OneThing21: seeing structures, naturally

Click to go to a Donella Meadows essay archive

Donella Meadows’ Thinking in Systems asserts all systems have three characteristics:  elements, behaviors, and structures.

By elements she means a few things, among them are stocks or levels one might find in the world, such as trees or people or worms or water or cars or magma. These things usually occupy space – a forest or a city or a garden or lake  or a freeway or a cavern.

By behaviors she means the things we see or experience through time: forest will grow, burn, succumb in part to locusts, diversify, become more or less tropical as climate shifts, et cetera.  More broadly, then, all stocks fluctuate over a course of time – centuries or lifetimes or weeks  or seasons or rush hours or millennia. Within these time frames, various stocks will change – they’ll grow, they’ll decay; or they’ll do a little of both, oscillating through stretches of time.  For instance, people increase and multiply, cities grow and decay, garden productivity shifts, worm populations increase until they reach a carrying capacity – a limit imposed by natural surroundings – and then subside.

All that notwithstanding, the core lesson of system dynamics resides in recognizing structures. And by this she means that stocks, and their attendant flows, are arranged in particular relationships with other stocks . . . and there are surprisingly few of these primary structures. Within forests, there may be multiple systems at work; but when one hikes through the Mt. Hood National Forest, one immediately steps on the deep cushion of woody debris and decaying detritus sloughed from the enveloping trees which, in turn, generate vital nutrients for the seedling conifers to lay a root claim on the forest floor, where – in turn – their wood volume will increase for decades.

Coarse woody debris decomposes, creating a nutrient-rich loam for a forest’s succeeding generation of trees.

Within a city, thousands and millions throng. People are born and die, move in and move out, and each of these flow phenomena may depend on other variables in a broader system: economic forces, disease, education level of women, et cetera.

We observe the behaviors of these multivariate systems and can usually articulate them, but we rarely understand the dynamics that underlie them.  However, once a person can at least identify the primary stocks in a system then the structure of that system – the dynamic relationships of that system – may begin to emerge from the fog and fray of daily living. And that is wondrous start indeed.


2 comments on “OneThing21: seeing structures, naturally

  1. Pingback: OneThing30: I’ll show you my mental model, if you show me yours « itsallonething

  2. Pingback: OneThing21: seeing structures, naturally « itsallonething | Structural Change

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