The parts of a system
The Anatomy of a System
A system can be broken down into three fundamental components, as illustrated by the analogy of people paddling a boat.
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Elements : These are the tangible and intangible "parts" or "things" in a system. For example, the paddlers, the boat, the water (tangible), and the paddlers' skill level (intangible).
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Interconnections : These are the relationships that hold the elements together. For example, how the paddles apply force to the water, the communication between paddlers, or how the wind affects the boat. A key insight from Donella Meadows is that changing the interconnections has a far more significant impact on a system's behavior than changing its elements.
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Emergent Properties : These are the properties or behaviors that arise from the system as a whole but are not present in any of the individual elements. For example, a "phantom" traffic jam is not a property of any single car but emerges from the collective interactions and reaction times of all the drivers.
The Engine of Systems: Feedback Loops
Feedback loops represent circular causality, where the output of an action "feeds back" to influence subsequent actions. This is different from simple linear cause-and-effect thinking. There are two primary types of feedback loops.
| Type | Behavior | Also Known As | Example |
|---|---|---|---|
| Reinforcing Loop | Amplifies change. It creates a "snowball" effect, leading to exponential growth or decline. More leads to more; less leads to less. | Positive Feedback | Fast Fashion: Cheap production → more marketing → more purchases → more profit → even more cheap production. |
| Balancing Loop | Seeks stability. It resists change and tries to keep the system at a desired goal or level. | Negative Feedback | Thermostat: If a room gets too hot, the AC turns on to cool it (counteracting the change). If it gets too cold, the heater turns on. |
Note: "Positive" and "Negative" do not mean "good" or "bad." They describe the loop's function—to amplify or to stabilize.
Unintended Consequences & Leverage Points
Because of these complex interactions and feedback loops, systems often produce outcomes that were not originally intended.
- Definition: Unintended consequences are desirable or undesirable side effects that are generated by a system, even when it is achieving its primary goal.
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Key Examples:
- Industrial Agriculture: The intended outcome is high crop yield, but an unintended consequence is long-term soil degradation.
- Fast Fashion: The intended outcome is profit, but an unintended consequence is a massive increase in landfill waste.
- The Goal: Understanding these dynamics allows us to identify leverage points—small, strategic interventions that can create significant, positive changes throughout the entire system.
Exam Tip: The most critical concept in this lecture is the ability to define and differentiate between reinforcing and balancing feedback loops. Provide a clear example for each. Understanding how systems produce emergent properties (like a traffic jam) and unintended consequences (like landfill waste from fashion) is also a key insight.
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