Energy Saving Architecture
Energy Saving first via Architecture then via technology
What do ant colonies, slime moulds and the teeming streets of your average city have in common? Viewed through the lens of complexity theory, they are all examples of complex adaptive systems, and a hall-mark of such systems is that they display emergent behaviour. Steven Johnson's book does not dwell too much on detailing complexity theory to any great extent, there are other books (such as Mitchell Waldrop's or Philip Lewin's pop-science books Complexity), instead Johnson is more interested in the real examples of emergence all around us.
Emergent phenomena, such as the cleaving of a city into different neighbourhoods or the apparent collective intelligence of an ant colony, are by-products of the interactions of thousands of simple agents. An individual ant is fairly unintelligent and is largely driven by instinct. An ant follows a few simple rules: get food, dump waste, tend young, defend the colony. It has limited means of communications with its fellow ants, and what there is largely based on pheromone signalling. But when thousands of ants interact with each other, what you get is not teeming chaos but a global behaviour that can solve problems, keep the colony fed, protect it from attack and can adapt to a changing environment. This is what emergence is all about, this qualitative difference between the simple rules of the agent and the complex behaviour of the mass.
Slime moulds, a favourite example of Johnson's, exhibit even greater levels of emergent behaviour. Slime moulds, and biofilms in general, are formed by individual bacterial cells who somehow get together and organise themselves to act as a collective mass. To all intents and purposes the individual bacteria group together and start acting as though they are a single organism. For a long time it was assumed that there had to be a leader, some super bacterium that controlled and cajoled the rest of the colony. However, surprisingly perhaps, scientists could discover no such microbial dictator. So, who controls the pseudo-organism made up of thousands of individuals? No one.
Just as the ant colony is not controlled and direct by the queen, so the slime mould is not controlled and directed by any single bacterium or group of bacteria.