[From Bill Powers (2010.03.26.1325 MDT)]
Bruce Gregory (2010.03.26.1524 EDT) –
BG: I think of the brain as a
dynamic memory. To the extent there is a model in the brain, it consists
of memories. This seems to be consistent with what neuroscience is
telling us. That is, the basic process in the brain is the strengthening
and weakening of neural connections.
BP: That’s pretty much the PCT position, too, though I think we use those
changes in synaptic strength in a different context. If you’re not used
to computational modeling it probably wouldn’t make much sense to you.
Actually there isn’t much agreement yet, in neuroscience, about just how
memory works – they’re still trying to use the “reverberating
circuit” (a closed circle of neurons in which impulses can go around
and around and around) as a model of memory, as well as other models,
none of which work very well. Nobody can really say how it is that a
choir director can blow a tone on his pitch pipe and after a short delay,
the people in the choir remember that pitch and match their own
“AAAAH” to it.
I do think that any brain models consist in large part of memories, but
there are arguments about that too: Heinz von Foerster of cybernetics
fame wrote a piece called “Memory without record,” putting
forth the idea that all memories are reconstructions, not playbacks as
from a tape recorder. And anyway the brain has to do a lot more in
addition to remembering – it has to produce behavior and control
present-time perceptions, too. Part of brain models, in addition,
involves creating new actions or perceptions, which takes us at least
partly out of the realm of memory.
BP earlier: We can let [the
model] run as the real reality and our own actions make it run, or we can
make parts of it work in the imagination mode – we can make the model
run as if parts of it were different from the way they are in the normal
mode. What if …
BG: Doesn’t this imply that all perceptions must be controlled? I am
having trouble making sense of what you are saying. That is definitely my
limitation, not yours, since Rick and Martin seem to have no trouble.
BP: I think we can control perceptions in imagination that we can’t
control in reality. I can imagine the sun rising in the west and setting
in the east, which obviously I can’t make the real sun do (you would have
noticed). I can’t make the real sun do anything, but I can do all kinds
of things to the imagined one, like turning it green. I can actually
scare myself by imagining walking right up to the edge of the Black
Canyon of the Gunnison and looking straight down between my toes at the
river 1500 feet below, something I could never in the world really do.
Oy, I get a lurch of the stomach just thinking about it. In reality, I
couldn’t get within 30 feet of the edge when I was there, even with the
railings, after the first attempt showed me what it looked like.
Understand, none of these imaginings is as vivid and real as present-time
perceptions, but here and there it gets close. When I was a pre-teenager
I had a very vivid imagination, much more than now. I used to sit outside
under a tree and imagine flying an airplane, actually figuring out how it
would feel and how the controls would have to be used. I got it pretty
close, too. It was all based on decriptions I had read, of course, and
just reasoning out why airplanes had to bank to turn, and so on.
People have very different experiences of imagination. Check out this
link:
[
http://psychclassics.asu.edu/Galton/imagery.htm
](http://psychclassics.asu.edu/Galton/imagery.htm)In 1880, Galton describe some investigations of imagery. Part of this
report is as follows:
···
=============================================================================
The first results of my inquiry amazed me. I had begun by questioning
friends in the scientific world, as they were the most likely class of
men to give accurate answers concerning this faculty of visualising, to
which novelists and poets continually allude, which has left an abiding
mark on the vocabularies of every language, and which supplies the
material out of which dreams and the well-known hallucinations of sick
people are built up.
To my astonishment, I found that the great majority of the men of science
to whom I first applied, protested that mental imagery was unknown to
them, and they looked on me as fanciful and fantastic in supposing that
the words ‘mental imagery’ really expressed what I believed everybody
supposed them to mean. They had no more notion of its true nature than a
colour-blind man who has not discerned his defect has of the nature of
colour. They had a mental deficiency of which they were unaware, and
naturally enough supposed that those who were normally endowed, were
romancing. To illustrate their mental attitude it will be sufficient to
quote a few lines from the letter of one of my correspondents, who
writes:–
“These questions presuppose assent to some sort of a proposition
regarding the ‘mind’s eye’ and the ‘images’ which it sees … This points
to some initial fallacy It is only by a figure of speech that I can
describe my recollection of a scene as a ‘mental image’ which I can ‘see’
with my ‘mind’s eye’ … I do not see it any more than a man sees the
thousand lines of Sophocles which under due pressure he is ready to
repeat. The memory possesses it, &c.”
Much the same result followed some inquiries made for me by a
friend among members of the French Institute.
On the other hand, when I spoke to persons whom I met in general society,
I found an entirely different disposition to prevail. Many men and a yet
larger number of women, and many boys and girls, declared that they
habitually saw mental imagery, and that it was perfectly distinct to them
and full of colour. [p. 303] The more I pressed and cross-questioned
them, professing myself to be incredulous, the more obvious was the truth
of their first assertions. They described their imagery in minute detail,
and they spoke in a tone of surprise at my apparent hesitation in
accepting what they said. I felt that I myself should have spoken exactly
as they did if I had been describing a scene that lay before my eyes, in
broad daylight, to a blind man who persisted in doubting the reality of
vision. Reassured by this, I recommenced to inquire among scientific men,
and soon found scattered instances of what I sought, though in by no
means the same abundance as elsewhere. I then circulated my questions
more generally among my friends, and so obtained the replies that are the
main subject of this memoir. The replies were from persons of both sexes
and of various ages, but I shall confine my remarks in this necessarily
brief memoir to the experiences derived from the male sex alone.
=============================================================================
Most of the argument about eidetic imagery has had to do with its
veridicality, and the evidence is pretty good that the details of what is
experienced are not good reproductions of what is supposedly being
recalled. But that is not what Galton was so amazed by: regardless of the
accuracy of this sort of imagery, some people experience imagery and some
apparently do not and have a hard time believing that anyone can. That is
what he was amazed by. Along with Rick, I remember discussing this with
Tom Bourbon, and his insistence that actual mental images simply don’t
exist. He said he couldn’t imagine what we were talking about. Of course
it’s hard to prove to anyone that you’re seeing something in imagination,
especially if your imagery isn’t a particularly accurate reproduction of
a real scene. Fortunately, the argument that “you’re just imagining
that” is actually an admission that you are probably experiencing
what you say you are.
I’ve run into a similar problem with awareness and consciousness. I have
a vivid sense of being an Observer occupying a particular viewpoint,
quite separate from the things I am observing. But I have encountered
people who I consider to be just as smart and observant as I am, who deny
that any such thing exists. They can describe a scene or a thought, but
apparently without any consciousness of being the observer of the scene,
thought, or other experience. I rather suspect that this may be the
origin of the arguments about monism and dualism. I am a dualist because
I can experience being an observer separate from the observed. Someone
who can experience only the observed sees nothing else to report on, and
may think I am lying or perhaps only deluded, and at least am committing
a logical error.
I’m not sure that the term “deficiency” that Galton used is
quite fair. Do I have a deficiency if I’m not as greedy as other people?
Do I lack a greediness gene? Some people see the world one way, others
see it in other ways. Which way is better or more true? Better for what?
True compared with what?
It wouldn’t be so hard to accept such differences as only natural,
considering all the ways in which people can differ from each other, if
it weren’t for the problem of Reality. The scientists Galton interviewed
wouldn’t be bothered by a mere difference of opinion. But the implication
that other people – laymen, no less – are able to observe something
that the scientist is unable to observe is hard to believe, or admit,
even if it’s true. A scientist makes his living by observing carefully
and accurately. If there’s something that even uneducated people can
observe that the scientist has no hint of, it’s rather like an oenologist
discovering that everyone but him can detect something called
“bouquet” in wine. It’s a threat to the very
profession.
Clearly such differences are not often very important in everyday life,
or they would have made themselves more evident. But they also could
account for problems – disagreements – that are otherwise inexplicable.
It seems to me that this is a subject that could do with a lot more
exploration.
Best,
Bill P.
I have never figured out how to get the cusor icon to disappear using Java. Try the integral control condition; results tend ot be a bit more interesting.