Expansion in the Fermi paradox isn't a freebie

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 with mature expansionism at 1. A given civilization is bestowed by its civilizational heritage with some range of expansionist tendencies that it might instantiate at a given time. So is the most expansionist the civilization can act and the least.

The reasoning is that natural selection ought to yield some sequence with 1 in eventually. But the selection is for expansionism as a civilizational disposition, that last word meaning that across all particular points in time a given civilization acts more expansionist, and more so than it’s ancestors. So we’re actually saying something like is increasing and is decreasing. More expansionist and more rigidly expansionist.

Decrypted, this says

1. We have a sequence of civilizations
2. None of these civilizations are mature expansionists yet
3. They’re becoming more expansionist over time, so more inclined to destabilizing transitions
4. 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.