Preston Kutney's Reviews > Thinking in Systems: A Primer

Thinking in Systems by Donella H. Meadows
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it was amazing
bookshelves: how-the-world-works, re-readable, saving-the-planet

Word for word, this is one of the best books I've ever read. It simply packs a TON of useful, paradigm-shifting information into a fairly short book. Many times I felt myself underlining whole paragraphs and entire sections, I kept thinking "jeez, maybe I should just screenshot this whole chapter into Evernote".

Systems Dynamics is neat. It's a way of analyzing, mapping, understanding, and attempting to predict (even systems researchers at the top of their fields admit it's an art as much as a science) complex systems. Systems have three components: individual elements, connections between elements, and an overarching behavior or purpose of the group of elements. High-functioning systems work really well. They are resilience, they can self-organize into efficient hierarchies, and they can learn and adapt to new circumstances. However, modern life has necessitated that we strip out many of the redundancies in systems, that more rigid controls be placed around them to reduce their variability and dynamism, and many of the key features of good systems have been lost. The resultant fragility can be seen in financial markets, ecosystems, etc., basically in any modern system where men have significantly intervened.

This book is about how to design better-functioning systems and repair ones that are broken. The starting place is learning how to untangle the structure of a system - how to map stock and flow diagrams with feedback loops. Once you understand the structure of the system, and the directions and relative strengths of the feedbacks, you are ready to identify common traps and pick leverage points for action. The author has created a great step-by-step- guide to working with complex systems, has clear diagrams, helpful lists, and fantastic examples, one of which I'll share to illustrate the enlightening insights produces by systems dynamics:

A simplified model of a fishery economy is affected by three nonlinear relationships: price (scarcer fish are more expensive); regeneration rate (scarcer fish don’t breed much, nor do crowded fish); and yield per unit of capital (efficiency of the fishing technology and practices).

This system can produce many different sets of behaviors. In one example, we see capital and fish harvest rise exponentially at first. The fish population (the resource stock) falls, but that stimulates the fish reproduction rate to replenish. For decades, the resource can go on supplying an exponentially increasing harvest rate. Eventually, the extraction rate rises too far and the fish population falls low enough to reduce the profitability of the fishing fleet. The balancing feedback of falling harvest reducing profits brings down the investment rate quickly enough to bring the fishing fleet into equilibrium with the fish resource. The fleet can’t grow forever, but it can maintain a high and steady harvest rate forever.

Small changes in the relative strengths of feedbacks can have dramatic results. For example, if the yield per capital unit does not fall (ie, if the marginal catch does not get more expensive as fish get scarce) due to technology advances, then the harvest rate can continue to increase, along with capital stock as profits are reinvested, causing a drop in the fish stock past the critical threshold where reproduction is spurred by low density, and population collapses.

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Reading Progress

September 22, 2014 – Shelved
September 22, 2014 – Shelved as: to-read
April 5, 2016 – Started Reading
April 29, 2016 – Shelved as: how-the-world-works
April 29, 2016 – Shelved as: re-readable
April 29, 2016 – Shelved as: saving-the-planet
April 29, 2016 – Finished Reading

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