systems theory

Systems theory is the field that studies systems as wholes: how components interact, self-organize and produce behavior that cannot be predicted from the parts alone. Its key branches are cybernetics (control and communication in systems), complexity theory (emergent behavior from simple rules) and dynamical systems (the evolution of state over time).

Systems theory is the field that studies systems as wholes: how components interact, self-organize and produce behavior that cannot be predicted from the parts alone. Its key branches are cybernetics (control and communication in systems), complexity theory (emergent behavior from simple rules) and dynamical systems (the evolution of state over time).

Ashby's Law of Requisite Variety (1956) says that a controller must match the variety of its environment (the first law of cybernetics, and a deep constraint on all adaptive systems including RL)

Feedback loops are the fundamental mechanism: negative feedback stabilizes (thermostat, KL divergence in RL), positive feedback amplifies (reward hacking, model collapse)

In ML, the distinction between SFT/DPO (open-loop, no feedback) and RL (closed-loop, with feedback) maps directly onto the reactive and adaptive classes of systems theory.

Emergence is the central phenomenon: system-level behaviors that no component was designed to produce. Emergent behavior in RL-trained models is a textbook example.