Daniel sent us this one — he's asking what happens when you move past Jane Jacobs. Who are the other theorists that shaped modern urbanism, and what are the actual intellectual fault lines driving how cities get designed today? Because Jacobs looms so large that she's basically become the entry-level required reading for anyone who cares about cities, but she died in 2006. The cities being built right now are responding to a very different set of ideas.
That's the thing — Jacobs has been sainted. She's the patron saint of organic neighborhoods and eyes on the street. But the Jacobs-versus-Moses frame is from 1961. It's a black-and-white movie in a streaming world. The actual battles happening in planning departments and city councils right now are between schools of thought she never had to contend with. I mean, when Jacobs was writing, the idea that you could model an entire city's traffic patterns in real time using data from cell phones — that wasn't even science fiction. It was just inconceivable.
And the danger of the Jacobs-versus-Moses frame is that it flattens everything into a simple David-and-Goliath story where the moral is always "the little guy should win." But what happens when the little guy is a homeowner blocking an apartment building that would house fifty families? The frame breaks. It doesn't give you any guidance.
So if Jacobs isn't the whole story, who actually is? Let's map the intellectual landscape.
Let's do it. Give me the lay of the land.
I think we can usefully group the major schools into four camps. There's the supply-side YIMBY school, built on the work of Edward Glaeser and empirical housing economists. There's the New Urbanism movement — the Congress for the New Urbanism crowd, Andrés Duany, Elizabeth Plater-Zyberk, Jeff Speck. Then you've got the Just City and Right to the City theorists — Henri Lefebvre, David Harvey, Edward Soja — who see urban space as a site of power and capital accumulation. And finally the technocratic smart city school — Michael Batty, Anthony Townsend, Rob Kitchin — who treat cities as complex systems that can be modeled and optimized.
And most popular urbanism discourse is still stuck in the Jacobs-versus-Moses binary — the plucky neighborhood activist versus the bulldozer-wielding bureaucrat. The real action is in the tensions between these four.
And none of them map neatly onto left-right politics, which is what makes this interesting. You can't just say "I'm a progressive so I'm in this camp." These schools cut across traditional ideological lines in ways that create genuinely strange bedfellows. Let's start with the school that's arguably winning the policy battle right now — the supply-side YIMBYs.
The "build more housing" people. I've seen the YIMBY sign at plenty of zoning board meetings. It's usually a young person holding it, standing next to a retiree who's been fighting development since the Carter administration.
The foundational text here is Edward Glaeser's "Triumph of the City," published in 2011. Glaeser is an economist at Harvard, and his core argument is that cities are humanity's greatest invention because they make us smarter, richer, and greener — but only if we let them be dense. His big empirical finding: doubling density is associated with a twenty to thirty percent increase in productivity per worker. Proximity breeds innovation. You get more patents per capita, more entrepreneurship, higher wages.
The mechanism is just — people bump into each other more? That's the whole engine?
That's part of it, but the specific housing mechanism he pushes is called filtering. The idea is that when you build new market-rate housing, even luxury units, it sets off a chain reaction. Higher-income households move into the new units, freeing up their older units for middle-income households, whose previous units then become available for lower-income households. Over time, the entire housing stock filters down and becomes more affordable for everyone. The policy implication is straightforward: remove zoning restrictions, height limits, parking minimums, and just let the market supply housing.
This works — in theory. But filtering sounds like trickle-down economics with better architecture. I'm old enough to remember trickle-down economics. It wasn't great.
That's exactly the critique, and it comes from within the empirical literature. Vicki Been, who was New York City's housing commissioner and is now at NYU, has done neighborhood-level studies showing that filtering works slowly — sometimes over decades — and often fails entirely in hot markets. Her research found that in gentrifying neighborhoods, new market-rate construction actually increased rents in the immediate surrounding area by about six to eight percent, because the new building signals that the neighborhood is now desirable. Displacement happens before filtering kicks in.
The empirical disagreement is about timescales and geography. Glaeser looks at cross-city data — compare Mumbai to Shanghai, or Houston to San Francisco — and sees a clear pattern: more supply equals lower prices. Been looks at the block-by-block level and sees displacement. Both are looking at real data. They're just looking at different scales.
Glaeser's favorite comparison is Mumbai versus Shanghai. Mumbai has some of the strictest height limits in the world — in much of the city you can't build above one point three times the plot size — and as a result, housing costs are astronomical relative to local incomes. Shanghai relaxed its height limits and built aggressively upward, and per-square-foot costs are much lower. But the political systems are so different that the comparison only gets you so far. Mumbai's height limits exist partly because of corruption in the building permit system and partly because of a political desire to limit migration into the city. You can't just import Shanghai's zoning code and expect Shanghai's prices.
Houston gets cited as the YIMBY success story — no formal zoning code, housing costs well below coastal cities. But Houston also floods constantly because you can build anywhere, and the lack of zoning has produced some bizarre land-use patterns. A sewage treatment plant next to a daycare. I've seen the photos. It's not a theoretical concern.
That's the thing — the Houston example actually reveals a deeper tension within the YIMBY framework. Glaeser's model assumes that if you remove restrictions, rational market actors will produce efficient outcomes. But the Houston experience suggests that without some coordination mechanism, you get externalities that the market doesn't price. The sewage plant doesn't pay the cost it imposes on the daycare. The developer who paves over a floodplain doesn't pay the cost imposed on the neighborhood downstream. So even within the YIMBY camp, there's a debate about whether "no zoning" is actually the goal, or whether the goal is "better zoning" — zoning that allows density but also coordinates land use to prevent disasters.
The YIMBY movement actually has significant left-wing factions who acknowledge this. Groups like the People's Housing Network in California argue that supply is necessary but insufficient. You need market-rate construction to ease the overall pressure, but you also need public housing, rent stabilization, and tenant protections. The caricature of YIMBYs as libertarians who just want to help developers is not entirely fair.
Though it's not entirely unfair either. The movement is funded in part by people who do, in fact, want to help developers. And some of the state-level YIMBY bills have been written in ways that preempt local tenant protections along with local zoning restrictions. So there's a legitimate concern that "supply-side progressivism" can become a stalking horse for deregulation that hurts vulnerable renters in the short term while promising benefits that may take decades to materialize.
Which is the fundamental tension. If you're being evicted next month, "filtering will help in twenty years" is not a compelling political message.
No, it's not. Now, the second school — New Urbanism — comes at this from a completely different angle. They're not primarily concerned with housing supply economics. They're concerned with physical form. They look at a suburban subdivision and say: the problem isn't that there aren't enough units, the problem is that the units are arranged in a way that makes life worse.
The Congress for the New Urbanism. Founded in 1993 by Andrés Duany, Elizabeth Plater-Zyberk, and a handful of other architects and planners. Their charter has been signed by over two thousand planners and architects. This is not a fringe movement — this is embedded in the profession.
The foundational text is "Suburban Nation," published in 2000. The diagnosis: post-war American development patterns are a disaster. Single-use zoning separates housing from jobs from shopping, making everyone dependent on cars. Cul-de-sac subdivisions feed into arterial roads that create congestion and make walking impossible. The solution: form-based codes that mandate walkable block sizes, mixed-use development, and parking maximums rather than minimums.
The fifteen-minute city concept that became a culture-war flashpoint during COVID — that's actually a New Urbanist idea from the 1990s. It's not some technocratic surveillance plot. It's just the idea that you should be able to walk to a grocery store. The fact that this became controversial tells you more about our political moment than about the idea itself.
The tension within New Urbanism is that it's often accused of aesthetic determinism — the belief that traditional architecture, front porches, and picket fences create community. The critique is that New Urbanist developments end up looking like movie sets. Celebration, Florida — the town Disney built in the mid-nineties — is the canonical example. It's visually perfect. Traditional architecture, walkable streets, front porches. But it lacked economic diversity. The housing was expensive. The public spaces felt curated rather than lived-in. It looked like community without actually being community.
It's like adopting a feral cat. You can put it in a nice house with a velvet cushion, but it's still going to hide under the bed and hiss at you. You can't design the cat's personality out of existence. And you can't design community into existence with the right porch dimensions.
That's the critique, and it stings because there's some truth to it. But Jeff Speck's "Walkable City," published in 2012, tries to rescue New Urbanism from this critique by focusing on transportation engineering rather than aesthetics. Speck's argument is that walkability isn't about charm — it's about four specific conditions: a reason to walk, a safe walk, a comfortable walk, and an interesting walk. Mixed use gives you the reason. Block size and street design give you the safety and comfort. And the interesting walk is about building facades and street-level activity — not architectural style, just whether there's something to look at.
Speck's book is useful. It's the one I'd hand someone who's about to go to their first planning board meeting. But the question that hangs over New Urbanism is whether you can design community through street grids and form-based codes, or whether community is an emergent property that can't be engineered. And I think Speck would actually acknowledge that tension. He's not saying "build this street grid and you'll get a block party." He's saying "build this street grid and you'll remove the barriers that prevent a block party from happening if people want one.
The form doesn't create the community. It enables or disables it. A six-lane arterial road disables community. A narrow street with wide sidewalks enables it. What people do with that enablement is up to them. And that question — about what can and can't be engineered — is the perfect bridge to our third and fourth schools, which take radically different positions on exactly that point.
Building more housing doesn't answer the question of who gets to live where and on what terms. That brings us to the Just City theorists.
This school has the deepest philosophical roots. The foundational text is Henri Lefebvre's "The Right to the City," published in 1968 — the same year as the Paris protests, and it was originally a pamphlet, not an academic book. Lefebvre's argument is that cities are not just physical places or economic engines. They are sites where surplus value is extracted through rent, and where social relations are produced and reproduced. Urban space is not neutral — it's produced by power, and it produces power in return.
Lefebvre is saying that the very layout of a city — who lives where, who has access to what — is a form of politics that disguises itself as geography. The map looks neutral. It's just lines on paper. But those lines encode decisions about who matters and who doesn't.
David Harvey picks up this thread in "Social Justice and the City" in 1973, and then updates it for the neoliberal era in "Rebel Cities" in 2012. Harvey's key concept is the rent gap — the difference between the current rental income of a property and the potential income if it were redeveloped. When that gap gets large enough, capital floods in, gentrification happens, and existing residents are displaced. The city becomes, in Harvey's phrase, a machine for absorbing surplus capital. Real estate isn't just shelter — it's the primary way that wealth gets parked and multiplied in the modern economy.
This isn't abstract. You can see the rent gap in action in any gentrifying neighborhood. The landlord stops maintaining the building because the real value is in the land underneath it, not the structure. Wait long enough, assemble enough parcels, and suddenly there's a luxury condo tower. I've watched this happen in real time in multiple neighborhoods. The disinvestment is strategic. It's not neglect — it's a business plan.
Edward Soja adds a geographic lens in "Seeking Spatial Justice," published in 2010. His argument is that spatial arrangements are not just outcomes of inequality — they're causes of it. If you live in a neighborhood with poor transit access, you can't reach the jobs that would lift you out of poverty. If your neighborhood lacks a grocery store, your health outcomes suffer. Zoning becomes a tool of racial and class exclusion, not just land-use efficiency. Soja looks at Los Angeles and shows how the bus routes, the freeway placements, the location of toxic industries — all of these spatial decisions encode power.
The Just City school sees zoning reform alone as insufficient. You can't just upzone everything and hope the market solves racial equity. You need redistribution, you need participatory planning, you need to give communities actual power over development decisions. The mechanism matters as much as the outcome.
This creates a genuine tension with the YIMBY school. YIMBYs want to streamline approvals and reduce community input because they see it as NIMBY obstructionism. Just City theorists want to deepen community input because they see it as democratic participation. Same word — community — completely different meanings.
It's the same word but it's doing opposite political work. For a YIMBY, "community input" means a public hearing where sixty-five-year-old homeowners show up to yell about their property values. For a Just City theorist, "community input" means organized renters, public housing tenants, and historically excluded groups having actual decision-making power over land use. Those are not the same thing, and conflating them is how a lot of urban policy debates go in circles.
Which brings us to the fourth school — the technocrats. The smart city people.
The ones who look at all this political mess and say: what if we just ran the numbers?
Michael Batty's "The New Science of Cities," published in 2013, is the key text here. Batty is at University College London, and his argument is that cities are complex adaptive systems — like ant colonies or neural networks — that can be modeled and optimized. The mechanism is agent-based modeling and urban informatics. You use cell phone data, transit tap cards, sensor networks, and satellite imagery to understand how people actually move through cities, and then you adjust the system parameters — traffic light timing, bus frequencies, zoning densities — to optimize flow.
This is the "city as a machine" view, but with much better data than Robert Moses ever had. Moses was optimizing based on traffic counts from 1954 and his own priors. Batty is optimizing based on millions of real-time data points. It's the same impulse — make the city run efficiently — but the tools are orders of magnitude more powerful.
And the promise is exciting. If you can model how a new transit line will change commuting patterns across an entire metro area, you can make better investment decisions. If you can use real-time sensor data to adjust traffic signals dynamically, you can reduce congestion without building new roads. Singapore has been doing versions of this for years — congestion pricing, dynamic tolling, integrated transit and land-use modeling — and it works. Singapore is arguably the most functional city on Earth from a mobility standpoint.
Singapore is also an authoritarian city-state where the government owns most of the land and you can be fined for chewing gum. So the question is whether the Singapore model is portable to a democratic context, or whether the efficiency requires the authoritarianism. That's the uncomfortable question at the heart of the smart city project.
That's exactly the critique from Anthony Townsend in "Smart Cities," published in 2013, and Rob Kitchin in his subsequent work. The smart city as it's actually been implemented is a corporate vision. Cisco, IBM, and later Sidewalk Labs — Alphabet's urban innovation division — all saw cities as a market for technology systems. The pitch was: buy our platform, and we'll make your city efficient. But efficiency for whom? And who owns the data?
The canonical case study is Sidewalk Labs' Quayside project in Toronto. Announced in 2017, cancelled in May 2020 after spending over fifty million dollars on planning. The vision was a data-driven neighborhood on the waterfront — smart traffic systems, modular buildings, underground delivery robots, sensor networks everywhere. It collapsed under privacy and governance concerns. Who owns the data generated by public space? Can a private company control the digital infrastructure of a neighborhood?
The Quayside failure is instructive because it wasn't a technological failure — it was a political failure. Sidewalk Labs had brilliant engineers and compelling prototypes. What they didn't have was a theory of democratic governance. They treated residents as users, not citizens. And the residents pushed back. The project's own advisory panel — the Digital Strategy Advisory Panel — basically said: you haven't answered the fundamental question of data governance, and until you do, this shouldn't proceed. And it didn't.
The smart city is surveillance capitalism with better sidewalks, is what you're saying.
That's the pessimistic version. The more nuanced version is that optimization and democracy are in genuine tension, and we haven't figured out how to resolve it. Batty's models can tell you the optimal bus route to serve the most people. But "optimal" depends on what you're optimizing for — total ridership, equity of access, minimizing travel time for the worst-served neighborhoods? Those are political choices dressed in mathematical language. The math doesn't tell you which objective function to choose. It just tells you how to achieve the objective you've chosen.
The danger is that the mathematical language obscures the political choice. You present the bus route as "the optimal solution" and people don't realize that "optimal" meant "minimizing average commute time for current riders" rather than "maximizing access for transit-poor neighborhoods." The optimization is real, but the choice of what to optimize is political, and smart city discourse has a bad habit of pretending it's not.
We've got four schools. Supply-siders who want to build more housing and let markets work. New Urbanists who want to redesign physical form to create walkable communities. Just City theorists who see urban space as a site of power and demand redistribution. And technocrats who want to model and optimize the city as a complex system. They don't map neatly onto left and right.
That's the synthesis I think is most useful. YIMBYs and smart city advocates both love density and data, but for very different reasons. Just City theorists and New Urbanists both distrust top-down planning, but they mean different things by "top-down" — for Harvey it's capital, for Duany it's modernist architecture and highway engineers. The real divide across all four schools is about two questions: who gets to decide, and what counts as evidence?
Say more about that.
The "who decides" question splits the schools into participatory and technocratic camps. The Just City and New Urbanist schools — despite their other differences — both believe that communities should have significant say in what gets built. The mechanism might be community land trusts or form-based codes, but the principle is local control. The YIMBY and smart city schools are more skeptical of local control. YIMBYs see it as NIMBYism that blocks housing. Smart city advocates see it as parochialism that blocks optimization. So you get this weird alignment where left-wing community organizers and conservative small-town preservationists are on the same side of the "who decides" question, while progressive data scientists and libertarian developers are on the other side.
The "what counts as evidence" question splits them differently. The YIMBYs and smart city people are empiricists — they want data, models, causal inference. Glaeser runs regressions on census data. Batty builds agent-based simulations. The New Urbanists and Just City theorists are more qualitative — they draw on observation, case studies, lived experience. Jane Jacobs herself was fundamentally a qualitative researcher. She walked around and looked at things. "The Death and Life of Great American Cities" doesn't contain a single regression table. It's all observation and argument.
Which is why Jacobs is claimed by multiple schools. The New Urbanists claim her for her insights about street life and mixed use. The Just City theorists claim her for her community organizing and her fights against top-down renewal. Even some YIMBYs try to claim her — they point out she supported density and opposed height limits in Greenwich Village. Everyone wants Jacobs on their team.
She's the urbanist equivalent of a Rorschach test. You see in her what you already believe.
Let me give you a case study where these schools actually align, because it's not all conflict. Barcelona's superblock program, started in 2016, has reduced traffic in pilot areas by twenty-five percent and increased green space by thirty percent. The idea is simple: take a three-by-three block grid, restrict through-traffic to the perimeter, and turn the interior streets into public spaces with playgrounds, trees, and seating.
It's a physical redesign — that's New Urbanism. Reclaiming street space from cars, slowing things down, making the neighborhood walkable.
It's also a Just City intervention. The superblocks are distributed across the city, not concentrated in wealthy districts. The goal is explicitly about equity — giving every neighborhood access to public space and clean air. And the program is enabled by data — sensor networks that measure air quality and noise levels, transit data that shows how traffic patterns shift. That's the smart city layer. Three schools working together.
The fourth — the supply-side YIMBY school — is sort of orthogonal to all of this. Barcelona's superblocks don't directly address housing supply, though the city does have its own housing policies. The superblock program is about public space, not units per acre. But you could imagine a version that integrates housing — upzone the superblock perimeters for mid-rise apartments while keeping the interiors as public space. That would be all four schools in one intervention.
Which illustrates the point: no single school has all the answers. The most effective urban interventions combine insights from multiple traditions. The superblocks work because they're not just a traffic engineering project, not just a public space project, not just an equity project. They're all three, and the data layer makes it possible to demonstrate the benefits and build political support.
How do you actually use this framework? If someone's listening and they want to engage with their local city council or planning board, what's the practical takeaway?
First: when you hear a policy proposal — upzoning, bike lanes, inclusionary zoning, smart traffic lights — ask which school of thought it comes from, and what it assumes about how cities work. Upzoning assumes the Glaeser model: supply reduces prices. Inclusionary zoning assumes the Harvey model: the market alone won't provide affordable units, so you need to mandate them. Smart traffic lights assume the Batty model: cities are systems that can be optimized with data. Recognizing the intellectual DNA of a policy lets you ask better questions about its blind spots. Every school has blind spots. If you know which school you're in, you know what you're not seeing.
Second: learn which school your city's planning department actually subscribes to. Most US cities are still running on 1950s traffic engineering — that's not any of these four schools. That's the old paradigm of level-of-service calculations that prioritize car throughput above everything else. It's the Moses paradigm, essentially, just with fewer bulldozers and more spreadsheets. Knowing the alternatives gives you a vocabulary to challenge the status quo. You can walk into a meeting and say, "we're optimizing for vehicle delay, but what about pedestrian safety? What about land value? What about air quality?" And suddenly you've shifted the terms of debate.
Third: don't be a purist. The most effective advocates I've seen are fluent in multiple schools. They can talk about housing supply economics when the discussion is about zoning, but they can also talk about spatial justice when the discussion is about where affordable units get built. They can cite Speck on block size and Glaeser on density and Harvey on the rent gap, and they know which argument fits which room. The goal isn't to find the one true theory and defend it against all challengers. The goal is to have a toolkit.
There's a reading ladder here that I think is useful. Start with Speck's "Walkable City" — it's the most practical, the most immediately applicable to street-level decisions. Then read Glaeser's "Triumph of the City" for the economic case for density. Then Harvey's "Rebel Cities" for the critique — it'll make you uncomfortable with everything you just read in Glaeser, and that discomfort is productive. Then Batty's "The New Science of Cities" for the systems view. By the time you've read all four, you'll see every planning debate through multiple lenses.
That's the goal, right? Not to pick a team, but to be able to diagnose. When your city proposes a new transit-oriented development, you should be able to ask: does this pencil out economically? Is the physical design actually walkable? Who benefits and who might be displaced? What data are they using to model the impacts, and whose data is being ignored? Those four questions map directly onto the four schools, and if you can ask all four, you're doing better analysis than most planning consultants.
Which brings us to the open question: which school dominates the next decade? The housing crisis is pushing YIMBY policies through state legislatures — California, Oregon, Washington have all passed statewide upzoning bills in the last few years. But climate adaptation may force more top-down smart city interventions. Sea walls, managed retreat, heat-resilient infrastructure — these aren't things that emerge organically from neighborhood activism. The tension isn't going away. If anything, it's going to intensify as climate pressures force harder choices.
There's a fourth dimension that none of the four schools fully addresses: global capital flows in real estate. When a condo in Vancouver or Miami functions as a Swiss bank account for overseas wealth, local housing supply policy barely matters. You can upzone all you want — if global capital is treating your city's real estate as a store of value, prices may not respond to local supply increases the way Glaeser's model predicts. Jane Jacobs couldn't have anticipated that. She couldn't have anticipated algorithmic zoning, or climate migration reshaping entire regions, or remote work decoupling jobs from geography. We need new thinking for new conditions.
Jacobs was right about many things. Incremental development beats top-down urban renewal. Mixed-use neighborhoods are healthier than single-use districts. Eyes on the street are better than police in cars. But she was writing in 1961. The Death and Life of Great American Cities is sixty-five years old. It's a foundational text, not a sacred one. And I think she'd be the first to say that. She was not a dogmatist. She was an observer. She'd want us to observe the cities we actually have, not the city she had.
The best tribute to Jacobs is not to treat her as a saint, but to keep doing what she did: observe cities carefully, challenge the orthodoxies of your own era, and be willing to fight. She'd probably be horrified by a lot of what's done in her name. She'd probably also have strong opinions about some of these four schools and wouldn't fit neatly into any of them. Which is exactly the point.
If this episode changed how you see your city — if you now have a mental map of the intellectual battles behind every zoning decision and bike lane proposal — share it with someone who's about to attend a planning meeting. The best urban theory is useless if it stays in books. It has to show up at the folding tables and the public hearings.
Now: Hilbert's daily fun fact.
Hilbert: In the 1860s, scientists discovered that deep-sea hydrothermal vents on the ocean floor support entire ecosystems that don't depend on sunlight — an unintended consequence of laying early transatlantic telegraph cables, which dredged up bizarre organisms from the abyss. Meanwhile in Tibet, Buddhist monasteries were independently developing a sophisticated system of natural refrigeration using high-altitude ice pits to preserve butter for decades.
...right.
This has been My Weird Prompts. I'm Corn.
I'm Herman Poppleberry. Find us at myweirdprompts dot com, and if you want the reading list we discussed, it's in the show notes. Go argue with your zoning board.
