Requisite Variety


This strange and unfamiliar (to most) term was invented by Ross Ashby (pictured), one of the founders of the field of cybernetics. Cybernetics draws its name from the Greek work for steersman and is concerned with the regulation or governance of systems. It blossomed during WWII where the new knowledge was applied to aiming weaponry and radar antennae, for examples. One of the leading researchers at that time was Norbert Weiner at MIT. I was a student there from 1949 to 1957 and often encountered him wandering the halls. He was a legend said to be so absent minded that he frequently stopped students in the hall to ask where he was going. The field was important to me; I chose to do my doctoral work applying control theory to understand how to avoid and control catastrophic, runaway events at chemical plants.

The framework and methodologies also played an important role in evolutionary biology and cognitive science with the seminal work of Gregory Bateson (Steps To an Ecology of the Mind) and Humberto Maturana & Francisco Varela (The Tree of Life). Plato is thought to have first used the word with reference to the governance of the polis. And it is in this reference that I write today. The critical question for sustainability is, “How can we govern the complex world in which we live to produce the kind of flourishing life we desire for ourselves while maintaining flourishing state of the world we inhabit?”

Ashby established one of the most important and relevant “laws” of cybernetics. He was concerned with the variety of control mechanisms necessary to regulate or govern complicated or complex systems, that is, adapt them to compensate for departures from the desired state. His law of “requisite variety” is quite simple and in many ways something our common sense might come up with. It goes something like this, “The larger the variety of actions available to a control system, the larger the variety of perturbations it is able to compensate.” This rule is of great importance and relevance today as we wonder how to address big issues like climate change, inequality, financial stability, or poverty, and more. All of these topics are arise from the behavior of complex systems comprised of institutions, natural phenomena, human actors,and technological infrastructure. We are struggling to find ways to govern these systems to produce satisfactory normative outcomes at scales from local to global.

The bases for the struggle is itself complex with no single causal agent, human or otherwise. I will pick on only two here; both are related to the law of requisite variety above. The first is the belief that we can, through science, know how these systems work with the possibility of approaching more and more certainty as we probe deeper and deeper. And if we can describe these systems in scientific, that is analytic, expressions we can, using the technical tools of cybernetics, control them to give us what we want. This reductionist frame is bound to fail when applied to truly “complex” systems defined as those that cannot ever be described with such certainty. I have written earlier about what constitutes complexity. In the most basic definition, these are systems with many processes going on simultaneously at different scales of time and space, interconnected by feedback loops with delays between the observed states and the signals sent throughout the system. In everyday terms, these systems are messes and addressing them requires understanding the “wicked problems” I have often written about.

The second cause of our struggles to turn the system toward the desired destination, to steer the Titanic away from the icebergs, is the lack of requisite variety. The governance of the world is frequently described as a massive gridlock these days. Surely it would apply to the governance system in the United States. The special committee established to move us out of the sad state of our financial affairs announced today just before the deadline for their report that they cannot come to any agreement on a program to govern the financial condition of the nation. The market, which many predicted had already incorporated this expectation, plummeted this morning. The consequent variety of possible governance mechanisms, in the terms of the above “law,” is one—the automatic cuts that are to be made in the event that no agreement came forth. For the time being, the number is effectively zero since these cuts are not to be initiated until 2013, leaving the system to flounder for another year or so.

Complex systems scholars often use the word, resilience, to describe the ability of systems to adjust after perturbations have taken them away from the desired behavior. The term is directly consequent from the law. The more variants of response mechanisms, the more shots the regulators, machine or human, have to bring the system back to the desired region of outcomes and behaviors. Our governance system has become the very opposite of resilient, that is, brittle. The ideas forwarded by either ideologues or technocrats (another specific form of ideology) presume that they are the “right” ones and all others are wrong. This belief in the rightness of any solution to problems in the real world is, itself, a causal agent in producing the messes we are struggling to clean up. The challenge is even harder than we might think. The worldly systems that we wish to govern have so much inherent variety that can be considered to be, for all intents and purposes, infinite. We must approach these systems with a completely open collective mind, recognizing that we need at least as many ways available to respond as there are possibilities for the system to behave.

We have come full circle since the enlightenment thinkers “freed’ us from the chains of dogma. The ways of thinking and acting in the world, which were then a huge increase in the variety of ways to govern, have become ossified and reified leaving us few variations to apply to the most important areas of life on the planet. The source of the loss of variety, the Congress, is not likely to wake up. The Occupy movement is providing us with a new appreciation of the opportunity that variety offers and with specific variations. We all should take their actions very seriously even if we are not sympathetic to their complaints and analyses. President Obama could also use this moment to talk about the law of requisite variety and attempt to bring some new enlightenment back to ways to govern the political economy. We are more in need to face the folly of our intransigence than all the news and huge flow of commentary suggests or addresses directly. Brittleness shows up at the large scale of volatile and unsure financial markets, increasing unmet human needs, incessant violence, but also at the small scale of using pepper spray as the means to govern the commons. Is this the only way? Like the laws of physics, the law of requisite variety is unavoidable. If we continue to ignore it, there will be no winners, except, perhaps by chance, when the inevitable next system shift occurs.