The Legacy of Christopher Alexander: Form Language, Pattern Language, and Complexity
A Form language consists of a set of definitions and vocabulary of building and design components that can be combined coherently. These comprise specific geometries, shape and size of pieces, particular materials, etc. To most people, this is what characterizes architectural “style.” Evolved form languages always adapt to locality, culture, and use—in fact, they’re an essential part of cultural identity. Design geometry may be freely invented within those constraints. Yet, the remarkable thing is that most form languages also satisfy general geometrical constraints known as Alexander’s “15 Fundamental Properties.”
Fulfilling the 15 properties guarantees that the components’ assembly will result in a coherent composition. An important consequence of morphogenesis is that satisfying these basic constraints creates healing environments through biophilia (our innate connection to living structure). It also turns out that ornament is an essential part of any adaptive form language, representing the smaller scales of a whole. That’s because Biophilia and ornament are intimately related through neuroscience. There exist infinite possible adaptive form languages satisfying strict conditions, although there are far fewer of them than the number of non-adaptive superficial visual styles.
Form languages that obey Alexander’s 15 fundamental properties generate healing environments through Biophilia.
A Pattern language consists of design patterns, which are socio-geometric relations discovered in evolved (not “designed”) building typologies and urban fabric. Patterns link geometrical configurations to optimized human movement and uses. The pattern for a specific solution defines a set of relationships, not a rigid geometry. A building’s surface appearance doesn’t reveal the patterns that make it work well for its users—they’re hidden in the structure. Evolutionary selection according to what is the most healing type of environment identified the archetypal design pattern in each case. It is very often transferable to a different location, situation, and time.
Pattern language is in large part universal, and only some of its patterns are strictly local. A pattern language cannot be invented—it must either be discovered in actual use, or adapted to a new situation by methods of trial and error. But arbitrary (not socio-geometric) visual patterns on a scale larger than traditional ornament will hinder human actions, and could make the built environment dysfunctional and unhealthy. Pattern language helps to design healing spaces, not the form language, and for this reason, an adaptive design method has to include both.
Pattern language is necessary to determine the design of spaces and volumes so that they are going to provide a healing experience.
Organized complexity is found in any complex structure that contains a comparable degree of organization to its raw complexity. Raw complexity is measured by the number of individual components—analogous to word count in a document. Organization is then estimated as the number of connections and relations among those components. The “degree of life” may be identified as a product of raw complexity times number of connections.
Mimicking the evolution of organisms, an artificial system builds up organized complexity piecemeal in an iterative cycle. The procedure is to add complexity, but only enough that is needed in each step to adapt to uses and form. At the same time, organize that added complexity so it becomes coherent with the existing structure. Repeat this process, removing any unnecessary complexity after every step. Eventually, complexity and organization will increase together. The higher the degree of organized complexity, the closer the system approaches living systems. This process works on all levels of scale, linking the different scales into a connected hierarchy just like in a fractal.
Design that adapts to human neurophysiology needs to understand how we respond to distinct types of complexity, and learn how to generate organized complexity.
The complexity of a form language plays a hugely important role in determining whether design is adaptive or not. A form language’s adaptive potential may be judged according to its degree of internal complexity, independently of anything else. Its vocabulary content must be large enough to adapt to the requisite variety of human actions and uses. Its linguistic and combinatorial rules must separately allow for adaptive adjustments towards coherent complex form.
Traditional form languages evolved richness of expression, to accommodate human life and all the higher applications of social interaction and culture. Design innovation within adaptation is possible only with a complex form language that has a robust grammar. If a form language’s organized complexity is below a threshold, then it can never express adaptive solutions. A simplistic visual style, on the one hand, cannot pretend to be a form language — its complexity is too low. On the other hand, a complex style that lacks coherence in its grammar is just as unsuitable for adapting to human uses.
Just as with spoken/written languages, form languages with organized complexity are essential for designing environments that satisfy the variety of human actions and emotions.
An adaptive design method joins pattern language to form language. These are the two essential tools for creating healthy environments. As pattern language evolved by adapting to complex human biology and culture, it has an intrinsic high degree of organized complexity. This is fixed and cannot be reduced. Form language has to seamlessly blend with pattern language; otherwise the built structure is not adapted to human use. Mathematically, a form language is required to have comparable complexity to the pattern language. If it doesn’t, a form language cannot join with the pattern language to generate a built environment that helps human life.
Adaptation depends directly upon organized complexity, which critically distinguishes among different form languages. The industrial minimalist form language, and offshoots that define today’s dominant architectural culture, do not have the correct degree of complexity (it’s typically far too low). Even when they do, then they don’t have the correct type of complexity (it’s disorganized instead of being organized). Design styles adopted in the Twentieth Century erased the requisite degree of organized complexity that traditional form languages developed in adapting to human needs. Hence it became impossible for them to link to pattern language.
Design that liberates human creativity and life is founded upon combining unconventional tools such as form language, pattern language, biophilia, neuroscience, etc.
By understanding these concepts, design innovation may be steered towards human adaptation, and away from abstract visual expression. Alexander’s goal, however, does lead to a confrontation with dominant architectural culture used to doing things the old way.
The preceding essay was adapted from a lecture given by the author to the Building Beauty Master’s Program, in April. All sketches are by the author. Featured image: Buddhist temple in Nepal, via Wikipedia Commons.