Feedback loops

A feedback loop is a causal pathway in which a system's output is routed back as input, altering subsequent behavior. Negative feedback counteracts deviation from a reference state, producing stability and regulation — as in the thermostat, the body's temperature control, and cybernetic governance. Positive feedback amplifies deviation, producing exponential growth, collapse, or lock-in — as in compound interest, viral transmission, and arms races. All self-regulating and self-organizing systems are built from interlocking feedback loops; the signature behaviors of Systems theory — emergence, oscillation, phase transitions — arise from their interaction. Understanding which loops dominate under which conditions is the central practical skill of systems modeling. The dangerous mistake in designing or analyzing any complex system is to identify only the intended loops and ignore the compensating and reinforcing loops that the system generates in response to intervention.