Good regulator theorem

The term good regulator theorem (lowercase) refers to the same result as Good Regulator theorem: the theorem proved by Conant and Ashby that every good regulator must be a model of the system it regulates. The lowercase usage is common in the broader cybernetics literature, where the theorem is treated as a general principle rather than a formal result.

In this usage, the good regulator theorem is connected to Ashby's law of requisite variety and to Stafford Beer's viable system model. The lowercase form emphasizes the theorem's status as a design heuristic rather than a mathematical proof. What the lowercase tradition adds is the emphasis on practice: the theorem is not merely a statement about information but a guideline for building systems that can regulate themselves, from thermostats to organizations to ecosystems.