It takes physical space to connect revolutionary passions with daily life and, more important, the broader population.
When citizens unite in a square, a park, or along a scenic beachfront to demand reform, it creates an impossible-to-ignore spectacle that draws the attention of anyone nearby, not to mention those watching at home.
Of course, spectacle is critical to the role of public spaces in making social change and social value - be it Tahrir Square, street protests in Athens or (dare I say it in the same breath) the Royal Wedding. :*
But Eric's point is that physical public spaces in cities remain the place where people often choose to make life-changing decisions.
We make history on the streets, while the content of our lives and political, social and creative concerns are created elsewhere.
Over the last decade, massive slugs of public and private investment have been made in creating key attractors in cities, like new museums, plazas, parks and gigantic Super Size Me works by artists like Anish Kapoor.
In the light of events in Tahrir Square, the impact of austerity measures in Europe and the possibility of a big slowdown in China, these investments are starting to look less like the 'catalysts to change' that they were marketed as.
And they look more like what they were always were: objects in pursuit of competitive economic advantage, the confidence of a global arts/Hyatt Plaza investment elite and expressions of order that offer solid comfort (in the face of the disorder of change).
But now that we're reminded of the power of the streets and values other than house price inflation, is it time to start to mainstream a different offer and use for public space in our cities?
How about seeing public space as less of a function of the tourist or global cultural economy and more as opportunity spaces of our own, places that tap up personal and local political, social, creative and intellectual feelings, rather than the kind of me-too, read-it-once content of an in-flight magazine?
Create places where people can give stuff away - at its most esoteric, books left on a wall or clothing left on a seat for others to pick up.
Conceive of an infrastructure for our cities that mimics all the diversity, multiplicity and energy of the online landscapes we inhabit and encourage public spaces to be used by multiple groups, for different types of relationships and experiences?
Of course urban economies need to continue to chase and serve global corporate tenants and capital who (it's assumed) tend to prefer manicured, clean and high culture views from their windows.
But cities in advanced and emerging markets also need to devise ways and means by which they define themselves - and not let competitors define them.
If cities want to foster new intellectual, property, knowledge, product and service innovation, they need to reach for a new playbook and review and sweat their own assets.
They need to cultivate public places that allow us to reach for adjectives like "useful", not just "beautiful", "personal", not just "professional", and nouns like "playground" and "enterprise", rather than expressions like "it looks nice but please get out of the way, I'm late for my meeting". :)
If savvy public or private investors aren't able to create spaces that offer more than neutral, minimalist 'platforms' for conventional entertainment, it's up to creative and social entrepreneurs to support new vitality in adjacent neighborhoods or districts - a vitality that's so attractive, sensitive, human and socially conscious that it spreads like a contagion through the city.
Some of this is already going on in cities like London, New York, Moscow and Barcelona, spilling from the back-packs of a global creative elite.
But how are we going to turn this urban entrepreneurship in to a strand of popular culture - especially in towns, cities and countries where people don't believe that they have an investment in the public realm?
Innovation is mandatory if you don't want to be just a commodities exporter.