[From Rick Marken (930313.1000)]

Bill Powers (930312.2100) --

In my last post I came across an idea (control systems reject
information from disturbances) that has now led to a further
development that may (or may not) help resolve all these 'tis-so-
'taint-so squabbles.

I think you are a bit more optimistic than I am about resolving this
matter. The only resolution I see is realizing that it 'tis so (sensory
inputs contain no information about the disturbance), that it 'taint
so (sensory inputs contain complete information about the disturbance)
or that it doesn't matter. I think Allen Randall has stumbled upon
the characteristic of PCT that makes it truly revolutionary and totally
unacceptable in conventional behavioral science. I am enthusiastically
picking at this "'tis-so-'taint-so" dispute, not because I am interested
in "dissing" (as my daughter would say) IT but because I consider
acceptance of the point (that the sensory input is a dependent variable;
not an independent variable in control systems) to be the main stumbling
block to correct understanding and acceptance of PCT by conventional
behavioral scientists.

There are those on this net who don't like referring to PCT as
"revolutionary". But Allen Randall has put his finger right on the
revolutionary button of PCT. If there is ONE thing on which ALL
conventional behavioral scientists agree it is that sensory input
is an INDEPENDENT VARIABLE -- it is the beginning of the causal chain
that ends in behavior. Even conventional behavioral scientists who
believe that the feedback effects of behavior are important would
still agree with this basic point -- sensory input is an independent
variable. This is the absolutely fundemental assumption of ALL research
in in the behavioral sciences -- ALL OF IT. What PCT says (in no
uncertain terms) is that this assumption is FALSE -- sensory input
is NOT an independent variable in a living control system (ie. all
living organisms) -- it is a DEPENDENT variable (the independent
variable being the reference signal inside the organism). I think
it is clear that, if PCT is right about this then the WHOLE edifice
of behavioral science comes crashing down -- somwthing up with which
most behavioral scientists will unquestionably not put.

There is obviously not much room for a compromise resolution to this
argument. PCT is just inherently revolutionary; and efforts to make
it seem "not revolutionary" require tacit agreement with the fundemental
assumption of the behavioral sciences -- that sensory input is an
independent variable. This kind of compromise leads to the kind of PCT
done by Carver/Scheier and their ilk. So while I agree that crying
"revolutionary" all the time can be annoying, the fact is that PCT
IS revolutionary -- whether we like it or not -- and failure to
accept PCT as revolutionary prevents one from giving up (dropping,
forgetting about, saying goodby to, etc) all the things that MUST
be given up if one is going to do PCT correctly. You can't do space
science (easily) with a Ptolmeic model; it is equally difficult
(actually impossible) to study control in the context of a
sensory input -- response output model of organisms (the one used
when you do a conventional behavioral science experiment).

I don't expect anyone (especially conventional behavioral scientists)
to just sign up to the "sensory input is not an independent variable"
canon of PCT; I want people to test it as harshly as possible; that's
why I welcome this debate with Allen Randall. I hope Allen sticks with
it and tries like mad to show that the PCT view can't possibly be true.
I want him to think of experimental tests, mathematical proofs -- whatever--
to try to convince ME that my argument (sensory input is NOT an independent
variable) is false. I want him to push on this little point as hard and
persistently as possible because this is where (for the behavioral
sciences anyway) the rubber really meets the road (how's that Ed?). If
I lose this debate -- and Allen is able to convince me that sensory
input does carry information about the disturbance and, thus, is
an independent variable that causes output -- then everyone will be happy
because I will then have to shut up about PCT being revolutionary. If
however, Allen relents and agrees that sensory input is always and
only a dependent variable (in a closed loop negative feedback system)
then maybe (but still unlikely) we can get some of the behavioral scientists
who are looking in on this net to abandon their misguided efforts and start
doing some PCT based research.

I know that you (Bill P.) are looking for ways to take what people can
already accept and move them gradually and gently to the PCT perspective.
That's fine with me; but I don't think one can make a gradual shift into
PCT (any more than one can make a gradual shift from an earth to a sun
centered view of the solar system). I don't think your approach will be
any more or less successful than mine -- the only people who will really
"get" PCT are the one's who want to -- no matter who is teaching it or
how. But I want to pursue this argument about the "information in
the stimulus" because 1) it's fun and 2) it's public so ANYONE on the
net who thinks PCT is wrong about this can explain why -- and I really
am interested in what they have to say.

So, again I claim 1) that there is typically no information about
disturbances in sensory input (and when such information is
available it is either unnecessary or, if used, it reduces the
amount of information transferred from disturbance to output) even
though system outputs perfectly mirror the information in these
disturbances) and 2) sensory input is always a dependent variable,
never an independent variable, in living sytems, thus there is virtually
nothing that can be learned about the nature of organsisms in the
framework of the typical (independent variable- dependent variable)
behavioral science experiment.

'Tis so.



[Avery Andrews 930316.0939]
  (Rick Marken (930313.1000))

>There are those on this net who don't like referring to PCT as
>"revolutionary". But Allen Randall has put his finger right on the
>revolutionary button of PCT. If there is ONE thing on which ALL
>conventional behavioral scientists agree it is that sensory input

Well, Chomskyan linguists are different - they are quite uninterested
in dependent vs. independent variables, and don't learn to analyse things
this way in graduate school- they just ask `what's the pattern,
and why'. I suspect that many non-psychologist `cognitive scientists'
are similarly unschooled.