Basic Notions - Equilibrium
Tapping into physics and Newton’s first law of motion, we know that “an object at rest will stay at rest, and an object in motion will stay in motion unless acted on by a net external force.” Therefore, as long as the forces imposed on an object cancel each other out, it will remain in its original state, with no change. The same goes for any system, and as the psychologist and system theorist William R. Ashby puts it, “all machines started in a basin will come to a state of equilibrium, if one exists.” Therefore, we can define equilibrium as a state of a system in which the combined result of all imposed forces to the system is nil.
Adopting this notion in social settings, the object depicted in figure above can represent a person in an equilibrium state. The individual is experiencing different forces, but since these are all counteracting each other, the individual remains in the equilibrium state.
As an example, an employee may experience a demanding work environment and performing several difficult tasks; but as long as incentives are perceived as fair for that work, these opposing forces (difficulty vs. incentives) will cancel each other, the equilibrium state remains unaffected, and the employee will remain at the job.
 Ashby, W. R. (1956, October). An Introduction to Cybernetics (Vol. 37). London: Chapman & Hall.