Why are there So Many Different Kinds of CYcles?

Isn't it interesting, the ubiquity of cycles? There are cycles at work within our bodies, such as the citric acid cycle in our mitochondria, and there are cycles all around us, such as the life cycle of the Monarch butterfly and Pacific Salmon.

Some cycles are quite long by comparison, such as water cycles and carbon cycles.

The ouroborous, as drawn by Theodoros Pelecanos in 1478

Cycles are so ubiquitous that we encounter them often in cosmology, philosophy, and metaphysics. Karma, or "what goes around comes around" is a well known example. The Oroborous, a snake eating its own tail, has likewise been a symbol of periodic renewal and rebirth since Antiquity. The Tau Teh Ching also asserts the importance of cycles: "a time for growth, a time to decay; a time to be up, a time to be down" (29). Finally, the Maya are among several ancient civilizations whose cosmology reckoned time as circular.

Time does appear to pass in cycles, despite our current cultural bias to perceive time as linear: solar cycles, lunar cycles, and seasonal cycles. While it may not be that time is actually cyclical in nature, at very least we must admit that we seem predisposed as a species to perceive and experience it in this way, our own Western cosmology notwithstanding. We even write cycles into the pages of own history: the Greek philosopher Polybius, for example, suggested the Anacyclosis theory of history, also known as the liberty-tyranny cycle, in which societies move from monarchy to tyranny, aristocracy, oligarchy, democracy, ochlocracy, and back again. Cycles are used to tell natural history as well, in the water and carbon cycles noted above but also in the release and renewal of forest succession and other examples of the "adaptive cycle" that is now popular among resilience researchers.

The Maya Calendar Round

But what, if anything, can we make of these cycles. Are they instructive? Are they predictive? Are they explanatory? Are they even real?

Just as G.E. Hutchinson elevated scientific discussion about the origins and meanings of biodiversity with his address in 1958 to the American Society of Naturalists, “Homage to Santa Rosalia, or, why are there so many kinds of animals,” I believe that the future of sustainability science lies in this question, “why are there so many different kinds of cycles?”

Whether real or perceived, cycles are a compelling heuristic for describing patterns of stability and change over time. This adaptive cycle of resilience thinking, for example, can be appplied to forest succession just as easily as it can be applied to the dynasties of China or the history of the American Circus.

So what? I believe that the ubiquity of cycles is important because pattern recognition is the first half of the scientific process. Patterns are the basis on which scientists develop theory: when we observe patterns in empirical data we get curious. We get to thinking about possible explanations for those patterns and about what those patterns might tell us about other aspects of the natural world.

Pareidolia, or faulty pattern recognition

Of course, observing a pattern is not the same thing as understanding the process at work. We can never be sure when we think we have discovered a pattern, no matter how cogently seductive the pattern seems as an explanatory device, whether we are seeing something real or if we are experiencing a kind of pareidolia – a psychologically or culturally driven kind of pattern recognition. As patterns, cycles can reflect something about us, or about the real world, or both. We must be cautious when we invoke cycles, therefore, whether the adaptive cycle or the liberty-tyranny cycle, as to whether these patterns are the product of our own cultural or cognitive frames of reference and biases, or whether they are reflective of order.

But the question still stands: why so many cycles? I argue that cycles are compelling because they provide a way to reconcile the apparent contradictions between stability and change. The most basic example is the thermostat – a favorite of anthropologist Gregory Bateson, to whom I owe inspiration for a number of the ideas explored here. A thermostat does not keep a room at a constant temperature; rather, once it brings a cold room to the desired temperature it then switches the heat source on and off, achieving a sigmoid (S-shaped) pattern much like that which characterizes animal populations constrained by carrying capacity. The thermostat achieves stability with a cycle.

To put it another way, stability of temperature at a coarse scale is driven by cycles of temperature change at a finer scale.

There is a lesson in this for sustainability.

(though I'm still working out what that is!)

Note: Much of the text above is adapted from a keynote that I delivered to the 2011 meeting of the American Association for the Advancement of Science, Arctic Division meeting in Dillingham, Alaska.