And Desirable Owing to continuously changing conditions and requirements, to the fact that orders always precede the response to them, and to the fact that a body in motion tends to remain in motion, a gun mount is never in perfect alignment with its ordered position. Error is always present in any dynamic system. Because error is always present, there is a need not just for standards, but also for tolerances, for some acceptable margin of error regarding performance. Not only is error always present, its presence is essential to the proper functioning of a dynamic system. With no error signal, the gun mount would not move, it would remain wherever it happened to be.
Error is essential if things are to change.
Thus, error-free performance is not only unattainable but a certain amount of error is necessary to the proper functioning of the system. Unlike gun mounts, people have minds of their own. It is the means whereby they achieve the goals and objectives they have set. Unlike gun mounts, people do not simply do as they are told. Although the gun mount or technical model of feedback cannot be applied directly to people, the modification required to make use of it is surprisingly simple.