*
An important distinction must be drawn between ant colonies and cities, though, and it revolves around the question of volition. In a harvester ant colony, the individual ants are relatively stupid, following elemental laws without anything resembling free will. As we have seen, the intelligence of the colony actually relies on the stupidity of its component parts: an ant that suddenly started to make conscious decisions about, say, the number of ants on midden duty would be disastrous for the overall group. You can make the case that this scenario doesn’t apply at all to human settlements: cities are higher-level organisms, but their component parts—humans—are far more intelligent, and more self-reflective, than ants are. We consciously make decisions about where to live or shop or stroll; we’re not simply driven by genes and pheromones. And so the social patterns we form tend to be substantially more complex than those of the ant world.
Even Gordon herself is sympathetic to the objection. “In a human society, every person always thinks they know what they’re doing, even if they’re wrong,” she says to me near the end of my visit. “It’s very hard to imagine any human society in which people would go around responding to what happened at the moment without any conception of why they’re doing what they’re doing. That’s why I’m always hesitant to make analogies from ants to people, because ants are so unlike people. In fact I think it’s the alienness of ants that makes them so intriguing.”
Gordon’s caveats are important, and as we have already seen, cities involve countless elements that are the exact opposites of those bottom-up systems. (Even SimCity has a mayor!) But the fact that humans think for themselves, and the fact that city organization relies on both hierarchies and heterarchies, does not mean that Wordsworth’s “anthill on the plain” belongs purely to the world of metaphor. Certain key elements of traditional urban life—indeed, some of the elements that we most cherish about our cities—belong squarely to the world of emergence. What ants do and what cells do and what sidewalks do should be seen as instances of the same idea, the same activity built out of varied material, like a musical score played by different instruments. But to see beyond the objections of individual human volition, we need to think about cities on the right scale. The emphasis on free will only matters on the scale of the individual human life. We need to think about cities the way Gordon thought about ant colonies—on the scale of the superorganism itself.
The decision-making of an ant exists on a minute-by-minute scale: counting foragers, following pheromone gradients. The sum of all those isolated decisions creates the far longer lifetime of the colony, but the ants themselves are utterly ignorant of that macrolevel. Human behavior works at two comparable scales: our day-to-day survival, which involves assessments of the next thirty or forty years at best; and the millennial scale of cities and other economic ecosystems. Driving a car has short-term and long-term consequences. The short term influences whether we make it to soccer practice on time; the long term alters the shape of the city itself. We interact directly with, take account of—and would seem to control—the former. We are woefully unaware of the latter. Our decisions to shop at a local boutique or move from one neighborhood to another or even leave the city altogether are all made on the scale of the human lifetime—and usually a much shorter time frame than that. Those decisions we make consciously, but they also contribute to a macrodevelopment that we have almost no way of comprehending, despite our advanced forebrains. And that macrodevelopment belongs to the organism of the city itself, which grows and evolves and learns over a thousand-year cycle, as dozens of human generations come and go.
Viewed at that speed—the millennium’s time-lapse footage—our individual volition doesn’t seem all that different from that of Gordon’s harvester ants, each of whom only lives to see a small fraction of the colony’s fifteen-year existence. Those of us who walk the sidewalks of today’s cities remain as ignorant of the long-term view, the thousand-year scale of the metropolis, as the ants are of the colony’s life. Perceived at that scale, the success of the urban superorganism might well be the single most momentous global event of the past few centuries: until the modern era less than 3 percent of the world’s population lived in communities of more than five thousand people; today, half the planet lives in urban environments. Just as the social insects deserve to be seen as some of the planet’s most successful organisms, so too should the superorganism of the city; not necessarily because cities are more humane or civilized places, but because they have done such a good job of replicating themselves, drawing in migrant populations from around the world, and encouraging—for the most part—higher birth rates and longer life spans within their confines. You can debate the merits of the transformation, but the fact is that human life on earth now unfolds in cities more often than not. Quantitatively, we are a species of city dwellers now.
Why has the city superorganism triumphed over other social forms? As in the case of the social insects, there are a number of factors, but a crucial one is that cities, like ant colonies, possess a kind of emergent intelligence: an ability to store and retrieve information, to recognize and respond to patterns in human behavior. We contribute to that emergent intelligence, but it is almost impossible for us to perceive that contribution, because our lives unfold on the wrong scale. The next chapter is an attempt to see our way around that blind spot.
3
The Pattern Match
In the final decades of the twelfth century, the Societas Mercatorum, the organization of merchants that had presided over the commercial culture of Florence for nearly a hundred years, began to break apart into splinter groups: guilds with names like the Arte di Por Santa Maria and the Arte di Calimala, structured around specific trades—blacksmiths, moneylenders, wine merchants. A few guilds incorporated diverse groups under one umbrella. One such guild, the Arte di Por Santa Maria, included both silk weavers and goldsmiths.
The creation of the guild system, by all accounts, proved to be a reorganization that literally changed the world. Historians like to talk up the aesthetic accomplishments of the Renaissance, but the guild system pioneered in Florence had as much of an impact on Western civilization as anything dreamed up by da Vinci or Brunelleschi. The gold florin, the local coin minted by the Florentine guilds, was for a long stretch the standard currency of Europe, and one of the first since Roman days to be honored so widely. A number of inventions that turned out to be essential to modern commercial life—double-entry accounting, to name one—date back to the golden age of the guilds. If the engine of history restarted in Italy during the twelfth and thirteenth centuries, as the canonical story goes, the guilds were its turbines.
The guild of Por Santa Maria took its name from a central street that leads directly to the ancient Ponte Vecchio, the much-photographed bridge spanning the River Arno, overloaded with shops and a secret corridor built for the Florentine duke Cosimo I in 1565. There are records of silk weavers setting up shop along the Por Santa Maria as early as 1100, a century before joining forces with the goldsmiths to form their own guild. Merchants who were in the silk trade and other wealthy Florentines could stroll down to the Por Santa Maria comparison shopping, while their servants combed the Ponte Vecchio for the meat sold by the butchers who populated the bridge for the first centuries of the millennium.
They are still there today. Walk north of the Ponte Vecchio on a weekday morning, and you’ll still find stores selling fine silks, some of them hawking processed items such as blouses and scarves, others selling the raw goods directly, as they did nearly a millennium ago.
Do cities learn? Not the individuals who populate cities, not the institutions they foster, but the cities themselves. I think the answer is yes. And the silk weavers of Florence can help explain why.
*
Learning is one of those activities that we habitually associate with conscious awareness—such as falling in love or mourning the loss of a relative. But learning is a complicated phenomenon that exists on a number of
levels simultaneously. When we say we “learn someone’s face,” there’s a strong implication of consciousness in the statement—you feel something different when you see someone you know, and that feeling of recognition is part of what it means to learn, so much so that it can sometimes seem interchangeable with the experience itself.
But learning is not always contingent on consciousness. Our immune systems learn throughout our lifetimes, building vocabularies of antibodies that evolve in response to the threat posed by invading microorganisms. Most of us have developed immunity to the varicella-zoster virus—also known as the chicken pox—based on our exposure to it early in childhood. That immunity is a learning process: the antibodies of our immune system learn to neutralize the antigens of the virus, and they remember those neutralization strategies for the rest of our lives. We don’t come into the world predisposed to ward off the chicken pox virus—our bodies learn how to do it on the fly, without any specific training. Those antibodies function as a “recognition system,” in Gerald Edelman’s phrase, successfully attacking the virus and storing the information about it, then recalling that information the next time the virus comes across the radar.
Like a six-month-old infant, the immune system first learns to recognize things that differ from itself, then sets out to control those things. It is only part of the wonder of this process that it works as well as it does. What’s equally amazing is the fact that the recognition unfolds purely on a cellular level: we are not aware of the varicella-zoster virus in any sense of the word, and while our minds may remember what it was like to have chicken pox as a child, our conscious memory has nothing to do with our resistance to the disease.
The body learns without consciousness, and so do cities, because learning is not just about being aware of information; it’s also about storing information and knowing where to find it. It’s about being able to recognize and respond to changing patterns—the way Oliver Selfridge’s Pandemonium software does or Deborah Gordon’s harvester ants. It’s about altering a system’s behavior in response to those patterns in ways that make the system more successful at whatever goal it’s pursuing. The system need not be conscious to be capable of that kind of learning, just as your immune system need not be conscious to learn how to protect you from the chicken pox.
Imagine a contemporary citizen of Florence who time-travels back eight hundred years, to the golden age of the guilds. What would that experience—the “shock of the old”—be like? Most of it would be utterly baffling: few of modern Florence’s landmarks would exist—the Uffizi, say, or the church of San Lorenzo. Only the baptistery of the Duomo would be recognizable, as would the ancient city hall, the Bargello. The broad outline of most streets would look familiar, but in many cases their names would have changed, and our time traveler would find almost nothing recognizable in the buildings lining those streets. The cultural life of the city would be even more disconcerting: the systems of trade and governance would look nothing like those of present-day Florence. Our time traveler might catch some familiar words in the spoken tongue, since the Italian language is a product of Florentine culture, dating back to the turn of the millennium. But if he traveled anywhere else in Italy, he would face serious linguistic hurdles—until the late thirteenth century, Latin was the only language common to all Italians.
And yet, despite that abject confusion, one extraordinary thing remains constant: our time traveler would still know where to buy a yard of silk. Fast-forward a few hundred years, and he’d know where to pick up a gold bracelet as well. And where to buy leather gloves, or borrow money. He wouldn’t be equipped to buy any of these things, or even to communicate intelligibly to the salesmen—but he’d know where to find the goods all the same.
Like any emergent system, a city is a pattern in time. Dozens of generations come and go, conquerors rise and fall, the printing press appears, then the steam engine, then radio, television, the Web—and beneath all that turbulence, a pattern retains its shape: silk weavers clustered along Florence’s Por Santa Maria, the Venetian glassblowers on Murano, the Parisian traders gathered in Les Halles. The world convulses, sheds its skin a thousand times, and yet the silk weavers stay in place. We have a tendency to relegate these cross-generational patterns to the ossified nostalgia of “tradition,” admiring for purely sentimental reasons the blacksmith who works in the same shop as his late-medieval predecessors. But that continuity has much more than sentimental value, and indeed it is more of an achievement than we might initially think. That pattern in time is one of the small miracles of emergence.
Why do cities keep their shapes? Certain elements of urban life get passed on from generation to generation because they’re associated with a physical structure that has its own durability. (Cathedrals and universities are the best examples of this phenomenon—St. Peter’s Basilica has fostered a religious-themed neighborhood west of the Tiber for a thousand years, and the Left Bank has been a hotbed of student types since the Sorbonne was founded in 1257.) But because those neighborhoods are anchored by specific structures, their persistence has as much to do with the laws of physics as anything else: as long as the cathedral doesn’t burn down or disintegrate, there’s likely to be a religious flavor to the streets around it. But the Florentine silk weavers are a different matter. There’s nothing in the physical structure of the shops that mandates that they be occupied by silk weavers. (Indeed, many of the buildings along the Por Santa Maria have been rebuilt several times over the past thousand years.) They could just as easily house bankers or wine merchants or countless other craftsmen. And yet the silk weavers remain, held in place by the laws of emergence, by the city’s gift for self-organization.
You could argue that the silk weavers stay put not because they are part of an emergent system, but because they are subject to the laws of inertia. They remain clustered along the Por Santa Maria because staying put is easier than moving. (In other words, it’s not emergence we’re seeing here—it’s laziness.) The objection might make some sense if we were talking about a fifty-year span, or even a century. But on a thousand-year scale, the force of cultural drift becomes far more powerful. Technological and geopolitical changes obviously have a tremendous impact—killing off entire industries, triggering mass migrations, launching wars, or precipitating epidemics. Neighborhood clusters are extremely vulnerable to those dramatic forces of change, but they are also vulnerable to the slower, mostly invisible drift that all culture undergoes. Over twenty or thirty generations, even something as fundamental as the name of a common item can be transformed beyond recognition, and the steady but imperceptible shifts in pronunciation can make a spoken language unintelligible to listeners. However difficult it is to read Chaucer’s Canterbury Tales in the original, it would be even more disorienting to hear it read aloud by an inhabitant of fourteenth-century Britain. And if words can transform themselves over time, the changes in social mores, etiquette, and fashion are so profound as to be almost unimaginable. (Parsing the complex sexual codes of thirteenth-century Florence from a modern perspective would be a daunting task indeed.) Viewed on the scale of the millennium, the values of Florentine society look more like a hurricane than a stable social order: all turbulence and change. And yet against all those disruptive forces, the silk weavers hold their own.
Cities are blessed with an opposing force that keeps the drift and tumult of history at bay: a kind of self-organizing stickiness that allows the silk weavers to stay huddled together along the same road for a thousand years, while the rest of the world reinvents itself again and again. These clusters are like magnets planted in the city’s fabric, keeping like minds together, even as the forces of history try to break them apart. They are not limited to Italian cities, though Florence’s clusters are some of the most ancient. Think of London’s Savile Row or Fleet Street, clusters that date back hundreds of years. In Beijing, street names still echo the pockets of related businesses: Silk-Brocade Hat Alley, Dry-Noodle Street. In Manhattan today you can see the ear
ly stirrings of clusters, some of them only a few decades old: the diamond row of West Forty-seventh Street, the button district, even a block downtown devoted solely to restaurant supply stores. The jewelry merchants on West Forty-seventh don’t have quite the pedigree of their colleagues on the Ponte Vecchio, but then New York is a young city by Italian standards. Look at those Manhattan streets from the thousand-year view, the scale of the superorganism, and what comes to mind is an embryo self-organizing into recognizable shapes, forming patterns that will last a lifetime.
*
“From its origins onward,” Lewis Mumford writes in his classic work The City in History, “the city may be described as a structure specially equipped to store and transmit the goods of civilization.” Preeminent among the “goods” stored and transmitted by the city is the invaluable material of information: current prices in the marketplace; laborsaving devices dreamed up by craftsmen; new remedies for disease. This knack for capturing information, and for bringing related pockets of information together, defines how cities learn. Like-minded businesses cluster together because there are financial incentives to do so—what academics call economies of agglomeration—enabling craftsmen to share techniques and services that they wouldn’t necessarily be able to enjoy on their own. That clustering becomes a self-perpetuating cycle: potential consumers and employees have an easier time finding the goods and jobs they’re looking for; the shared information makes the clustered businesses more competitive than the isolated ones.
Emergence Page 9
