ABSTRACT
This chapter examines closed-loop circuits from a different angle. Whereas control looks at the circuits as a means for reaching and maintaining a goal, observation looks at these same circuits from the perspective of making judgments about the world. In control or observer systems the comparator is the point at which the output is fed back and ‘compared’ with the input to compute an error signal. It should be clear that for the pilot and more generally for most cognitive or biological control systems, the signals involved in the comparator process may be in diverse forms or currencies, The system must have feedback about both position and velocity in order to control the vehicle. For biological and cognitive systems, the problems of control and observation go hand-in-hand. For example, a decision about moving to a new neighborhood might depend on the ability to judge whether the safety of the neighborhood is changing.
