The Age of the Unthinkable

Studies of food webs or trade networks, electrical systems and stock markets, find that as they become more densely linked they also become less resilient; networks, after all, propagate and even amplify disturbances. Worse, the more efficient these networks are, the faster they spread those dangers. Interconnections such as the ties between brokers and banks or between the health of every passenger on a long-distance airplane flight are vehicles for sharing risk, for triggering hysteresis. In a simple linear system, say one bank and one farm, you can map out the effects of a crisis as if you were plotting the route of falling dominoes. But in a networked society, lit up by revolutionary change, such easy prediction is a fantasy. Drop a shock into a network and you get, the strategist Edward Smith has written, “the chain reaction that is set off when a single ping-pong ball is tossed onto a table covered with mouse traps upon which other ping-ping balls are balanced —an almost explosive reaction whose direction and end-state cannot be predicted.” The more closely we are bound together, the weaker we may become.