Why Nonexistent Boundaries Surprise Us

• Stock-and-flow diagrams have beginnings and ends that are shown as clouds. These clouds stand for wherever the inflows come from and outflows go to. They are stocks that are being ignored at the moment in order to simplify the present discussion. In other words, they mark the boundary of the system diagram.
• However, they rarely mark a real boundary, because systems rarely have real boundaries. As they say, everything’s connected to everything else, and not neatly. And as such, these clouds or boundaries are prime sources of system surprises.
• Usually, there are only boundaries of word, thought, perception, and social agreement. In other words, these tend to be artificial, mental-model boundaries.
• The greatest complexities arise exactly at the boundaries. However, disorderly, mixed-up borders are sources of diversity and creativity.

Nonexistent Boundaries for a Car Dealer

• For instance, in a diagram for a car dealer, a flow of cars into the dealer’s inventory may be shown as coming from a cloud. But of course, cars don’t come from clouds. They come from the processing of a stock of raw materials.
• Similarly, the flow of cars out of inventory doesn’t go to a cloud. Instead, it goes through sales to the households and businesses of customers.
• Whether it’s important to keep track of raw materials or customers’ home stocks, or whether it’s acceptable to replace them in a diagram with clouds, depends on whether those stocks are likely to influence the behavior of the system over the period of interest.
• If raw materials will be abundant and customers will continue to demand the cars, then clouds will do fine. But, if there could be a shortage of materials or a product surplus, and you created a boundary around the system that didn’t include these stocks, then you might end up being surprised by future events.
• But there are still clouds in this diagram for a car dealer, which means that the boundary can be expanded even further.
• Raw materials come from chemical plants, smelters, or refineries, whose input ultimately comes from the earth. Discarded consumers’ stocks go to landfills, incinerators, or recycling centers. Recycling centers move materials back into the production stream.

Including the Full Flow or Making Boundaries

• Whether it’s important to think about the full flow from beginning to end depends on who wants to know, for what purpose, and over how long of a timeframe.
• In the long term, the full flow is important. And as the economy grows and society expands, the long term is increasingly becoming the short term.
• On planet Earth, there usually are no system “clouds,” no ultimate boundaries. Everything physical comes from somewhere, everything goes somewhere, everything keeps moving.
• However, this isn’t to say that every model needs to follow each connection until it includes the whole planet. Clouds are a necessary part of models that describe flows.
• If we are to understand anything, we have to simplify, which means we have to make boundaries. Usually, that’s a safe thing to do.

Boundaries That Are Too Narrow or Too Large

• On the other hand, this lesson of boundaries is hard even for systems thinkers to get. There’s no single, legitimate boundary to draw around a system. We have to invent boundaries for sanity and clarity. But boundaries can produce problems when we forget that we’ve artificially created them.
• When you draw boundaries too narrowly, the system can surprise you. For instance, if you try to deal with traffic problems without thinking about settlement patterns, you build highways. These highways attract housing developments along their whole length. And those households, in turn, put more cars on the highways, which then become just as clogged as before.
• If you try to solve a sewage problem by throwing the waste into a river, the towns downstream make it clear that the boundary for thinking about sewage has to include the whole river.
• But systems analysts often fall into the opposite trap. In other words, they make boundaries too large. They produce diagrams that cover several pages with small print and many arrows that connect everything with everything else. And if you’ve considered anything less, you’re academically illegitimate.
• This game results in overly complicated analyses which may only confuse the answers to the question at hand. For instance, modeling the earth’s climate in full detail may not be necessary to figure out how to reduce a country’s CO₂ emissions to reduce climate change.

The Answer to Boundary Problem

• The right boundary for thinking about a problem rarely coincides with the boundary of an academic discipline, a national boundary, or a political boundary. For instance, national boundaries mean nothing when it comes to greenhouse gasses in the atmosphere.
• Ideally, we’d have the mental flexibility to find the right boundary for thinking about each new problem. But we’re rarely that flexible. We get attached to the boundaries that our minds have become used to.
• Think about how many arguments have to do with boundaries. There are national boundaries, ethnic boundaries, boundaries between public and private responsibility, and boundaries between the rich and the poor.
• It’s a great thing to remember that boundaries are of our own making. And, that boundaries can and should be reconsidered for each new discussion or problem.
• It’s challenging to stay creative enough to drop the boundaries that worked for the last problem, and to find the right boundaries for the next question. But it’s also necessary if we want to solve problems well.

This is part ten of the summary of Thinking in Systems by Donella Meadows. If you’d like to review, here are parts one, two, three, four, five, six, seven, eight, and nine of the summary.

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