One key characteristic of a complex system—be it a forest ecosystem, city, or an organization—is that it demonstrates “emergence." Think of city; it is far more than the sum of its parts (buildings + people + streets). Out of a city emerges culture, innovation, and economic growth. But what does emergence even mean?
The concept of emergence has been around since at least the time of Aristotle. It describes the fact that complex behaviors can emerge from a set of interacting elements. A good example of observable emergence is a school of fish that self-assembles in the water as one collective, responsive mass. Or the unique, complex structures of a snowflake that emerge from freezing water molecules.
As elements in a system increase, so do the new and subtle interactions between them; thus, making the prediction of emergent behavior increasingly difficult. Interactions between elements demonstrate a couple common patterns:
- Negative feedback is when elements introduce constraints that serve to fix or maintain outcomes. For example, a thermostat kicking on and off to maintain the desired room temperature.
- Positive feedback is when elements perpetuate and support change in a particular direction. This is displayed in an unmitigated rabbit population or more terrifying nuclear arms race.
Emergence is important to understand when intervening in complex systems because, all too often, our “solutions” lead to unintended consequences that exacerbate the problem (remember ethanol?).