Complex Systems and Complex Failure
9 June 2011
There is a famous verse that exists in many different forms, but is most familiar, I think, in this version of For Want of a Nail:
For Want of a Nail
For want of a nail the shoe was lost.
For want of a shoe the horse was lost.
For want of a horse the rider was lost.
For want of a rider the battle was lost.
For want of a battle the kingdom was lost.
And all for the want of a horseshoe nail.
Today we know this as the “Butterfly Effect.” We are familiar with the Butterfly effect from popular expositions of chaos theory. Choas theory has rapidly become the central theoretical reference point for studying complexity, but we don’t even have to invoke chaos theory in order to discuss cascading failures in complex systems.
The “for want of a nail” scenario above is a classic evocation of a cascading failure, and indeed the story illustrates a small failure that cascades all the way to catastrophic failure. (NB: not all cascading failures culminate in catastrophic failure.) It is in part because such scenarios of cascading failure begin with small and simple events that it becomes easy to think of failure as a simple thing. But it is not. Failure is not always simple, though it may sometimes be simple.
Complex systems fail in complex ways. Moreover, the scope of a catastrophic failure of a complex system is commensurate with the scope of the complex system. This is easy to see intuitively since a catastrophic cascading failure in a complex system must penetrate through all levels of the system and encompass both core and periphery.
This sense of the complexity of failure was brought home to me when I received a copy of Emergency Management magazine. I don’t know how I got on their mailing list, but the magazine was of interest to me. The article Deepwater Horizon Oil Spill Is an Ominous Sign for Critical Infrastructure’s Future by Austen Givens explicitly formulated the equivalence of complexity of failure with the complexity of the system that fails:
“…as complex systems continue to proliferate — converging people, processes and technologies — equally sophisticated failures of those systems are likely to emerge.”
Complex failures are all about failures that are as sophisticated as the systems themselves that experience failure. Another article, Black Swan Events Require Expanded Thinking, Planning by Eric Holdeman, made a similar point:
“The world has been experiencing a series of extreme events — political, technological and natural… Japan was hit by a triple whammy: an earthquake, followed by a tsunami and then a partial meltdown of nuclear reactors. This natural disaster led to cascading events, including the deaths of tens of thousands, the evacuation of hundreds of thousands and electrical power shortages that will continue for months.”
While considering complex systems and their complex failures, I will also point out that this holds for the increasing complexity of human societies, and even the increasing moral complexity of human life. Life today is more complex than at any earlier time in our history. The number of concerns that must be juggled by the average individual is staggering, and all of the dizzying complexity of life in the contemporary world has a moral dimension.
I can see now that when I discussed the moral complexity of life in Spots Upon the Sun that I did not there go far enough. The revolution, terror, and genocide that marks our time, and the weaponization of eliminationism that I have discussed are instances of complex moral failures only possible in a morally complex world.
There is a sense in which the complex failure of complex systems is reliant upon ecological mechanisms as well as the fact that ecological mechanisms are all but inevitable to emerge within complex systems. If failures could be compartmentalized, failures would not cascade and would not prove catastrophic. It is only when each level of the functionality of a system is related to the functionality of every other level that a system as a whole is compromised when a part of the system is compromised.
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