The PCT difference

[From Dag Forssell (940318 12.00)]

Inspired by Bill's post on the uses of PCT (930412.2000 MDT), I am
working on the following graphic presentation of the difference between
descriptive and generative theory as a way to explain what is different
about PCT.

What follows is four overhead slides with commentary for each.

COMMENTS WILL BE APPRECIATED! I am open to suggestions in every area
here. Choice of words, structure, commentary - please let me have
suggestions and reactions. By Monday morning I expect to mail the first
copies to contacts, but that is of course only the start of the never-
ending process of continuous improvement.

I have picked the field of "Mechanical Engineering" (loosely defined,
perhaps it should be reduced to "Engineering") because I think most
people will appreciate the existence and power of generative theories
when it is pointed out to them. (And perhaps because I are one, so it is
comfortable for me). Some such analogy is mandatory since generative
theories are absent in the life sciences, and there are no illustrations
to be found in any of those fields.

···

=====================================================================

DESCRIPTIVE PERSPECTIVE: Mechanical Engineering

(Slide 1 of 4)

                          Bridges Plumbing
            Weapons \ / Roads
                     \ _| |_ /
                        \ ______________ /
                         _| | | |_
        Vehicles -----> | ENGINEERING | <--- Buildings
                             > PRACTICE | |
                             >______________| |
                                    > >__(observations)
                                    >
                                    v

                                EXPERIENCE
                                    >
                                    >
               _____________________v___________________
              > >
              > OBSERVED PHENOMENA / EMPIRICAL LAWS |
              > >
              > "Strength" "Performance" "Quality" |
              > "Function" |
              > >
              > Engineering rules (of all kinds) |
              > "(Rules of thumb)" "(Codes)" |
              >_________________________________________|

  SCIENCE/THEORY/RULES/PARADIGM/CRAFT/ART (synonyms)

  based on: Experience
                Observed regularities (statistics, intuitive
                Descriptions or formal)

=====================================================================

Commentary: Slide 1 of 4

      People down through the ages have accomplished plenty of engineering
      feats we still admire today. Sophisticated compound bows and arrows.
      Ocean crossing ships and canoes. Roman aqueducts. Large bridges.
      (Caesars soldiers built a bridge over the river Rhine in less than
      12 days, so they could pursue the barbarians).
      Most of our daily lives depend in the same way on simple "common
      sense" and accumulated experience. We learn what works by "trial and
      error", and develop "rules of thumb" for most aspects of our
      existence.

      We make plenty of predictions based on empirical laws. Basically,
      the predictions say that: "Last time I did X, Y happened. Therefore,
      I predict that if I do X again, Y will happen again. If
      circumstances are indeed similar, chances are good the prediction
      will prove correct.

      A very large part of "engineering" practice is still an extension
      of this age-old natural approach to learning.

=====================================================================

DESCRIPTIVE PERSPECTIVE: Human Condition

(Slide 2 of 4)

                            Psychotherapy Psychology
               Counseling | /
                       \ | / Sociology
          Education \ | /
                  \ \ | / Management
      Linguistics \ _| v |_ /
                        \ ______________ / Biology
                         _| | | |_
      Parenting -------> | HUMAN | <------ Neurology
                             > CONDITION | |
                             >______________| |
                                    > >__(observations)
                                    >
                                    v

                                EXPERIENCE
                                    >
                                    >
                                    v
               _________________________________________
              > >
              > OBSERVED PHENOMENA / EMPIRICAL LAWS |
              > >
              > "Stimulus - Response" "Reinforcement" |
              > "Cognition / Planning" |
              > >
              > "Common sense" "Research results" |
              > "Rules of thumb" (of all kinds) |
              >_________________________________________|

  SCIENCE/THEORY/RULES/PARADIGM/CRAFT/ART (synonyms)

  based on: Experience
                Observed regularities (statistics, intuitive
                Descriptions or formal)

=====================================================================

Commentary: Slide 2 of 4

      In religious thinking and in academic "life sciences" as well as in
      common age-old wisdom, we have a very large body of experience and
      rules of behavior, accumulated in the same way as the engineering
      wisdom we just discussed.

      And still in the same way, most of our daily lives depend on simple
      "common sense" and accumulated experience. We learn what works by
      "trial and error", and develop "rules of thumb" for most aspects of
      our existence.

      We make plenty of predictions based on empirical laws. Basically,
      the predictions say that: "Last time I did X, Y happened. Therefore,
      I predict that if I do X again, Y will happen again. If
      circumstances are indeed similar, chances are good the prediction
      will prove correct.

      (Almost?) all of our "human condition" practices/sciences (are still
      an extension of) practice this age-old natural approach to learning.

=====================================================================

GENERATIVE PERSPECTIVE: Mechanical Engineering

(Slide 3 of 4)

               _________________________________________
              > >
              > FIRST PRINCIPLES |
              > >
              > Physical laws of nature |
              > >
              > "Newtonian" laws of attraction, |
              > motion, etc. |
              >_________________________________________|
                                   >
    PLUS: |
               ____________________v____________________
              > >
              > THEORY, MODELS |
              > >
              > Engineering theories of structure, |
              > bending, configuration, mechanism |
              > thermal effects, gas laws, material |
              > elasticity, plasticity etc. etc. |
              >_________________________________________|
                                    >
                                    > _ (predictions)
                             _______v______ |
                            > > >
       Vehicles <------- | ENGINEERING | ----> Buildings
                            > PRACTICE |
                           / -------------- \
                         / | | \
             Weapons |_ v v _| Bridges
                            Roads Plumbing

  SCIENCE/THEORY/RULES/PARADIGM/APPLICATIONS

  based on: First principles
                Theory, Modeling
                Testing, 100% validity

=====================================================================

Commentary: Slide 3 of 4

      With the advent of the "newtonian" laws of nature in the late
      1600's, and the new rigor of careful measurement and test of theory,
      the engineering sciences began a development which is *qualitatively
      different* from the previous development by "trial and error".

      It has become possible to "generate" designs and predictions from
      tested first principles. Because of this, the last few centuries
      have seen unprecedented progress in engineering. The theories,
      coupled with empirical data (about such things as material strength)
      have allowed us to extrapolate from small experiments and even to
      know how far it is prudent to extrapolate.

      With the *descriptive*, empirical theories, we could not go beyond
      existing data from direct observations.

      With *generative* theories based on first principles, it is possible
      to deduce and predict NEW functional relationships. The generative
      theory thus contains much more useable information. The difference
      is that a wider (potentially MUCH wider) realm of functional
      relationships can be predicted by the generative theories.

      (For some additional thoughts on this, see Greg Williams letters to
      Dennis Delprato, posted: Wed Jan 01, 1992 5:46 am PST)

      The Golden Gate Bridge, modern aircraft, space craft, (computers). -
      -- The list of accomplishments is long. They all DEPEND on the
      modern development of GENERATIVE theories.

      Yet few people in our population have much appreciation of the
      difference between descriptive theories based on trial and error,
      and generative theories, based on first principles and deduction.

      (Question for the net: In this context, what is a good word for the
      purely logical constructs of reasoning theories? I'll use
      reasoning).

      Besides *descriptive* (empirical) and *generative* (deductions from
      first principles) theories, there is a third category which must be
      mentioned: *reasoning*. Reasoning theories are found in fields like
      mathematics, geometry, logic. These are similar to the generative
      theories in that they depend on deduction, but very different in
      that they start from one or more stated hypothesis, not from a
      tested law of nature. Thus they are not based on first principles,
      but on a few arbitrary statements. The reasoning theories are often
      employed in support of the generative theories, but cannot, *in and
      of themselves*, tell us _anything_ about nature.

      The group most able to appreciate the differences are engineers,
      because they are deliberately trained to learn and apply generative
      theories. People who have no training that depends on and uses
      generative theories may not immediately comprehend what they are and
      recognize their utility and power. That assumption is the reason for
      this presentation.

=====================================================================

GENERATIVE PERSPECTIVE: Human condition

(Slide 4 of 4)

               _________________________________________
              > >
              > FIRST PRINCIPLES |
              > >
              > Physical laws of nature |
              > >
              > "Newtonian" laws of attraction, |
              > motion, etc. |
              >_________________________________________|
                                   >
    PLUS: |
               ____________________v____________________
              > >
              > THEORY, MODELS |
              > >
              > Perceptual Control Theory, which |
              > recognizes engineering practice and |
              > developments in cybernetics, as well as |
              > biology and neurology. |
              >_________________________________________|
                                    >
                                    > _ (predictions)
                             _______v______ |
                            > > >
     Parenting <------- | HUMAN | ----> Neurology
                            > CONDITION |
      Linguistics /|______________| \ Biology
                         / / | \ \
                       / / | \ _| Management
        Education |_ / | \
                         >_ | _| Sociology
            Counseling v
                           Psychotherapy Psychology

  SCIENCE/THEORY/RULES/PARADIGM/APPLICATIONS

  based on: First principles
                Theory, Modeling
                Testing, 100% validity

=====================================================================

Commentary: Slide 4 of 4

      Based on the "newtonian" laws of nature and the new theory called
      Perceptual Control Theory, the "human condition" sciences can now
      embark on a development which is qualitatively different from the
      previous development by "trial and error".

      It has become possible to "generate" effective practices and
      predictions from tested first principles. Because of this, the next
      few centuries will see unprecedented progress in the life sciences.
      The theories, coupled with empirical data (about such things as
      ??? and ??? (Neural path lengths, neural signal
      travel speeds, neural signal frequency ranges, sensor sensitivity
      and function, memory cell recording and playback mechanisms)) will
      allow us to extrapolate from small experiments and even to know how
      far it is prudent to extrapolate.

      With the *descriptive*, empirical theories, we could not go beyond
      existing data from direct observations.

      With *generative* theories based on first principles, it is possible
      to deduce and predict NEW functional relationships. The generative
      theory thus contains much more useable information. The difference
      is that a wider (potentially MUCH wider) realm of functional
      relationships can be predicted by the generative theories.

      Effective counseling, productive and satisfying professional
      relationships in the work place, non-manipulative business practices
      of buying and selling, loving family relationships, effective
      education, confident individuals, a better understanding of biology
      and neurology. --- The list of accomplishments will be long. They
      will all DEPEND on the modern development and application of
      GENERATIVE theory, (applied in a field of science where they have
      not been available before).

      With time, the people in today's life sciences will be exposed to
      and understand the difference between (the present) descriptive
      theories based on trial and error and generative theories, based on
      first principles and deduction. More people will recognize and
      benefit from the power of carefully tested and validated generative
      theories.
-------------------------------------------------

Again, comments solicited. Best to all, Dag

Dag Forssell
23903 Via Flamenco Valencia, Ca 91355-2808
Phone (805) 254-1195 Fax (805) 254-7956