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  • Michael Mehaffy

How Christopher Alexander's "Fifteen Properties" can guide us to create buildings and neighborhoods that are more alive

The legendary architect's later magnum opus The Nature of Order, not as well known as his earlier work, contains a hidden treasury of geometric resources for designers

ABOVE: An excerpt featuring Christopher Alexander's explanation of his ideas in his later book The Nature of Order. Here he explains why he felt the book was necessary as a followup to the landmark A Pattern Language, and how a consistent set of "fifteen properties" can guide designers to create more life in their work.

NOTE: This post is part of a series presenting topics for discussion at the upcoming International Making Cities Livable (IMCL) conference in Cortona, Italy, October 29-November 1, 2024. The conference, titled "The Ecology of Place: Learning from Nature, Culture, and History," will feature a focus on the work of Christopher Alexander, and others.

CORTONA, ITALY - One of the topics we will explore in the 61st International Making Cities Livable conference is how to create urban places that are more supportive of human life and flourishing. We will see many great precedents of urban space in Cortona and the surrounding hill towns, and we will hear from many leaders in the field about the latest developments and resources for great placemaking.

One of the leaders in the field for many decades was the late architect Christopher Alexander, whose well-known book A Pattern Language: Towns, Buildings, Construction, has become a perennial best-seller. The book offers a widely influential set of design ideas that have had an impact far beyond the world of architecture. For example, the book sparked a major new methodology in computer science known as "design patterns" -- which in turn led to wiki (and Wikipedia), Agile Methodology, and other highly influential developments in software and beyond.

Within the fields of environmental design, too, many people regularly use Alexander's pattern language methodology, expressed in the original collection of 256 patterns. Added to them are the patterns of many other books and websites published since then (including our own A New Pattern Language for Growing Regions: Places, Networks, Processes, also available as a wiki created by Wiki inventor Ward Cunningham).

Less well known, though -- and even now offering exciting new opportunities -- is Alexander's later magnum opus, The Nature of Order: An Essay on the Art of Building and the Nature of the Universe. As Wikipedia summarizes it:

In his earlier work, Alexander attempted to formulate the principles that lead to a good built environment as patterns, or recurring design solutions. However, he came to believe that patterns themselves are not enough to generate life in buildings and cities, and that one needs a "morphogenetic" understanding of the formation of the built environment as well as a deep understanding of how the makers get in touch with the creative process.

That "morphogenetic" understanding is rooted in the natural processes of form-creation, or order-creation - for example, the morphogenesis of beautiful plants and animals. These structures undergo a consistent set of transformations, which often result in a consistent set of geometries. These include the familiar geometries of symmetry (bilateral, rotational, translational, scaling, etc) as well as others. They also produce the stunning variety and beauty -- and adaptive success -- of the natural world, as recent research has shown.

ABOVE: Adaptive morphogenesis is responsible for

generating the stunning variety and beauty of the

natural world. Drawings: A.M. Zorn, J.J. Audobon.

In turn, these geometries manifest in a consistent set of what Alexander calls structural "properties" -- including "local symmetry," "levels of scale," "strong centers," "borders," and "alternating repetition".

A simple example comes from a famous strobe photograph by the MIT professor Harold Edgerton. In the photo series, a small sphere of milk strikes a plane that contains another thin layer of milk. The sphere's symmetry is broken by the collision -- but instead of a disordered mess, the result of this "symmetry-breaking" is the genesis of many other structures with their own new forms of symmetry - their own new geometric "properties."

ABOVE: Harold Edgerton's strobe photographs of a milk drop shattering as it strikes a think plane of milk. Couretesy of the Edgerton Digital Collection, MIT.

Even in this simple example, these new structures do manifest a number of the universal geometric properties identified by Alexander. He was able to identify fifteen of these common recurrent properties, seen frequently in many natural examples. The list of them includes more local ones (Strong Centers, Boundaries) and ranges to more global and even cosmic ones (The Void, Not Separateness) that remind us of the essential connectedness of all structures. This is not an esoteric idea, but an immensely practical one: we need to make sure that our own structures are deeply integrated into the natural world beyond our own abstractions.

ABOVE: Alexander's "Fifteen Properties." (Image by the author.)

It turns out that the "Fifteen Properties" do not just exist in the natural world, but also in the human world of building -- or at least, the greatest and most enduring buildings of human history. They exist, Alexander says, because of the step-wise, transformational and evolutionary way they were made (as he discussed in his earlier classic book The Timeless Way of Building.)

ABOVE: Some simple examples of buildings that include a number of Alexander's "Fifteen Properties." They exist both because of the natural processes of geometric transformation, and because humans embellish and enrich these structures in order to enhance life and flourishing. Photos by the author.

But what are the practical lessons, and the practical methods that designers can apply effectively to their work? We might summarize them as follows:

  1. Above all, environmental design is an evolutionary process rooted in place, not a single act of creative expression rooted in abstraction. This means there must be a stepwise methodology (or set of methodologies over time) that all participants in the design will follow. Each process will begin with the existing context, and at each successive step, always seek to enhance and enrich the whole, noticing and enhancing the fifteen properties as they arise. This is a process of articulating and crafting -- not unlike the way the great cathedrals were done over many decades, using very few formal drawings, and many mockups, shop drawings and crafted elements.

  2. Environmental design is also essentially a collaborative process. Different people may take on different parts of the design, and at different times and under different but related procedures. The successiveness of their work adds to the richness. (See for example Alexander’s earlier book, A New Theory of Urban Design.)

  3. Designers can incorporate evolutionary design knowledge into patterns that they can apply to the design. They can apply the original 253 patterns from A Pattern Language as well as other new patterns. They can also write their own "project pattern language," expressing the collective vision and genetic design material for their specific project. (This is a more formal recapitulation of what already happened naturally within many cultures.)

  4. Designers should work incrementally, and avoid the over-dominance of permanent and unchangeable structures. They should use mockups and other temporary changes to test out their design ideas, refine them, and make them more permanent.

  5. Designers must be willing to incorporate good design solutions from whatever time and place, including those of traditional cultures. The important question is not whether a design incorporates "novelty" per se (or the even more childish idea, “modernism”), but whether it is a good adaptive fit to the human need and the natural context.

  6. Designers need to develop a fluency in the language of form. This includes the ability to recognize and embellish various forms of symmetry that exist in the environment, as well as related qualities of enclosure, variability, rhythm, harmony, connection and disconnection, and layering. 

Just as people have diverse needs and choices, the design of the environment must offer diversity and choice. Our urban world must offer affordances to its users -- the capacity to partially shape their own environment so as to maximize comfort and well-being. We need, in our homes and neighborhoods, a range of choices of connectivity and privacy, exploration and rest, excitement and calm, throughout the day, the year and the life.

And just as there are patterns of form, there must also be patterns of process – that is, designers must have a stepwise methodology to create successful and beautiful forms. Alexander later referred to these patterns of processes as “sequences,” and larger collections of them as “generative codes.” This work is still ongoing today by some of Alexander's former colleagues. 

The larger point about process is worth emphasizing. If we were to shift from a product-based emphasis to an evolutionary process-based emphasis, that would represent a major turning point in the technologies that shape our world. To be sure, generativity does exist in many forms in our world (informal processes, DIY building, etc). But the dominant systems are fundamentally static, because they are built upon static abstractions.

This is a crude stage of technological culture, and an immensely destructive and dangerous one. As many commentators have noted, reforms are urgently needed if we are going to achieve anything like true sustainability. Although aesthetics is involved at a deep systemic level, much more is at stake than whether we find our homes and neighborhoods visually attractive.

Recent revolutions in the software world have embraced this more dynamic, process-based approach. Examples of this embrace include Agile methodology, Scrum management, and pattern languages of programs, or "design patterns." it is interesting that Alexander’s ideas contributed to so many of these developments in the world of software, which have gone on to demonstrate -- far more than in Alexander's own world of the built environment -- how these ideas can apply effectively to urgently-needed reforms in our systems.

Now we are entering a fascinating and dangerous new world of artificial intelligence. Interestingly, Alexander’s ideas do have a lot to say about these challenges: in particular, how we can navigate them to create a flourishing world, and not a dystopian one.

There is still much work to do to develop the practical applications of these ideas, and to disseminate their practical results to drive needed reforms. At the 61st International Making Cities Livable conference in Cortona, we will join with many Alexander scholars and students, including those from the Sorrento-based Building Beauty program, to develop and advance this fascinating and promising frontier.



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