Terminology of purposive behavior

[From Bill Powers (930926.1315 MDT)]

Ken Hacker (930926) --

Terms like intention, purpose, goal, desire, want, aim,
objective, plan, design, end, motivation, ambition, and so on
form a cluster around a central concept. Until control theory
gave it one, this concept had no name: it was referred to only
indirectly, in terms of the surrounding circumstances in which it
was observed. This is why there are so many words that allude to
it without naming it.

The central concept, which in control theory is named the
reference signal or reference condition, concerned selection of
an outcome of actions before the outcome has occurred. It is
"that for the sake of which" all actions pertaining to it are
performed. This concept has been missing from science for most of
its history. Those who kept putting forward ideas relating to
reference conditions were regularly taken to be talking about
something supernatural or magical, something that belonged to a
separate "mental" universe that had nothing to do with the
physical one. It was assumed that no physical system could
perform actions with a preselected outcome, because that would
reverse cause and effect, giving a nonexistent future state of
affairs a determining influence on present actions.

Before control theory, the only way to guess at an outcome of
physical processes was to extrapolate from present conditions.
This meant that outcomes were necessarily uncertain, being
subject to unforseeable events that could happen between the time
of prediction and the time when the outcome was to be observed.
The very concept of prediction implies leaving room for
unknowable future perturbations, disturbances, and changes in
conditions, with the expectation that they will in fact occur and
will cause significant deviations of the outcome from the one
predicted. Predictions therefore almost necessarily apply to
multiple repetitions of a process, in which no one repetition is
expected to produce something near the expected outcome. Only
over a long series of predictions, over which the perturbations
are assumed to average out to zero, can the average result be
expected to approach the predicted result. The observed outcomes
are expected, on a trial-by-trial basis, to be exactly as
variable as all the possible variations of extraneous influences
might be.

The concept of a reference condition, together with the control-
system organization that gives it meaning, changes our
expectations. An outcome that is controlled relative to a
reference condition is very much more certain than one that is
merely predicted from initial conditions. It is no longer
necessary to add "ceteris paribus" to predictions, because under
normal conditions quite large perturbations and changes in
conditions have no important effects on the outcome of a control
process. The reference condition supplies a fixed point around
which actions are organized; whatever unpredictable variations
may arise, the control organization automatically adjusts to keep
the actions pointed toward the accomplishment of the reference
condition right up the the time that the desired outcome occurs.
Random perturbations no longer cause a random walk away from a
predicted outcome. Instead, the action of the system changes as
the perturbations come and go, in just the way necessary to
maintain progress toward the preselected end.

The word we use to refer to reference conditions and the control
process depends on ancillary considerations. If we are very
confident that we can retain control and create the specified
outcome, we say we intend for the outcome to occur. If we aren't
quite sure that an overwhelming perturbation or some other major
problem won't occur, we might say that the aim or goal is to
reach the outcome. At the low end of confidence we describe the
reference condition as a desire, a hope, or a wish. If we are
explaining the actions by which we are progressing toward the
goal, we commonly use the term "purpose": the purpose of moving
my arms this way is to direct an orchestra, the purpose of
pushing this machine over the grass is to mow my lawn. If we want
to focus on the reference condition rather than our current
relationship to it, we might refer to a goal, an end, an
objective, implying that it is not yet met. So we pick words that
cover more than just the reference condition or the control
actions, shedding light on surrounding conditions and our own
attitudes toward the process.

I hope this helps you in sorting out the connotations of various
terms that refer to reference conditions and control.

Best,

Bill P.