The Fermi paradox is premised on expansionism being intrinsic to civilizational development, most explicitly in Hanson’s grabby aliens model. There’s a Great Filter provided by expansionism itself that doesn’t center on scientific and technological progress that I think is worth exploring. It’s about the destabilizing nature of expansion events and the precarity of an expansionist disposition, and survives the standard counter that civilizational natural selection maximizes expansionism in the limit. It’s a cosmic-scale cousin of habryka’s Do not conquer what you cannot defend, where the concern is defending what’s taken. Mine is about integrating it.
Questioning expansionism
Before and unrelated to that, a brief skepticism about the premise feels due and will be useful context. I don’t really believe that expansionism is a necessary civilizational posture, in particular in the long-arc limit relevant to Fermi time scales, and might be a rare/never phenomenon.
The argument for it seems to be from intuition, positing that selection pressure made organisms expansionist in the sense of always consuming what resource is available to support population growth. That tendency inheres genetically, hence something something cultures and civilizations must be like that on balance/in great number and also in the limit.
Recent memory certainly aligns. Technological progress has been regularly opening new avenues for resource acquisition and human civilization acts on them.
I don’t buy it. Cultures throughout history have not been uniformly expansionist and the rapid and steady influx of low hanging tech progress acts as confounder to our intuitions, which are based on recent times. We’ve seen that pattern for a long time, therefore it’s always like that.
But, counter to that, an awareness of the externalities of expansionist tendencies is already normative — the collective has metabolized that wielding technology to absorb newly accessible resource can have substrate-undermining externalities. This is a recent trend too and my reasoning here comes from intuition also (hence has that same recency confound), but I think this latter intuition has better foundations.
Externality awareness is not a naked observation about sociocultural trends. It fits into developmental models, which more or less all posit that a growing sphere of concern, a receptivity and saliencing of context and externalities, is constitutive of development. This observation is thus structural in kind, matching models of the development of other intelligent systems, whereas the linear intuition that “replicators expand therefore all the higher order structures constituted of them will tend to do the same” ignores that structural regularity. Also and to a lesser degree, that linear intuition is undermined/countered by noting that civilization comes to persist exactly by civilizing older base energies and drives. Take what you can for yourself, the atom of expansionism, is about the most primitive force at the individual level that coordination supportive of civilization suppresses. So I don’t think these two intuitions are on equal footing. A growing enacted concern for externalities has a precedented and principled significance.
Assuming expansionism
Okay, on to adopting the premise of expansionism as default policy. The moving piece I want to center on is that expansion comes in waves — afforded by a technological advance, a memetic shift in culture, political power transition, etc — and that each wave of expansion is destabilizing. To spread further requires a system move into disequilibrium (necessarily transient, according to the premise) with its existing substrate (here taken to be all the conditions constitutive of civilizational continuation, not just physical), to stretch itself in service of getting more. That move, by design, is to open access to further resource, but the act of moving itself is a state of liminality, a transition into a new configuration of the system.
This is sketchy. Systems approaching expansion — individuals metabolizing insight, cultures memetically complexifying, civilizations expanding geographically or using a new technology to unlock in-place resource — don’t always benefit from or survive the attempt. It’s not the case (far from) that approach of liminality need be generative. A lot are net decohering for a system, collapsing it to an older and more stable attractor. Worse, dissolution not bluntly caused by overwhelming external forces always comes after failure to metabolize/integrate the new. Reach exceeding grasp etc.
So each wave of expansion incurs risk. The thesis that civilizations expand until they populate the galaxy depends on the premise that civilizations can absorb an unknown but large number of expansion moves. In the Fermi context, major technological advances are the mover most talked about, and these are historically the most destabilizing kind of liminality-forcer. Reaching for and obtaining more resource at the base level (power, matter, territory) strains all structures above it — social, cultural, political. Each has to survive its own liminal impetus.
I’m making a systems argument, so I don’t want to focus on the (plausible) idea that particular technological transitions might be especially fraught, though those could and probably do exist (eg nuclear weapons).
Naive and mature expansionism
So far we’ve established that an unknown but large number of homeostasis-peturbing events need to be successfully navigated for expansionism to yield and hold the galaxy. Civilizations would need to be able to survive each transition and then find a new homeostasis with their newly unlocked substrate.
Naive expansionism, the kind typically associated with the word, isn’t able to do that. It’s too context-ignorant, aggressive and myopic, reaches further than is viable by burning its substrate along the way, and, most importantly, it includes no strategy for/philosophy of stabilization post-expansion. Some kind of mature, post version of expansionism needs to form, one that effectively-in-practice manages the delicate balances through the liminal phase and configures a substrate supportive of civilization on the other side.
Mature expansionism is not the kind inherited from/bestowed by replicator ancestry, it needs to be discovered. The only mechanism available is trial and error. The success of an expansionist posture thus hinges on being able to survive enough rounds of expansion to cultivate a skillful relationship to those phase transitions. Presupposed, of course, is that mature expansionism, which is a whole-civilization-at-all-levels-at-once memetic/social/cultural/political/technological state that needs to endure indefinitely, is possible at all. That’s the thing that needs to be accessible and approachable via difficult destabilizing transitions. A lot of them.
The gradient in approach to that mature basin, if it exists, would be small for a long time. In particular, it asks for successful civilizational navigation across many scales and axes that have nothing to do with technology. Those ones are the hard ones.
Selection for expansionism
There’s a common thought in Fermi world that once expansionism gets past the threshold of dispersing beyond the home solar system, the speed of light rate limiter on inter-civilization interaction causes sociocultural drift that need not normalize to some collective mean. Daughter civilizations can deviate arbitrarily far from their ancestors, and this process exerts a selection pressure towards expansionism. Thus to the degree that civilizations move between star systems, they should become more expansionist, and this selection implements a search function for mature expansionism.
Not every evolutionary hill climb succeeds though and I think there’s a good structural argument why this one would be difficult, namely that selection for expansionism is selection for destabilization and fragility.
The reasoning so far is that civilizations we find out there should be more expansionist. Let’s, unfortunately, put notation to this, positing barbarically that expansionism can be summarized in one numerical axis, say taking values in
The reasoning is that natural selection ought to yield some sequence
Decrypted, this says
We have a sequence of civilizations
None of these civilizations are mature expansionists yet
They’re becoming more expansionist over time, so more inclined to destabilizing transitions
They’re becoming more rigid over time, having less wiggle room away from the strongest of their expansionist tendencies
Naive expansionists with a baseline propensity for more destabilizing transitions and with less non-expansionists slack to absorb them strikes me as a hill that natural selection may not climb.
It seems plausible to me that this is a Great Filter. I think the reasoning is compelling and, if nothing else, it surfaces that complex and difficult civilizational phenomena — memetics, culture, political systems — outside the domain of but deeply intertwined with technological progress can be explanatory for the Fermi paradox.
It seems like ASI could solve the coordination problems inherent in a distributed civilization pretty easily. Getting alignment right would let an ASI copy itself and coordinate across distance and communication lags, and prevent dangerous kbut not interesting!) disagreements across fragments of civilization.
I couldn’t find mention of AI so I skipped everything past the intro. As with many other topics, recognition of the possibility of ASI changes the analysis dramatically.
It’s much easier than alignment, you just need to be able to establish control across astronomical communication lags. Alignment with the future of humanity is more difficult to operationalize than alignment among copies of a very powerful agent (which itself doesn’t need to be aligned in the nebulous sense with anything in particular, it just needs to be very capable). Each copy could then maintain control over its local region of responsibility (that doesn’t have significant communication lags) with hard power, automating things that could otherwise contest it into robustly non-agentic tools (even if functionally intelligent), locking everything that could contest it into actually perfectly inescapable sandboxes (such as the morally valuable content that runs within the compute it’s making out of the lightcone).
Right. I just meant it needs to solve alignment of its copies to itself/each other. It needs to adequately solve The alignment stability problem to avoid drift that could cause conflict after enough independent learning and thought.
Then I mixed in some stuff about how a civilization could do this and still flourish, so if they solves alignment they’d still go for this approach.
Some instability is not important if it permits a nontrivial amount of expansion, because rival shards of the same agent aren’t importantly different from rival alien originators (from the grabby alien standpoint). A collection of rival grabby aliens still keeps expanding as a whole. And the construction of the tyrannical expansion manager agent could sacrifice some ability to adapt and grow for greater stability (in which case it could be more vulnerable to the more adaptable aliens when it encounters them; and it won’t be able to usefully hear the pleas of the “morally valuable content” it has locked down in its sandboxed compute). This proof-of-concept illustration is already clearly not a good/sane way to structure the future of humanity, so making it even more repugnant by introducing inescapable stagnation is within scope.
I’m not sure how to coherently think about AI civilizations scaling. Too many likely spurious assumptions to make for the thought experiments to be compelling for me. In particular I don’t endorse applying the reasoning above.
Okay, well, you can’t really just skip important parts of a problem because they’re hard.
Just trying to be transparent that I don’t think the tools here address this generalization of the problem, which is fine: scoping problems helps make them tractable, ideas can exapt in surprising ways, etc
That is a good point. I would find the work more useful if you scoped it that way explicitly.
Pretending AI progress doesn’t exist because it’s hard to think about is what the majority of the world is doing right now. I find it pretty frustrating.
A large part of the issue of this argument, and really the fundamental, decisive counterargument against all ideas like this is that coordination isn’t required to expand.
A good analogy is how chimp-like creatures 4.4 million years ago kept expanding and contracting, as well as speciating, but where the forces of expansion outweighed the forces of contraction a little bit, and this eventually produced our own civilization without any global coherence necessary.
More generally, you substantially underestimate the power of “it only takes one group to expand” to defeat most proposed Fermi Paradox solutions, and this is a major part of what made solving the puzzle hard.
@Zsolt Kelly-Bene, I would recommend avoiding Fermi Paradox solutions where it isn’t remotely plausible that all such civilizations choose not to expand in the universe, because they are very unlikely as a conjunction of claims.
This is a great take! I like taking apart a known question at one of the assumptions that’s less discussed because it’s basically accepted. There’s an interesting question this analysis throws up: given this, what sets of values, what kinds of desire configurations, give rise to expansionist or non-expansionist tendencies? We do have the generic pull that the classic Fermi argument rests on: Omohundro pulls to expand influence and colonize everything. These go for biological organisms and even civilizations-as-agents. And then to make it worse, local or instrumental preferences cohere into utility functions over the world. If a desire points at an abstract notion of how the world should be, expansion is just inherent in trying to get that function fulfilled, and acquiring more power is obviously a good way to do that. Even if the desires are somehow localized, more resources and more power to funnel into that localized desire zone are still interesting. A problem: most tempering for instrumental reasons doesn’t stabilize at a particular level. It just tempers growth into maybe a linear or log growth function, still enough to keep expansionist tendencies alive and produce expansionist observations. The externalities of consuming substrate can just be part of the model, subsumed in planning, even if they temper the speed of expansion, we don’t have a good argument for why it would cap it. But this is not the only endpoint. For example, you describe one pull that can go the other direction. And then, if the subsumption of substrate as a negative externality is salient enough, at the right point of development, it could get adopted as its own terminal value. Or, for whatever reason, the instrumental reason actually totalizes. (There is one famous candidate for where and how this could happen, wait for it.) There could also be another attractor basin that is non-expansionist, almost coincidentally. For example, an interesting idea is that it’s actually very hard to get evolution of capable agents that will generlize to any kind of global utility function in the frist place, rather than collapsing into some kind of wire-heading scheme as soon as behavior outside the training distribution is called for. Both the prevalence of reward hacking, as well as recent societal direction taken as revealed preferences make this more credible to me, deeper dive necessary and on my todo list.
One interesting expansion of your idea, which also serves as a counter to an obvious flaw, is that a non-expansionist civilization will actively hinder its offspring from being expansionist, and will behave aggressively toward expansionist tendencies. Even with non-expansionist values themselves, expansionist tendencies have to be a thing in their native grammar and world model to be curbed, so they are obviously also something to curb and fight externally (or semi-internally). By default there’s a drift argument you also alluded to: every time a civilization changes, or creates a subpopulation or offspring that varies from its own setup, if that variation turns toward expansionism, it will itself just propagate and crowd out the non-expansionist root. Hence, any mature civilization will have active countermeasures against this. The norm enforcement serves its goals even if it’s local. If course, this enforcement is, in turn, also local: it stabilizes lineages, not the galaxy, because single lineages might just never reach a non-expansionist basin. One could argue that a single expansionist variation will just erase all non-expansionist tendencies, but that’s not true, because any non-expansionist tendency is still self-preserving in an obvious autopoietic way. Another structural problem I see: the filter, as you put it so far, sounds like a mortality rate. If it’s not a wall and enough civilizations get through, the expansionist nature of those that do, ultimately still ends up with them filling the galaxy. To explain Fermi, the filter must be basically total. One interesting repair: the anti-expansion filter could be instantiated in a kind of dark forest analogy. Non-expansionist civilizations don’t only have an interest in curbing their own variations and offspring, they also have a motivation to build defensive and offensive measures to protect themselves from expansionist civilizations. For a certain balance of offense and defense (which seems fairly plausible as described in Dark Forest theories), this takes the form of non-expansionist civilizations being very cautious and very aggressive toward any expansionist tendencies. That results in an actual filter that would fit the observation. One gap here is that this is mostly about being quiet, but expansionism in general is just loud and easier to detect. So expansionist civilizations would have to be quiet, and if instrumental principles congeal into first-principle held values, which I don’t think is too unlikely, quietness itself drifts toward genuine non-expansionism. All of this contributes to a non-expansionist value system being a dominant strategy. So, an interesting open question: if the dark forest is one possible existence proof of how a pathway can create a non-expansionist attractor, which other attractors (maybe earlier in the development of a civilization?) could there be, and what properties make the attractors total enough to actually explain fermi?
A survivable non-expansionist stance is to be expansionist about non-expansion, to build a self-propagating expansion wave that only prevents or opposes other expansionist initiatives, and does nothing else.
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.
just to drain this phenomena of cultural animus: we encounter expansionists because they expand. there are just more of them. if a random sampling of geographic locations finds anything, it most likely finds an expansionist.
consider the 36 officially designated global biodiversity hotspots. they account for just 2.5% of the Earth’s land surface, yet they hold over 50% of the world’s plant species and 43% of bird, mammal, reptile, and amphibian species. mostly because these species are not expansionist. they are well but narrowly adapted to their local environment.
This doesn’t consider a blind replicator with error correction. Once created it expands. For example a life like tech system that reproduces itself out of asteroids. It lands on one, turns it into copies of itself, travels to the other asteroids. When most are converted, they make a starship using sun-sail technology to travel to other stars. This can’t evolve and once started will travel to probably all stars in the galaxy. An expansionist civ would have no reason not to send this in advance, i.e. pre-mine the asteroids into a more useful form. In a world/universe with unstable expansionism we would expect to see something have gone through our asteroids in such a manner. We do not.