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Thinking in Systems

By Donella H. Meadows

  • A system is a group of connected elements with a shared purpose
    • behavior of a system breaks down into stocks and flows, which change over time
    • Stocks are the elements of a system that can be accounted for at any given time. Ex - Water in a bathtub, books in a store or money in a bank.
    • Flow is the change in stock over time as a result of inflows, which add, and outflow, which subtract. Ex - births and deaths or purchases and sales
  • Every sustainable system relies on some kind of feedback for stabilization
    • Self balancing feedback
      • If a force stabilizes the difference between the actual and desired levels of stock
      • Such a feedback is a chain for rules or physical laws that relate to the level of stock and have the ability to change it. ex - thermostat with radiator
    • Reinforcing feedback
      • Perpetually generates more or less of what already exists.
      • Ex - The more money you have in savings account, the more interest you accure, and the more interest you accure, and the more money you have in your account
      • The reinforcing mechanism can produce constant, even exponential, growth or destruction
  • Well-functioning systems are resilient, self-organized and hierarchical
    • As systems build new, increasingly complex structures, they naturally organize themselves based on a hierarchy.
    • Why hierarchies? Because they reduce the level of information any given part of the system has to handle
  • Corrupt systems are produced by disproportionate power and can enable overuse
  • Systems can be physically adjusted to improve efficiency
    • By changing buffers, system design and delays, we can produce more effective systems
  • Systems can be made even more efficient by adjusting their internal mechanisms and rules
  • Paying attention to the inner workings of systems will help you better understand the world
  • Emergence: Emergence is a simple but powerful concept. It means that when things come together, something new and unexpected happens. And this new thing isn't present in the individual elements. It's biological as much as social. A caterpillar becomes a butterfly.
  • Actionable advice - Always expect a positive outcome, not a negative one.