Why “a building is not a tree”

Or, how Christopher Alexander’s landmark 1965 paper can still guide us in thinking about the coronavirus, and other urban challenges

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The UK Urban Task Force demonstrated in this figure that the same population density can take very different forms, with very different connective properties (red lines added), and different impacts on health and vitality — including disease transmission.

The coronavirus pandemic has forced a sober reassessment of a number of urban characteristics, and none has been more maligned – inaccurately so, I fear – than urban density. A closer look reveals that clustering of people in certain environments (like nursing homes) is far more likely to spread infections than in other places with similar population densities – notably public spaces. As I have written elsewhere, it’s quite possible to maintain “sociable distancing” in many kinds of public and semi-public spaces.

What are the lessons for urban density in private places? One of the topics that needs careful assessment in the wake of the pandemic is the impact of tall buildings, which also tend to bring many people into close contact — notably in their elevators, lobbies, and other spaces.

Epidemiologist Shai Linn has observed that the incidence of infectious spread can be high in tall buildings. He draws an analogy to the spread of coronavirus and other diseases in cruise ships: in both environments, people tend to crowd into elevators, stairs and other common areas. In both environments, infections (of all kinds) can spread rapidly.

There is an important point to be drawn from Linn’s work and others’. The issue is not merely that many people are in spatial proximity, but that they must pass through “choke points’ of centralized spaces, where airborne transmission is much more efficient. (Successive touching of “fomites” like door handles and buttons is also part of the problem, but can be controlled more easily.)

What is the deeper problem with these centralized spaces? One can think of the structure of a tree, where all the branches, twigs and leaves are connected only through the trunk. Similarly, in a tall building or a cruise ship, all the parts are connected through central elevators, stairways and common areas.

By contrast, a web-network doesn’t have to concentrate everyone into central spaces – even when a given unit of space has the same number of people, that is, the same “density.”

The drawing at the start of this post makes this point. We can contrast a tall building with a street lined with tightly packed rowhouses, or a series of small apartment buildings, each with its own entry on the street. Such a web-network allows people to be in social proximity – able to practice what I have called “sociable distancing” – without being forced into the kind of adjacency that allows transmission of pathogens.

As it happens, the urban and architectural theorist Christopher Alexander described these two kinds of structures in a famous 1965 paper. Alexander, who is better known as the author of the classic book A Pattern Language, wrote in his paper that “A city is not a tree” – or at least, a good city is not. That is, the best cities are not dominated by centralized tree-like structures, but rather, they have many web-like sets of connections that he referred to as “semi-lattices.”

An obvious example of a tree-like structure can be seen urban street patterns. Many sprawling suburban communities show a tree-like pattern that is easy to differentiate from, say, the web-like grids of many older cities (as in the figure below). The trouble with tree-like patterns is that they force traffic into limited “choke points” where it becomes congested and hostile to pedestrians. This pattern doesn’t allow vehicles or pedestrians to connect through other shorter trips between the branches, as is the case with the web-network. That usually means neighborhoods with tree-like structures are not walkable, are not very well suited to transit, and are prone to traffic congestion.

For Alexander, there is an even more fundamental problem for cities organized as “trees.” Cities get their vitality and their dynamism from these inter-connections — from the diversity of people who come into mutual contact, from the mixing of different activities and movements, and from the “overlaps” that happen when things are not neatly segregated into tree-like schemes.

He concluded:

It must be emphasised, lest the orderly mind shrink in horror from anything that is not clearly articulated and categorised in tree form, that the ideas of overlap, ambiguity, multiplicity of aspect, and the semilattice, are not less orderly than the rigid tree, but more so. They represent a thicker, tougher, more subtle and more complex view of structure.

If good vibrant cities are not “trees,” what about buildings? It seems the same logic applies: at the scale of buildings too, and especially as they connect to the public realm, we should seek overlap, multiplicity of aspect, and the other characteristics that Alexander celebrates. We should seek buildings that are more fine-grained, with redundant connections to the street, rather than one centralized “tree trunk,” as tall buildings typically feature.

In structural terms, we can compare a tall building to a kind of “vertical cul de sac” – or a kind of vertical gated community, with all the same potential problems of that problematic structural form.

And as we can now see, for similar structural reasons, such structures are also more resilient in the face of a pandemic.

The diagram at the top of the post, developed by the UK Urban Task Force in 1999, shows three schemes, each with exactly the same relatively high population density (75 Units/Hectare or 30 Units/Acre), but with very different network structures. The scheme of small flats to the lower right offers many different connections to the street, and it avoids centralized “choke points” where everyone must come into close proximity.

It’s often assumed — wrongly, as research has shown — that tall buildings are necessary to achieve higher population densities. Yet these three schemes all have exactly the same density. They only differ in the way that those populations can connect — as “trees,” or as “web-networks.” The tall building is clearly a tree, with all its structural vulnerabilities.

Unfortunately, at this moment in urban history, the growth of tall buildings around the world is nothing short of explosive. As research is showing, the factors that propel their growth seem to have less to do with best practice knowledge, and apparently more to do with the dynamics of short-term capital, images, branding, and even the egos of their promoters. This is not the path to sustainable or resilient cities. It may in fact be the path to catastrophe.

Let us hope that, as this pandemic prompts a reassessment of recent urban orthodoxy, the tall building, along with other mega-structures, will be part of a much-needed critical re-assessment.

How will the coronavirus pandemic affect public space?

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During the pandemic and at other times, it’s possible to maintain “sociable distancing” — to control our level of exposure to others for a variety of reasons.

Its biggest impact may be in prompting a re-assessment of the way we think about public space and density, says Michael Mehaffy of the Centre for the Future of Places.

EDITOR’S NOTE: In a podcast at public radio station WPKN of Bridgeport, Connecticut, architect and author Duo Dickinson talks to Centre researcher Michael Mehaffy about lessons from the current pandemic.   The link to the podcast is here, and the transcript below has been lightly edited for readability. 

Duo Dickinson: Well, I guess we’re back on Home Page Radio. In the miracle of wired radio, we’re having Home Page Radio generate from five separate sites this month, and this is the fifth site we’re going to be connecting with.  Which is Michael Mehaffy – Michael, are you there?

MM: I’m here, hey Duo!

Duo: Good to talk to you. We had just been on the phone before with Steve Mouzon, who told us the plain and simple truth, that things like copper door knobs and multiple entries are the old lessons of safety in a pandemic world, that are lost on, perhaps – it was Governor Cuomo that said that density is our enemy. We also talked to Ann Sussman who talked about the fact that design is not necessarily from on high or from a big box, but the way we think about the world actually empowers us to rethink the way our world is when we are sequestered at home, sheltering in place.

Well, Michael Mehaffy is an author and educator, a researcher, designer, consultant, all over the world… A Senior Researcher at the Ax:son Johnson Foundation, the Centre for the Future of Places, and he’s also Executive Director of something called Sustasis, and Sustasis Press. And he’s also taught all over the place, but he’s really very well-known. And how I’m associated with him is working with Christopher Alexander, author of A Pattern Language, a very famous book, and other people that deal with design in a different way than I think is usually presented in the press or by public perception.  And in that way, Michael, I’m going to ask you a very interesting question.  We’re all living at home now, we’re all sort of separated and segregated intentionally from each other.  In your lifetime of looking at congregating people in a good way, tell us what we can learn from this forced separation.

MM: Yeah, I think it’s really interesting actually. I think in a way this is a “teachable moment,” because it really forces us to think about how we interact with other people, and how we do that through the places that we live. You know, by the way, I’ve seen a lot of people just anecdotally, or heard about a lot of people, coming out onto their porches and their stoops, and trying to visit with each other, in spite of the social isolation that’s required in this pandemic.  And creating a kind of, I would call it, “sociable distancing” – you know, where we are still in proximity to each other, and that’s very very important, to still have that human contact. And in fact the research is showing that that in itself is really an important component of resilience, and of the way that people survive these kinds of crises.  The sociologist Eric Klinenberg has written about that, about the need for “social solidarity.”

And so I think we’re beginning to really re-assess the way that we have been building over the last 50 years or so — you know, as Steve was talking about: the sort of single-family detached, often isolated home that’s not very well connected to the public realm, that’s very car-dependent and so on.  And what I’m afraid of, frankly, is that this will reinforce some of those tendencies, of, you know, exclusion and isolation and car dependency.  You know, people holing up in their houses, binge-watching TV and so on. And not recognizing that we have to have that other component too, that sociable interaction – “sociable distancing” I would call it.

And also that density, as Steve was alluding to, is not just one thing. It’s not just all hyper-density all the time, but many different forms of density, and many different ways that we can sort of dial in our own comfort, our own degree of interaction with people – whether it’s because of a pandemic, and we have to be a little bit further away from people, you know, or just the level of comfort that we have as individuals at different times of our lives. That we want to be jam-packed and, you know, elbow to elbow with people at one time, and maybe we want to be more secluded at other times. And the spaces of our houses and our buildings, if they’re designed well, they allow us to do that, they allow us to self-organize our relationships with one another. And in turn, self-organize the buildings, and the way the buildings evolve and change over time.

Duo: Well let’s take that one step further.  So, where are you calling us from – or where are we calling you, actually?

MM: Well, I’m actually in a little town called White Salmon, right around the corner from where my daughter lives, one of my daughters.  The other daughter lives in the next town over, and she has a big wraparound porch that’s a great space. I was just over there visiting them – on the porch, because, you know, we can’t get too close to each other! But we –

Duo: (Laughs) What state is that in?

MM: They’re actually on the Oregon side of the Columbia Gorge, and I’m on the Washington side. It’s a really beautiful area.

Duo: Wow. This is pretty exciting to me, to basically see an entirely different world through your eyes. What I’d like you to – you know, I know of your work – you’ve actually studied I think the way humans live together as well as anybody that I know of. And I’d like to you sort of – now that you’re forced to essentially detach yourself from other people as much as possible – could you let everybody listening to you, with all of your experience, tell us of any things you’ve learned in this last week or two, where you’ve been forced to be alone in your place.

MM: Well, I think it’s just reinforced to me the importance of this social solidarity, as Klinenberg refers to it. And “sociable distancing.”

You know, both of my daughters and I live in small towns, but they are very urban places, they’re walkable, they’re very well interconnected. And you know, as Steve was talking about with Barcelona, a city that has lots of spaces that interconnect with the public realm. Not just one big tall building where everybody is, you know, they come down and they’re suddenly in a very very high density environment, like might be the case in Manhattan, for example. I mean that’s one extreme of density, but the other – it’s not just two choices here, it’s not that versus holing up in your apartment alone.  In fact that, as Klinenberg showed us, is very very dangerous in a crisis, because people tend to die. They lack the social connections that help them to adapt and survive.  So we need all those different gradients of interconnection with each other, and we need them in our environments, in our built environments.

So you know, I think people tend to look down their noses, some architect friends of mine who are avant-garde designers, at the idea of porches, for example. Well that’s, you know, old-fashioned or something.  Well, no, it’s simply a form of evolution that’s very intelligent, and we need to start thinking that way.  And I think, get off this – Ann Sussman alluded to this a little bit too – get off of this sort of industrial art approach to human environments.  That we’re sort of costuming up with our avant-garde abstract art, these industrial products that are often quite toxic to human well-being. And we need to get back to the kind of thing that Steve Mouzon is thinking about, of a more natural, evolutionary way of thinking about human environments.  And why human environments are healthier for us, and easier for us to connect to one another – easier for us to make changes that make us more comfortable, so we are actually more willing to be sociable and interact.

So I think that – to me, this experience has been fascinating, and scary, and disturbing in many ways – but also inspiring in many ways. You know, when I heard about the people in Italy coming out onto their balconies and opening their windows and singing, and seeing people coming out onto their porches and stoops, and you know, having “sociable distancing” rather than just isolating themselves. And so I think we’re seeing in a way, first-hand, this kind of self-organization that happens, this kind of resilience that happens.  And we’re seeing it working really well in some places, and not so well in some places. And I think that’s a really interesting lesson right now.

Duo: So as you’re dealing with these macro issues of how people live, in terms of creating, for lack of a better word, walkable places – places which are not dependent on gigantic cars and gasoline, really places that are not, don’t even have sidewalks, the normal mid century American lifestyle. And you’re thinking about this reality, that humans should be closer together, that’s actually becoming now, I think, a general social consensus, humans should be denser. When you’re looking at the present situation, where density can be called toxic by the governor of New York, tell us – because this is a rare opportunity, now that you’ve had a chance to really self-separate, from a life of extreme social integration and intellectual thinking about what has happened – tell us what you think of the future of the world after this. Because this will change, I think, the way people think about the way they live.  And tell me what you think, how that will change.

MM: I hope so. Again, I think it’s a teachable moment – I hope it’s a teachable moment. Because we do have a moment of opportunity to rethink some of our assumptions. And one of them is that whole idea of density, as you said. People think of density as sort of being all one thing or all not one thing. It’s like either super crowded, you know, Manhattan streets or it’s nothing, it’s isolated behind your, you know, gated community and your car dependent neighborhood. No! There’s a whole tissue of relationships and kinds of urban spaces that can exist, and should exist, and does exist in many places, including the small town where I am right now. And I think it’s important for us to think polycentrically that way – that there’s big cities, there’s small towns, that everybody can have that kind of interconnected web of relationships in their neighborhoods and their towns.

And there’s international policy agreements that are really beginning to describe that in detail. There’s something called the New Urban Agenda, which was agreed to by all 193 countries of the United Nations – a lot of this language described in it. We’ve been involved in that for a number of years now. And there are other things going on – you mentioned Christopher Alexander, I think a lot of people are beginning to come back to his work. And we have a new book as I think you mentioned, A New Pattern Language for Growing Regions, which describes some of the work that’s going on in the New Urban Agenda, and the idea of walkability and sociability, and all these ideas that we’re beginning to in some cases discover, and in some cases rediscover. And I think it’s an exciting time in that sense.

Duo: Well, in these closing minutes, the one thing I’m really fascinated by is the fact that the zeitgeist of a month ago, the zeitgeist in, really, the world, of massive systems of connection, of massive ways of eating, of interacting, where people would essentially cook less and less at home, would be more outside of the home, would be completely engaged in stream behavior, now that the pandemic has forced us to snap a lot of that, and actually depend more on streams to connect rather than disconnect, and also to cook as opposed to order food, I would love to hear your analysis of – and if you don’t know him out there in radio land, Christopher Alexander, who has for fifty years, recreated the way architects should think about things in the world and how they design – tell us how the pattern language book that you’re dealing with now… tell us how the essentials of that relate to how people might look at their homes in this house-bound time.

MM: Well, I think you put it very well.  I think this moment, this crisis, is forcing us to recognize how non-resilient a lot of our systems are, how non-adaptive they are, and how vulnerable we are. And the antidote to that is to be more resilient, and that means more interconnections, more sort of polycentric approaches instead of the too-big-to-fail approach, which is obviously getting us into trouble. And the idea that we can have different levels of scale of things going on in our lives, that allow us to cope, and to interact, and to solve problems.

You know, that’s a whole other subject, what is resilience and how do we get it.  But I think this moment is really forcing us to think about that in a way that I think is a great opportunity, if we’ll use this crisis to, again as I said, as a teachable moment, to think about how we can make more resilient, more sustainable kinds of ways of living.

And I think Chris Alexander is one of the guidestars for that way of thinking, along with people like Jane Jacobs and a number of others. Again, people are beginning to come back to read these folks again, and recognize that what they’re saying has a whole lot to do with where we are right now in history with this pandemic. So again I think it’s a time to move forward with some innovations, but also to recognize some of the mistakes we’ve made with the, you know, novelty approach, and the abstract art approach, and begin to focus more on human beings, and human adaptation, and human environments.

Duo: Well it’s been great to have you on the show, Michael Mehaffy, and we really appreciate your time, and we’ll have you back again! So thank you very much.

MM: Delighted, Duo.

Is it time to revive the pattern language?

Software and other fields have made brilliant progress with the methodology, while built environment fields lag badly – mired in parochial debates over a 1977 bible-like volume

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Launch of A New Pattern Language for Growing Regions: Places, Networks, Processes book and wiki at the 2020 World Urban Forum in February. Wiki inventor Ward Cunningham was interviewed by collaborator Michael Mehaffy.

Although virtually everyone uses Wikipedia routinely today, what is remarkable is how few know its surprising provenance in the world of planning and architecture.

Wiki, the methodology that powers Wikipedia, was invented by a computer scientist seeking to create a web-based system to share “pattern languages of programming” – an idea he and his colleagues had exported from architect Christopher Alexander’s 1977 classic A Pattern Language: Towns, Buildings, Construction.

Pattern languages are, at heart, nothing more than “a method of describing good design practices or patterns of useful organization within a field of expertise,” as Wikipedia describes them. The “pattern” encapsulates some key relationship within the set of design elements, which, if configured in the “right” way, will produce the desired outcome. Each pattern typically includes a name, problem-statement, discussion conclusion, and hyperlinks.

The genius of the method is that each pattern is nested within many other patterns, connected by hyperlinks, and forming a relational web-network. The patterns can then be applied in a contextual, language-like way. Software designers clearly found the method enormously productive: pattern languages of programming (or “design patterns”) have been put to use in most game software, many other programs, and many operating systems.

Ward Cunningham, the wiki inventor, actually envisioned each wiki page as a kind of pattern in its own right, with title, photo, summary, discussion, and hyperlinks.  A few years after his 1990s invention, the developers of an early online encyclopedia enthusiastically applied the new system (and its name) to their embryonic creation, with now-familiar results.  Nor is wiki limited to Wikipedia, of course, but it permeates the web (Google Sites, Wikihow, Mediawiki, etc).

Pattern languages have had other phenomenal applications too, growing out of software (leading directly to Agile, Extreme Programming and Scrum) and also an astonishing range of other fields, from molecular biology to sociology to engineering to manufacturing, to seemingly countless others. One can find online citations to papers on pattern languages for music composition, pattern languages for weddings, even pattern languages for writing patterns. (!)

The one field that has lagged most conspicuously is, curiously, the very one for which pattern languages were invented, the built environment. What can explain this anomaly? It seems there are a number of likely factors – the bias of architects against anything that they imagine might limit their “creative freedom” (a debatable idea at best), the greater willingness of other fields, especially technology,  to embrace functional innovation (not just novelty for its own sake), and the more pragmatic, less ideologically constrained nature of other disciplines in relation to architecture.

But perhaps the most powerful explanation is the very success of the 1977 book. Resembling a nothing so much as bible, it is full of pronouncements that were forever locked in print, and never allowed to be tested and refined.  The cult-like veneration shown by some was matched only by the contempt held by others.

Yet this outcome was contrary to the explicit aims of the authors, as they made clear in the introduction:

You see then that the patterns are very much alive and evolving. In fact, if you like, each pattern may be looked upon as a hypothesis like one of the hypotheses of science. In this sense, each pattern represents our current best guess as to what arrangement of the physical environment will work… But of course, no matter what the asterisks say, the patterns are still hypotheses, all 253 of them — and are therefore all tentative, all free to evolve under the impact of new experience and observation. (Alexander et al., 1977, pages xv-xvii)

But that evolution never happened, of course.  Instead, the 253 patterns became trapped in their original bible-like volume, protected even by copyright, and never to be altered, added to or differentiated. Other fields, unencumbered by such a dominant first corpus, made brilliant progress, while work in the built environment stagnated.

So what can be done now to push forward more productive work in the built environment?  Two developments offer an opportunity for a fresh start.  One of them is the development of a new framework agreement on urbanization, adopted by acclamation by all 193 countries of the United Nations, and known as the New Urban Agenda. Many of the elements of the New Urban Agenda can be expressed in pattern-like forms, offering the potential for a new collection of patterns based on this document.

The other development is a new generation of wiki, authored by the original inventor, Ward Cunningham. This “federated” wiki allows copies to be made, shared and altered more easily, using handheld or desktop devices. Its limitations are as broad as the limitations of new app capabilities – data calculations and modeling, field measurements, augmented reality visualization, and a host of other new capabilities undreamt of by the original pattern language authors.

Accordingly, our team, based at the Centre for the Future of Places at KTH University in Stockholm and at Sustasis Foundation in Portland, Oregon, have partnered with Ward Cunningham and other collaborators to develop a new pattern language collection, together with a companion wiki. A New Pattern Language for Growing Regions contains 80 new patterns, many encapsulating elements of the New Urban Agenda.  The companion wiki, at npl.wiki, contains the same patterns in wiki form. The wiki is currently read-only, but will become editable and shareable in the near future.

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The companion wiki (available online at npl.wiki) can be used on a smartphone or desktop. Each pane is a pattern, linked to other patterns through networked hyperlinks, and able to be navigated and assembled for application in specific projects. The wiki will soon be editable, allowing the revision and addition of patterns for a wide range of potential project applications.

The new patterns reflect not only the New Urban Agenda, but the new thinking about urbanization and its requirements for a more sustainable age – reformist ideas going back to the work of Jane Jacobs and others. They include patterns on mixed use, walkability, public space, multimodal transportation, interconnected street grids, and other characteristics of diverse, well-connected urbanism.  There are also patterns covering historic regeneration, slum upgrading, suburban retrofit, and other timely issues.  Other patterns cover new technologies, like citizen data and autonomous vehicles.  Another category covers implementation tools, including financial mechanisms, governance structures and the like.  A more experimental category covers geometric characteristics – similar to those later explored by Alexander – including local symmetries, fractal patterns, grouping and framing.

As with the first generation of patterns, the aim is to set out normative propositions supported by evidence, and accordingly, each pattern has one or more research citations justifying its claims.  Of course these can all be debated, and the aim is not to end discussion, but to begin it.  If another party has an alternative pattern, justified by alternative evidence, let them present it, and let us have a proper debate on the evidence.  Let us not continue to argue ex cathedra for sectarian dogma. That is not how the other fields have made such progress in meeting their challenges.

Another point is the normative nature of the patterns. These are unabashedly so, in the belief that all work in the built environment is shaped by normative judgments, and the only question is whether these values are on the table for examination and challenge. As Kevin Lynch pointed out in Good City Form, the danger is not having values, but failing to make them transparent. Too often these values are cloaked behind claims of expertise or artistic privilege, rather than sound examination and collective evaluation.

Some will note that we adhered closely to the original design of the patterns as printed in the book.  This is because the original patterns have been proven user-friendly and successful, and attempts at altered versions in the built environment have proven less so. Furthermore, a similar format also helps to make the original patterns more useful as part of larger project-based collections.  Alexander and his colleagues also described “the essential purposes behind this format,” which suggest that alterations without cause are unwise. This project is intended to be rooted in evidence of what works, and the evidence that the original pattern structure has worked is undeniable.

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Copes of the new pattern language book on display at the World Urban Forum.

Finally, this project is meant not as an end but a beginning.  The first collection of 80 patterns is only a small and partially representative sampling of what is possible, and surely necessary, as we confront a new generation of challenges.  The wiki should make it possible to produce many hundreds or thousands more, just as Wikipedia grew from a few hundred entries to today’s vast collection. The patterns can be collected periodically into print editions, or continue in online form, or both. More importantly, they can be applied to specific projects and specific contexts in different parts of the world, adapted, refined and added to, so that the most universal patterns can be widely shared, and the entire collection can grow and diversify.

Whether or not this particular project is the spark of a revival of pattern languages in the built environment, we are convinced that such a revival is long overdue.  A profound transformation is under way in our technological systems, reflected by Agile Methodology, Scrum, wiki, and yes, patterns. The transformation is driven by a recognition that the old linear methods have failed us, and we need better web-networked ways of working. In the built environment especially, the need for ways to document and share successful evidence-based design methodologies, capable of achieving desired goals, is matched only by the current gap in achieving them.

Michael Mehaffy is Senior Researcher at the Centre for the Future of Places, and Executive Director of Sustasis Foundation and International Making Cities Livable (livable-cities.org). He was a student and long-time collaborator of Christopher Alexander, and he has been a collaborator of Ward Cunningham for over a decade. More information is available about the wiki and book at Sustasis.net/APLFGR.html.

 

Reactionary modernism strikes again

EU urban development policy is taking a big step backward by embracing an outmoded ideology governing new construction in historic contexts

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Under the new Article 16, the faithful reconstruction of, say, the campanile in Venice after a collapse (as happened in 1902) would be forbidden as an “extension” of the “monument” of Piazza San Marco. Instead, a “contemporary” insertion would be required – perhaps like this Madrid building?

Michael W. Mehaffy and Nikos A. Salingaros

Imagine the following scenario. It is 1902, and to the great shock and distress of the citizens of Venice, the beautiful campanile tower in its Piazza San Marco has just collapsed. That very evening, the city’s communal council votes to approve 500,000 Lire for the prompt rebuilding, “com’era, dov’era” — “as it was, where it was.” Future residents and visitors alike may now continue to enjoy this beautiful structure, which had also been restored and added to many times previously.

But then a bureaucrat from far away steps up to speak. “Our standards do not allow this! Our funding policies require that ‘a project shall use contemporary design’ — which means that you may use only current styles of which we approve, and you may not use the traditional styles of Venice. That would be a ‘falsification of history’, a ‘mingling of the false with the genuine’, and we decree that this would have harmful consequences!” The project does not go forward, and something entirely “contemporary” is built instead.

The first part of this scenario did in fact occur — the campanile was rebuilt, to the delight of citizens and visitors for over a century since. The second part of the scenario is in fact what would occur under a current EU proposal governing new construction in historic contexts that would restrict funding for such projects unless they are “stylistically correct” — that is, unless the authorities deem them to be suitably “contemporary” in design.

The last few phrases of the scenario come verbatim from a document written by a group of modernist architects in 1933, one that was deeply influential upon architectural theory — to the great detriment of cities and their inhabitants (and their broader heritage) ever since. Their ideology still haunts current policy, and drives the current proposal. We will come back to examine this point in more detail later.

Meanwhile, the current provision at the EU is “Quality principle/recommendation number 16” of the “European quality principles for EU-funded interventions with potential impact upon cultural heritage.” It states:

“When new parts/elements are necessary, a project shall use contemporary design adding new value and/or use while respecting the existing ones.” (Emphasis added)

This is a subtle but radical provision. In addition to prohibiting the reconstruction of the Venice campanile, it would decree, for example, that the reconstructions of historic Warsaw, Dresden, Potsdam, and many other cities obliterated during World War II, would not be permitted. Individual buildings, too, could not be reconstructed, except as “contemporary designs” — which is to say, again, only those particular styles that the authorities deem to be “contemporary”. To make this determination, civic and political authorities of course defer to architects with a “contemporary” stylistic agenda. That might mean, for example, something like a swoopy new spire would be mandated for the reconstruction of Paris’ Notre Dame Cathedral. The reconstruction of the beautiful spire destroyed by the 2019 fire, or any other traditional design for that matter, would be forbidden.

This provision surely warms the hearts of those architects who would prefer to build their own contemporary novelties, without competition from other architects who may be more skilled in traditional design. However, for the citizenry at large, for city leaders, and for those in other disciplines, Quality Principle Number 16 ought to be deeply troubling, for several reasons.

First, there is the sheer value of economic development in places like, for example, the rebuilt historic center of Warsaw. Tourists come to such a place to revel in its atmosphere and its beauty, and to dig into its history — whereupon they may learn, through appropriate interpretive materials, all about the postwar reconstruction (a historic event in its own right). A prohibition against creating such an economic as well as cultural treasure — forbidden purely on stylistic grounds — would carry potentially enormous negative economic impacts. In some cases, these impacts would be felt most by remote communities that can ill afford to do without the appeal of reconstructed heritage (suitably identified as such).

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Warsaw’s beautiful and popular Old Town, a major economic engine of the city. The district was entirely rebuilt after the German army leveled it in World War II.  Such a reconstruction (an “extension” of a “monument”) would be forbidden under the new EU standard. (Image courtesy https://fshoq.com)

Second, there is the troubling spectacle of experts arrogating to themselves the exclusive right to dictate what kinds of environments regular citizens may occupy and enjoy. Human environments must accomplish many goals, only one of which is to tick professional boxes of what some group considers as historic “authenticity”. They must also delight, comfort, support, and adapt to human need. One of the ways we ensure they do so, particularly in a democracy, is to involve the citizens in the shaping of their own environments. By contrast, there is something fundamentally undemocratic about experts dictating “a project SHALL use contemporary design”. Of course, it is those same experts who then deem what constitutes “contemporary” design.

Third, this proposal betrays an appalling fallacy in thinking — namely, that every period of history is “authentically” represented by one and only one style, which is “contemporary” to that period. Therefore, under this logic, every new act of building must be fully legible as to its period of creation, offering up the one and only correct semiotic expression of its historic identity.

This is complete nonsense. History is not a line but a fugue, with revivals and recreations and novelties all mixed up together. Nor is there one authoritative source of the “correct” expression of a given time and place, but rather, there are almost always multiple competing claims to expression of a given time or a given culture. That is an essential part of history, and we do ourselves no service by oversimplifying history to a neatly linear one-track scheme. Historians today acknowledge this complexity and multiplicity, and are focused on providing interpretive materials to allow viewers to sort out these complex and often competing narratives for themselves.

Where, then, did the impetus for this stylistic dictate come from? The answer is all too simple: from ideological architects, who believe that modernism (and its postmodern variants) is the one and only authentic architecture of our time. Curiously, it was also the architecture of the 1930s, 1950s, 1960s… and apparently, all future time too. One thing is certain: anything like revival or reconstruction of what existed before 1930 — or even any new construction building on traditional pattern and precedent — is a cardinal sin.

This philosophy was perfectly summarized by the enormously influential Athens Charter, purportedly the outcome document of the 1933 Congrès Internationaux d’Architecture Moderne conference, but written mostly by the architect Le Corbusier and published a decade later. Here is Le Corbusier’s pronouncement, in Article 70 of the Charter, on new construction in historic contexts:

The practice of using styles of the past on aesthetic pretexts for new structures erected in historic areas has harmful consequences. Neither the continuation of such practices nor the introduction of such initiatives will be tolerated in any form. Such methods are contrary to the great lesson of history. Never has a return to the past been recorded, never has man retraced his own steps. (Emphasis added.)

Anyone acquainted with architectural history knows that this is, of course, the sheerest nonsense. Never has a return to the past been recorded? The Renaissance did not happen, Jefferson did not recapitulate Palladio, did not recapitulate Vitruvius, did not recapitulate the Greeks? Le Corbusier’s is a simpleton’s view of history, a single straight line in which everything moves forward, always forced to be new, always different.

We can be thankful that history is far richer and more complex, and that it exhibits the ready capacity to compound, to learn, and to evolve over time. Like natural systems, our human systems are able to build on what came before, not simply discarding it (in the modernist Walter Gropius’ tart phrase, “starting from zero.”) A biological analogy for that severe restriction might be that evolution may not use the rich genetic material of pre-existing organisms, but must always start over again with, say, amoebas.

But among architects, the 1933 Charter of Athens was a profoundly influential document, and it is difficult to over-state the impact it has had on the human environment ever since. Its application has been profoundly negative, as many scholars have documented. The idea that everything must be radically new, must be stripped of all ornament, must avoid ALL associations with the forms and patterns of the past — the enormity of that restriction is hard to grasp. Again to use an analogy from genetic evolution, this would be like saying to a dolphin, “your dorsal fin looks far too much like a shark’s, yet you are from 300 million years later — that fin design is old, outdated, and traditional, and therefore it has to go!” Perhaps the dolphin might adopt a swoopy fin too…

Those who are not associated with the architecture profession, as we are, might find it bizarre, then, that such an ill-considered ideology shapes human society, to this day. As one theorist observed, “modernism’s alchemistic promise, to transform quantity into quality through abstraction and repetition, has been a failure, a hoax: magic that didn’t work.” And yet this outmoded ideology, almost a century old, persists in some corners, as we see now. It persists in the status quo thinking of many architects and even some officials and members of the public — and it even persists in some legislation.

One place where this ideology persists is in the 1964 Venice Charter on the Conservation of Monuments and Sites, used by many governments to shape their legislation regarding conservation. Modernist architects are fond of quoting Article 9, which calls for new work to “be distinct from the original composition and must bear a contemporary stamp.” They interpret this article to mandate a “contemporary design”, i.e. a modernist or neo-modernist insertion. But a 2006 conference of heritage and conservation professionals concluded that the goal of legibility is only one goal, which needs to be considered in relation to others:

This goal must be dynamically balanced with other needs, including the need for coherent and enduring human environments. Thus, new work may be distinct from the original composition while still harmonizing with that composition. A contemporary stamp may be provided in a number of ways, including interpretive information or identifying marks or characteristics. It is not necessary to create a striking juxtaposition, which may violate the mandate to preserve the traditional setting or the relations of mass and color [as called for in Article 6].

This is a crucial point that is conveniently overlooked by modernist ideologues. Most importantly, Article 6 of the Venice Charter flatly states:

Wherever the traditional setting exists, it must be kept. No new construction, demolition or modification which would alter the relations of mass and color must be allowed. (Emphasis added.)

This article flies in the face of the mandate for “contemporary” insertions, which often violate the scale, mass, form, color, etc. (The crucial question not usually asked: why this stubborn insistence on breaking every form of harmony?) Article 6 also clearly opens the door to sympathetic new construction in a similar traditional form that acts to “preserve the traditional setting” and the “relations of mass and color” — assuming that the new work can be differentiated through some kind of “contemporary stamp”. This could be literally – as in the photo below –  a date stamp!

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This building in a traditional character, located in the historic Nob Hill District of Portland, has a literal date stamp on its front showing its construction in 1992.  No one would be fooled as to its historic origins. (Image: Google Maps.)

It must be noted here that, although the current standard is an EU one, this is not merely a European problem. After all, Europe has historically been enormously influential in imposing its urban and architectural theories on  the rest of the world, not least in its invention of the modernist “International Style.” The decision-making economic/political classes in other countries are unfortunately still swayed by these ideologies, as evidence shows – to the great detriment of local architectural and urban cultures. This is all the more ironic since, having ousted former colonial powers, many national governments continue to uncritically follow fashionable ideologies from power centers elsewhere.

The broader issue is this: will non-architects, and others not specialists in conservation, continue to allow an outmoded century-old ideology to cause the degradation of cities, even (especially) in their most historic and most beautiful cores? Or will we see a continued (and increasing) uprising of citizens, activists, non-architect professionals, and other concerned leaders, demanding that architects and other specialists raise their game, and create a new generation of more humane, more historically rich human environments? The current controversial standard poses an important and timely test of that question.


The full EU proposal can be viewed here: http://openarchive.icomos.org/2083/1/European_Quality_Principles_2019_EN.PDF

An ongoing series of essays updating notions of historic preservation and heritage for our times is published by the National Trust for Historic Preservation:

Building Tomorrow’s heritage. I. What historic structures can teach us about making a better future

Building Tomorrow’s Heritage. II. Lessons from Psychology and Health Sciences

Building Tomorrow’s Heritage. III. Correcting “Architectural Myopia”

About the authors: Michael W. Mehaffy received his Ph.D. in architecture at Delft Technical University and has had five appointments in university architecture departments in five countries. He is currently a senior researcher with the Centre for the Future of Places at KTH Royal Institute of Technology in Stockholm. Nikos Salingaros is a professor of mathematics and architecture, and an award-winning architectural theorist

Wonders of the “urban connectome”

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Cities, like brains, are immense networks of connective patterns built up over time. Understanding this evolving structure will help us to formulate better urban policies and practices.

Few developments in the sciences have had the impact of the revolutionary discoveries in genetics, and in particular, what is called the “genome” – the totality of the complex pattern of genetic information that produces the proteins and other structures of life. By getting a clearer picture of the workings of this evolving, generative structure, we gain dramatic new insights on disease processes, on cellular mechanisms, and on the ultimate wonders of life itself. In a similar way, geneticists now speak of the “proteome” – the no less complex structure of proteins and their workings that generate tissues, organs, signaling molecules, and other element of complex living processes.

An important characteristic of both the genome and the proteome is that they work as totalities, with any one part potentially interacting with any other. In that sense, they are immense interactive networks, with the pattern of connections shaping the interactions, and in turn being shaped by them. Proteins produce other proteins; genes switch on other genes. In this way, the structure of our bodies evolves and adapts to new conditions – new infections, new stresses, new environments.

It turns out that something very similar goes on in the brain. We are born with a vastly complex pattern of connections between our neurons, and these go on to change after birth as we experience new environments and learn new skills and concepts. Once again, the totality of the pattern is what matters, and the ways that different parts of the brain get connected (or disconnected) to form new patterns, new ideas and pictures of the world.

Following the naming precedent in genetics, this structure is now being called the neural “connectome” (because it’s a structure that’s similar to “genome”) and the race is on to map this structure and its most important features. (Much of this work is being advanced by the NIH’s Human Connectome Project.)

What do these insights have to do with cities? As Steven Johnson noted in his book Emergence, there is more in common between the two structures than might appear. There is good reason to think that, as with brains, a lot of what happens in cities has more to do with the overall pattern of connections, and less to do with particular elements.

As Jane Jacobs pointed out over half a century ago, the city is a kind of “intricate ballet” of people interacting, going about their plans, and shaping the life of the city, from the smallest scales to the largest. This intricate pattern is complex, but it’s far from random. As Jacobs argued, it exhibits a high degree of order — what she called “organized complexity.”

And it’s physical, starting at the scale of the sidewalk, and encompassing all the other movements and connections of urban activity. “Sidewalk contacts are the small change from which a city’s wealth of public life may grow,” she wrote. We may also be plugged in electronically by telephone and now Internet, but (as research by Robert Putnam and others is showing) the root of the system is the physical proximity with the people we know and work with.

More than that, this pattern of connections generates remarkable efficiencies, forming a kind of “network metabolism.” Jacobs has since become famous for observing highly local “knowledge spillovers,” casual transfers of knowledge about a job or a new tool or idea, that help to grow new enterprises and new economic activities. Her insight, now called a “Jacobs externality” by economists in her honor, helps to explain how a city generates wealth. As we have written before, this phenomenon might well help to explain why cities are so efficient with resources per person, relative to other places.

In the same vein, the brain scientists offer some other important insights. For one thing, more important than the density per se (of neurons, or of people) are the patterns of connections. So we have to be able to ensure that many “neural pathways” can form and re-form – in the case of a person’s brain, that the person is healthy and well-nourished enough to remember, and learn. In the case of cities, we have to ensure that we have well-connected, walkable cities, facilitating many cross-connections.

The brain scientists even believe now that this pattern of neural cross-connection is key to the formation of consciousness. In effect, the different parts of the brain join up into a larger system, and the result is that the system self-organizes into a state that is smarter and more aware. When a brain sleeps, this larger pattern seems to dissolve into fleeting sub-patterns – and we experience the loss of consciousness, and sometimes, dreaming.

Something similar might be going on with well-connected cities: they can self-organize to become “smarter” in their ability to generate great urban vitality with fewer resources. But this is true only if their “neurons” (the people) are able to be connected, especially physically connected, in this way.

Similarly, a city can “lose consciousness” by becoming too fragmented and too sprawling. Automobiles and other machinery can help to connect the parts of the city, but only in a very limited and encapsulated way. By contrast, a walkable public realm has vastly more capacity to form and re-form connections between people, allowing a dynamic pattern of interaction to form and sustain across the city’s urban fabric.

This lesson of self-organization carries an important implication for planners and urban designers. It suggests we need to focus less on the specific elements in relation to one another – and how we might imagine they are best placed – and focus more on how we can help them to self-organize into more complex (and more efficient) patterns.

On the other hand, human brains do not start from scratch as we once thought, nor do societies – we all have patterns that we learn and apply to new situations. So too, cities have patterns that facilitate this network structure. Like a good memory or innate knowledge, the best walkable cities of history offer us many good reusable patterns to create vibrant, walkable, resource-efficient cities.

A corollary is that in our automobile-connected suburbs, it seems we have been replicating this pattern of connections – but only with heavy and unsustainable inputs of resources. Furthermore, as noted before, the structure of encapsulated cars, and existing networks of people we already know, are no match for the open-ended nature of public space networks, and their capacity to exploit “propinquity and serendipity” – the accidental connections with people we don’t already know, where, as research shows, the new knowledge and innovations form. If we want more resource-efficient cities – and more creative and resilient economies – then it seems we will have to look much harder at this dynamic, and ways to exploit it to our advantage.

How can we do this, concretely? The brain scientists are working hard to map the connective patterns of particular brains, to get some idea of how the patterns tend to form characteristically within the “human connectome.” For cities, it seems we might do something equally useful: map the characteristic urban patterns that have proven most conducive to this connected vitality, and that also do not interfere with – or better yet that promote – the capacity for urban self-organization.

In a sense, we already do this when we speak of design types, or planning models. But this work is usually very constrained by parochial debates within the architecture and urban design disciplines over “progressivism” versus “historicism.” The result is that there has been a stagnation of real progress in this area. At worst, we have slipped into what Jacobs called a “neurosis” of “imitating empiric failure, and ignoring empiric success.”

By contrast, the brain scientists point to another, less ideologically constrained path. It seems we might have much to learn from a more open, aggressive mapping and re-applying the genetic patterns of such an “urban connectome,” looking at the most effective patterns from a range of cities around the world – and over centuries of evolution.