Worldbuilding with Dunbar’s Number

“What?” you might ask, “Worldbuilding with Dunbar’s number?” Dunbar’s number, simply put, is the reality that as human beings we can only conceive of a limited number of people in our minds as fully-formed, concrete, flesh-and-blood human beings instead of abstractions.

Dunbar’s Number

Although the general principle has been known since time immemorial, Robin Dunbar in the 1990s put it on a more scientific footing by finding a correlation between primate brain size and the size of social groups; extrapolating to humans the number of people we can have a stable interpersonal relationship with comes to 148, though a margin of uncertainty means the true figure could be anywhere from 100 to 250, and in any case it can be presumed it varies between individuals.

This number of 150 or so is reflected in a variety of human social organizations. Hutterite colonies split once their populations get much past 150, the finest-grained academic sub-disciplines have a maximum number of 200 or so scholars, and, most notably, military companies tend to have 80-200 people in them. Anecdotally, it’s very common for soldiers to to be eager to risk their lives for the sake of their comrades in their own company but to care little about the rest of their army. No doubt this is because they personally know the former, but are strangers to the latter.

Some Abstractions are better than Others

That’s not to say that people can’t, don’t, or even shouldn’t risk their lives or make sacrifices for strangers or for a group larger than a couple hundred people, but I will say that it’s much less common for a very good reason, and even then the concepts involved will be different, usually revolving around abstract ideas rather than any true relationship.

Among these abstract ideas are the principles of law and hospitality, that everyone, no matter whether they are friends, family, or strangers, has rights that you are bound to respect, which found their highest expressions in forms as diverse as the ancient world’s laws of hospitality and the Enlightenment’s concept of the universal and inalienable rights of man.

While the universal love some philosophies demand from people is truly deranged as an ideal, it is true that virtuous societies inculcate in their members some minimal universal standard of human dignity, and wicked societies inculcate in their members the opposite mentality, that strangers are unwelcome and are not entitled to any dignity. Truly evil societies, such as 20th century totalitarian regimes, go beyond mere wickedness, by pressuring its members to actively “otherize”, make unwelcome, and strip dignity from even people they know personally.

Dunbar’s Number made Practical

So human-shaped abstractions do matter, both for the one doing the abstracting and the ones abstracted. In practical terms the real number is actually even lower than 150, because to maintain a cohesive group of that size as much as half of each member’s time will have to be spent on social grooming, and they would have to stay in close physical proximity. Robin Dunbar speculated that only groups under intense survival pressure would actually achieve the 150 mark, and that groups under normal conditions would be much smaller than Dunbar’s number.

Hunter-gatherer bands, the primordial human society, usually range between 30 to 50 members in size, which is about the right balance between “many hands make light work” on one hand and the difficulty of maintaining real interpersonal ties on the other hand.

Dunbar’s Number: dooming Politics to Futility

This line of inquiry is actually really important, because the primordial way of deciding social questions is from friend to friend, to form a relationship with the other person so as to ensure both parties have their needs and wants met. After the agricultural revolution and the rise of “civilization” the scale of human societies rose to the point where that method didn’t work anymore, and we’ve flitted from political system to political system ever since in a fruitless attempt to replicate the greatness of the primordial system, where every man’s voice can be heard, every man has the right to leave the band if he so chooses, and every man’s needs and wants can be met to the extent feasible.

The problem is that in a society even of thousands, let alone millions or billions, that’s impossible. And this is where we come to the worldbuilding aspects of Dunbar’s number. Anyone with any interest in these questions, worldbuilders included, should realize that cultivating any real sense of community at scales beyond at best a few hundred people is basically impossible. No political system, short of a return to nomadic band society, will ultimately prove satisfactory.

That doesn’t mean all political systems are equally bad. Kleptocratic totalitarian dictatorship, at one end of the scale, is far, far worse than democratic liberal anarchy, on the other end of the scale. But it does mean that there is a certain amount of futility inherent in designing any political system that is anything other than man-to-man friendship.

The Purgatory of Agriculturalism

Having bashed society at scale for so long, one might wonder why I think people congregated in societies far larger than Dunbar’s number in the first place. Well, recent research has revealed that the agricultural revolution was a disaster for the human race, leading to a severe diminution of living standards, malnutrition, death, and the dawn, for the first time in man’s history, of oppression and its most sinister manifestation, the state.

Only during the industrial revolution has humanity (or at least the more-developed countries…) even recovered from this millennia-long depression, and even that unleashed its own pathologies, such as the modern state, and possibly other social maladies. Nevertheless the recent trend overall is positive, and industrialism will within centuries provide the toolkit needed for us to become an unsettled industrial-technological civilization, a race that roams the cosmic wild in bands while retaining the benefits of civilization.

As such, the reason why any people would submit to such a lifestyle as found in early agriculturalism (as opposed to late agricultural or especially industrial civilization) is more of a mystery than ever before. Nevertheless, it is obvious that society at scale is capable of feats that a single band of Dunbar’s number proportions could never hope to achieve. Imagine if our technology was limited to what a hundred or so people could build while on the move hunting game and gathering fruits and vegetables for a few hours every day.

Pathways to Complex Societies

Well, that’s food for thought to any intelligent worldbuilders reading this! There certainly would have been advancements in the past ten thousand years; interestingly, technological advancement was already exponential during the upper Paleolithic, even before agriculturalism. But none of our greatest feats would have even been feasible.

Sure, hunter-gatherer societies can scale up, as we saw in places like Japan and Cascadia; contrary to popular belief, agriculture is not necessary for this. Indeed, the correlation between agriculturalism and complexity so clear in the Old World becomes much murkier in the New World, suggesting to any worldbuilders out there that there are many pathways to complex societies, and indeed that humanity may have had an unusually rough transition from hunting and gathering to industrialism and thence to the stars (Cascadians and Japanese didn’t suffer the malnutrition early farmers did…). But rough or easy, the drawbacks of society beyond Dunbar’s number remain.

Levels of Abstraction

One of those drawbacks is not often discussed, but is of critical importance in a worldbuilding context: lines of communication and levels of abstraction. Let’s assume each person can personally know about 100 people, an even more rounded-off version of Dunbar’s number. Well, if these bands are all self-contained units, not too different from what we see in the military, each band of 100 can select a man to represent them, who can then assemble with a hundred others representing a hundred other bands.

In this way decision-making can be coordinated over a much larger scale. But the problem is that this over-band can’t communicate to the rank and file directly. The over-band has to make its decision and then rely on an intermediary, namely each representative, to communicate it to the rank and file. This decreases efficiency noticeably. Not too horribly, mind you, but it just doesn’t work as well as a normal band.

Beyond Dunbar’s Number: a social Phase Change

This is one layer of abstraction. 100 bands of 100 people each makes for a total size of 10,000 people. This is roughly the size of a large town. Keeping in mind that in practice social group sizes number about a third of that we’re down to small town territory. It’s not quite to the level of everyone knowing everyone else, but you will meet and see many of the same people every day.

If you’re in, say, the top 1% or even 10% of social status you’ll have relatively easy access to the leaders of your “community”. Even if you’re an ordinary person chances are high you’ll at least know someone who personally knows the leaders. At this level everyone who catches the eye of the leader of this society will get the chance to know him or her personally, even if it’s impossible for everyone to do so.

Dunbar’s Number exponentiated

These dynamics are quite different from a band, and we’re only at one level of abstraction! Imagine that the 100 representatives from each band each selected a representative to meet with 100 other such councils, forming an over-over-band. This is the second layer of abstraction, and forms a “community” of 1 million people.

Now we’re in the realm of a small to medium size city or a small country. If you’re in the top 1% of influence in this society you might have a good chance to meet with or get to personally know the leaders, but otherwise there’s very little chance you’ll even see them, much less really get to know anything about them aside from what you hear third-hand.

It’s also worth noting that at this level of abstraction, two levels, the leading council has to transmit their orders to each over-band, who then in turn has to transmit the orders to the members of each regular band. Much will be lost with this many links involved in the chain; like a game of telephone, with just two levels involved the ordinary members will probably get the gist of what the leadership wants but will be lucky to be able to do better than that.

Diseconomies of Scale

It’s worth noting that the largest employers in the world top out at around this level; Walmart employs 2 million people, and the largest governmental employer in the world, the U.S. Department of Defense, isn’t much bigger, at 3 million. Also consider that government regulation almost by its nature subsidizes gigantism among businesses even when it doesn’t try (and boy, does it try now!); in a freed market the largest businesses by number of employees would almost certainly be much smaller.

This suggests that for organizations diseconomies of scale start to dominate past the level of hundreds of thousands of members, possibly as few as tens of thousands. In the absence of violence subsidizing gigantism e.g. decentralized peaceable governments in a free market would likely top out in the tens to hundreds of thousands range, two layers of abstraction with 50 people in each band instead of 100. 50 instead of 100 makes sense, as does two levels of abstraction; past that even getting the gist of what the original sender wants becomes difficult to do on a consistent basis.

Even the State’s Gigantism has Limits

Interestingly, even violent organizations, i.e. states, top out at only one layer higher than that. If we take the over-over-band and add another layer of abstraction, making an over-over-over-band (henceforth we’ll call it a third-degree over-band) of 100, then we come to the scale of 100 million or so. With some adjustments this is roughly the scale of large countries. Transmitting orders down the chain of command at this scale becomes difficult. And this is at only three layers of abstraction!

Past a population of 5 million or so larger size is strongly correlated with worse outcomes across the board. Small countries are much freer, richer, and better-governed than large countries. Up to the size of a few hundred thousand or a few million it’s also common, though far from universal (Liechtenstein, for example, is highly decentralized despite being a microstate), for countries up to a million or so to have everything be more or less run from the central government. Larger countries, on the other hand, are more decentralized by necessity; some, like the United States or India, are de jure federations of states, but even others that are de jure unitary like China let their provinces operate with a large degree of de facto autonomy.

Sci-Fi World Government: doomed to Dysfunction

Where this becomes relevant for worldbuilders is the question of futuristic government and organization. Let’s consider a world government, a common trope in science fiction. Since the third layer of abstraction only gets us up to 100 million in size, we need to add another layer to get us up to 10 billion, a full four layers of abstraction. The ruling council has to issue its orders to the third-degree over-band, who in turn relays them to the second-degree over-band, who in turn relays them to the first-degree over-band, who in turn finally relays them to each member.

Efficiency is not going to be such an organization’s hallmark. To the extent it can coordinate at all it will be mostly because of shared cultural memes (Robin Hanson speculates that we already have such a global memetic regime emerging in the regulatory space!), information such as the market price system, one-to-many mass-media broadcasts from the rulers, and possibly bureaucratic inertia left over from when it was a much smaller organization. It will have all the rigidity of centralized control with little better coordination mechanisms than would be available anyway if the organization didn’t exist at all!

Scaling up to Galactic Space Opera

And that’s just with a population of ten billion or so, which is chump change compared to the teeming trillions galactic empires in science fiction can boast of! A fifth-order over-band would govern a population of 1 trillion. In Star Wars, for example, there are some single planets that have populations bigger than that, let alone a whole galaxy. It’s hard to imagine how a place like Coruscant would be all that governable, and the creators apparently agree with that assessment, hence Coruscant’s Underworld.

A sixth-order over-band would govern a population of 100 trillion, which equals roughly 10,000 Earth-sized worlds. That’s enough to have a great space opera, but is nothing compared to what’s out there in the totality of a decent-sized galaxy like the Milky Way (or the Star Wars galaxy). The number of Earth twins out there depends on your definition of an Earth twin and various assumptions, but the low-end estimates for our galaxy are in the hundreds of millions, and that doesn’t even cover not-so-Earth-like planets suitable for colonization by humans or the evolution of indigenous life. Throwing in considerations of space habitats in free space makes the calculation even murkier.

Galaxies are ungovernable

Again using Star Wars as an example, though, Count Dooku mentions the prospect of “ten thousand more systems” joining the Separatist cause in Attack of the Clones, and the opening crawl for the same film mentions “several thousand” systems having already joined. So just going by the films there seem to be at least several tens of thousands of solar systems in the Star Wars galaxy, in turn suggesting, in terms of our analysis here, a staggering seventh-order over-band to govern them. No wonder the Republic was so dysfunctional!

It actually gets even worse than that! The scale of the Star Wars galaxy has long been subject to vary depending on the writer, but The Essential Atlas provides the closest thing to a definitive estimate of the Republic’s figures: 50 million worlds with a total population of 100 quadrillion. Even an eighth-order over-band only gets us to 10 quadrillion, so this suggests the Republic has no less than nine levels of abstraction between the Senate leadership and the everyday citizens! Yikes.

At least in some takes of Star Wars in the expanded universe it’s implied that not only was the Republic dysfunctional the Empire didn’t function all that well either, being held together in large measure by Palpatine himself using the dark side of the force, the rest of the glue provided by the military, swollen from the exigencies of the Clone Wars, which operated more or less autonomously, efforts by the central leadership to establish order only truly effective in isolated pockets where they could focus their personal attention.

I could see a galactic-scale polity really being like this; indeed, it’s virtually inevitable in my view that it would be. Even on the scale of a single solar system the chain of command would be rather distended, and so you’d still see these characteristics. Indeed, the level of effectiveness we see from government in Star Wars for a whole galaxy may be typical of individual solar systems; it might turn out that a whole galaxy isn’t governable at all except in maybe the most nominal senses of the word.

Crypto-Anarchy: keeping the Human in the Equation

For all the talk about how technology extends and expands scale, particularly for the state, the human equation is inescapable, except by some superhuman being who has far more brainpower and is able to hold in its head far more interpersonal relationships than we can, reducing the layers of abstraction.

Such an entity might be able to effect a coup much like what God-Emperor Leto II managed in Dune, but imposing such a government upon the unwilling requires total surveillance to be effective, and as it turns out that is increasingly an impossibility.

Contrary to the mantra of the hard sci-fi worldbuilder that “there is no stealth in space”, it turns out stealth ships are probable; concepts already exist that can remain undetectable by any sensor technology permitted by the laws of physics at a range of two miles (!). Disappearing from view even in open space will be very easy in the future, and you can’t govern what you can’t see.

And ships and habitats won’t be the only thing rulers can’t see in the future; communications, too, will be hidden. Even now surveillance is slowly but inexorably becoming precluded by cryptography. The cypherpunks are winning. Encryption only advances with time, and the laws of physics dictate encryption is easier than decryption, suggesting that we will eventually cross a kind of historical event horizon, beyond which no encrypted messages will ever be decryptable by hostile parties again.

Might Technology contract Scale?

If anything in the future the maximum and average scales of governments and other organizations might actually contract markedly to their free-market size. Nomadism becomes very feasible in spacefaring civilization, and the very automation that on one hand makes governing larger domains more feasible also de-skills the industrial base, eventually permitting even a single person to roam through space and spawn the whole industrial technological base of civilization as he or she knows it using raw material from asteroids and comets.

The economic basis that drives the formation of large-scale societies may well collapse in the future, and in that case we can expect a reversion to the primordial pattern: band societies of 30-50 people, the Paleolithic with starships. Larger scales will likely still be needed for this or that project, but those will be loose and fluid associations. Even hunter-gatherers congregate in larger-scale groups occasionally, with the construction of Göbekli Tepe being perhaps the most famous such effort.

Three Poles of human Scale

So realistically, considerations of scale mean that science-fiction worlds, at least ones filled with humans, should range across a triangular spectrum with three poles: the first being the Paleolithic with starships, bands roaming the cosmos primeval, the odd space-age analogue or two of Göbekli Tepe the only representatives of what we think of as civilization; the second being the ungovernable galaxy, an empire of inconceivable vastness and dysfunction as local units and ordinary citizens slip through its fingers, but capable of great feats despite itself; and the third a profusion of more-or-less present-day sized polities of inconceivable number and diversity all vying for their little corner of the cosmos.

Any of these three scenarios is much more interesting than the usual science-fiction setup, which is much the same as our world with each planet representing a town or city, the issues with scaling up ignored completely. How boring. I expect worldbuilders, authors, and artists who read this blog to do better than that, and I hope after this post you will. So get out there and make those dreams that pepper your imagination come to life!

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