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Jane Jacob's "The Death and Life of Great American Cities"

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Urban planning theorist Jane Jacobs comes from a long line of deductive thinkers that can be traced back to empiricists like Thomas Hobbes and John Locke. In “The Death and Life of Great American Cities” she endeavors to apply such methods of inquiry to the modern American city. Just as Locke argued that the mind is a “tabula rasa,” Jacobs contends that most components of the urban landscape are not inherently badly or well designed; rather, the success or failure of such components — sidewalks, parks, blocks, neighborhoods — depends entirely on the surrounding environment in which they are deployed.

Setting herself in opposition to an entire history of city planning that includes preeminent figures like Ebenezer Howard, Le Corbusier, and Daniel Burnham, Jacobs argues that overarching principles and master plans cannot possibly allow for the formation of successful, effective cities.

Indeed, to call Jacobs a theorist is perhaps a misnomer, for what she proposes in “The Death and Life of Great American Cities” is no less than the radical idea that any theories based on lofty notions of what the American city “should be” must necessarily fail once they are applied to real-world situations. (In a later book, Jacobs similarly denounces the entire concept of ideology as overly hypothetical and detrimental to solving real problems on both the individual and societal scale.)

Instead, Jacobs prescribes a far simpler method of urban planning: study the every intricacy of real cities to determine what works and what doesn’t, and use that information in future plans. Thus, Jacobs could more accurately be characterized as an anti-theorist essentially applying the concept of realpolitik to American cities.

It is in this call for practical urban policies that Jacobs’ book most directly addresses topics we have studied in Emergence. Consider the following passage: “In city after city, precisely the wrong areas, in the light of planning theory, are decaying. Less noticed, but equally significant, in city after city the wrong areas, in the light of planning theory, are refusing to decay.” Clearly, city planners have a big problem on their hands: they have no way of predicting, from the initial plan of a city, which areas will thrive and which will fail.

From this passage, we can easily see the parallels between Jacobs’ description of the city and John Conway’s Game of Life: just as it is often impossible to predict the future state of the Game of Life, it is equally difficult, using conventional planning theory, to predict how various areas of cities will fare. And although in the city there is a smooth continuum between “dead” and “alive,” the two-state world of the Game of Life nonetheless maps reasonably well onto the admittedly more complex but essentially identical world of the city.

Such similarities are made more profound by the fact that “The Death and Life of Great American Cities” was first published in 1961, while Conway did not devise his game until 1970. If only Jacobs had had at her disposal the language of the Game of Life and other two-dimensional cellular automata when she wrote her book!

It is worthwhile to explore this analogy in more depth. In the Game of Life, the rules are simple: live cells with fewer than two or more than three live neighbors die; dead cells with exactly three live neighbors come to life. In the city, there are far more rules, but the individual rules are not much more complicated than in Conway’s game.

Consider, for example, the rules governing sidewalks. According to Jacobs, sidewalks have three primary functions: safety, human contact, and assimilating children. Jacobs then further breaks down each of these functions. A safe sidewalk must have a clear demarcation between public and private space, it must be under the watchful gaze of stay-at-home residents and business owners (the street’s “natural proprietors”), and it must lastly be in such a location that it enjoys fairly continuous usage.

A sidewalk that fulfills its duty as provider of human contact must have a public life that is based on mutual trust between residents. Sidewalk interactions must strike a balance between personal privacy and desire for socialization; people must be friendly enough that they will converse if they meet each other on the street, but not so friendly that they invite each other inside, thus shifting interactions from the public to the private sphere. (Jacobs uses this balance to criticize suburbs, in which, she contends, families often have a few friendly neighbors with whom they associate, while they have no interactions with any other neighbors. Such neighborhoods may have vibrant private life, but no public life whatsoever.)

Lastly, in order for a sidewalk to assimilate children, it must be sufficiently wide to keep those children out of public parks and playgrounds, which are statistically far more unsafe than most relatively well-traveled streets. Jacobs argues that such sidewalks promote mixed usage, which in turn promotes social interaction and public vitality.

Such specific and comprehensive observations are fascinating but essentially unrelated to Emergence. What is important is the way Jacobs goes about her work: taking complex phenomena and breaking them down into simple rules. Observing the city as a whole, we may be tempted to conclude that it is made up of nothing more than large-scale randomness, but Jacobs establishes beyond a doubt that such apparent randomness is really the work of simple interactions between agents.

In short, the stuff of “The Death and Life of Great American Cities” is the stuff of Emergence: the ways in which simple interactions among simple things can create a complex kind of order that is unanticipated by any architect or designer. (Now we can use the terms “architect” and “designer” literally.) Like Stephen Wolfram did for cellular automata in “A New Kind of Science,” Jacobs argues that the only way city planners can truly understand cities is by studying them first-hand. Concocting grandiose schemes that fail to take human behavior and human needs into account will not, and cannot, do.


Jane Jacobs. “The Death and Life of Great American Cities.” 1961.

Stephen Wolfram. “A New Kind of Science.” 2002. Available online at

Related sources of interest:

J.G. Ballard. “High Rise.” 1975. A terrifying deconstruction of the modern high-rise apartment building.