There was no TV; internet did not yet exist. Other seasonals with cars would buy groceries for us when they drove the 120 miles from Denali up to Fairbanks. My summer was working, hiking, and reading. I’d read about the natural history of the park and then go walking within it. Observing, then reading, then observing again, then reading, day after day. The reading would add to my understanding of the world I walked within; my walking experiences brought life to the ideas I was reading. Three books, in particular, significantly changed the way I saw the world around me.
A recommendation by Steward Brand in The Whole Earth Catalog led me to bring a book about general systems thinking (I can’t remember its title). It included a description of flypaper from a systems thinking perspective. A room is made up of surfaces, any of which can be landed upon by a fly. Later it flies away and lands upon another surface. Fly away, land somewhere else, repeat. The flypaper, however, creates a surface which can be landed upon but not flown away from. Therefore, the fly will flow from place to place to place, time after time, until it lands on the flypaper. End of its flow. The flypaper creates an endpoint that accumulates flies. This perspective of mathematical predictability charmed me. I read on. Amazingly, the Denali park library had a second book on systems thinking and I read that too. Then I’d go hiking on my weekends and see systems all around me. I started thinking systems thinking.
What is a system? The books I’ve read, then and since, have various definitions. For me, a system has come to mean a group of “things” behaving in such a way that is only possible within the workings of that group. The Sun could exist by itself. The Earth could exist by itself. But interacting together as a planet orbiting the Sun makes possible an inflow of life-sustaining energy and differential heating between the equator and the poles that creates winds and ocean currents, polar ice caps, and seasons. All this and more become possible. These possibilities could not arise with the Sun by itself nor the Earth by itself. They become possible only through the interactions between the two. The two together form a system within which all sorts of complex things become possible.
Many definitions of “system” wrestle awkwardly with “purpose.” Somehow a system exists to fulfill some purpose or to do some function. Purpose is easy to see in human-created systems like a car but harder to see in things like Saturn’s system of rings. So, over the years, my definition of systems detached itself from any notion of purpose. My vague definition of a system might not feel like a useful tool for thought. But thanks to systems thinking, this vague definition grows into this fractal swirl of patterns.
One major property of systems is that they are composed of subsystems. It’s implied within my definition of “a group of ‘things’ interacting”. Something as simple as a pencil has subsystems. There is the “lead”, of course, which does the writing, fulfilling the “function” of a pencil. But this thin, easily-broken graphite is reinforced within wood which also increases the diameter to an easy-to-hold proportion. The wood is protected by paint so the pencil lasts longer and is easier to see and carries the brand name. A metal band attaches an eraser to the other end to help the pencil undo mistakes. Each subsystem helps create more behaviors within the system of “a pencil”.
Our body is a system. Within it is a circulatory subsystem which distributes dissolved gases, nutrients, wastes and other materials throughout the body for processing. That subsystem can be broken into the subsystems of the heart, the lungs, the arteries, the veins, and the capillaries. The heart, in turn, is composed of chambers and valves, all made of cells, each of which has nuclei and mitochondria and DNA and on and on… (Just the other day, I learned from our eye doctor that the “tears” that moisten our eyes are composed of three different layers, three different sub-systems: a lubricating layer against the cornea, a saline solution, and an outer layer of fat to reduce evaporation.)
And “systems composed of subsystems” extends in the other direction, too. Every system exists within and functions as a sub-system within larger systems. You, as a system, are an important part of your nuclear family growing up within your home town and its street system connecting schools and churches and gas stations with homes. Systems nest, just like drainages do. (In fact, drainages are systems.) This nesting is such a fundamental characteristic of systems that one can think of “general systems thinking” as “general sub-systems thinking”. Any system you work with functions within and helps create the properties of a larger encompassing system. So when I went hiking in Denali, what I once saw as the “tundra” resolved into ripe blueberries growing upon a specific branch of a wild blueberry bush within a knee-high thicket of them, their slightly bluish, smooth green leaves extending hundreds of feet along the slope looking out at glaciated mountains and a stoney creek down below. All of these sub-systems of the world reside within one another, interacting to create otherwise impossible actions. The world I see becomes more dynamic as my mind opens to the interactions between details.
A second major property of systems is dynamic equilibrium. Dynamic equilibriums arise from the interactions between the things in the group. Equilibrium comes from equi = equal and libra = balance – referring to the resting state that a balanced scale comes to, both sides equally balanced. But in dynamic equilibrium, there is no nicely balanced final state. My favorite example is balancing a stick upright upon my finger.
The stick keeps swaying upon my finger and my finger must constantly adjust to that swaying in order to keep the stick upright. There is no predictable or repeatable cycle to this movement of stick and finger; it continues on its unique, never–repeating dance of interaction while remaining upright. Since dynamic equilibriums create stability through adjustability, they can endure a long time. Over time, the world fills up with them.
My first academic contact with dynamic equilibrium had been stream equilibriums in my college introductory geology textbook. If the grade of a river (how steep its channel is) was too steep in one section, the river would speed up, giving it the erosive power to wear down that section of streambed to a gentler angle. As the angle of the river grade becomes less, the water flows slower, gradually losing its erosive power until it flows along a nearly level river grade without further erosion. On the other hand, if the grade of a river was too gentle, then the river would slow down and drop some of its load of sand and gravel which raises the streambed over which the water flows. This steepens the grade, causing the water to flow a bit faster and deposit less until eventually the river flows across that stretch with neither deposition nor erosion. Given enough time, the various stretches of a river are worn down or built up until the grade of the entire river comes into the dynamic equilibrium of a smooth concave grade. I thought this was SO cool, the way a vast drainage system could come into a beautiful dynamic equilibrium expressed through the entire drainage.
Though not yet explicit in my mind, stream equilibriums introduced me to the idea that the behavior of the stream in moving towards a unified grade does not require conscious thought. Systems create certain behaviors, a major principle of systems thinking that we will return to later in the book.
Another example of dynamic equilibriums in my geology book was how wave refraction tends to straighten a coastline. As waves approach the shore, they slow and bend to crash more head-on against the land. Therefore, a portion of the coastline that projects out into the sea will receive more of the wave’s erosive power upon it, wearing it back faster. On the other hand, waves encountering a bay will have their energy diffused over a large area so that erosion will be minimal. The areas projecting out into the sea get worn back faster than recessed areas. Therefore, over time, shorelines tend to become straighter.
The human body is packed with dynamic equilibriums. If we become too hot, we sweat which cools us off. If we become too cold, we shiver which generates heat in our muscles. Blood sugar. Blood oxygen. Simply standing up. All of these are dynamic equilibriums.
My intellectual delight with dynamic equilibriums helps me understand what must have been Adam Smith’s delight as he came to understand how supply and demand could bring prices into a dynamic (not static) equilibrium. I’m sure economists can feel as rapturous about “free markets” as this naturalist did over stream equilibrium.
A third fundamental property of systems: feedback. Feedback is when a sequence of cause and effect actions loops back upon itself. At its simplest, what I call the basic four-stroke feedback cycle is:
A cause over there creates an effect here
which creates a cause here
which creates an effect back over there
which creates a cause over there
and round and round it can go,
Balancing the stick on my finger is a good example of this.
First stroke: tip of the stick starts falling in a certain direction, changing what I see.
Second stroke: what I see the tip doing changes how I move my hand.
Third stroke: my hand moves the base of the stick which changes its relationship with the stick’s tip.
Fourth stroke: the changed relationship causes the tip to start falling in a new direction.
Most feedback within systems is more complex than that. My first hitch-hiking summer in Denali, snowshoe hares (similar to rabbits) were everywhere in the spruce forest. On a nature walk, you would stop and see five to fifteen hares sitting in the area around you. You would see a hundred over the course of the walk. They often appeared not quite right in the head. The ranger explained that the snowshoe hare population cycled, increasing for about ten years and then crashing the next winter. Overgrazing of their browse in the summer would lead to inadequate winter browse, malnutrition and starvation. Their mental state was partly due to the stress caused by their density. There were too many pressed too close together. A hare couldn’t move without moving towards another hare which would cause stress for that hare. With every move they were stressing one another. There was no way to get away from it. Disease could easily spread through these closely-packed, stressed, hungry creatures. In addition, the nine-to-eleven year buildup of the hare population was feeding an increasing population of predators. Lynx and owls had been eating well. Most of their well-fed babies survived to parenthood.
The next summer, I saw only two snowshoe hares the entire summer. Only two where I had seen hundreds a day the year before. However, I did see three lynx – the secretive, seldom-seen larger relative of the bobcat. With their population now too large for the number of prey available, they were hungry and having to hunt in mid-day in search of something to eat. Come the long arctic winter, their babies (if any) would starve.
The population of the snowshoe hares and the lynx and the plant vegetation and the disease pathogens were connected within a sequence of feedback. Feedback arises whenever a sequence of cause and effect loops upon itself so that eventually the effect of an ongoing cause somehow comes around to change that cause. The growing abundance of hares allows the population of lynx to grow. But when the hare population overreaches the carrying capacity of the spruce forest, the hare population crashes. This gives the hares’ food plants a reprieve and a chance to recover. It also causes the lynx population to crash the following year. The crash in the predator population removes much of the predatory pressure on the hares, allowing more of them and their offspring to survive and the hare population begins to grow again.
Feedback plays a prominent role in systems thinking because it’s what usually underlies a dynamic equilibrium. The official term is “feedback loops” but when I tried to teach feedback loops to kids, they got confused. They couldn’t see how the feedback could loop back in time to the starting place. They were right; it doesn’t. Their legitimate confusion led me to think of feedback as spiraling forward through time.
Therefore, I will use the phrase “feedback spirals” throughout the rest of this book whenever I refer to sequences normally labeled as feedback loops.
There are two kinds of feedback spirals. The mathematicians who first explored this topic labeled them “negative” and “positive”. These labels referred to their mathematical characteristics and had absolutely nothing to do with an emotional judgment of the feedback spiral. System thinkers have coined several more descriptive, less confusing names for these two kinds of feedback. In this book, I will use balancing feedback spirals and reinforcing feedback spirals.
Balancing feedback was originally called negative feedback because if a change happens in one direction, the feedback undoes it, moves it back in the other direction. Balancing a stick on one’s finger is an example of balancing feedback. If the tip of the stick starts falling one way, I move my finger (and the base of the stick) in such a way that the tip of the stick changes direction and starts falling back the other way. Balancing feedbacks can sometimes be good – such as all the systems that maintain our bodies’ dynamic equilibriums. They can also be bad – such as the withdrawal symptoms that make it so hard for an addict to kick a habit.
Reinforcing feedback was originally called positive feedback because if a change happens in one direction, the feedback helps more of it happen, increasing it. The feedback of a screeching microphone is the classic example of reinforcing feedback. The microphone amplifies a sound which gets fed back into the microphone to get amplified again which gets fed back into the microphone again….
When someone “gives you feedback”, it’s supposed to be reinforcing feedback. You attempt something; they give you feedback to help you do it better next time. Thanks to their feedback, you can do it better next time which allows the other person to give you new feedback so that you can do it even better the next time. However, if somebody gives you feedback in a critical, arrogant way, it can be balancing feedback, assuring that you will never make the attempt again and you are back where you started.
Learning to read is an interesting example of reinforcing feedback. Learning letters helps the young one recognize words, which fills the writing with meaning, which makes reading more interesting so that one tries reading more, learning more words which link together to describe actions, places, thoughts and on and on it goes. This process got amplified when Gutenberg developed his movable type printing press. Books could be printed faster and cheaper which increased the number of books which increased opportunities for practicing literacy which increased the market for more books which led to more ideas being communicated in books which led to the spread of these ideas which inspired new thoughts which led to yet more books. A less eminent example of reinforcing feedback is the speculative housing bubble of the 2000’s. Housing prices were going up because people were buying houses as an investment because the housing prices were going up because people were buying houses as an investment….
The fourth fundamental property of systems: inflow and outflow. None of the systems we see around us on earth existed at the beginning of time. They all were assembled by an inflow of atoms from elsewhere. Those atoms will eventually flow somewhere else. As Odum’s diagrams showed, systems are sustained by a cycling flow of atoms and a flow-through of energy. During Denali’s Augusts, one of the most impressive outflows is the long, diarrheatic purple streaks from grizzly bears chowing down on blueberries. The energy of the twenty-hour Arctic days has flowed into miles upon miles of ripening tundra blueberries. Now it flows into the bears where the sugars will be converted into fat for hibernation and the purpled water will flow back out onto the ground.
All of the graphs and diagrams in Odum’s book had already introduced me to this way of thinking. Almost everything around us is sustained by the inflow of solar energy doing the heavy work of lifting the oceans into the sky, driving the winds and currents, fueling the photosynthesis at the bottom of the life-sustaining food pyramid. But inflow and outflow extends beyond that. A community has an inflow of births and an outflow of deaths. A budget has an inflow of income and an outflow of expenses. A child has an inflow of unique experiences resulting in an outflow of unpredictable creativity.
Inflow and outflow are one of the main connectors between subsystems. When I butcher chickens, the organ systems can all be easily teased apart along differentiating membranes until I come to the tubes where that organ gets its inflow or where it sends its outflow. Those places can’t be teased apart. They must be cut, must be severed. Every sub-system’s inflow is some other sub-system’s outflow and every sub-system’s outflow is some other sub-system’s inflow. A mother nurses her young. Ocean water falls as rain upon the land. My spending becomes someone’s income. We exit the freeway onto the city streets.
Going deeper with inflow and outflow leads us into the sense of direction shaped by the Second Law of Thermodynamics. Water flows spontaneously downhill. It can be pushed uphill, but moving that direction requires energy from elsewhere. Some flows happen spontaneously; others require energy. The young salmon can follow the current down to the sea but the returning adult salmon has to use its fat reserves to go against the flow back up to its birthplace. If there is no energy source, flows will go only one way – towards less usable energy – and what is flowing will accumulate down at the bottom. Only that which can be “lifted” back up, recycled, can be used again. Odum’s book described all the ways that life has found to empower the recycling of nutrients essential to life. The nitrogen cycle. The phosphorous cycle. The sulfur cycle. Life (mostly bacteria) has evolved ways to “lift” these limited but essential atoms back “up” so that they can be used over and over again.
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