A new focus is, well, emerging in my thinking: the idea of emergent urbanism*--that is, the tying of models of how cities behave (urbanism) to a descriptive framework of complex phenomena called emergence.
The reason for this comes out of my rereading of Jane Jacobs, particularly Death and Life, for school. Jacobs' argument in this text is actually exceedingly simple: urban growth and urban decay both occur in self-reinforcing feedback loops, due to cities' organized complexity (as far as I'm aware, Jacobs' use on pg. 432 is one of the first uses of this phrase in scientific thinking)--whereas the planning profession up to her time persisted in attempting to analyze the city in two-variable (e.g. Newtonian) terms. Since planners are bringing entirely the wrong sort of methodology to the table, Jacobs says, their solutions are inadvertently catalyzing negative feedback cycles**, and as such, the entire enterprise of planning in her day is doomed on the face of it to failure***.
This critique has been such a powerful critique that it has resulted in a crisis of confidence among planners, and repeated attempts to re-analyze and re-think Jane Jacobs (usually presented as using new evidence to challenge her). Unfortunately for them, it's almost always easier to think of such new phenomena in Jacobean terms (gentrification, for example, as a particular subset of unslumming), and usually emergently. Once one begins to utilize a methodology based on feedback cycles, such emergent phenomena will crop up^.
So the question turns to: what is emergence? Emergence is most abstractly defined as "the way complex systems and patterns arise out of a multiplicity of simple interactions", as it is on Wikipedia. In other words: the perfect description of a city. It is the phenomenon that is colloquially referred to when someone references the "butterfly effect". It is the major outgrowth of the complexity theory that first arose in the information sciences, and repackaged via chaos theory into the overarching framework of non-linear dynamics (a phrase with two meanings: as a pure mathematical theory, and conversely as a way of describing complex systems, via the identification and analysis of feedback cycles and their catalysts and suppressants).
Jane Jacobs very definitely understands the structure of complexity, but since the technical language was in its infancy at the time Death and Life was written, she had no access to the language of complexity. As this language matured, however, it found its way into her later work; similarly, an early inflection of it influenced Alexander's Pattern Language--and it is due to this source in complexity theory that these two books retain their living vitality and intrinsic accuracy.
So what's the problem? Why are academic urban planners so desperate to disown Jacobs? Why do they always have to "rethink" her and attempt to frame more recently understood phenomenon in a way as detrimental as possible to her? Maybe it's because they don't like her theory? A great deal of urban planning--although not the type of planning literature I tend to read or think about--draws from sociology, and one of the things I've noticed about sociologists is the deep distrust they have of any ideas that didn't originate in their field^^--a distrust which seems to extend to adopting a confrontational stance when a good idea comes out (which should be relevant to them) they didn't think of. But ideas like complexity theory are good ideas which are now being studied and debated across a variety of fields--physics, meteorology, biology, information science, information theory, etc.--and are even being applied in very definitely sociological contexts, such as attempting to explain the architectures of Web 2.0. Yet there is undeniable resistance to applying them to the problem of the city: why? There is especially the dogmatic cant I hear in my school's sociological department: "Jacobs just has a collection of anecdotes: there is no theory". Bullshit. Anecdotes are the foundation of any good theory, and counter-anecdotal theory (like phlogiston) tends to be thrown out the window real fast. Jacobs has the evidence gathered from the street, and has the framework for explaining it. She has a theory in Death and Life--albeit one as basic as the field whose terms the theory would be best explained in at the time she wrote it; it is telling that the theory changed as she expanded on it and applied it to additional fields (although its structure did not) through later works like The Economy of Cities and Cities and the Wealth of Nations^^^, and her rather pessimistically-named last work The Fall of the West.
But the evidence of reality weights on her side. In my last post, I talked about the fallacy of naming all informal settlements "slums", and how there are in fact aspects of improving informal settlements (I talked about built form evidence; there is also (were the academics not so blind!) sociological evidence, economic*^ evidence, historical evidence**^, and so on) very different from those of true slums. This is a perfect example of emergent urbanism creating a community, and is part and parcel of emergent phenomenon referring to the redevelopment of already-settled areas, such as what Jacobs and most developed-world urban theorists concentrate on*^^. Today's urban phenomena, like yesterday's, like tomorrow's, are best explained in the framework of complexity theory and emergence Jacobs first showed us the way towards--someday I hope we as a whole can internalize this to the point where we can use her framework to supersede her, like biologists have done to Darwin; unfortunately, as long as the academic community stands in her way instead of embracing her, and the best ideas in urban thinking come from fields very definitely far afield of urban studies, this will not happen.
* Yes, there was a blog dedicated to this sort of thing. I wasn't the first and I certainly won't be the last to discover and understand this reading. But do an academic search for "Jane Jacobs" and "emergence" and you'll be lucky if you find one thing. A minorly famous (he'll certainly disagree with me on this) philosopher, Prof. Lewis Gordon, has a term for this sort of thing: disciplinary decadence, and it's frankly rife all over the social sciences.
** As already noted, the language of complexity theory was (at best) barely in a formative stage when Death and Life was written (much less published!); as such, Jacobs had no access to the terminology I'm using, and tended to use the terms virtuous circle and vicious circle for what we would today call positive and negative feedback loops (or cycles); virtuous and vicious being freighted, as they are, with unnecessary moral weight.
***I'd go a step further and say that the urban planning of the era, freighted by the prescriptive mentality of its intellectual heritage (Ebenezer Howard, Daniel Burnham, etc.)--grown out of the desire to reform cities more than describe them, and thusly (in e.g. Lewis Mumford's Culture of Cities--witness the extremes of what he calls "slums", and the way he attempts to rationalize what is on the face of it a reductio ad absurdum) morally weighting their descriptive elements of cities to an exorbitant degree. (Another way to look at it: urban planning is a nostalgic discipline; Howard, Mumford, and even Andrés Duany, the best urban thinker going, all look to the past for inspiration.)
^ This has particular relevance when parsing Glazer's Triumph of Cities. Glazer mentions therein he thinks Jacobs is in error, yet at the same time that text's strongest argument, and major intellectual contribution, is the presentation of a solid case for the role of education in the feedback structure of cities! Disciplinary decadence at its finest, folks.
^^ Which is to say, most all of them.
^^^ ...They're on my to-read list (much like Proust and Pynchon).
*^ My chief grievance against economics is their devotion to the myth of symmetry. Economics models have to balance for no better reason than math has to balance, and thus a mathematical artifact has been elevated to a "basic premise" of economics models. The reality is, of course, much messier.*
* That said, I agree with the Keynesian concepts of the government as the employer of last resort and the need for government to generate stimulus and create jobs when the private sector is unwilling or unable to; particularly since the (non-Keynesian) way we're going about our recession today is clearly not working.
**^ In the form of the layout of premodern cities viz. that of informal communities. See, for example, the street network of Matera, Italy, Córdoba, Spain, Porto, Portugal, Frankfurt, Germany, or Manchester, England v. Rocinha, Rio de Janeiro, Brazil, Villa 31, Buenos Aires, Argentina, or Ankara, Turkey. Stable informal communities are little different than traditional urban cores in the developed world.
*^^ Mike Davis is the exception to this rule. Unfortunately, his Mumfordian style does just as much harm as good (much like Mumford himself).