Diventity is a concept that links diversity, density, and identity, and I define it as such:
Diventity allows identity to recursively emerge from the density of diversity, when that density reaches a critical mass.
I propose one simple caveat urban design should strive to implement:
“Good urban space optimises Diventity”.
Readers interested in the “new sciences” of complexity, chaos theory, self-regulation, emergence, and so on, and in the worldview some call the post-Cartesian worldview (I have called it the Quantum paradigm) – will recognise in this definition notions of great relevance to living organisms, in particular to contemporary cities.
A city is much more than its stones, a city is memories and relationships and friendships and fears and ambitions; it is stories and histories interacting in the society-space-time continuum.
We form these subjectivities only if the city provides us the right opportunities, because a city is first and foremost our memory-forming medium. We remember our first kiss through who we kissed and when and where we were when we kissed.
In Arabic and in Hebrew, the word for Man – zakar – shares the same root as zakira: memory. We are our memories – and only the right person and/or the right setting will help make a memory unforgettable. To maximise the chances of finding these moments, our very soul strives for diversity and differentiation in our physical and social environments.
A place with enough differentiated identities (spatial, social, etc), distributed in the right proximity (or density) to allow them to interact without obliterating one another, might create enough such moments to allow for identity-shaping memories to emerge. We can say that such a place has Diventity.
Because the concepts of identity, density and diversity are themselves generic and scalable, Diventity is scalable enough to allow comparing otherwise unrelated systems (e.g. the ethnic composition of London City versus the ethnic composition of Cheltenham), and generic enough to address such wide indicators as environment, geography, demographics, events, aesthetics, socio-economic class, ethnicity, volume, patterns, sensorial stimuli, functions, landscape, morphology, meaning, typology, texture, choice, etc.
The diverse notes that make up a music sheet create an emergent identity: a guitar track. This emergent identity then is confronted to the bass, drums and horns tracks, and the voice of a singer, to create a new emergent identity: the song. If the product of a music band is recognisable as a song, then that band has Diventity.
An ecosystem has Diventity if the diverse species of fauna and flora meet in the right density to create an emergent, sustainable identity, for example a tropical jungle.
The European Union is a new identity emerging from the diverse identities of its constituent nations: it has a Diventity that it is trying hard to sustain at workable levels. The former Yugoslavia’s ethnic and cultural Diventity was hard to sustain, so it split up into its constituent bits. Similarly, the small country of Lebanon, with its 18 different religious confessions on 10,000 square kilometres has had uneven successes with stabilising its Diventity, yet it is this very density of diversity that allows it to have an emergent identity differentiated from its relatively homogeneous Islamic and Arab environment.
Diventity is a crucial quality of vibrant urban settlements: the figures speak for themselves, in the case of London versus other British Regions: not only does London have by far the highest density of population per square kilometre, but 30% of its population is made up of ethnic minorities, (versus less than 3% for the regions) – and that does not include tourists. In other words, London’s minorities’ density is 1380, while the average of the other regions is a mere 15 people per square kilometre!
Confront these figures to the number of restaurants and leisure and public spaces and buses and trains in the city (a Diventity of urban functions – as many opportunities for diverse citizens to mix and form shared memories and emergent identities) and the relative diversity of architectures (particularly iconic monuments that help the city’s visitors identify it and form their own memories), and the picture is almost complete.
More layers of diventity in an important capital come in the form of social class diversity, sometimes varying street by street. Or sexual and lifestyle diversity, again with the right settings to permit them to be sustained but not ghettoised (e.g. Soho, gay neighbourhoods, etc); spatial diventity, or the diventity of density itself: high-rise city centre, middle rise towers, terraced housing and semi-detached houses, all available in relative proximity, as long as you move around the city. Clothing and accessories fashion is a fascinating layer; age group diversity also: teenagers, baby boomers, active pensioners moving around in the same public spaces makes for a much more vibrant communal identity than a forced segregation… the list is almost endless.
You can think of a hundred more examples of diventity at work, but it is imperative to keep in mind that the concept of identity, and hence of diventity, is directly linked to the human mind’s inherent needs to recognise patterns and categorise differences. Diventity requires that the emergent identities be recognisable by the end user; that is why this notion needs to be continuously checked against its social, spatial, and historical contexts. In fact that is precisely what makes diventity such a potent concept with which to tackle urban space in our post-Cartesian paradigm.
The deceivingly simple axiom we set up at the beginning of this text holds many layers of implications to the way we feel, think and make cities. When well understood, the quality of diventity may help release the power of human intuition in the design of organic cities.
 “Diventity” was first introduced in Quantum City (A. Arida, Architectural Press, 2002) as the main quality used to compare complex self-organising systems, including socio-cultural, urban, and economic systems. When used in a deceivingly simple axiom “good urban space optimises diventity”, it offers potent triggers and implications to built form that promise positive change in the urban realm.
 As a city and as a region, London is at 4600 versus under 500 for the next highest, the North West region, while the average large city density throughout the UK is around 2600.