Imagine you’re out for dinner with your friends. You order a large pizza. After fifteen minutes of eager anticipation, you are served bare pizza crust on a platter. In a bowl next to it is the mozzarella cheese; in another bowl the green peppers; in another bowl the diced tomatoes; in still another bowl, the mushrooms. You are rightly disappointed. Don’t they understand what a pizza is? All the toppings are supposed to be mixed together on the crust. That’s what makes a pizza so good: the mix.

Urban theorist Leon Krier once compared the city to a pizza. Just as you expect a pizza to have all the toppings in each slice, so you should expect to find all the basic elements that make for a good city in each of its neighborhoods. You should expect to enjoy a convenient, interesting, and lively mix of housing, office, retail, civic buildings, parks, and squares. Instead, in functional zoning it was decided that these elements were somehow incompatible and should therefore be physically separated from each other. Hence the housing subdivision in one place, the shopping mall in another place, and the office park in still another. The city hall cast at random on the side of an arterial. The park way out on the edge, on left-over land. How strange.

The idea that different land uses within a city should be physically separated came from the modernist movement of the early twentieth century. Modernism, generally speaking, was the attempt to do away with the old and, starting from scratch, reconstruct society along strictly rational lines. Modernist architects, as a rule, had no use for traditional cities. Those cities appeared too messy, too irrational, a “picture of chaos,” as one of them famously put it. Not fit for the modern age of the car and machine production, of science and efficiency. Best to analytically separate out the distinct functions of a city, siting each in its most advantageous location as determined by the relevant sciences, and reconnect them all by the high-speed transit now afforded by the automobile. Generally speaking, cities are built to provide access—access to work, school, home, cultural amenities, goods, and services. The traditional city provides access on the basis of proximity; the modern city was to provide access through mobility. The “means of transport are the basis of all modern activity,” according to a modernist manifesto of 1922. And those cities that do not adapt to the means of transport afforded by the motor-car “will be stifled and will perish.”

In the summer of 1933, a prominent group of modernist architects met on a boat sailing from Marseilles to Athens. On board they discussed a number of principles for city planning that would later be codified in the Charter of Athens, a new vision for cities of the future. They distinguished just four functions within the city: housing, work, recreation, and traffic. Each function would have its own exclusive location, assigned to it after a careful study of climate and topography. “Land will be measured and assigned to various activities,” (Charter of Athens, section 85) thus “bringing order to urban territory” (section 81). Space for recreational activity and broad highways would be created by building vertically, sweeping all development up into high towers in a park. The planning of what they called the “Functional City” would be under the control of specialists and technicians invested with public authority. No longer would it be left to “vulgar private interest” (section 95). Private interest must be entirely subordinated to the collective interest. If this program is to work, we must of course have “an enlightened population that will understand, desire, and demand what the specialists have envisaged for it” (section 91).

This sentiment is typical of the modernist program for the top-down, theory-driven reconstruction of society according to a singular logic of machine-like efficiency. It thrives on elite culture; it has little use for participatory democracy.

In a later work, The Radiant City (1935), the lead author of the Charter of Athens, Swiss architect Le Corbusier, envisioned his urban ideal: “The cities will be part of the country. I shall live 30 miles from my office in one direction, under a pine tree; my secretary will live 30 miles away from it too, in the other direction, under another pine tree. We shall both have our own car. We shall use up tires, wear out road surfaces and gears, consume oil and gasoline. All of which will necessitate a great deal of work . . . enough for all.” Corbusier’s dream of full employment based on dispersed, auto-dependent development has become in large part a reality in North America—and the nightmare of later generations who find themselves bound to a car and stuck in traffic. Adults between the ages of twenty-four and fifty-four now spend on average over an hour a day in their cars. If the earth could dream, Corbusier’s ideal would be the earth’s nightmare as well. Cars account for roughly one third of our greenhouse gas emissions, putting out twenty pounds of carbon dioxide per gallon of gas.

We can readily see the widespread influence of functional zoning across post-war development in America. Practically all land uses are now separated. And the car is the only way to get around. On average, 87 percent of the trips we make are by car. The idea of towers in a park took hold in the downtown areas of our cities that underwent urban renewal in the 1960s—another modernist intervention. Four years after the close of World War II, President Harry S. Truman signed the Housing Act of 1949. In this act, Congress set aside federal funds to support cities in the “clearance of slums and blighted areas” (section 2). And cities were given the power of eminent domain to get the job done. Local authorities were encouraged to identify blighted areas, condemn them, acquire them through eminent domain if necessary, and tear them down. They could then turn around and sell or lease those areas for private or public development. The act made one billion dollars available in loans and another five hundred million available in capital grants.

The focus of the 1949 act was on the creation of low-rent housing. In 1954, the act was amended to make federal money available for the redevelopment of civic centers as well. It was bolstered by a Supreme Court decision in that same year (Berman v. Parker) that allowed the government to take private land not only for public use but also for more broadly defined public purposes. In both cases, the new, federally supported development followed the planning ideas of the Functional City together with Le Corbusier’s vision of towers in a park—and his vision of what had to be done to create those towers. It is my “settled opinion,” Corbusier wrote in 1925, “that the centers of our great cities must be pulled down and rebuilt.” Wherever urban renewal went, the fine texture of the city was erased. Existing buildings were demolished to establish a clean slate. Many streets were eliminated to create superblocks. The redeveloped areas were typically restricted to a single use: residential or office. Towers went up in park-like settings for housing and on vast concrete plazas for civic centers.

Grand Rapids, Michigan, was one of the first cities to go in for the complete redevelopment of its downtown area using Title III money from the 1949 Housing Act as amended in 1954. In 1959, Grand Rapids invited to town John Paul Jones, a planning consultant from the New York firm of Ebasco. He blew in with lots of energy and big ideas for the complete reconstruction of downtowns using federal funds to cover two thirds of the cost. In July of that year, he proposed more than a million square feet of government office space and 13,500 new parking ramp spaces. Retail and residential uses were no longer part of the picture. They were separated out. In August of 1960, the citizens of Grand Rapid were sold on the plan to revitalize the downtown. They approved a 1.75 mill property tax hike to the pay the city’s share of the redevelopment costs. In September of that year, Jones was appointed the new planning director of Grand Rapids, and soon the wrecking balls and bulldozers went to work, taking down all the buildings in a forty-acre, twenty- two-block area. The Richardsonian Romanesque city hall andKent County buildings were reduced to rubble. Sleek office towers were built on huge superblocks, creating a sterile urban environment that few would visit unless they worked for a bank, were called for jury duty, or wanted to contest a utility bill. The promised revitalization of the downtown did not happen. After 6 pm, the place is a ghost town.

The towers in a park idea was also used in the creation of federally sponsored public housing, known as “the projects.” Between 1949 and 1973, the heyday of urban renewal, over 2,000 urban communities were plowed under and 4,000,000 individuals displaced. Most of the communities affected were African-American, leading novelist James Baldwin to claim that “urban renewal” was actually about “negro removal.” Many claimed with good reason that the new public housing towers were an attempt to isolate, concentrate, and contain the urban African-American population, keeping it from spreading to white neighborhoods. For the most part the projects only created dead urban spaces and social disasters. On July 15, 1972, at 3:32 in the afternoon, someone pushed a button, and the Pruitt-Igoe public housing towers in St. Louis were demolished. Built in early 1950s in keeping with the ideas of the Functional City, they were, in the end, judged to be completely dysfunctional. Some take that event as the official death of modernism in the realm of architecture. Not long after, Congress passed the Housing and Community Development Act of 1974, which focused on the redevelopment of existing neighborhoods rather than their demolition. Since then other public housing towers have been taken down, most notably Cabrini-Green and the Robert Taylor Homes in Chicago. They were replaced by, of all things, traditional urbanism—mid-rise mixed-use buildings on re-established street networks with a combination of market rate and affordable housing.

Perhaps a lesson should be drawn from the modernist experiments of the mid-twentieth century. Traditional urbanism represents the cumulative wisdom of building the human habitat over some 6,000 years of experience. It developed slowly over time by incremental acts of innovation and much trial and error as it adjusted to standing human needs and physical constants as well as technical advances and differences in local climate, custom, and materials. Modernism was a revolutionary program, born of a theory sprung from a few heads. But reality is wondrously complex and notoriously difficult to capture in a theory. Theories are inevitably abstract and often one-sided. Applying them on a large scale regularly leads to all sorts of unintended consequences.

Catherine Bauer, who was deeply involved in the formulation of federal housing policy in the 1930s and 40s, came to realize this point in retrospect. The modernist architects and planners, she wrote in 1955, “too frequently assume that there must be a single rational, logical solution . . . which results in vast housing projects that are apparently viewed by their designers mainly as huge pieces of technocratic sculpture, abstract forms that have little to do with satisfying, pleasing or delighting the occupants, as places to live in.” Later, in 1971, David Rockefeller, then CEO of Chase Manhattan Bank, rightly put his finger on the problem of abstraction, of focusing on one element of the urban ecology in isolation from others. The federal urban renewal program, he pointed out, “concentrated almost exclusively on housing and not on other related community activities The funds were not used to build a rounded community; they merely built houses.” Troubled urban neighborhoods were bulldozed; but what replaced them was only one element of the rounded community.

Tradition is certainly not infallible. And on some points—such as longstanding practices of slave labor or racial segregation— it is rightly opposed. But surely tradition deserves some respect, especially in areas of craft and practical endeavor. Why start with the idea that it needs to be entirely overthrown? What reason do we have to think that our big untested ideas will not just make things worse? Michael Pollan recently argued in his book In Defense of Food that our scientific/industrial approach to food has in fact diminished our diets and damaged our health. He suggests that we turn an appreciative eye to time-tested traditional diets, note the strong correlation between them and the health of their populations, and return to “real food”—unprocessed, without all the additives invented by people with chemistry degrees. Why not try something similar with respect to our built environment? Why not start with something like appreciative inquiry, where we identify, observe, and learn from what actually works, figure out why it works, and then critically and creatively appropriate it in our own times?

Lee Hardy is a professor of philosophy at Calvin College. His latest book is The Embrace of Buildings: A Second Look at Walkable City Neighborhoods, from which this article is adapted. Copyright 2017 Lee Hardy.

Follow New Urbs on Twitter for a feed dedicated to TAC’s coverage of cities, urbanism, and place.