
As we’re thinking about the qualities of public spaces — how they work, how they fail, how we can improve them — it’s critical to understand what happens at their edges, and within the web of complex relationships they have between their different public and private parts.
If we look at the human environment as a whole, we can readily see that many structures and processes are operating and interacting simultaneously across a range of scales – some with pronounced effects, some with subtle ones. This complex symphony in turn shapes the interactions, behaviors and experiences of human beings. What happens within the particular network of public spaces is particularly important (and therefore that is a particular focus of our center).
A number of well-developed theoretical systems have been able to model important aspects of this complex structural process: Graph Theory, Space Syntax, Pattern Languages, Multiple Centrality Assessment, and others. Other less well-developed frameworks suggest additional important aspects, including certain schools of environmental psychology, the young field of biophilia, and the “organized complexity” (and related insights) of theorist Jane Jacobs.
But we believe the theoretical picture presented by these different systems is incomplete and spotty, and there is no clear, unified, normative guidance presented to practitioners. This lacuna is particularly important in light of the challenges of sustainability and resilience, and the egregious failure of modern practices to respond in what can be regarded as plausibly adequate to these challenges.
As Kevin Lynch argued, we need a “theory of good city form,” if for no other reason than to make clear our assumptions and values. This line of thinking suggests that there is a need to unify these somewhat disparate and incomplete theoretical models, into a kind of “unified theory of spatial structure.” Such a model would give an over-arching explanation of these structural relationships across scales, and moreover, offer a general explanation of their dynamics of formation and human interaction. This in turn could serve as a badly needed guide to best practice in design, conceived now as a broader project that re-engages its humane responsibilities.
We believe the elements of such a “unified theory” do exist, provided by the partial theoretical systems mentioned above — but that they need to be assembled into a more integrated picture. Such a picture – which we term “Place Network Theory” for reasons we will explain below – might have the following key elements:
- Ability to generally describe the linked and fine-grained structure of urbanism across scales, from regional to neighborhood to street to building to small details and textures
- Ability to account for the phenomenological aspects of place, as structural and geometric phenomena.
- Ability to explain how such structures arise through the interactions of human beings with their environments, as processes evolving through time.
- Ability to explain the crucial syntax of public to private space, its capacity for modulation by users, and its role in modulating levels of interaction.
- Ability to account for the experiences of layering and sequence, and their importance.
- Ability to account for biophilic phenomena, such as the psychological benefits of plants, water, animals, and other biological geometries.
- Ability to account for the desirable and “livable” qualities of place.
- Ability to account for the capacity of urban spatial networks to facilitate economic interactions, following power laws and other related network phenomena.
- Ability to account for the capacity of urban spatial networks to reduce per-capita resource use, while still delivering a high quality of life
- Ability to analyze failing spaces, and create models of the failures with diagnostic value. (Especially the ubiquitous failures of modern environments.)
Such a theoretical picture may seem a very tall order, but as suggested, is already outlined by the insights already developed. It is above all a network model, mapping the connections between spaces within the built environments as room-like entities, with clear centers, edges and modulated boundaries. (Christopher Alexander has developed a very similar picture with his theory of “centers,” which, combined with patterns, do provide the strong outlines of such a Place Network Theory.)
As we see it, this “place network theory,” then, would combine the following elements:
- An understanding of the working units of space as room-like structures or “places” with membrane-like boundaries affording connections to one another (though they may be very small, or conversely, very large).
- An understanding of the network connections of these places (hence “place networks”), consisting of hierarchical aspects (lower units are constituents of upper units) as well as overlapping aspects.
- An understanding of the processes of their forming and transforming, and how certain rule-based actions govern these.
- An understanding of the tendency of “attractors” or “patterns” to form (relatively stable configurations that are repeated as solutions or resolutions to problems or conflicts).
- An understanding of the evolutionary system that is generated by this pattern-forming process, and its ability to build greater problem-solving capacity over time, and greater complexity and beauty (and these are related, as they are in biological systems).

We spoke of the need for “normative guidance.” What guidance would such a theoretical picture offer? We suggest the following:
- Urban structures (buildings, streets, landscapes etc.) must provide for users to make ready adaptations across a range of scales, so as to control their own degrees of interaction. (Simple examples are doors, windows, curtains, gates, etc – but more permanent alterations must be possible too). This is the basis of urban self-organization, a critical capacity for ecological resilience.
- Related to this, patterns of spatial activity must provide an essential framework of space, with a gradient from public to private, and a modulated, self-organizing system of connections across this gradient.
- Following this, urban structures need to be easily repairable and adaptable to new uses, with the involvement of local participants in the economy, and local (renewable) resources.
- Related to this, urban structures must be seen as tools for the generation of local and sustainable economic activity, and the relation of economic vitality to sustainability must be codified and reinforced within a range of economic and planning tools.
- Related to this, the repositories of previously evolved urban structures, and also patterns of natural structure with important capacities for human beings (patterns, prototypes, design motifs, etc) are essential sources of genetic material.
Therefore, patterns of spatial activity must be conserved for later learning and re-adaptation. Precedent must not be rejected in the name of artistic novelty. This is at present a serious, even catastrophic failing of modern design instruction.
Such a unified theory is therefore urgently needed, in view of the ongoing failures of far too much work in the environmental planning, design and building professions today. As the saying goes, “Rome burns.”



