William T. Powers

William T. Powers (born August 29, 1929) is a maverick scientist (that is, without institutional affiliation) who has developed perceptual control theory, which finds that the behavior of living things is not controlled by them, but rather is their means of controlling their inputs by negative feedback. It differs from engineering control theory in that the reference variable for each control loop in a control hierarchy is set from within the system, rather than by a separate controller.