t much of a constraint.
So if your stable civilizational attractor actually requires preventing expansion, how do you enforce it?
I see three main possibilities.
The first is that the same infrastructure that permits interstellar launch is used to prevent it. If somebody attempts to leave, you destroy them.
With beam-rider infrastructure, that isn’t particularly difficult in principle. The civilization already possesses immense directed-energy systems. You can send relativistic kill-missile swarms after the escapee. If your attitude is that there is no such thing as overkill when preventing an uncontrolled replicator from escaping, you can dump a noticeable percentage of a power satellite’s output in their general direction. If you’re concerned that they might have dropped something stealthed along the way, an antimatter beam weapon saturating the entire relevant volume is also naturally on the table.
The second option is to ensure that nobody ever diverges from the enlightened values sufficiently to attempt this.
But now we have to ask what that entails over a million years.
Softer forms of propaganda and socialization are likely to be leaky on those timescales, which means you still require the first solution as a backstop. The gentler version of something that might actually be robust enough is ubiquitous surveillance combined with operant conditioning through mature mind-machine interfaces. You have to make sure that people not only generally agree with the stable civilizational values, but that nobody, anywhere, ever diverges sufficiently to attempt exit.
The third possibility is simply never to create off-world infrastructure capable of industrial closure.
You become extremely paranoid about satellites containing enough machinery to bootstrap anything from their own mass or locally available resources. You ensure remote installations cannot reproduce themselves. You avoid the self-replicating industrial machinery that would otherwise be an obvious part of a mature economy.
That seems likely to require a fairly extreme form of technological primitivism to remain stable, and probably a decent dose of option two as well.
And crucially, all three solutions create the conditions that make preventing any successful exit imperative.
Because suppose somebody gets out.
They now have excellent reason to be extremely resentful of the parent civilization, and even better reason to be paranoid about it. If they know Sol considers their continued existence an unacceptable replication risk, announcing where they’ve gone would be insane.
A perfectly reasonable counter-strategy would be to disappear.
Spend ten thousand years spreading silently across a thousand solar systems. Then prepare a decoy system and let the parent civilization discover evidence that uncontrolled expansion has occurred there. Observe whether Sol launches a relativistic strike to sterilize it.
If Sol does, you now have your answer.
And Sol may subsequently discover relativistic counter-launches arriving from a hundred other solar systems. Even if it successfully destroys dozens of them, Sol itself probably does not survive in anything resembling its previous form. Earth’s biosphere and the upper few kilometers of crust of planetary objects seem somewhere near the minimum expected casualties from that kind of exchange.
If Sol has invested heavily in distributed infrastructure—solar satellites, deep habitats, installations buried in gas giants, etc.—then parts of the civilization might survive and continue launching replicator swarms to counter the invading replicator swarms.
But now you’ve bought yourself a millennia-long struggle to secure the Solar System, interspersed with relativistic artillery barrages arriving from other stars.
I’m not saying this exact scenario is inevitable. I’m giving a concrete example because I think it demonstrates the escalation dynamic contained in what you’re proposing. If your stable basin requires preventing uncontrolled expansion, then somebody escaping that basin is not merely a dissident. They are potentially the ancestor of an exponentially expanding civilization that has very good reason to regard you as an existential threat.
Which gets me back to substrate dependence, because I think this is where your argument becomes almost inverted.
You say intelligence, understood as relevance realization, should increasingly produce concern about externalities and awareness of substrate dependence. I agree!
But I don’t think that leads naturally to remaining confined to one planet or refusing to exploit the resources of your solar system.
You fail to appreciate the size of a Dyson swarm—or alternatively you think such a structure would never be built, which can certainly happen, but requires a rather extreme denial of available resources and avoidance of using what is available.
Keeping everyone in the same biosphere creates enormous civilizational vulnerability. Everyone is sitting underneath the same atmosphere, capable of carrying biological or nanic weapons to effectively every entity on the planet. Everyone is exposed to the same planetary catastrophes. Your civilization has deliberately retained enormous correlated failure modes despite possessing the ability to distribute itself.
That seems inherently unstable to me. Civilizations engaging in that kind of behavior probably have a limited lifespan until something inevitably goes wrong.
And there is another problem: stars themselves.
I think the standard trajectory looks something like this.
A technological civilization appears in a solar system, either because life evolves there or because an interstellar probe arrives. It establishes industry around sources of volatiles and metals and claims the relatively small amount of material required to bootstrap a Dyson swarm.
In Sol, something like Mercury and Ceres would already be enormously more than you need. You unleash self-replicating industry and convert perhaps one percent of their combined mass into the infrastructure required to access essentially the entire energy output of the Sun.
At that point, much of that energy can ultimately be directed inward toward star lifting, because the Sun contains about 99% of the mass in the Solar System.
And this isn’t entirely optional in the long run.
Sun-like stars eventually evolve into giants and wreck their inner systems before ending as white dwarfs. For sufficiently massive stars—roughly those above eight solar masses—the issue becomes much more dramatic, because core-collapse supernovae are not merely inconvenient to the civilization occupying that system. They become an externality imposed on surrounding systems as well.
If nearby systems are inhabited, allowing your own star eventually to explode becomes a strategic problem for everybody around you.
Now imagine a civilization saying: no, manipulating the star violates our mature values. We are going to leave this enormous strategic-class object unmanaged even though we know its eventual evolution can destroy us and harm our neighbors.
That doesn’t look like concern about externalities and substrate dependence to me. It looks like the opposite.
And the surrounding civilizations have enormous amounts of time and very obvious motives to coordinate around ensuring that the civilization with the potential strategic-class weapon is no longer in a position to endanger everyone else.
Which gets us straight back to the same strategic dynamics as the escaped colony retaliating against Sol.
So, ironically, I think concern about externalities and substrate dependence strongly favors the construction of the Dyson swarm and eventually star lifting.
Once you have that infrastructure, over sufficiently long periods you can extract the useful resources from the star and turn it into something more manageable—perhaps one or several red dwarfs, if ordinary stellar fusion remains the best available long-term energy source. Red dwarfs are enormously longer-lived and much less obnoxious pieces of infrastructure than Sun-like stars.
And then I actually agree with you.
Once you’ve claimed the useful resources of the system, built the swarm, secured your substrate, managed the star, and neighboring systems are themselves occupied, expansionism stops making much sense.
Unchecked expansion by conscious agents may actually become dangerous. There isn’t even necessarily anywhere meaningful left to expand into: every nearby star has been claimed by daughter civilizations, siblings, or unrelated civilizations doing approximately the same thing.
So I do think civilizations eventually mature out of expansionism.
I just think the mature equilibrium comes at the end of the expansionary process rather than the beginning.
Arrival. Industrial closure. Dyson swarm. Stellar engineering. Eventually a steady state.
At that point, further expansion becomes irrational.
But refusing to walk toward that logical end state—refusing to distribute your civilization, refusing to use the resources sitting around you, and allowing your own star eventually to destroy the substrate you depend upon—also seems deeply irrational.
In fact, I can hardly think of anything more directly aligned with “concern with externalities and awareness of substrate dependence” than making sure the enormous fusion reactor your civilization lives next to neither destroys you nor wastes almost all of the accessible matter and energy in your system.
And being bullish on physics changing doesn’t really resolve the disagreement.
FTL mostly changes the distances and timescales involved. Getting around entropy would be more interesting, because then securing negentropy and preventing stars from destroying valuable matter might become even more attractive, or perhaps cease to matter for entirely different reasons.
There is also the old idea of subliming or transcending—most plausibly into some bespoke computational environment or, if physics permits something sufficiently exotic, custom pocket universes vastly more favorable to computation.
But none of those necessarily change the underlying dynamic.
Someone might still want to expand in real space.
Even if I grant you essentially a Dungeons & Dragons or Harry Potter-style magic system waiting somewhere inside deeper physics, I’ve only distorted the scale of the problem. I haven’t removed it.
Someone can still disagree.
Someone can still leave.
Someone can still reproduce elsewhere.
And in the final analysis, if your stable enlightened civilization regards that as an unacceptable externality, you still have to decide whether you’re willing to shoot them when they refuse to go along with your more enlightened way of thinking.
If you let them leave, your Brownian process continues outside the basin.
If you don’t let them leave, then the civilization you’re describing needs to be capable of reliably enforcing that prohibition across astronomical infrastructure and geological time.
That’s the part where I think your metastability argument becomes much harder rather than easier.
The following discussion originally took place over WhatsApp and has been lightly cleaned up for spelling, punctuation, and readability. The substance and wording have otherwise been left essentially unchanged.
I discussed this with OP elsewhere before being asked to move the discussion here. Anything before RESPONSE is context.
Me:
I think the core issue all your arguments about future civilization and related things have is that you don’t grok the scale of things out there. Maybe intellectually, but definitely not emotionally or intuitively.
A central issue I feel you have is that you aren’t well versed in the plausible limits and capabilities of an advanced civilization, as they are implied by physics. And even if some things turn out to be wrong, that only distorts such a base model instead of breaking it.
In other words, your thoughts on advanced civilizations are foolish (if you forgive me the use of the term), because you don’t grasp the affordances and limitations of them.
You apply and use sophisticated extrapolations of the current state. But that will only ever get you to bigger cannons; a rocket is an idea beyond the horizon of your thought experiments. Never mind a relativistic beam rider.
Sorry if this comes across as harsh. I just noticed this and wanted to see how you would reply.
OP:
I guess this is a fundamental difference of views, because I don’t think limits set by physics have much to do with where social creatures’ endeavors end up going, aside from providing absolute upper bounds.
Like, I do just believe that endless expansionism is naive. Sometimes it serves, but always there is a master, and it’s not physics.
Me:
But again, I think you fail to appreciate the timescales involved for a civilization that actually survives long enough. Physics doesn’t merely provide abstract upper bounds; over sufficiently long timescales, those bounds increasingly become the practical limits of what someone will eventually try.
You don’t need endless expansionism to be a universal social value, or even a particularly common one. Given thousands, tens of thousands, or millions of years, immortals—or even sufficiently wealthy and leisurely mortals—produce enough Brownian motion in values, institutions, subcultures, ambitions, and experiments that eventually somebody explores almost every physically accessible niche.
That’s the asymmetry I’m pointing at. Expansionism doesn’t need to remain the master of civilization. It just needs to recur occasionally, somewhere, and be capable of propagating when it does. Preventing that indefinitely seems to require not merely that most societies stop expanding, but that civilization becomes extraordinarily effective at suppressing deviation and remains essentially steady-state over geological timescales.
So I think “there is always a master, and it isn’t physics” understates what a million years of social variation means. Masters change. Cultures change. Values drift. Dissidents appear. Physics doesn’t.
OP:
I get the timescale stuff, selection, and Brownian reasoning, yeah. I suspect the atom for me is that I don’t think a civilization that lasts for anything like those timescales remains capable of participating in its environment with the disposition that would lead to those outcomes, because inhering in such a posture is something fundamentally dangerous that, via those same sorts of in-the-limit/sampling considerations, ends it early.
Trying to sense into it, most of it seems to come from an intuition about metastability. Natural selection is shitty at crafting organisms to avoid undermining their substrates, but it still happens in some ways via indirect means. Plants don’t produce byproducts that are toxic to ~all life, e.g., despite it maybe being locally adaptive to do so. They don’t because they can’t; the process that made them plants isn’t able to access that part of the search space.
I think it’s this nature of confinement that cuts down the civilizational search space—the process that makes civilizations able to endure isn’t able to make them certain other ways.
I forgot a central bit here: intelligence, most abstractly, is about relevance realization, which is a force towards concern with externalities and awareness of substrate dependence directly. I think this radically empowers the mechanism above, since values, ethics, etc. are new axes that are fundamentally about externalities and are civilization-shaping ones.
At present we see lots of variance in those, but I don’t see why we should expect that to continue. There may be ideal basins that support civilization. Our search so far certainly wouldn’t have found them—we just started making variance in these available at scale within the last, like, 100 years.
My guess is, if there are stable long-term attractors, they tend pretty strongly towards externality mitigation.
Also, and totally unrelated, I’m a lot more bullish on physics changing. It seems naive also to believe in the constraints our current approximations have yielded. Though that’s not quite to your point, as I don’t think the way those might lax need be along axes we’d find legible at the moment.
RESPONSE
I think this clarifies where our disagreement actually is, because fundamentally, and somewhat ironically, I don’t disagree with you about civilization eventually accepting a boundary and becoming non-expansionist. I disagree about what it takes to get there, and what a civilization capable of remaining in your stable basin would actually have to do.
The first issue is another category error about the scale of the constraint.
You seem to be imagining a civilization with mature values becoming sufficiently opposed to expansionism that it simply stops undertaking civilization-scale projects analogous to Apollo. But under reasonable assumptions about self-replicators—which I would expect to be basic building blocks of any advanced civilization’s economy—and better models of interstellar flight, particularly beam-rider concepts, the actual constraint is much harder.
The problem is closer to preventing any individual or small group of actors from acquiring a ship capable of crossing the Atlantic and then doing so.
Assume a mature Dyson swarm containing billions of large power satellites. A beam-rider launch might require diverting a single dozens-of-gigawatts power satellite and keeping it on target for a few days. That’s not Apollo. That’s someone getting temporary control over one industrial installation among billions.
And relativistic self-replicating probes are only one of the more conspicuous ways to escape. Something like a hydrogen steamer stealth ship could intercept an interstellar asteroid and crawl out of Sol over centuries or millennia with a small colony civilization aboard. On the timescales we’re discussing, taking a thousand years to escape isn’t much of a constraint.
So if your stable civilizational attractor actually requires preventing expansion, how do you enforce it?
I see three main possibilities.
The first is that the same infrastructure that permits interstellar launch is used to prevent it. If somebody attempts to leave, you destroy them.
With beam-rider infrastructure, that isn’t particularly difficult in principle. The civilization already possesses immense directed-energy systems. You can send relativistic kill-missile swarms after the escapee. If your attitude is that there is no such thing as overkill when preventing an uncontrolled replicator from escaping, you can dump a noticeable percentage of a power satellite’s output in their general direction. If you’re concerned that they might have dropped something stealthed along the way, an antimatter beam weapon saturating the entire relevant volume is also naturally on the table.
The second option is to ensure that nobody ever diverges from the enlightened values sufficiently to attempt this.
But now we have to ask what that entails over a million years.
Softer forms of propaganda and socialization are likely to be leaky on those timescales, which means you still require the first solution as a backstop. The gentler version of something that might actually be robust enough is ubiquitous surveillance combined with operant conditioning through mature mind-machine interfaces. You have to make sure that people not only generally agree with the stable civilizational values, but that nobody, anywhere, ever diverges sufficiently to attempt exit.
The third possibility is simply never to create off-world infrastructure capable of industrial closure.
You become extremely paranoid about satellites containing enough machinery to bootstrap anything from their own mass or locally available resources. You ensure remote installations cannot reproduce themselves. You avoid the self-replicating industrial machinery that would otherwise be an obvious part of a mature economy.
That seems likely to require a fairly extreme form of technological primitivism to remain stable, and probably a decent dose of option two as well.
And crucially, all three solutions create the conditions that make preventing any successful exit imperative.
Because suppose somebody gets out.
They now have excellent reason to be extremely resentful of the parent civilization, and even better reason to be paranoid about it. If they know Sol considers their continued existence an unacceptable replication risk, announcing where they’ve gone would be insane.
A perfectly reasonable counter-strategy would be to disappear.
Spend ten thousand years spreading silently across a thousand solar systems. Then prepare a decoy system and let the parent civilization discover evidence that uncontrolled expansion has occurred there. Observe whether Sol launches a relativistic strike to sterilize it.
If Sol does, you now have your answer.
And Sol may subsequently discover relativistic counter-launches arriving from a hundred other solar systems. Even if it successfully destroys dozens of them, Sol itself probably does not survive in anything resembling its previous form. Earth’s biosphere and the upper few kilometers of crust of planetary objects seem somewhere near the minimum expected casualties from that kind of exchange.
If Sol has invested heavily in distributed infrastructure—solar satellites, deep habitats, installations buried in gas giants, etc.—then parts of the civilization might survive and continue launching replicator swarms to counter the invading replicator swarms.
But now you’ve bought yourself a millennia-long struggle to secure the Solar System, interspersed with relativistic artillery barrages arriving from other stars.
I’m not saying this exact scenario is inevitable. I’m giving a concrete example because I think it demonstrates the escalation dynamic contained in what you’re proposing. If your stable basin requires preventing uncontrolled expansion, then somebody escaping that basin is not merely a dissident. They are potentially the ancestor of an exponentially expanding civilization that has very good reason to regard you as an existential threat.
Which gets me back to substrate dependence, because I think this is where your argument becomes almost inverted.
You say intelligence, understood as relevance realization, should increasingly produce concern about externalities and awareness of substrate dependence. I agree!
But I don’t think that leads naturally to remaining confined to one planet or refusing to exploit the resources of your solar system.
You fail to appreciate the size of a Dyson swarm—or alternatively you think such a structure would never be built, which can certainly happen, but requires a rather extreme denial of available resources and avoidance of using what is available.
Keeping everyone in the same biosphere creates enormous civilizational vulnerability. Everyone is sitting underneath the same atmosphere, capable of carrying biological or nanic weapons to effectively every entity on the planet. Everyone is exposed to the same planetary catastrophes. Your civilization has deliberately retained enormous correlated failure modes despite possessing the ability to distribute itself.
That seems inherently unstable to me. Civilizations engaging in that kind of behavior probably have a limited lifespan until something inevitably goes wrong.
And there is another problem: stars themselves.
I think the standard trajectory looks something like this.
A technological civilization appears in a solar system, either because life evolves there or because an interstellar probe arrives. It establishes industry around sources of volatiles and metals and claims the relatively small amount of material required to bootstrap a Dyson swarm.
In Sol, something like Mercury and Ceres would already be enormously more than you need. You unleash self-replicating industry and convert perhaps one percent of their combined mass into the infrastructure required to access essentially the entire energy output of the Sun.
At that point, much of that energy can ultimately be directed inward toward star lifting, because the Sun contains about 99% of the mass in the Solar System.
And this isn’t entirely optional in the long run.
Sun-like stars eventually evolve into giants and wreck their inner systems before ending as white dwarfs. For sufficiently massive stars—roughly those above eight solar masses—the issue becomes much more dramatic, because core-collapse supernovae are not merely inconvenient to the civilization occupying that system. They become an externality imposed on surrounding systems as well.
If nearby systems are inhabited, allowing your own star eventually to explode becomes a strategic problem for everybody around you.
Now imagine a civilization saying: no, manipulating the star violates our mature values. We are going to leave this enormous strategic-class object unmanaged even though we know its eventual evolution can destroy us and harm our neighbors.
That doesn’t look like concern about externalities and substrate dependence to me. It looks like the opposite.
And the surrounding civilizations have enormous amounts of time and very obvious motives to coordinate around ensuring that the civilization with the potential strategic-class weapon is no longer in a position to endanger everyone else.
Which gets us straight back to the same strategic dynamics as the escaped colony retaliating against Sol.
So, ironically, I think concern about externalities and substrate dependence strongly favors the construction of the Dyson swarm and eventually star lifting.
Once you have that infrastructure, over sufficiently long periods you can extract the useful resources from the star and turn it into something more manageable—perhaps one or several red dwarfs, if ordinary stellar fusion remains the best available long-term energy source. Red dwarfs are enormously longer-lived and much less obnoxious pieces of infrastructure than Sun-like stars.
And then I actually agree with you.
Once you’ve claimed the useful resources of the system, built the swarm, secured your substrate, managed the star, and neighboring systems are themselves occupied, expansionism stops making much sense.
Unchecked expansion by conscious agents may actually become dangerous. There isn’t even necessarily anywhere meaningful left to expand into: every nearby star has been claimed by daughter civilizations, siblings, or unrelated civilizations doing approximately the same thing.
So I do think civilizations eventually mature out of expansionism.
I just think the mature equilibrium comes at the end of the expansionary process rather than the beginning.
Arrival. Industrial closure. Dyson swarm. Stellar engineering. Eventually a steady state.
At that point, further expansion becomes irrational.
But refusing to walk toward that logical end state—refusing to distribute your civilization, refusing to use the resources sitting around you, and allowing your own star eventually to destroy the substrate you depend upon—also seems deeply irrational.
In fact, I can hardly think of anything more directly aligned with “concern with externalities and awareness of substrate dependence” than making sure the enormous fusion reactor your civilization lives next to neither destroys you nor wastes almost all of the accessible matter and energy in your system.
And being bullish on physics changing doesn’t really resolve the disagreement.
FTL mostly changes the distances and timescales involved. Getting around entropy would be more interesting, because then securing negentropy and preventing stars from destroying valuable matter might become even more attractive, or perhaps cease to matter for entirely different reasons.
There is also the old idea of subliming or transcending—most plausibly into some bespoke computational environment or, if physics permits something sufficiently exotic, custom pocket universes vastly more favorable to computation.
But none of those necessarily change the underlying dynamic.
Someone might still want to expand in real space.
Even if I grant you essentially a Dungeons & Dragons or Harry Potter-style magic system waiting somewhere inside deeper physics, I’ve only distorted the scale of the problem. I haven’t removed it.
Someone can still disagree.
Someone can still leave.
Someone can still reproduce elsewhere.
And in the final analysis, if your stable enlightened civilization regards that as an unacceptable externality, you still have to decide whether you’re willing to shoot them when they refuse to go along with your more enlightened way of thinking.
If you let them leave, your Brownian process continues outside the basin.
If you don’t let them leave, then the civilization you’re describing needs to be capable of reliably enforcing that prohibition across astronomical infrastructure and geological time.
That’s the part where I think your metastability argument becomes much harder rather than easier.