Notes on Critical Mass: The Physics of Society by Philip Ball (2004, William Heinemann).

Also informed by his appearence on at the ICA on the panel debate Dying of Consumption and lecturing at the Royal Institution.

Philip Ball’s massive tome is full of ideas, but I can’t but help but feel that he’s not saying anything radically new. This might come from having lived with Dan and hence being happily privilaged in my available head-food.

Anyway, he’s a very British writer. Unlike those other guys (Gladwell, Buchannan) he doesn’t read like someone who spends half their time in business consultancy seminars. He reads like someone who is too well read for their own good. The historical and philosophical context he gives to the ideas is a joy, although not really as motivating as the high-octane brashness of the New World science writers on the same topic). His deconstruction of conventional economic theory (more of this at the NEF debate than in the book perhaps) is classic and convincing.

The material is what you might expect, but done by someone with a rigourous background in the hard sciences. Self-organisation, phase transitions, emergent dynamics (slime moulds, flocking behaviour), chaos, attractors, bifucation points (and hightended senstivity to noise at the same), power-laws (aha, a Power Law, i hear you say, the signature distriubtion of mutual influence amoung sub-units of a system), small worlds, preferential attachment (DLA) networks, evolutionary game theory…

There’s a nifty demo of crowd dynamics at

An interesting observation: the tension between predictive scientific social models and individual free will has a historical ancedent in the nineteenth century discovery of statistical regularities in population statistics. If we can predict from census records that the number of suicides in a parish in a year will be around seven, where does that leave the free will of those who choose (or don’t choose) to kill themselves there? The use of such statistics was deeply controversial at the time, in a way that’s hard to fully appreciate now.

The important point
The value of a physics of society is that it is an attempt to understand how global phenomena can arise from local actions. Philip Ball is saying that, yes, there is a kind of intelligence to the group (but not that it is sublime).

Thinking about the studies that inform Critical Mass, and Dan’s thesis, what other lessons are there from CAS? (I’m going to adopt Dan’s term and use CAS – Complex Adaptive Systems – to subsume a whole managerie of theories dealing with dynamic, iterated, evolutionary, chaotic and/or computational models of both the cellular and agenic types).

– non-linearity. Don’t always look for [simple] causation, don’t say small things can’t have big effects and don’t always expect big things to cause large changes .

(see the discussion of, e.g., ‘broken windows theory’ in Gladwell’s The Tipping Point)

– theory won’t do the work for you. You must investigate each system and establish it’s workings

– we need to recognise that markets are constructions and, alhtough they operate in complex and adaptive ways, we inevitably play a role in defining the framework within which they operate.

(as if buying and selling are acts divorced from culture! As if culture isn’t a political construction! Ha!)

– level crossing. There is reciprocal causation between individual and group behaviour (Remember mamet on polls)

I think – and I should credit many hours squabbling with ralph for this – the use of CAS in politics and postmodernism are grappling towards a way to express the same kind of ideas, to talk about the same kinds of, non-intuitive, systems. There is the same deconstruction of agency, the same willingness to cross levels of analysis, to recognise the the validity of multiple similtanous views rather than stick dogmatically to one paradigmatic/ideological view.

Another observation by PB(in response to a question on catastrophe theory at the RI lecture): Catastrophe theory ‘came and went’ because it was a phenomenological theory.
(reminds me about the stuff in my thesis about explanation. What constitutes an explanation? A theory which connects a phenomenon to the behaviour of more fundamental elements. Catastrophe theory just posits a dynamic without an attempt to investigate the instantiation of that dynamic. Sounds familiar…).

Two miscellaneous quotes:

By developing mathematical and computer models of the spatial patterns of communities ranging from traditional villages to modern towns, Hillier and Hanson have shown that urbanisation tended to increase and diversify people’s interactions up until the time when new templates for planning were introduced during the Industrial Revolution
– p173 (see Hillier & Hanson (1984) The Social Logic of Space. CUP, p266).

Batty and Longley calculate that between 1820 and 1962 the fractal dimension of London increased from 1.322 to 1.791
– p186