Adaptive vs. Random Complexity, Part 1.
Architects often assume that complexity, in general, must be designed. That's a misconception, and rarely conducive to human wellbeing.

Adaptive complexity cannot be designed

Nature and the built environment are both complex. But they don’t always have the same type of complexity. Nature shares much of its organized complexity with (portions of) what we build, and this affects our body and eventually our health. The greatest healing effects are found in man-made environments of traditional and vernacular character (Mehaffy & Salingaros, 2015). Architects would love to know how to use mathematical knowledge to design complex forms, and then build them as actual structures. But “natural” complexity is not “designed” in the sense that one person – the designer – determines all details beforehand.

Architects and the educated public often assume that complexity, in general, must be designed. That’s a misconception, and rarely conducive to human wellbeing. Designed (invented) complexity cannot automatically reproduce or imitate the organized complexity found in nature, except in the most superficial, non-functional manner. And yet we certainly want to understand how to employ complexity so as to generate a better, more adaptive environment. True sustainability depends upon creating genuinely organized complexity, where all different structural scales link together coherently. The “organized” part is its most vital characteristic, hence the most difficult to achieve.

That doesn’t stop architects from trying to “design” complexity. Computer programs generate complex, innovative shapes that look impressive on a screen. But these designs are relevant only to style, not to functionality. They fail to embrace the primary quality of evolutionary adaptation, the organized response to variable conditions. Many complex contemporary structures are mathematically disorganized, hence random. There exists a simple criterion for determining whether a structure’s impact on adaptation is organized or random: if any other structure could be erected in its place, and its degree of adaptation to conditions does not rise or fall, it is randomly adaptive.

Look at any one of a number of recent award-winning buildings meant to be museums of contemporary art, public libraries, concert halls, or government offices. Their shapes are interchangeable (except for specialized interior features that actually serve a function). After such a virtual switch, the substitute building does not adapt any better to its site, nor to its surroundings. The original did not adapt, and neither does any contemporary alternative. The reason is that we have a group of fashionable buildings that do not care to adapt to anything at all.

Random design, typically conceived by architects as jagged surfaces, or as curved anomalies in a building’s interior or exterior form, is not meant to be adaptable to human needs. It is abstract art, design as styling, a pursuit dealing with appearance and not the function of a building or the needs of its users. Using random input for generating a design might produce a visually striking sculpture. If that’s what the client wants, then everybody concerned is satisfied – except perhaps the hapless user in those cases, hardly infrequent, where client and user are different people.

The methods of generating organized complexity are to be found rather in techniques of design that are deliberately adaptive. Those techniques organize existing elements that are responding to actual and latent complexity, which makes it imperative to be sensitive to and gather feedback from such responses. Forget about generating complexity: the sequence of steps followed in adaptive design will generate it for you. All you have to do to design adaptively is to organize emerging complexity as it is being generated in each step. By focusing on adaptation and organization, the result will be organized complexity that is adaptive to human use and physiology.

How to build up organized complexity

The secret to adaptive design is to organize the emergent complexity during the design process, instead of trying to eliminate it. The standard techniques for organizing complexity (Alexander, 2001-2005; Salingaros, 2006) include:

(i) Connecting the parts of a system or structure through various geometrical means, most often with multiple connections.

(ii) Aligning multiple adjoining flows so they reinforce each other (but not to a rigid axis or grid).

(iii) Creating local symmetries (but not an imposed global symmetry).

(iv) Implementing spatial correlations using similarities at a distance and scaling symmetries (i.e. similarity under magnification).

(v) Repeating things adaptively, so that they will vary in each repetition. Monotonous repetition, on the other hand, implies a lack of adaptation.

(vi) Building up a system or structure using a sequence of adaptive steps, where the organized complexity arises from an evolutionary process.

(vii) Recognizing complexity as the result of dynamic processes rather than as the result of a conventional static appliqué of “art.”

These tools create organization. A sequence of adaptive design steps generates the complexity required for a specific project brief or set of functions. The designer implements a step-by-step procedure that allows feedback into the design process, at the same time as it is being carried out. Design components arise from adapting every detail to human dimensions and movements, and to the human psychological response to spaces and uses. This procedure requires paying attention to all scales.

Applied to the development of a street or other multiple or single structures, to the construction of a single building, or components such as a staircase or a porch, the method requires feedback. Begin by defining those forms and dimensions that are constrained by the project. Those are less flexible (or not at all) after construction. Experience the shape or space using your own body and, with the help of other volunteers, make possible adjustments. Use full-scale mock-ups from cheap materials that help to feel the actual dimensions. Then decide on the next most-rigid part of the design, model that somehow, and again use feedback for adjustments. Proceed downwards in this manner to the smaller and smaller scales, and don’t hesitate to change what’s on an initial drawing.

In adaptive design there exists no regularization – as with monotonous repetition, for example – because that reduces the information content of a complex system. Adaptation breaks monotony. The principle of variation in music illustrates a crucial point: each variation on a theme is not generated by arbitrary randomness. Instead, it comes from following an organizational framework that generates a particular variation from the basic theme. Randomness is out of place in tonal music. The direction of a variation is not entirely unexpected but intuitively anticipated by the listener. It is a carefully premeditated and controlled excursion by the composer into tonal possibilities, applying the constraint of organization and coherence. A similar phenomenon animates the development of adaptive design.

As human beings, we find ourselves in a complex world that we did not create, but which we manipulate and transform in profound ways. We see complexity embodied in different forms all around us, and in response we constantly produce “structures” having various degrees of complexity. Those structures involve the systems we create, more or less unconsciously, to negotiate the complexities that we encounter. Buildings and streets that help us do so are often outgrowths of their designers’ understanding (conscious or not) of how successful buildings and streets actually work. People tend to forget that there is a dynamic reason for observed complexity. A working mechanism and its variety of supporting frameworks generate a complex product that depends on dynamics and organization.

The complexity of traditional buildings is highly organized, motivated by forces analogous to those that drive natural and biological complexity. The traditional built environment was shaped adaptively to contain our movements and vital actions. A building itself doesn’t change in response to our needs (except when renovated), but we experience buildings over time as expressions of ever-evolving techniques for designing them. Those techniques incorporate the knowledge acquired from the success or failure of their predecessors at addressing our needs.

We embrace here neither a deliberate attempt at randomness, nor its opposite, the attempt to create simplicity for its own sake. Instead, a determined yet unconscious drive mimics in human creations the high degree of organized complexity found in nature. Nature provides the template for useful complexity, and human beings are hard-wired to follow it. In doing this, we are not really copying nature’s forms, but instinctively try to reproduce one of its essential mathematical qualities.

When we do observe either randomness (as disorganization) or extreme simplicity (as uniformity) in traditional buildings and urban fabric, it is there because it is the simplest and easiest energy alternative; or it is a byproduct of forces that have built up organized complexity elsewhere. In this second case, randomness or simplicity are left over after focusing on organizing complexity nearby, where function is more important. In nature as in traditional settlements, there are functional reasons for what is happening and where it occurs, and it does not arise merely from a designer’s whim.

Conserving versus reducing complexity in computer science

Computer scientists conjecture that functional complexity is conserved. When a specific task is simplified, what actually happens is that the organized complexity needed to perform it is merely shifted somewhere else. For example, simplifying a computer-human interface throws the complexity onto the invisible part of the system (Tesler, 1984). Within software, simplifying on one abstraction level usually shifts the complexity to another level. You cannot just throw out complexity from a functioning system without damaging it.

Another type of implementation transfers complexity from hardware to software. Building a more elegant computer (inside, among its circuits, not its surface appearance) requires paying the price of increased complexity elsewhere. Attempts at modularization, driven by the desire to simplify the interchangeability of hardware modules, shift the complexity burden from hardware onto software and interface: again, there is no net reduction in organized complexity (Coward & Salingaros, 2004). Today, our cleanest interfaces are driven by millions of lines of software code: a huge increase in software complexity leading to an equally huge improvement of “user-friendliness” compared with their more clunky ancestors.

Implications for the built environment

Conservation of functional complexity in the built environment provides a key insight into socio-geometric processes. A given set of human actions and movement, together with the structures that adaptively contain them, define a working threshold of organized complexity. They are linked into one system. Often, on a grand scale, stylistically driven simplification reduces the organized complexity of the built environment, with serious negative effects. To accomplish the same task or goal, human actors often must handle far more complexity than before. If people are unable or unwilling to assume the burden of additional complexity, a useful activity may cease. Thus, a net reduction of complexity in the built environment can eliminate useful life functions.

But here, complexity is actually lost. The analogy with computer complexity no longer holds true, since computers are designed to execute specific functions. The objective of simplification is easier use, not less capability. Users of information and communication technology demand more features making computers and electronic devices easier to use, but they would cry out if functionality were reduced. They wish to do what they always did and more, and in an easier, faster, and more efficient manner, calculated in electricity usage, or keystrokes, etc.

In contrast with the user-driven example of computers, our built environment is replete with instances where geometrical simplification has killed off formerly lively and vibrant community life. A good example here is replacing human-scale intricate urban fabric with giant, faceless monoblocks. This invariably arises from misguided, top-down urban policy implementation. The lesson is that complexity in the built environment (assuming it is the kind that contains and supports living processes) is inseparable from human life. In many places, simplistic design replaced the variety in components of healthy individual and social life with a deadening sterility that has damaged cities and even entire regions.

Adaptation requires a high level of the right type of organized complexity, which is not something that can be “designed” in the sense of the term that architects understand. Design that imposes either simplistic or random forms for reasons of style, aesthetics, or political ideology avoids the need to adapt to the complexity inherent in human life and society. Such image-driven design is not useful to and is often detrimental to life. Indeed, governments consciously use architectural and urban simplification as a tool of social engineering. Minimalist forms, spaces, and environments have unexpected problems of functionality that their designers, concerned only with their style, never imagine.

Adaptive vs. Random Complexity, Part 2.
Nourishing environments are complex yet highly organized, but cannot be minimalistic.

Why complexity needs to be organized

We intuitively suspect that the tedium felt in minimalist environments may be blamed on their lack of complexity. That is correct (Salingaros, 2005; 2012; 2015). And yet trying to fix such dead places by adding the wrong sort of complexity only adds to their imbalance. It is common nowadays to design and build using non-adaptive complexity, which adds no vitality, liveliness or life to a place. Complexity is organized or disorganized. Organized complexity adds to a place’s existing framework of adaptivity, fostering life by building on a place’s life-enhancing architectural features, understood as such by a history of use, tested by human action and interaction. The opposite of this, disorganized complexity, is random. Either it adds little to the absent adaptivity of a dead minimalist environment or it undermines the adaptivity of a complex, living environment. The two types of complexity do not add to a place’s adaptive stability, but cancel each other out.

Humans cannot “plug into” randomness; disorganized complexity cannot feed into life processes (Mehaffy & Salingaros, 2015). Our sensory and cognitive systems have evolved to process only what is organized. That’s not surprising, since we are part of nature, and our life is just another natural process of system organization. There is no way we can profit from or profitably connect to randomness. It follows that built randomness actually degrades human life.

Iconic buildings and urban projects that embody random form are arbitrary whims, designed without human needs in mind. These forms do not adapt to the built environment, but impose themselves brutally over it (Salingaros, 2015). The disorganized complexity of these structures almost never matches (and then only by accident) the organized complexity of people’s emotional and functional needs. There is a basic mismatch in the kind of complexity. Apply the substitution test: any randomly complex design can be replaced by any other, or even by a minimalist one, without making any difference, because their adaptivity to life is negligible.

Design and construction was different in the past. For millennia, organized complexity was a natural feature of the building process. Vernacular buildings were erected in ways that satisfied human needs, functions, psychological dimensions, etc. Their designers did not need to consciously incorporate adaptivity to human needs, because the parts of all buildings and the challenges of fitting them together in the way that worked best had been thought through already. There were no well-established building parts or time-tested ways of putting buildings together that did not adapt to human needs. Changes in such needs had always influenced design and building practice going forward. For centuries design flowed directly from human experience. Nothing was ever built or even conceived that did not facilitate connectivity, necessary flows, economy of movement, climatic needs, life functions, and the dynamic utilization of space as defined by human perception on the ground.

Only the most monumental of structures were designed with such human functionality taking second place to aesthetic symbolism. Typically, very few things were designed as abstractions on a drawing board. Buildings and associated structures (urban space and street furniture) evolved from the best accommodation to human use. Over time, they evolved into the complex forms of traditional architecture that we inherited, and would have continued to evolve had disorganized complexity – in the guise of artistic novelty – not interrupted a natural process that intuitively incorporated the DNA of success.

Today we are used to exerting direct control over every aspect of our environment, and that includes our constructions. The design process has become terribly deliberate. But our anxious deliberations negate the possibility of adaptively evolving a design using a framework of organized complexity. Our randomly shaped iconic buildings are designed directly by sophisticated software that generates construction drawings and even building components, without much mental exertion, let alone real creativity. Our taste for design as sculpture, supported by engineers paid to push the envelope of the laws of physics, leads us to misunderstand and denigrate the essential adaptive processes from our past.

Complexity and living structure

People are beginning to ask crucial questions, such as: What properties of the built environment make it more “alive,” in the sense (deeper than surface appearance) that it works like an organism or ecosystem? The answers will determine how humankind can finally go forward in a sustainable and resilient manner – which is far different from the current focus on technological gadgets and “gizmo green” responses to environmental degradation. Fortunately, a lot of work has already been done on this topic, although it remains far outside conventional design discourse.

Christopher Alexander devotes much of The Nature of Order to defining living structure (Alexander, 2001-2005). Following Alexander’s thinking, I introduced a model that measures life as organized complexity (Salingaros, 2006). A quantitative model estimates the “life” of any building as its degree of organized complexity, based on simple estimates using design metrics such as detail, differentiations, symmetries, curves, color, and contrast.

Kenneth Masden and I developed this topic further by listing seven properties of living structure (Salingaros & Masden, 2006), and discussing how they arise in architectural and urban form. This model relates to artificial intelligence and explains how mobile robots work, in a remarkable parallel to how adaptive architecture affects its users.

We identified the seven properties of living structure as follows:

(i) Organized-complexity.

(ii) Metabolism.

(iii) Replication.

(iv) Adaptation.

(v) Intervention.

(vi) Situatedness.

(vii) Connectivity.

Architects wishing to create a new, sustainable built environment can apply this line of investigation to generate architecture with life. The green building movement would do well to incorporate these and related scientific principles from outside the architectural mainstream. Up until now, innovative design for a better future has been held back by a confused idea of what constitutes living structure. A detailed description of the above seven properties is given in our paper (Salingaros & Masden, 2006; Salingaros, 2013: Chapter 31).

The key to the creation of living structure lies in organization, which reduces entropy or randomness. The above model quantifies complexity, and is based on thermodynamics. It formulates the problem in terms of physics instead of style or appearance (Salingaros, 2006). Living structure arises from the collaboration of processes that generate complexity even as they use specific mechanisms to organize it. Observed complexity merely reflects deeper phenomena at work. Up to a certain point, we talk about a general type of living process, and only then do we have to branch out into two related but distinct cases: organisms on the one hand, and the design of the built environment on the other.

Biological information vs. man-made information

The energy collected by life forms is converted into matter to sustain and expand their complex bodies. It is used to run metabolic processes. It is also encoded into DNA, which permits the living mechanism itself to be perpetuated – reproduced – before the structural materials and repair processes come to the end of their natural span. Life is the urge to encode structural information as complex material configurations, which permits life forms to use energy from the environment to continue their existence.

Man-made complexity can be viewed as a sophisticated extension of the life process. Humans have the innate urge to encode useful information into the material structures of their surroundings. This mechanism is responsible for the invention of writing as a means to preserve spoken language. Let’s go back further. Spoken language is itself a complex invention of regularity and patterns that convey meaning. Words enabled our ancestors to communicate and cooperate among family members and a social group. The success of the relatively weak humans over other, naturally stronger animals is as much due to social cooperation and coordination as it is to our evolved innate intelligence.

Going even further back in our evolution, recording insights arising from observations of our natural environment required us to invent mechanisms of physical documentation: regular markings on bone and stone; paintings on cave walls; patterns on pottery; regular patterns of the sound of our voice that became song and language; and regular complex patterns of the movement of our bodies that became ritual dance, etc. We humans needed to create complex patterns whose organization encoded information and meaning vitally important for understanding the world. Every parent selectively exposes their children to complexity, teaching them how to handle it by organizing the knowledge, and the types of order they need to process it, in their memory. This is the process of learning.

When we finally reach historical times, written language in the West decouples from ornamentation in the built environment. This important practice continues in the Islamic world, however, where calligraphy is an indivisible part of architecture, or was until very recently. A major problem arises when the built environment no longer carries meaning through organized complexity: it loses its psychological coherence. Because the modern built environment no longer, for the most part, encodes information relevant to human life, architecture has become random for the first time. Until the 20th century, designers instinctively and correctly regarded randomness as destroying information encoded through ordered complexity in our environment, and was shunned. But with the paradigm shift of erasing this information, our environment is fast becoming either minimalist (no information) or random (lots of useless information).

Uniformity and randomness destroy organization

There exist two distinct opposites to organized complexity: disorganized complexity or randomness, and extreme simplicity or uniformity. Neither of these extremes is recognized by our cognitive apparatus as representing a working complex system. Complexity is not a linear problem, so don’t think of one line with opposite ends but rather of two separate axes in a mathematical space where we can plot different degrees of complexity (Salingaros, 2006; 2014).

One distinct opposite of organized complexity is disorganized complexity (randomness). This occurs when many elements, not necessarily complex, lack mutual connections. Randomness has no organization. Individual pieces do not link together into a working system. If they do work at some level, connections are weak and there is no coordination with other levels. Any organization that might be present within individual pieces is unexpected. A random state is heterogeneous without any correlations, since it consists of many different non-interacting pieces.

The other distinct opposite of organized complexity is extreme simplicity (uniformity). It represents the homogeneous case – it is without variety. Extreme simplicity occurs when a group’s various components are essentially copies of one component. Here, every piece is expected, and the group carries no additional information because there is no variety or complex structure. The set no longer has any distinguishing characteristics. Every piece decomposes into its simplest components (which are the same). The end result of reductionistic simplicity is uniformity. Even with possible correlations among its component pieces, there is insufficient variety to define a system, and therefore it could not have arisen naturally.

In conclusion, humans have evolved to recognize and respond to complex systems in nature. The most sophisticated systems are virtually alive. By contrast, a non-system such as a built environment that celebrates unnatural or non-living qualities detaches us from the world. Ordered complexity is the foundation of our ability to adapt. Its absence is the root of all confusion, or worse.

The lesson from complexity found in nature

The organized structure of matter offers the most basic example of natural complexity. Components of matter on different scales, from the subatomic to the microscopic to the macroscopic, bind coherently to define larger and more complex structures. What is observed is the result of stability among all the components, which is a consequence of system organization (otherwise it wouldn’t survive, and we wouldn’t be seeing it).

Organic forms arose for the purpose of converting energy into information. Energy input from the sun, but also from some geothermal sources, drives organisms over eons of time to structure their bodies to utilize this energy. The energy goes into building and upkeep of the organism’s complex structure. More evolved life forms show precisely the same elements of organization relevant to their design: alignment, local symmetries, spatial correlations, and scaling symmetries that aid life processes.

Life thus defines a definite direction for the transformation or build-up of organized complexity: proceeding from simple or random states toward states of concentration in complex and highly organized systems. The same holds true for adaptive environments. Energy and information are locked up in either static systems or in dynamic systems that are highly organized. This has implications for us, since human life evolved in highly organized, complex, natural environments. But life also extends itself outside the body: whenever organisms are able to erect surrounding structures, those embody the same type of organized complexity as living structures.

Transformations of organized complexity also take place during metabolism. Animals eating food digest complex organic matter that dissolves into slightly simpler components (nutrients), which are then re-assembled as essential components into the complex body of the animal. Animals feed on complex organic molecules, whereas unintelligent plants feed on rather minimalist chemical compounds. Chemical energy stored in the food is released and used to power the metabolism of the organism doing the eating. Organisms profit from various energy cycles they have invented (which work by transforming complexity).

The death of an organism marks the onset of decay, where more complex structures become less complex, less organized, and the organism’s constituents break down into chemical states either of more randomness or of uniformity. When natural structures decay, scaling hierarchies and local symmetries dissolve, generating randomness as the level of organization decreases, accompanied by the production of components unrelated to each other. That’s how a system decomposes.