“[T]he concept of control is seen to be role based – that is, which part of a linked feedback system is the controller and which the controlled is not clear-cut, but depends on a point of view. In traditional terms, the thermostat controls the heating system. But what controls the thermostat, making it switch state? The answer, of course, is the ambient temperature – which is a (nonexclusive) product of the heating system. In this respect, the heating system at least partially controls the thermostat.”
Ranulph Glanville (1982), Inside every white box there are two black boxes trying to get out, Behavioral Science, 27(1), 1–11 (p. 7).