As a simple way of thinking about how people live you could start with a divisible equation;
The numerator is the sum of many different inputs (homes, jobs, activities, hotels, and so on) adding up to just one catch-all expression—people.
For the denominator, there’s a much simpler expression—land.
People divided by land. You can categorize all patterns of human settlement through the output of that equation. What we call “rural” is when you have a small number of people living across a lot of land. What we call “urban” is when you have a large number of people living in a small land.
There are a lot of qualitative and quantitative ways to take the measure of a city, but they all distill to that same formula. What makes a skyline? What makes a transportation crossroads? What makes an audience for major league sports, or art museums, or theaters, or news organizations? Density of people is what gives definition to the word urban and all its derivatives and associations.
Simple models like this don’t help us answer detailed technical questions of policy, but they are useful because they provide a foundation for our thinking. Abstraction can help us step back from the blinders of local context and provide clarity to the underlying forces at play.
When it comes to contemporary urban issues, there is typically much greater focus on the top half of the equation, the people side. This makes a lot of intuitive sense, it’s the presence and density of people that makes a city. Moreover, people can speak for themselves and in defense of their own interests. When we talk about housing, we talk in terms of rents and prices as experienced by consumers. When we talk about transportation, we talk in terms of commute time and individual access as experienced by travelers. Our understanding of a city and the language we use to argue over it is deeply personal.
But the urban equation consists of two components that operate upon each other. Without also thinking about land, and specifically the scarcity of it in cities, we cannot properly understand how urban areas function. Land does not stand up in public meetings and advocate for itself. It is up to us to intuit it and understand how it operates upon the actions of people. It is the mediating influence of land that gives coherence to the tendency in study and advocacy that we commonly call “urbanism.”
A Very Simple Model Of Urban And Rural Economics
Urban areas sit at one end of a continuum of human density whose other sections are not clearly demarcated and yet are constantly subjects for discussion. It may not always be clear when a landscape has shifted from urban to suburban or suburban to rural, but it is clear that such landscapes exist. Moreover, underlying each landscape is a kind of economic logic and social justification that has enormous influence on the people who occupy it and the activities they undertake there.
In a society shaped by a market economy, focusing on the economic structures that sustain these different landscapes is especially essential to understand them and their relationship to one another. This is one of the oldest lines of inquiry in geography. The primary variable is one outcome of the same equation; how much people value (i.e. the cost of) land. In urban areas, where demand is high and supply is low, land is typically expensive. In rural areas, where demand is low and supply is high, land is typically cheap.
Crucially, it is the actions of other people that makes one piece of land more valuable than another for the purposes of human settlement. Some major cities were founded at places of obvious strategic or economic significance (such as Istanbul or New York) and derive significant wealth from this positioning. Others (most famously planned capitals like Madrid or Washington DC) were founded for highly contingent or even arbitrary reasons. In either case, but especially obviously for the latter group, what made these points into major urban centers was human activity. There are profound strategic, economic, and social advantages to simply living and working in a place where other people are already living and working.
Economic logic shifts across the urban to rural continuum. The way to increase the wealth of urban areas is to increase the productivity of their people. The fundamental attribute of a market economy through people become more productive is the division of labor. In cities, it is to every person’s advantage to focus on developing the skills for which they have a comparative advantage, knowing that they can use the surplus of their own labor to purchase products made by the labor of others. Population growth compounds this advantage, because new people bring with them additional human and financial capital. Education and innovation flourish when people with different talents and resources occupy the same constrained land, such that they invariably encounter, teach, inspire, and support one another. When city economies become undiversified, they can stagnate and eventually collapse.
The way to increase the wealth of rural areas is to increase the productivity of land. The fundamental attribute of a market economy through which land becomes more productive is private property. In rural areas, by apportioning land to private interests, individuals have an incentive to cultivate or exploit their own property to the fullest, knowing that if they do not it will go unused and they will reap no benefit. This does not necessarily mean recruiting an ever-increasing amount of labor, and especially not on a permanent basis. Natural resources may remain limited or otherwise not especially elastic depending on the population available to work them. But embarking upon a large-scale effort to collectivize agriculture is the surest way to demolish the productivity of land and create a famine.
The dynamic synthesis of a market economy comes from bringing both urban and rural systems together through trade, so that both can gain from the efficiency of the other. Cities require food and raw materials from rural areas. Rural areas require finished goods and innovations from cities. It is rare to find a big city that does not pull from a rich hinterland, nor is it common to find a productive rural area that lacks an central hub. Urban and rural economies are unsteady in isolation but wealth-building machines in tandem.
A Very Simple Model Of SubUrban Economics
In between urban areas and rural areas are suburbs.
Suburbs can be difficult to define directly because they sit at neither end of the density continuum. Often they are more considered in terms of what they are not. They have fewer people than urban areas and less commonly possess major nodes of human activity. But they have less land than rural areas and rarely host any kind of cultivation or exploitation of natural resources. Instead, they attempt to bring together in one landscape the best elements of both. Often they succeed at achieving neither.
The essential logic of the suburb is to have it both ways; proximity to a diversity of labor and yet ample private property. A verdant backyard and a pool on one hand, and a 20 minute commute into downtown on the other. Yet in seeking to offer the best of urban and rural environments, suburbanism becomes reliant on both without offering its own distinct economic advantages in return. And because the suburban model cannot guarantee an equal ratio of people to land indefinitely, suburban landscapes ultimately must set up a choice between dissolution on one hand, or harmful social outcomes on the other.
When an urban area densifies, it draws in people and spins off knowledge to surrounding rural places. When a rural area develops new methods of extraction, it pours resources into adjacent urban nodes. But suburban areas cannot become more of themselves without becoming something different. The very fact of increased demand to live in suburbs presents a profound crisis for suburbs. If they add more people to existing land they become more urban. If they dilute people across more land, they become more rural.
There are only two ways suburban landscapes can perpetuate themselves. One approach is to sprawl, in essence rejecting the idea that the supply of land is limited and matching new people with new acreage. But sprawl is self-defeating because it is not self-sustaining. The first rule of real estate is that location matters. The value of suburban landscapes is not intrinsic, it comes from their proximity to both urban and rural landscapes. Sprawl pushes one or the other further away. There is only so much land close to city centers and only so many people willing to tolerate certain distances of remove. When the willingness of people to accept increasingly distant plots of land runs out, the logic of suburbanism founders. To fit people into land more efficiently can’t be done by creating more suburban landscapes.
So then the second approach for suburban landscapes is to reject the other end of the equation and deny the idea that all people who want to can live in suburbs. In other words, if a suburban landscape cannot urbanize or sprawl, it’s only remaining choice is to embrace efficiency’s opposite—exclusion.
Coherent Thinking About People And Land
This is not to say that every extant place that codes as “suburban” is by default exclusionary.
Rather, the exclusionary error is to think of these landscapes as permanent, especially when posed against the alternative of growth. However populated with residents, employees, or passers-through a given area is today, there is usually no physical reason why tomorrow it might not be significantly different, should circumstances change. A specific town or neighborhood might see increases in demand from people based on broader factors. However much the residents of a place might like it, however aesthetically pleasing the housing stock, however quaint the shops, however placid the streets; it is a deliberate choice to deem these features sacrosanct at the cost of maintaining a permanent policy of exclusion.
There will always be, however, a chorus of people insisting otherwise. Sometimes they are self-interested. Other times they have an ideological objection. Every now and again, I’ll see commentary from a person with libertarian leanings who supports more housing, but questions the need for robust public transit. On other occasions, I’ll see commentary from a person with leftist sympathies who supports robust public transit but is skeptical more housing.
These positions appear on paper to be opposites, but what unifies them conceptually is a refusal to think critically about human settlements as a relationship between people and land. At the most fundamental level, where you have high demand (from people) and low availability (of land), you must choose between efficiency or exclusion. Multi-story buildings and shared vehicles are extremely land efficient. Low-rise buildings and private vehicles are wasteful of land. Choose the path of the efficiency and it comes with the whole package.
For this reason, exclusionary perspectives share an ideological enemy in urbanism. Urbanism is a threat to these groups because it takes as a core principle the people/land relationship and it settles the question in favor of efficiency. In our contemporary context, this is manifest in two ways.
First, urbanism represents a challenge to the current fabric of American metros which is the product of over half a century of denying the importance of the urban core and rural periphery (“urbanism” and “ruralism” ought to be natural allies) in order to assert the independence, primacy, and permanence of the suburban middle. Urbanism sees this as an exclusionary imposition of elite tastes and a costly deviation from the laws of economic geography.
Second, urbanism is ascendant because it works as a unified program in ways that the status quo, because of its inefficiency, does not. Over half a century of pursuing the same model of inflexible suburban growth has left American homes unaffordable, utilities overbuilt and unaffordable to maintain, highways choked with cars, transit systems starved of riders, metropolitan fringes creeping unsustainably outward, and metropolitan cores facing a difficult post-COVID transition.
Urbanism reclaims the simple truth that human uses (housing, employment, transportation, etc.) are inextricably linked to one another through the medium of by land. It makes sense to build abundant housing in physical proximity to places with abundant jobs, abundant access, and so on, and to avoid doing the reverse.
For two decades, the ground has been shifting under the feat of metropolitan politics. Core cities have seen renewed but spottily investment. First ring suburbs have diversified unevenly. These shifts have changed the narrative about America’s urban and suburban places, but they have yet to overturn the way of thinking about cities that too often ignores the mediation of land. Markets are changing but attitudes about public policy and public investment has not always followed in tandem. Can we do better? Urbanism offers the most cohesive and compelling vision for how.
Looking Backwards And Forwards
What is urbanism? Why am I an urbanist? This is my answer.
Many (most?) people are of course led to urbanism because they start with an affinity for urban buildings or urban transport or urban spaces. Only later do they arrive at an intuitive understanding of the math behind it. Others are led to oppose urbanism because they start with an affinity for their suburban landscape and don’t want it to change. Theirs is an exercise in denying the math of efficiency, although not everyone will have the courage of their convictions and mount a defense of exclusion.
Understanding the foundations of urban places is important because it helps us feel secure in our thinking. We should embrace inclusion over exclusion. We should embrace efficiency over inefficiency. We should be thinking always about how to bring people together in shared spaces. We should be thinking about how to break down or bridge barriers in the landscape. We should be mindful of the land that activities take up and the opportunity costs of that use.
And yet also—the texture of human settlements is rich and multi-layered. Economics mixes freely with society. It is not always persuasive to go around repeating “people, land, people, land” like a mantra (however reasoned a basis for analysis). It is more compelling to speak about how urbanism can offer more; an explanation for why we love existing urban spaces and a roadmap to building future urban spaces that will be loved. When a lot of people occupy not a lot of land, their collisions do not just produce economic surplus and technological innovation, they also produce art and music and theater and dance and food and festivals and so much more.
Consider these two perspectives, the hard-headed and the romantic, and see how they intertwine. What is growth in cities, but the byproducts of inclusion? What is change in cities except evidence that new people with new ideas, new talents, and new resources, are coming to collide? Urbanism is a celebration of both this process and this outcome. The very idea of a city contains within it a coherent model of positive-sum relationships, building on each other steadily, expressing themselves as a landscape of human flourishing.