higher level controls lower level - think to "move leg"
even higher level controls level below it - walk (move one leg the another), etc...
control theory is how thermostat works, too low temperature? heat up - too high? cool down - powers argues that we do same thing on multiple different levels (from body temperature, to food, to social interactions) - all seem related to homeostasis
we switch effortlessly between concentrating on low-level concepts and high-level concepts that make the low-level ones automatic
"everything is a control system" is an attempt to improve on "everything is stimulus-response" (behaviorism)