Emergence

by Steven Johnson

  There are manifest purposes to a city—reasons for being that its citizens are usually aware of: they come for the protection of the walled city, or the open trade of the marketplace. But cities have a latent purpose as well: to function as information storage and retrieval devices. Cities were creating user-friendly interfaces thousands of years before anyone even dreamed of digital computers. Cities bring minds together and put them into coherent slots. Cobblers gather near other cobblers, and button makers near other button makers. Ideas and goods flow readily within these clusters, leading to productive cross-pollination, ensuring that good ideas don’t die out in rural isolation. The power unleashed by this data storage is evident in the earliest large-scale human settlements, located on the Sumerian coast and in the Indus Valley, which date back to 3500 B.C. By some accounts, grain cultivation, the plow, the potter’s wheel, the sailboat, the draw loom, copper metallurgy, abstract mathematics, exact astronomical observation, the calendar—all of these inventions appeared within centuries of the original urban populations. It’s possible, even likely, that more isolated groups or individuals had stumbled upon some of those technologies at an earlier date, but they didn’t become part of the collective intelligence of civilization until there were cities to store and transmit them.

  The neighborhood system of the city functions as a kind of user interface for the same reason that traditional computer interfaces do: there are limits to how much information our brains can handle at any given time. We need visual interfaces on our desktop computers because the sheer quantity of information stored on our hard drives—not to mention on the Net itself—greatly exceeds the carrying capacity of the human mind. Cities are a solution to a comparable problem, both on the level of the collective and the individual. Cities store and transmit useful new ideas to the wider population, ensuring that powerful new technologies don’t disappear once they’ve been invented. But the self-organizing clusters of neighborhoods also serve to make cities more intelligible to the individuals who inhabit them—as we saw in the case of our time-traveling Florentine. The specialization of the city makes it smarter, more useful for its inhabitants. And the extraordinary thing again is that this learning emerges without anyone even being aware of it. Information management—subduing the complexity of a large-scale human settlement—is the latent purpose of a city, because when cities come into being, their inhabitants are driven by other motives, such as safety or trade. No one founds a city with the explicit intent of storing information more efficiently, or making its social organization more palatable for the limited bandwidth of the human mind. That data management only happens later, as a kind of collective afterthought: yet another macrobehavior that can’t be predicted from the micromotives. Cities may function like libraries and interfaces, but they are not built with that explicit aim.

  Indeed, traditional cities—like the ones that sprouted across Europe between the twelfth and fourteenth centuries—are rarely built with any aim at all: they just happen. There are exceptions of course: imperial cities, such as St. Petersburg or Washington, D.C., laid out by master planners in the image of the state. But organic cities—Florence or Istanbul or downtown Manhattan—are more an imprint of collective behavior than the work of master planners. They are the sum of thousands of local interactions: clustering, sharing, crowding, trading—all the disparate activities that coalesce into the totality of urban living.

  All of which raises the question of why—if they are so useful—cities took so long to emerge, and why history includes such long stretches of urban decline. Consider the state of Europe after the fall of the Roman Empire: for nearly a thousand years, European cities retreated back into castles and fortresses, or scattered their populations across the countryside. Imagine a time-lapse film of western Europe, as seen by a satellite, with each decade compressed down to a single second. Start the film at A.D. 100 and the continent is a hundred points of lights, humming with activity. Rome itself glows far brighter than anything else on the map, but the rest of the continent is dotted with thriving provincial capitals: Córdoba, Marseilles, even Paris is large enough to span the Left Bank. As the tape plays, though, the lights begin to dim: cities sacked by invading nomads from the East, or withered away by the declining trade lines of the Empire itself. The Parisians retreat back to their island fortress and remain there for five hundred years. When the Visigoths finally conquer Rome in 476, the satellite image suggests that the power grid of Europe has lost its primary generator: all the lights fade dramatically, and some go out altogether. The system of Europe shifts from a network of cities and towns to a scattered, unstable mix of hamlets and migrants, with the largest towns holding no more than a thousand inhabitants. It stays that way for five hundred years.

  And then, suddenly, just after the turn of the millennium, the picture changes dramatically: the continent sprouts dozens of sizable towns, with populations in the tens of thousands. There are pockets on the map—at Venice or Trieste—that glow almost as brightly as ancient Rome had at the start of the tape, nascent cities supporting more than a hundred thousand citizens. The effect is not unlike watching a time-lapse film of an open field, lying dormant through the winter months, then in one sudden shift bursting with wildflowers. There is nothing gradual or linear about the change; it is as sudden, and as emphatic, as turning on a light switch. As the physicist Arthur Iberall once described the process, Europe underwent a transition not unlike that between H2O molecules changing from the fluid state of water to the crystallized state of ice: for centuries the population is liquid and unsettled—and then, suddenly, a network of towns comes into existence, possessing a stable structure that would persist more or less intact until the next great transformation in the nineteenth century, during the rise of the industrial metropolis.

  How can that sudden takeoff be explained? Cities aren’t ideas that spread, viruslike, through larger populations; the town system of the Middle Ages didn’t reproduce by spores, the way the city-states of ancient Greece did. And of course, Europe was no longer united by an empire, so there was no command center to decree that a hundred cities should be built in the span of two centuries. How then can we account for the strikingly coordinated urban blossoming of the Middle Ages?

  Start by taking the analogies literally. Why does a field of wildflowers suddenly bloom in the spring? Why does water turn to ice? Both systems undergo “phase transitions”—changing from one defined state to another at a critical juncture—in response to changing levels of energy flowing through them. Leave a kettle of water sitting at room temperature in your kitchen, and it will retain its liquid form for weeks. But increase the flow of energy through the kettle by putting it on a hot stove, and within minutes you’ll induce a phase transition in the water, transforming it into a gas. Take a field of tall meadow buttercups accustomed to nightly frost and ten hours of sun, then raise the temperature thirty degrees and add four hours of sunlight. After a month or two, your field will be golden yellow with buttercups. A linear increase in energy can produce a nonlinear change in the system that conducts that energy, a change that would be difficult to predict in advance—assuming, that is, you’d never seen a flowering plant before, or a steam room.

  The urban explosion of the Middle Ages is an example of the same phenomenon. We saw before that the idea of building cities didn’t spread through Europe via word of mouth, but what did spread through Europe, starting around A.D. 1000, were a series of technological advances that combined to produce a dramatic change in the human capacity for harnessing energy flows. As the historian Lynn White Jr. writes, “These innovations … consolidated to form a remarkably efficient new way of exploiting the soil.” First, the heavy wheeled plow, which tapped the muscular energy of domesticated animals, arrived with the German invaders, then swept through the river valleys north of the Loire; at roughly the same time, European farmers adopted triennial field rotation, which increased land productivity by at least a third. Capturing more energy from the soil meant that
larger population densities could be maintained. As larger towns began to form, another soil-based technology became commonplace, one that was even more environmentally friendly: recycling the waste products generated by town residents in the form of crop fertilizer. As Mumford writes, “Wooded areas in Germany, a wilderness in the ninth century, gave way to plowland; the boggy Low Countries, which had supported only a handful of hardy fishermen, were transformed into one of the most productive soils in Europe.” The result is a positive feedback loop: the plow and the crop rotation makes better soil, which supplies enough energy to sustain towns, which generate enough fertilizer to make better soil, which generates enough energy to sustain even larger towns.

  We sometimes talk about emergent systems “bootstrapping” themselves into existence, but in the case of the Middle Ages, we can safely say that the early village residents shat themselves into full-fledged towns. But those residents aren’t setting out to build bigger settlements; they’re all solving local problems, such as how to make their fields more productive, or what to do with all the human waste of a busy town. And yet those local decisions combine to form the macrobehavior of the urban explosion. “This acceleration in urban development,” writes philosopher-historian Manuel De Landa, “would not be matched for another five hundred years, when a new intensification of the flow of energy—this time arising from the exploitation of fossil fuels—propelled another great spurt of city birth and growth in the 1800s.” And with that new flow of energy, new kinds of cities emerged: the factory towns of Manchester and Leeds, and the great metropolitan superorganisms of London, Paris, and New York.

  *

  We are, by all accounts, in the midst of another technological revolution—an information age, a time of near-infinite connectedness. If information storage and retrieval was the latent purpose of the urban explosion of the Middle Ages, it is the manifest purpose of the digital revolution. All of which raises the question, is the Web learning as well? If cities can generate emergent intelligence, a macrobehavior spawned by a million micromotives, what higher-level form is currently taking shape among the routers and fiber-optic lines of the Internet?

  I first started thinking about this question a few years ago, during the promotional tour for my last book, Interface Culture. As it happened, my book’s publisher also specialized in “contemporary spiritual” titles, and so the in-house publicist sent galleys of what I thought was a decidedly un–New Agey book to every New Age radio station, print zine, and ashram in the country. What’s more, some of them ended up taking the bait, and so the tour assumed a slightly schizophrenic air: NPR in the morning, followed by a Q&A with alternative magazines like San Francisco’s Magical Blend in the afternoon.

  The questions from the Harmonic Convergence set turned out to be as consistently smart and forward-thinking and technologically adept as any I’d encountered on the rest of the tour. The New Agers were sensitive to the nuances of my argument, and refreshingly indifferent to the latest IPO pricing. (Contrast that with the TV reporters, who seemed incapable of asking me anything other than “What’s your take on Yahoo’s market cap?”) But just when I’d start kicking myself for embarking on the interview with such prejudice, my interlocutors would roll out a Final Question. “You’ve written a great deal about the Web and its influence on modern society,” they’d say. “Do you think, in the long term, that the rise of the Web is leading towards a single, global, holistic consciousness that will unite us all in godhead?” I’d find myself stammering into the microphone, looking for exit signs.

  It’s a question with only one responsible answer: “I’m not qualified to answer that.” And each time I said this, I thought to myself that something was fundamentally flawed about the concept, something close to a category mistake. For there to be a single, global consciousness, the Web itself would have to be getting smarter, and the Web wasn’t a single, unified thing—it was just a vast sum of interlinked data. You could debate whether the Web was making us smarter, but that the Web itself might be slouching toward consciousness seemed ludicrous.

  But as the years passed, I found that the question kept bouncing around in my head, and slowly I started to warm up to it, in a roundabout way. Some critics, such as Robert Wright, talk about a “global brain” uniting all the world’s disparate pools of information, while other visionaries—such as Bill Joy and Ray Kurzweil—believe that the computational powers of digital technology are accelerating at such a rate that large networks of computers may actually become self-aware sometime in the next century.

  Did Arthur C. Clarke and The Matrix have it right all along? Is the Web itself becoming a giant brain? I still think the answer is no. But now I think it’s worth asking why not.

  *

  Begin by jettisoning two habitual ways of thinking about what a brain is. First, forget about gray matter and synapses. When someone like Wright says “giant brain,” he means a device for processing and storing information, like the clustered neighborhoods of Florence. Second, accept the premise that brains can be a collective enterprise. Being individual organisms ourselves, we’re inclined to think of brains as discrete things, possessed by individual organisms. But both categories turn out to be little more than useful fictions. As we’ve seen, ants do their “learning” at the colony level—growing less aggressive with age, or rerouting a food assembly line around a disturbance—while the individual ants remain blissfully ignorant of the larger project. The “colony brain” is the sum of thousands and thousands of simple decisions executed by individual ants. The individual ants don’t have anything like a personality, but the colonies do.

  Replace ants with neurons, and pheromones with neurotransmitters, and you might just as well be talking about the human brain. So if neurons can swarm their way into sentient brains, is it so inconceivable that the process might ratchet itself up one more level? Couldn’t individual brains connect with one another, this time via the digital language of the Web, and form something greater than the sum of their parts—what the trendy philosopher/priest Teilhard de Chardin called the noosphere? Wright’s not exactly convinced that the answer is yes, but he’s willing to go on the record that the question is, as he puts it, “noncrazy”:

  Today’s talk of a giant global brain is cheap. But there’s a difference. These days, most people who talk this way are speaking loosely. Tim Berners-Lee, who invented the World Wide Web, has noted parallels between the Web and the structure of the brain, but he insists that “global brain” is mere metaphor. Teilhard de Chardin, in contrast, seems to have been speaking literally: humankind was coming to constitute an actual brain—like the one in your head, except bigger. Certainly there are more people today than in Teilhard’s day who take the idea of a global brain literally Are they crazy? Was Teilhard crazy? Not as crazy as you might think.

  Part of Wright’s evidence here is that Homo sapiens brains already have a long history of forming higher-level intelligence. Individual human minds have coalesced into “group brains” many times in modern history, most powerfully in the communal gatherings of cities. In Wright’s view, the city functions as a kind of smaller-scale trial run for the Web’s worldwide extravaganza, like an Andrew Lloyd Webber musical that gets the kinks out in Toronto before opening on Broadway. As in the urban explosion of the Middle Ages, a city is not just an accidental offshoot of growing population density—it’s a kind of technological breakthrough in its own right. Sustainable city life ranks high on the list of modern inventions—as world-transforming as the alphabet (which it helped engender) or the Internet (which may well be its undoing). It’s no coincidence that the great majority of the last millennium’s inventions blossomed in urban settings. Like the folders and file directories of some oversize hard drive, the group brain of city life endowed information with far more structure and durability than it had previously possessed. Wright’s position is that the Web looks to be the digital heir to that proud tradition, uniting the world’s intellects in a way that would have astonished
the early networkers of Florence or Amsterdam. Macrointelligence emerged out of the bottom-up organization of city life, he argues, and it will do the same on the Web.

  I’m obviously sympathetic to Wright’s argument, but I think it needs clarifying. Emergence isn’t some mystical force that comes into being when agents collaborate; as in the freeways vs. sidewalks debate, there are environments that facilitate higher-level intelligence, and environments that suppress it. To the extent that the Web has connected more sentient beings together than any technology before it, you can see it as a kind of global brain. But both brains and cities do more than just connect, because intelligence requires both connectedness and organization. Plenty of decentralized systems in the real world spontaneously generate structure as they increase in size: cities organize into neighborhoods or satellites; the neural connections of our brains develop extraordinarily specialized regions. Has the Web followed a comparable path of development over the past few years? Is the Web becoming more organized as it grows?

  You need only take a quick look at the NASDAQ most active list to see that the answer is an unequivocal no. The portals and the search engines exist in the first place because the Web is a tremendously disorganized space, a system where the disorder grows right alongside the overall volume. Yahoo and Google function, in a way, as man-made antidotes to the Web’s natural chaos—an engineered attempt to restore structure to a system that is incapable of generating structure on its own. This is the oft-noted paradox of the Web: the more information that flows into its reservoirs, the harder it becomes to find any single piece of information in that sea.

  Imagine the universe of HTML documents as a kind of city spread out across a vast landscape, with each document representing a building in that space. The Web’s city would be more anarchic than any real-world city on the planet—no patches of related shops and businesses; no meatpacking or theater districts; no bohemian communities or upscale brownstones; not even the much-lamented “edge city” clusters of Los Angeles or Tyson’s Corner. The Web’s city would simply be an undifferentiated mass of data growing more confusing with each new “building” that’s erected—so confusing, in fact, that the mapmakers (the Yahoos and Googles of the world) would generate almost as much interest as the city itself.