Viable System Model

A viable system is one that can survive in a changing environment. Beer's claim is that any such system has the same five functions: operations, coordination, control, intelligence and policy. The model is recursive, so each operational unit is itself a viable system containing all five, and the pattern holds from a team up to a state.

The architecture behind Project Cybersyn.

On requisite variety

Ashby's law, that a regulator must have at least as much variety as the disturbances it must absorb, is recorded here as an alias rather than as a concept of its own. It is the constraint the model was designed around, and within this collection it has no source the model does not already have. If a Work record for Ashby is added, it should be split out.