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Date:         Sat, 3 Oct 1992 07:36:47 -0600
From:         "William T. Powers" <POWERS_W%FLC@VAXF.COLORADO.EDU>
Subject:      the perceptual basis of HPCT

[From Bill Powers (921003.0600)]

Greg Williams (921002) (re-posted by Dag Forssell, thanks) --

>Quite frankly -- I've told Bill, of course -- I have never bought
>into Bill's  hierarchy AT ALL except as a (not very well fleshed-
>out) existence proof for  AN instantiation of PCT details. At this
>stage, I think PCT has a lot to learn from living organisms before
>pushing HPCT as THE instantiation.

It's interesting how easy it is to overlook the one living organism
from which we can learn the most, and the most directly: ourselves. We
experience directly the perceptual activities of our own brains. Our
brains deliver to us a world whose organization reflects the types of
perceptions the brain is equipped to derive from its raw inputs. By
examining that world as evidence about the organization of perception,
instead of as evidence about a physical outside universe, we can find
regularities and dependencies in it that are universal, independent of
any particular scene or experience yet common to all. This is the
basic principle behind HPCT.

Unfortunately we become accustomed from earliest childhood to
accepting this world as an external given, as something that exists
independently of us while we peer at it through two windows looking
out of the dark cave inside our heads. All the action is outside the
cave; that's where everything is and where everything happens. We
stand permanently in the mouth of the cave, from which we can see
approximately a hemispherical view of that world; we can reach out and
touch it, we can smell it and taste it and exert efforts on it and
bring pieces of it inside us (where they disappear).

The result is that when we talk about studying perception, we look in
the wrong place. We try to turn around and look into the depths of the
cave, turning our backs on that bright and solid world outside it. But
of course there are no perceptions inside the cave. We can't even turn
around to look in there. The best we can do is to shut our eyes or
wait for dark and imagine another world. So the first thing we do in
trying to understand perception is to shut it off and ignore it, and
create an imagined world -- still outside us, the observers, of course
-- with which we try to explain perception.

We try to imagine what is going on inside someone else's brain. We
open up other brains and put electrodes in them, and look at the
displays on oscillographs where trains of blips go marching by (all
the time perceiving these things). We believe that we have learned
something valuable about perception, because now we can look at the
blips, and look at the world impinging on the other person's senses,
and see a correlation between the blips and the world. We tell
ourselves that behind our backs, as we stand at the mouths of our
personal caves observing and doing these experiments, there is another
gray mass of filaments like the one before us, and that inside our
caves, behind us where we can't see, there is a universe of blips like
those on the chart or display screen outside us where we can see it.
In this way we get the feeling of knowing a little about our own
perceptions.

All the while, of course, perception is displayed before us with a
resolution that reveals the tiniest details of the smallest objects,
completely filling the field of vision and taste and smell and feel
and sound. And we ask ourselves, "How can I find a way to study the
brain's perceptions of this world?"

When the physical sciences began to develop, we discovered a strange
thing about this world outside us: it is full of things we can't see,
taste, smell, feel, or hear. It contains mass, heat capacity, charge,
density, atoms, compounds, energy fluxes some of which pass invisibly
right through us, attractive and repulsive forces, and vacuums. This
discovery led to great confusion: how can it be that we experience one
world directly, and a completely different one through our scientific
instruments? What is this world that we see, hear, and so forth, if it
is not the physical world itself? Most scientists solved this problem
by ignoring it; they accepted the instrument readings as the true
picture of the world, the physical-chemical world, and dismissed the
world of common experience as an incompetent misrepresentation related
only loosely and ambiguously to the REAL world. Just why this
incomplete and unreliable world should exist outside us, and why our
senses should respond to it rather than to the real world, nobody
could explain. The world to which our senses respond (and that is how
they put it) was, at best, an illusion. Studying it had no possible
scientific value.

So the only valid way of studying perception became that of comparing
the readings of scientific instruments against the readings of other
scientific instruments attached to the brain, or of studying
scientifically measurable responses of the muscles when physical and
chemical events occurred. The world of direct experience, having no
scientific value, was left to laymen as an illusion to keep them busy.

There is, of course, another interpretation of all this, the one
underlying HPCT. It is that the world we experience directly has
ALREADY passed through the sensory inputs by the time we experience
it. It is the direct manifestation of the brain's way of reading the
same world that scientific instruments read. It is the brain's way of
realizing, of making apparent, the ordering of the universe.
Scientific instruments create a different realization of, we presume,
the same underlying order.

If the direct and the scientific views of the world give different
information, that is because the brain's realization is organized
differently from the devices that produce scientific meter readings.
To understand how the brain's perceptual system is organized,
therefore, we should look for aspects of the experienced world that
are not represented in the world of scientific meter readings. We
should look at experience as consisting of a different sort of meter
readings (in which, of course, scientific meter readings themselves
are embedded). We should look for properties of the directly
experienced world that are not among the properties we derive from
observation through scientific instruments.

These properties are not hard to find, once you realize that they are
properties of perception. There are, for example, relationships. One
object can be larger or rounder than another, or above or beside
another. Between the objects there seems to exist a connection, a
comparison, a dependency in which each of the objects adds meaning to
the other, or to both. Having seen a relationship like the distance
between two objects, we can then derive a scientific meter reading
from it, by placing a meter stick to span the objects and reading off
numbers from it in which to quantify distance. But in all of physics,
there is no THING called the distance between the objects. Between the
objects there is nothing physical that belongs to the objects in the
same way that their separation in space belongs to them in direct
experience. There is no physical quantity called larger-than, or
rounder-than, or above, or beside.

Once our attention is called to this "added value" in direct
perception, we notice other kinds. We notice, for example, the objects
that are related. Each object is a recognizeable thing, a shape in two
or three dimensions. There is no physical quantity called "shape,"
although perceived shapes can be approximated by physical entities
made of spheres, cones, rhomboids, and the like, and can be measured
through recording large numbers of meter readings. Shape is one of the
brain's ways of realizing the order in the universe.

As we get used to looking for non-physical properties of the
experienced world, more and more classes of properties appear. We see
that motion is a non-physical property; that the elements of vision
such as color and shading and so on are non-physical properties. Each
such property can be associated with meter-readings, given suitable
instruments, but the meter readings deliver up only numbers. There is
no meter that can say THIS is a shape, but THAT is a rotation. Such
realizations are the exclusive purview of the brain.

Continuing this exploration, we eventually pass out of the regions of
experience where scientific instruments can provide any readings. We
find, for example, that the world is divided into classes of things.
There is no meter that can indicate the class to which some arbitrary
item belongs -- indeed, one item might belong to many classes. We find
that sequence or ordering exists; that ABC is not the same as CAB.
While our brains can perceive the ordering in meter readings, no one
meter reading indicates an ordering in the physical world. Ordering is
not a property of the physical world.

We see, too, that the world is logical; that A can cause B, in the
sense that it is NOT true that A occurs and B does NOT occur, although
B may occur independently of A. We discover that at least one kind of
causation in the world is identical in form to logical implication.
This entity, causation or implication, has not even the remotest
existence in the world represented in scientific meter readings. It is
the brain's realization of another kind of ordering in the universe: a
perception of a higher level than the perception of A and B.

The longer we continue this kind of exploration of the world of direct
experience, the more personal become the discoveries; we place the
very essence of rationality into the world of perception created by
the brain. And that is the point of HPCT.

The point of HPCT is to notice everything that exists in the world of
direct experience, whether we class it as "inside" or "outside,"
"concrete" or "abstract," and place it into a model of the
organization of perception, which is, we say, a model of one aspect of
the brain's functions. This is not a "scientific" endeavor; it can't
be, because the meter readings which are the basis of physical
realizations of the world are themselves simply elements of the world
of direct experience. This is a process of noticing kinds of
perceptions which are not part of the physical realization of the
world, which "add value" to physical meter readings, and of putting
the components of experience thus recognized into an orderly system of
understanding, which we call a model of the brain. And in doing so, we
notice, of course, that we are doing this, and we add to the model a
kind of perception we can call system concepts.

With all these aspects of experience thus separated into discernible
kinds, we can ask how they are related. Here and there we can see
certain dependencies. For example, there is never an object but that
it is composed of sensations. We think of the sensations as attributes
of an object, but it is also true that when all attributes of an
object are removed, there is no object left, save in imagination. So
we see that objectness somehow depends on the attributes of
objectness, which we label sensations. But we can imagine an object
even in the absence of color, edges, and so on, so we suspect that the
perception of objectness is somehow derived from and exists separately
from the individual perceptions of sensations. And in general, we can
see that the attributes of any perception are themselves perceptions,
with the attributes acting like the arguments of a function, and the
perception "having" those attributes acting like the value of the
function. From there it is only a short step to a neural model in
which all perceptions are neural signals, related by computing
functions that make one signal dependent on the value of signals at a
lower level.

The current form of the HPCT model describes what are purported to be
eleven kinds of perceptual realizations that we see in the world as we
stand in the mouths of our caves. We see all these aspects of
perception not behind us, in the cave, but in front of us, out there
in that unscientific world of direct experience. Even such nonmaterial
things as relationships and sequences and logical propositions and
principles and system concepts we see out there, as aspects of that
world. Only when we imagine does that world appear to move inside --
but then we are attending neither outside nor inside, but in a
different way.

Each person must discover the components of perception and their
relationships to one another, by careful examination of direct
experience. Only when each person does this, independently, is it
possible to reach a consensus on whatever aspects of direct experience
are in fact common to all human beings. This is as public as any
observation can be, even though the basic idea says that all
observation is private. We reach consensus through communication,
through asking if you're experiencing what I'm experiencing and if you
call it what I call it, and if it behaves for you as it behaves for me
in circumstances we classify in the same terms. And of course, under
HPCT, we control these perceptions, and ask others to control them
also, and look for conflicts that arise from differences in our
perceptual worlds. In this way our worlds become mutually consistent,
although we can never know whether they are identical.

If fewer people took the world of direct experience for granted, and
if more people began to see it as evidence of how the brain perceives
(and controls), the organization of HPCT might seem less arbitrary,
less like a pronouncement handed down from on high and more like a
description of one's own world.
-------------------------------------------------------------------
Best,


Bill P.
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU