And they are only simple examples, but a lot of fractals, including Sierpinski carpets and the Mandelbrot set are actually hierarchical. Show me a city based on a Julia set with an infinity attractor and I’ll say “uncontrolled sprawl”, but pretty from the air.

So while a building facade probably gains from being scale invariant to a degree and having a bit of a fractal dimension, I’m not convinced that the same necessarily holds at the urban scale. For one thing, social networks are no longer as localized as they once were, and I would refer you to Barry Wellman’s work on locality. Urban space is only locally metric, and measures of distance vary according to means of transportation and communication. Stores and friends can be close by foot and far by car or vice-versa based on several factors controlled by planners. But Facebook and eBay are always the same distance.

A city is always responding to changing conditions, but I am not certain the response necessarily restores an equilibrium. So for instance a random fluctuation can create a local demand for a rendering plant or a bagpipe school, things that have a negative impact on neighbours. Satisfying demand, in the absence of planning, can create its own dislocations, with people who can afford it gradually moving away over a period of years. Emergent phenomena are not necessarily static solutions even long after the perturbation is gone. That’s not necessarily bad, but what I don’t like is the cyclical theory of urban development, where it is believed that a community must fall into decrepitude and then be redeveloped as a natural cycle. This is only applied to dispossess the poorest communities and hand them over to developers. This type of feedback cycle (poor=bad, rich=good) tells me something is broken in the system, where a drop in land prices through the mechanism of human misery is required in order to restore overall equilibrium.

I think what Patrick is getting at is that you need to recognize how the transition from merchant/agrarian capitalism to industrial capitalism played a big part in altering the process of urban growth. Changes in the scale of production and the concentration of capital did allow for the “natural” emergence of factory towns and other forms of dictated development. They were natural in the sense that they grew in the absence of government planning. Yet your narrative starts more than a century later with the introduction of the first modern suburban subdivision (or so I assume that’s what you are referencing). By doing this you pass over a lot of history where government planning evolved in response to correct the pathologies generated by industrial development. This is unfortunate, because I suspect that this period represents an instructive middle ground for planners and developers trying to find the right trade-off between spontaneity and predictability.

The Birmigham development process that Patrick describes sounds like a decent blend of the two, which is to say it allows for much more spontaneity than your typical master-planned subdivision. The developers (and builders subsequently) did not have to zone the land, get planning commission approval, defend their plan at public hearings, apply for permits, conduct environmental impact assessments and traffic studies, and pay hefty “impact fees” to grease the palms of local officials. And as CG points out, the very idea of starting a new town based on a grid, then allowing the land developers to sell to builders who had mostly free reign is a foreign concept to modern town planning regimes.

Twitter, facebook, blogs, etc… are a technologically advanced form of a 18th century town hall meeting or conversation over a beer. Contrast that with 20th century TV and radio (and even most of the newspaper) which is much more like listening to a speech, or rather, speech after speech after speech.

Modern suburbs don’t lack fractal or emergent qualities, they are just much much simpler than their predecessors because fewer voices were involved in crafting the rules.

In the 50s, people bought into the big yard and white picket fence not because that was the most wonderful thing, but because it was cheap for developers with cheap land outside cities to control public opinion.

As we begin to add new rules–informal or otherwise–and not merely add complexity to the existing ones, we have a chance to alter the entire development process. We can promote pedestrianism or sustainability, health or investment.

A very significant threshold was passed, however, when the land developer as a subdivider was transformed into the land developer as real estate salesman. Subdividing land has always been part of the process of urbanization, and many of the patterns of spontaneous cities can be explained by property owner subdividing their lots to increase the density and benefit from the higher demand for urban land. 19th-century regulations obliged land subdividers to uphold street grids, but the idea of “infrastructure” was not well-developed, and in fact streets were typically nothing more than dirt paths that required no investment.

It was the advent of infrastructure and municipal utilities that forced land subdivision to become today’s development industry. Municipalities wondered how the extension of utilities and public services were to be paid for. The solution was to impose the costs onto developers, who were required to build infrastructure to regulation and turned to the banks to finance this additional work. What it meant was that the growth of the neighborhood had to be rapid enough to pay for all these utilities and it could not exceed the density for which the development was planned, which would impose higher costs on the municipality once the developer had long moved on. The developer therefore had to sell a lot of homogeneous houses very quickly, and those houses remained there ever since.

This is not to say that large-scale real estate development did not exist prior to the 20th century, as Patrick points out. But the concentration of capital necessary to realize them was quite rare during the 19th century, available at first only in England and then spreading to other countries gradually. The story of the renovation of Paris involves large banking oligarchies partnering with the prefecture to build new streets, and while these streets today are considered to be some of the most beautiful in the city, built with all the craftsmanship of 19th-century industrial production, they are not the most alive. They succeeded because they were inserted within the tissue of a spontaneous city and therefore came to complement it. New neighborhoods in the suburbs did not have this advantage, and unless they were close to a traditional village, still to this day do not have much life of their own.

In North America capital concentration came even later, the Federal Reserve System founded in 1913 and the Bank of Canada in 1935. Without this funding the modern system was not possible, and people who wanted to borrow to build a house had to borrow the savings of their neighbors through the local small-town bank.

The main differences from today were that 1) neighborhoods were built on tight grids around some existing infrastructure, rather than as isolated greenfield developments, and 2) although large developers bought farmland, subdivided it and sold it as early as the 1850s (even the CBD was created through a similar process in the 1780s), they did not actually build the houses themselves. My own street, very near downtown, was platted in the 1880s, with the first house completed in the 1890s, and the last vacant lot built on only in the 1960s. I think this is all fairly typical of the older portions of American cities.

While it’s certainly not anything like a spontaneous process — zoning laws would have stopped that 80 years ago regardless — the responsibility for the bulk of the built environment was nonetheless on the individual. You can still see evidence of this today in the dedication plaques on old commercial structures, which contain the name of an owner and the year the structure was built, indicating pride in the building and in individual ownership. The last one I have seen downtown is dated 1957.

Patrick makes an excellent point, but I think the differences in the pre-1950s pattern of urban development are fairly significant. I agree, though, that it would be going too far to imply that the the old process was “spontaneous.”

I do take issue with a couple statements, however.

“But for smaller towns the same project can double the size of the urban fabric.” This seems unlikely. Do you have evidence of this actually happening?

“The adoption of mass-production processes, or development, in substitution for spontaneous urban growth in the mid-20th century created for the first time a phenomenon of alienation between the inhabitants and their environment. ” Again, this seems like pure speculation. It hardly seems likely that no one was alienated from their environment prior to 1950. Consider the factory towns of the 19th century, especially the giant dorms of New England factory towns. These were not constructed incrementally by individuals, but were built en masse by factory owners.

One theme I notice in many of your posts is the idea that the planning/development system shifted from an individual-based system to a corporate-based system, dominated by developers, in the mid 20th century. But you never explain why you think this, and you seem to ignore the fact that developers played a large role in development prior to 1950 as well.

For example, Birmingham, Alabama, my home town, was developed in the 1870s and 1880s by industrial developers around steel mills. The land for the entire city was purchased by developers and subdivided into a system of blocks by the developer. So the developer owner the land. The developer subdivided the land. The developer sold the land. Individuals purchased the land and constructed the buildings, but they likely needed bank loans to do so.

So, while development happened more incrementally, banks and developers still controlled a great deal of development. This doesn’t look much like the spontaneous slums you write so fondly of. And it seems unlikely that any significant permanent development in the US and Western Europe has happened spontaneously since the middle ages. Can you address this?