How did engineering and economics problems help shape modern control theory?

Modern control theory emerged in the late 1950s and early 1960s when it was recognized that diverse problems in engineering and economics shared a common mathematical structure.1

While early control efforts were often isolated engineering inventions—such as James Watt’s flyball governor—these were eventually understood as variants of problems in differential equations and the calculus of variations. Initially, researchers devised special modifications of classical techniques to address individual challenges. The realization that these problems could be unified under a single mathematical framework led to the formal establishment of control theory as a distinct field.21

In this context, control theory provides the mathematical models necessary for optimization, allowing for the regulation of systems ranging from industrial machinery to economic activity. While engineering provides the hardware and implementation, the theoretical foundation relies on quantifying system behavior and disturbances to deduce optimal control laws. It is important to note, however, that while control theory is applicable to social and economic systems, the limitations of these models—particularly regarding non-linear systems—mean that claims regarding governmental control of human society should be viewed with caution.31