Eugene, Oregon
July 2003
Brother Bill:
I have thought about what I could put on paper that might be suitable for your
festschrift. I thought, for example, of writing an essay on what it means to
be called an expert—what an expert can and cannot do for the rest of us.
After all, you and I are both experts. Unfortunately, I found myself doubting
I could finish writing a decent piece by June.
I think both my last two books—Casting Nets and Testing Specimens”
and “People As Living Things—can be interpreted as appreciations
of your contributions to science and to good will toward humankind. For your
festschrift, I quote below the coda from Chapter 18 of “People As.”
Love,
Phil Runkel
Coda
Having [read] this far, I think you can take a deep breath, look around in your
thoughts, and see the grandeur of perceptual control theory.
I began reading the writings of W. T. Powers and his followers about 1985. As
I read and pondered, I found my previous views undergoing wrenching and even
frightening changes. I found myself having to disown hundreds, maybe thousands
of pages of my writings that I had broadcast to my peers with pride. I found,
then, that I could see order among my previous confusions about psychological
method. The sword that cut the Gordian knot––that cut through my
gallimaufry of methodological embarrassments––was the distinction
between counting instances of acts, on the one hand, and making a tangible,
working model of individual functioning, on the other. That idea, which in retrospect
seems a simple one, was enough to dissipate about 30 years of daily dissatisfaction
with textbook methods of psychological research. That simple bifurcation is
what I wrote about in my 1990 book.
The idea that permits making tangible, working models is, of course, the negative
feedback loop. And that, in turn, requires abandoning the almost universally
unquestioned assumption made by most people (including psychologists) of straight-line
causation––which, in turn, includes the conceptions of beginning
and ending. Displacing that theoretical baggage, the negative feedback loop
requires circular causation, with every function in the loop performing as both
cause and effect. That, in turn, implies continuous functioning (beginnings
and endings are relegated to the convenience of perception at the fifth level).
One cannot have it both ways. Living creatures do not loop on Mondays and straight-line
on Tuesdays. They do not turn the page with loops while reading the print in
linear cause-to-effect episodes. William of Occam would not approve.
Powers did not invent the loop. It existed in a few mechanical devices in antiquity
and came to engineering fruition after electrical devices had become common.
Some psychologists even wrote, haltingly, about "feedback." But the manner in
which living organisms make use of the feedback loop––or I could
say the manner in which the feedback loop enabled living creatures to come into
being––that insight was Powers's alone. That insight by itself should
be sufficient to put Powers into the pages of the history books as the founder
of the science of psychology. Historians of psychology will, I think, come to
name the year 1960 (when the two articles by Powers, Clark, and McFarland appeared
in Perceptual and Motor Skills) as the beginning of the modern era. Maybe the
historians will call that year the Great Divide. The period before 1960 will
be treated much as historians of chemistry treat the period before Lavoisier
brought quantification to that science.
Using the negative feedback loop as the building-block of PCT enabled Powers
to show how mathematics could be used in psychological theorizing. Powers's
true use of numbers made it possible at last to test theory by the quantitative
degree to which the data from any single individual approach the limits of measurement
error, as in other sciences.
Even making a science possible was not enough to fill the compass of Powers's
vision. He saw the unity of all aspects of human perception and action. He saw
that there was not a sensory psychology over here, a cognitive over there, a
personality in this direction, a social in that, and so on, but simply a psychology.
He gathered every previous fragment into one grand theoretical structure––the
neural hierarchy. The nature of the particular levels is not crucial. What is
crucial is the idea of the enabling effect of organization by levels––the
enabling of coordination among actions of all kinds. Previously disparate psychologies
with disparate theories can now all begin with the same core of theoretical
assumptions. Though it will take a long time to invent ways of testing the functioning
of the hierarchy at the higher levels, I find it exhilarating to realize that
Powers and others have already built models having two or three levels organized
in the manner of hierarchical control and that those models actually work.
The neural hierarchy is far more than a listing of nice-sounding categories.
The theory itself tells how we can recognize the relatively higher and lower
placements of levels. It tells us, too, some of the kinds of difficulties to
be anticipated in doing research at the higher levels. That kind of help from
early theory is a remarkable achievement.
I have mentioned three momentous insights: (1) that the negative feedback loop
is the prerequisite for life, (2) that numbers should be used to show the approximation
of model to human individual, and (3) that control grasps more aspects of the
environment through its hierarchical structure. For any one of those three momentous
insights, I think Powers deserves a bronze statue in the town square. To put
all three together in one grand system concept is the kind of thing that happens
in a scientific field once in a century or more.
After more than 15 years of reading, conversing, writing, and thinking about
PCT almost every day, I still feel the way Lewis and Clark must have felt when
they began rowing their boats up the Missouri River. I know the general nature
of the territory, I know that much of what I will come upon will be astonishing
and baffling, and I know that every mile of the journey will be hard going.
As I write this book, most parts of which are simply elaborations of the three
simple ideas set out above, I find time and again that I must take an hour or
a day to struggle with ways of keeping the words as simple as the idea. The
ramifications of those simple ideas are multifarious and subtle. As I begin
to describe a complication in the way those ideas work together, I find now
and again that I have opened further regions of complexity for which I am wholly
unprepared. Then I must take an hour or a day or a week to find my way back
to firm footing. I do not feel that I am trudging along a prescribed path. I
feel that I am taking every step with caution, but also with awe and exhilaration
as I wonder what I might add to my understanding. I am sure, however, that I
have only an inkling of the exploratory feelings Powers must have had as, day
by day and year by year, he built his theory. He guided his footfalls by experimentation;
I have guided mine only with thinking about the steps he took.