It is interesting to begin the analysis of hierarchical control structures by asking about the basic decision elements of which ranks and orders of command are in general composed. In nature, if we consider that most sophisticated control system, the brain, this element might be identified as a single nerve cell or neuron. In industry or government indeed in any strongly cohesive social group the element is some sort of manager.
Both the neuron and the manager have one really basic task to perform: to decide. In the neuron's case, a pulse must either be triggered down the output nerve or not. For the manager, the fundamental task is also to say yes or no. It true that managers do not spend their lives uttering these two words; they may never utter them. None the less, this is their task, and the subtleties, the nuances, the might-I-suggests and the perhaps-you-woulds are really socially intricate ways of saying yes or no.
In order to reach a binary decision, the decision element has to establish a threshold of decision. We may think of it as saying 0 until it is prompted to say 1 instead. This would be a permissive kind of management, in which the decision element does nothing until activated. It must not be activated by any stray impulse or noisiness that happens to be floating around the system, and this fact establishes the need for a threshold. Over-sensitive neurons would soon send either men or firms mad. When things really begin to happen, the decision element accumulates its evidence. When it is sure that there is real evidence demanding action, which is to say when the sum of inputs exceeds a threshold value, it fires.