Friday, May 9

Book: A Pattern Language

A Pattern Language, by Christopher Alexander et al., has to be one of the most fascinating books I've ever read. Thirty years later, it has grown into somewhat of a movement. Set up as a do-it-yourself reference book for building everything from metropolitan regions to window panes, it actually serves equally well as comprehensive philosophy of life. The patterns are heavily analytical (Alexander is not afraid to put precise numbers on just about anything) and are presented as "deeply rooted in the nature of things," yet they are intended to be pieced together by individuals in unique ways, even as a form of poetry. The larger the scale of the project, the more gradually it must be formed from grass-roots action and the cumulative input from thousands of small decisions. This is how a town is built, according to Alexander.

The medium of a blog post does not lend itself well to a full-scale summary of the book, because of the sheer volume and diversity of topics covered. The patterns range from highly practical to radical to the point of absurdity, like the suggestion that zoos ought to be abolished and instead wild animals should be unleashed to roam around an interconnected greenway in urban areas. If I could discern one underlying idea, it is that our built environment should be composed around the limits of human proportions rather than according to a modern rationalized form.

Here's my reaction to a few of the more interesting patterns that pertain to urban design:

Pattern #21: Four-Story Limit. There is abundant evidence to show that high buildings make people crazy. In any urban area, no matter how dense, keep the majority of buildings four-stories high or less. It is possible that certain buildings should exceed this limit, but they should never be buildings for human habitation.

This is the difference between Paris (La Defense excepted) and New York. Alexander takes four-stories to be the maximum amount people would be willing to walk up stairs and the furthest any dwelling should be separated from the vital social realm of street life. He cites evidence to suggest that high-rise buildings are correlated with mental health problems. This is probably the most famous of the patterns, and the precise psychological effects have been heavily debated by environmental psychologists. Yet it fits entirely within the larger picture, that buildings should be created around human potentiality and foster social connections.

Pattern #10: The Magic of the City. Put the magic of the city with reach of everyone in a metropolitan area. No one downtown can serve more than 300,000 people .. between 2 and 9 miles apart. Pattern #12: Community of 7000. Decentralize city government in a way that gives local control to communities of 5000 to 10,000 persons. Pattern #14: Identifiable neighborhoods. Help people to define the neighborhoods they live in, not more than 300 yards across, with no more than 400 or 500 inhabitants.

Here the concentric circles of human interaction are precisely defined. 300,000 is the population necessary to inculcate an undefinable cultural vibrancy that the city offers. Larger than this, and too many people are pushed to the margins. 7000 is the ideal unit for a self-governing democracy, so that no citizens should be two friends away from the highest point of the political hierarchy. Finally, Alexander's picture of the neighborhood has probably been the most influential for New Urbanists. 500 is the maximum number of people who can form a relational identity group that is capable of making cooperative decisions.

All of these levels of "community" are delineated spatially. A neighborhood cannot exceed a 3 block radius from any residence or people would not walk, and it cannot be bisected by a major road, and various geographical barriers can be used to separate out these population groups.

Pattern #18: Network of Learning. Instead of the lock-step of compulsory schooling in a fixed place, work in piecemeal ways to decentralize the process of learning and enrich it through contact with many places and people all over the city. Pattern #26: Life Cycle. Make certain that the full cycle of life is represented and balanced in each community. Set the ideal of a balanced life cycle as a principle guide for the evolution of communities. Pattern #40: Old People Everywhere. Old people need old people, but they also need the young, and young people need contact with the old.

A Pattern Language calls attention to a form of diversity that is often overlooked. Modern institutions, from grade-schools to retirement villages, are often formed around rigidly segregated age groups. As an individual passes through life, he is jolted from one context to another, losing the potential for a seamless fabric of memory attached to a particular place. And as a society, we lose out on the perpetual exchange of learned wisdom and creative energy that has long passed between the young and old. How can these peer groups be geographically integrated throughout the city? Alexander discusses specific ways to design small-scale institutions that can be mixed into the larger setting of the city.

There are hundreds of other patterns. How can design make the most of natural light? How can we minimize the damage done by automobiles? (parking should never take up more than 9% of the land. Pattern #22). What types and sizes of housing are appropriate for different family units? How can design reflect a healthy balance of privacy and community? How can naturally flowing water give life to urban areas?

An endless number of paths to explore. I'm holding onto this book. It took eight years to write but may taken even longer to properly read.


Brooktrout said...

Thanks for your review. I've been reading and re-reading -- and enthusiasticlly recommending -- A Pattern Language for at least 30 years. Even so, your observations help me see the bigger patterns in the work, and delight in them anew.


Oliver Swann said...

I hope you will find this illustration of 'A Pattern Language' using naturally built homes helpful.

Regards, Oliver