These are excerpts and elaborations from my book "The Nature of Consciousness"
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Control Systems The US electrical engineer
William Powers extended these ideas to a hierarchical organization of control
systems. First of all, he realized that a control system controls what it
senses: it controls its input (the perception), not its output (the behavior).
A thermostat controls the temperature, not the gas consumed by the heater.
Organisms change their behavior, but they do it in order to control a
perception. Behavior is the control of perception. A control system is a blind
performer of a specific function. It does not know the larger scope of its
function. For example, a thermostat does not know why it is keeping the
temperature constant. A control system has an internal goal (e.g., to maintain
temperature constant) and its behavior is determined by the difference between
what it perceives and its internal goal. Nonetheless, the control system
exhibits a behavior that appears to be "purposeful". Next, he envisioned a system
which is made of a pyramid of control systems, each one sending its output to
some "lower-level" control systems. The lowest level in the hierarchy
is made of control systems that use sensors to sense the environment and
effectors to act on the environment, and some "reference level" to
determine what they have to maintain at a constant level. For example, a
thermostat would sense the environment's temperature, effect the heater and
maintain the measured temperature at a constant level. At a higher level, a
control system senses and effects the reference level of lower-level control
systems. An engine could direct a thermostat to maintain a certain temperature.
The reference level of the lower level is determined by the control systems of
the higher level. Living organisms are made of
such hierarchies of control systems. "Instinctive" behavior is the
control system (organized in a hierarchy) that the organism inherits at birth.
They determine internally what parameters have to be maintain constant, and at
which magnitude. Behavior is a backward chain of behaviors: walking up the
hierarchy one finds out why the system is doing what it is doing (e.g., it is
keeping the temperature at such a level because the engine is running at such a
speed because
and so forth). The hierarchy is a hierarchy of goals (goals that
have to be achieved in order to achieve other goals in order to achieve other
goals in order to
) This hierarchy inevitably
extends outside the system and into the environment. A machine is part of a
bigger machine which is part of a factory which is part of an economy which is
part of a society which is part
The goal of a component of the machine is
explained by a chain of higher-level goals that extend into society. In the
case of living organisms, the chain of goals extends to their ecosystem, and
ultimately to the entire system of life. Back to the beginning of the chapter "Machine Intelligence" | Back to the index of all chapters |
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