Departing from the conventional view of the reasons for the behavior of living systems, this research presents a radical and unique view of that behavior, as the observed side effects of a hierarchical set of simple, continuous, and dynamic negative feedback control systems, by way of an experimental model implemented on a real-world autonomous robotic rover. Rather than generating specific output from input, the systems control their perceptual inputs by varying output. The variables controlled do not exist in the environment, but are entirely internal perceptions constructed as a result of the layout and connections of the neural architecture. As the underlying processes are independent of the domain, the architecture is universal and thus has significant implications not only for understanding natural living systems, but also for the development of robotics systems. The central process of perceptual control has the potential to unify the behavioral sciences and is proposed as the missing behavioral principle of Artificial Life.