Christopher Alexander – The Fifteen Properties in Nature
I chose to do a brief summary of this section, giving preference to the wholeness of the theme of the properties in nature (over giving more attention to each property). It was a journey, first reading through it, not knowing how/what to extract. By the time I read through, certain excerpts popped out of the latter properties and gave shape to this whole summary. All the images are inspired by the text though collected from the vastness of the internet (so inspired by and similar, but not the same as those in the book).
“If we are to use the theory of centers – and the concept of life – as the basis of all architecture, it would be reassuring to know that wholeness, together with the properties which bring centers to life, is a necessary feature of material reality, not merely a psychological aspect of things which arises during perception of works of art.
… According to a ‘cognitive’ interpretation, the centers could merely exist in the mind’s eye … and the fifteen properties … could also exist merely as artifacts of cognition …
… I shall argue that nature too is understandable in terms of wholeness … I shall try to show that the structure of centers I call wholeness goes deeper than mere cognition, is linked to the functional and practical behavior of the natural world … and is as much at the foundation of physics and biology as it is of architecture.
… in any system where there is good functional order it is necessary that there be functional coherence at different levels, hence necessary that there are recognizable hierarchies in the organization of these functional systems.
Many natural processes have centers of action. The action, or development, of force-field radiates outwards from some system of centers … In physics we have the fact that electric, magnetic, gravitational, and nuclear forces are created by spatially symmetrical fields, thus often creating centrally and bilaterally symmetrical structures.
In nature, we see many systems with powerful, thick boundaries. The thick boundaries evolve as a result of the need for functional separations and transitions between different systems. They occur essentially because wherever two very different phenomena interact, there is also a ‘zone of interaction’ which is a thing in itself, as important as the things which it separates.
In nature most of the repetitions which occur are alternating … Repetition itself of course occurs simply because there are only a limited number of archetypal forms available, and the same ones repeat over and over again, whenever the same conditions occur … In most of these cases of natural repetition, the repeating units do alternate with a second structure, which also repeats … The defining feature for alternating repetition lies in the fact that the secondary centers are coherent in their own right, are not left over.
In the majority of naturally developed wholes, the wholes and the spaces between wholes form an unbroken continuum. This arises because wholes form ‘from the inside’ according to their specific functional organization … the positiveness of the space – what we might also call the convexity and compactness of the centers which form – is the outward manifestation of internal coherence in the physical system.
Good shape is a geometrical figure – often curved – which has in it some major center that is intensified by various minor centers.
In general these symmetries occur in nature because there is no reason for asymmetry; an asymmetry only occurs when it is forced … In addition, the existence of local symmetries in nature corresponds to the existence of minimum energy and least-action principles. In the majority of these cases, it is also the presence of layer upon layer of subsymmetry at smaller scales which is important.
8: Deep Interlock and Ambiguity
Deep interlock comes about in many natural systems because neighboring systems interact most easily along extended or enlarged surfaces, where the surface area is large compared with the volume … Ambiguity, a similar phenomenon, comes about when a subsystem belongs to two different overlapping larger systems. One of the most important and dramatic example … exists in the case of the molecule … the molecule is given its structure by the overlap of the electrons in the outer electron shells of the component atoms … the stability of the molecule … is determined by the depth of overlap or interpenetration of the electron shells.
Many – perhaps all – natural systems obtain their organization and energy from the interaction of opposites … It would be extremely hard to show, from first principles, why contrast must arise, necessarily, as a property of any naturally occurring system, and one wonders whether the matter is not merely cognitive. We read contrast; our cognition depends on it; therefore we think its important. And yet, the fundamental contrast of dark and light, positive and negative, can hardly be an artifact of our cognition.
… Any time that a quantity varies systematically, through space, a gradient is established … The idea of regular gradient-like variation is fundamental to the whole integral and differential calculus, and it is the fact that these mathematical tools are closely mirrored in many phenomena of nature that is essentially responsible to the success mathematical physics has had.
An irregular world struggling to be regular always achieves a certain level of regularity which is interrupted by unusual configurations created by the very forces that produce the regularity as they act against a framework of three-dimensional constraints inherent in space … Roughness, far from being caused by inaccuracy … occurs where there is a partial misfit between a very well defined order and the space or configuration where it occurs. This forces an apparent irregularity, not for its own sake but to create a greater regularity.

In all natural systems, deep-lying fundamental processes ultimately give geometric forms to the static structure of the system. These processes repeat certain typical angles and proportions over and over again, and it is the statistical character of these angles and proportions which determines the morphological character of the system and its parts – even within parts which seem superficially different.
The void corresponds to the fact that differentiation of minor systems almost always occur in relation to the ‘quiet’ of some larger and more stable system. Thus smaller structures tend to appear around the edge of larger and more homogeneous structures.
Simplicity and inner calm is the Occam’s razor of any natural system: each configuration occurring in nature is the simplest one consistent with its conditions.
Not-separateness corresponds to the fact that there is no perfect isolation of any system , and that each part of every system is always part of the larger system in the world around it and is connected to them deeply in its behavior.
Summary
From the examples in this chapter, we see that the fifteen properties appear again and again throughout nature. They occur and recur at every scale … Virtually always, the specific structure of centers in a given case can be explained as a result of forces and processes which are mechanical in the conventional sense … However, such mechanical explanations do not explain why the properties themselves keep showing up.
… The reason that a human blood cell has a thick boundary is that it ‘needs’ a processing zone, where inputs to the cell are filtered and distributed before reaching the nucleus … The reason that the Rio Tapajos has an immense boundary when it enters the water of the Amazon is that the silt deposits which come down the river are hurled out into the water of the larger river, creating a chain of islands along both sides of the stream, for nearly one hundred miles … the reason that the sun has a thick boundary – the corona … is a temperature gradient from the hot interior of the sun to the cold of outer space … It does not seem possible to dismiss the appearance of thick boundaries as meaningless or as a coincidence. One guesses that there must be some higher order explanation …
… One wonders, then, if there might be a more general language for talking about function than the one we are used to …”
Christopher Alexander – The Nature of Order – Book 1: The Phenomenon of Life