According to the science of cybernetics, which deals with the topic of control in every kind of system (mechanical, electronic, biological, human, economic, and so on), there is a natural law that governs the capacity of a control system to work. It says that the control must be capable of generating as much "variety" as the situation to be controlled.

p. 37. - Management Science (1968) - Chapter 2, Chance, Risk and Malice