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AIList Digest Volume 2 Issue 063
AIList Digest Friday, 25 May 1984 Volume 2 : Issue 63
Today's Topics:
Cognitive Psychology - Dreams,
Philosophy - Essence & Identity & Continuity & Recognition
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Date: Mon 21 May 84 10:48:00-PDT
From: NETSW.MARK@USC-ECLB.ARPA
Subject: cognitive psychology / are dreams written by a committee?
Apparently (?) dreams are programmed, scheduled event-sequences, not
mere random association. Does anyone have a pointer to a study of
dream-programming and scheduling undertaken from the stand-point of
computer science?
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Date: Mon 21 May 84 11:39:51-PDT
From: Ken Laws <Laws@SRI-AI.ARPA>
Subject: Dreams: A Far-Out Suggestion
The May issue of Dr. Dobb's Journal contained an article on "Sixth
Generation Computers" by Richard Grigonis (of the Children's Television
Workshop). I can't tell how serious Mr. Grigonis is about faster-than-
light communication and computation in negative time; he documents the
physics of these possibilities as though he were both dead serious and
well informed. He also discusses the possibility of communicating with
computers via brain waves, and it this material that has spurred the
following bit of speculation.
There seems to be growing evidence that telepathy works, at least for
some people some of the time. The mechanism is not understood, but then
neither are the mechanisms for memory, unconscious thought, dreams, and
other cognitive phenomena. Mr. Grigonis suggests that low-frequency
electromagnetic waves may be at work, and provides the following support:
Low frequencies are attenuated very slowly, although their energy does
spread out in space (or space/time); the attenuation of a 5 Hz signal
at 10,000 kilometers is only 5%. A 5 Hz signal of 10^-6 watt per square
centimeter at your cranium would generate a field of 10^-24 watt per
square centimeter at the far side of the earth; this is well within
the detection capabilities of current radio telescopes. Further, alpha
waves of 7.8 and 14.1 cycles per second and beta waves of 20.3 cycles
per second are capable of constructive interference to establish
standing waves throughout the earth.
Now suppose that the human brain, or a network of such brains distributed
in space (and time), contained sufficient antenna circuitry to pick up
"influences" from the global "thought field" in a manner similar to the
decoding of synthetic aperture radar signals. Might this not explain
ESP, dreams, "racial memory", unconscious insight, and other phenomena?
We broadcast to the world the nature of our current concerns, others
try to translate this into terms meaningful to their lives, resonances
are established, and occasionally we are able to pick up answers to our
original concerns. The human species as a single conscious organism!
Alas, I don't believe a word of it.
-- Ken Laws
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Date: Thu, 24 May 1984 02:52 EDT
From: MINSKY%MIT-OZ@MIT-MC.ARPA
Subject: Essences
About essences. Here is a section from
a book I am finishing about The Society of Mind.
THE SOUL
"And we thank Thee that darkness reminds us of light." (T. S. Eliot)
My friends keep asking me if a machine could have a soul? And I keep
asking them if a soul can learn. I think it is important to
understand this retort, in order to recognize that there may be
unconscious malice in such questions.
The common concept of a soul says that the essence of a human mind
lies in some entirely featureless point-like spark of invisible
light.
I see this as a symptom of the most dire anti-self respect. That
image of a nothing, cowering behind a light too bright to see, denies
that there is any value or significance in struggle for
accomplishment. This sentiment of human worthlessness conceals itself
behind that concept of an essence of the self. Here's how it works.
We all know how a superficial crust of trash can unexpectedly
conceal some precious gift, like treasure buried in the dirt,
or ordinary oyster hiding pearl.
But minds are just the opposite. We start as ordinary embryonic
animals, which then each build those complicated things called
minds -- whose merit lies entirely within their own coherency.
The brain-cells, raw, of which they're made are, by themselves,
as valueless as separate daubs of paint.
That's why that soul idea is just as upside-down as seeking
beauty in the canvas after scraping off Da Vinci's smears. To
seek our essence only misdirects our search for worth -- since
that is found, for mind, not in some priceless, compact core, but
in its subsequently vast, constructed crust.
The very allegation of an essence is degrading to humanity. It cedes
no merit to our aspirations to improve, but only to that absence of no
substance, which was there all along, but eternally detached from all
change of sense and content, divorced both from society of mind and
from society of man; in short, from everything we learn.
What good can come from such a thought, or lesson we can teach
ourselves? Why, none at all -- except, perhaps, that it is futile to
think that changes don't exist, or that we are already worse or
better than we are.
--- Marvin Minsky
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Date: Wed, 23 May 84 09:49:21 EDT
From: Stephen Miklos <Miklos@YALE.ARPA>
Subject: Essence of Things?
It is not too difficult to come up with a practical problem in which the
identity of the greek ship is important. To wit:
In year One, the owner of the ship writes a last will and testament,
leaving "my ship and all its fittings and appliances" to his nephew.
The balance of his estate he leaves to his wife. In Year Two, he commences
to refit his ship one board at a time. After a few years he has a pile of
old boards which he builds into a second ship. Then he dies.
A few hypotheticals:
1. Suppose both ships are in existence at the time of probate.
2. Suppose the old-board ship had been destroyed in a storm.
3. Suppose the new-board ship had been destroyed in a storm.
4. Suppose the original ship had been refitted by replacing the old
boards with fiberglass
5. Suppose the original boat had not been refitted, but just taken
apart and later reassembled.
6. Suppose the original ship had been taken apart and replaced board
by board, but as part of a single project in which the intention was to
come up with two boats.
6a. Suppose that this took a while, and that from time to time
our Greek testator took the partially-reboarded boat
out for a spin on the Mediterranean.
In each of these cases, who gets the old-board ship? Who gets the
new-board ship? It seems to me that the case for the fallaciousness of
the argument for boat y (the new-board boat) seriously suffers in hypo
#6 and thereby is compromised for the pure hypothetical. It should not
be the case that somebody's intention makes the difference in determining
the logical identity of an object, although that is the way the law
would handle the problem, if it could descry an intention.
Just trying to get more confused,
SJM
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Date: Wed, 23 May 84 10:47 EDT
From: MJackson.Wbst@XEROX.ARPA
Subject: Re: Continuity of Identity
An interesting "practical" problem of the Greek Ship/Lincoln's Axe type
arises in the restoration of old automobiles. Since many former
manufacturers are out of business, spare parts stocks may not exist,
body pieces may have been one-offs, and for other reasons, restoration
often involves the manufacture of "new" parts. Obviously at some point
one has a "replica" of a Bugatti Type 35 rather than a "restored"
Bugatti Type 35 (and the latter is desirable enough to some people so
that they would happily start from a basket full of fragments. . .).
What is that point (and how many baskets of fragments can one original
Bugatti yield)?
In fact, old racing cars are worse. The market value of, say, a 1959
Formula 1 Cooper is significantly enhanced if it was driven by, say,
Moss or Brabham, particularly if it was used to win a significant race.
But what if it subsequently was crashed and rebuilt? Rebuilt from the
frame up? Rebuilt *entirely* but assigned the previous chassis number
by the factory (a common practice)? Under what circumstances is one
justified as advertising such an object as "ex-Moss?"
Mark
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Date: 18 May 84 18:58:24-PDT (Fri)
From: ihnp4!mgnetp!burl!clyde!akgua!mcnc!ncsu!uvacs!edison!jso @ Ucb-Vax
Subject: Re: the Greek Ship problem
Article-I.D.: edison.219
The resolution of the Greek Ship/Lincoln's Axe problem seems to be that
an object retains its identity over a period of time if it has an unbroken
time-line as a whole. Most of the cells in your body weren't there when
you were born, and most that you had then aren't there now, but aren't you
still the same person/entity, though you have far from the same characteristics?
John Owens
...!uvacs!edison!jso
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Date: Thu 24 May 84 13:00:04-PDT
From: Laurence R Brothers <LAURENCE@SU-CSLI.ARPA>
Subject: identity over time
"to cross again is not to cross". Obviously, people don't generally
function with that concept in mind, or nothing would be practically
identical to anything else. I forget the statistic that says how long it
takes for all the atoms in your body to be replaced by new ones, but,
presumably, you are still identifiable as the same person you were
x years ago.
How about saying that some object is "essentially identical" in context
y (where context y consists of a set of properties) to another object
if it is both causally linked to the first object, and is the object
that fulfills the greates number of properties in y to the greatest
precision. Clearly, this definition does not work all that well in
some cases, but it at least has the virtue of conciseness.
If two objects are "essentially identical" in the "universal context",
then they may as well be named the same in common usage, at least,
if not with total accuracy, since they would seem to denote what
people would consider "naively" to be the same object.
-Laurence
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Date: 22 May 84 22:48:39-PDT (Tue)
From: decvax!ittvax!wxlvax!rlw @ Ucb-Vax
Subject: A restatement of the problem (phil/ai)
Article-I.D.: wxlvax.281
It has been my experience that whenever many people misinterpret me, it is
due to my unclarity (if that's a word) in making my statement. This appears
to be what happened with my original posting on human perception vs computer
or robotic perception. Therefore, rather than trying to reply to all the
messages that appeared on the net and in my mailbox, let me try a new, longer
posting that will hopefully clarify the question that I have.
"Let us consider some cases of misperception... Take for example a "mild"
commonplace case of misperception. Suppose that I see a certain object as
having a smooth surface, and I proceed to walk toward it. As I approach it,
I come to realize visually (and it is, in fact, true) that its surface is
actually pitted and rough rather than smooth.
A more "severe" case of misperception is the following. Suppose
that, while touring through the grounds of a Hollywood movie studio, I
approach what, at first, I take to be a tree. As I come near to it, I suddenly
realize that what I have been approaching is, in fact, not a tree at all but a
cleverly constructed stage prop.
In each case I have a perceptual experience of an object at the end of
which I "go back" on an earlier attribution. Of present significance is the
fact that in each case, although I do "go back" on an earlier attribution, I
continually *experience* it "as" one and the same. For, I would not have
experienced myself now as having made a perceptual *mistake about an object*
unless I experience the object now as being THE VERY SAME object I experienced
earlier." [This passage is from Dr. Miller's recent book: Miller, Izchak.
"Husserl: Perception and Temporal Awareness" MIT Press, c. 1984.
It is quoted from page 64, by permission of the author.]
So, let me re-pose my original question: As I understand it, issues of
perception in AI today are taken to be issues of feature-recognition. But
since no set of features (including spatial and temporal ones) can ever
possibly uniquely identify an object across time, it seems to me (us) that this
approach is a priori doomed to failure. Feature recognition cannot be the way
to accurately simulating/reproducing human perception. Now, since I (we) are
novices in this field, I want to open the question up to those more
knowledgeable. Why are AI/perception people barking up the wrong tree? Or,
are they?
(One more note: PLEASE remember to put "For Alan" in the headers of mail
messages you send me. ITT Corp is kind enough to allow me the use of my
father's account, but he doesn't need to sift through all my mail.)
--Alan Wexelblat (for himself and Izchak Miller)
(Currently appearing at: ..decvax!ittvax!wxlvax!rlw)
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Date: 24 May 84 18:58-PDT
From: Laws@SRI-AI
Subject: Continuity
Other examples related to the Greek Ship difficulty: the continuity
of the Olympic flame (or rights to the Olympic name), posession of the
world heavyweight title if the champ retires and then "unretires",
title to property as affected by changes in either the property or
the owner's status, Papal succession and the right of ordained priests
to ordain others, personal identity after organ transplants, ...
In all the cases, the philosophical principles seem less important
than having some convention for resoving disputes. Often market forces
are at work: the seller may make any claim that isn't outrageously
fraudulent, and the buyer pays a price commensurate with his belief
that the claims are valid, will hold up in court, or will be believed
by his own friends and customers.
On the subject of perception and recognition: we have computational
methods of recognizing objects in images despite changes in background,
brightness or color, texture, perspective, motion, scale changes,
occlusion or damage, imaging technique (e.g., visual vs. infrared
or radar signatures), and other types of variation. We don't yet
have a single computer program that can do all of the above, but most
of the matching problems have been solved by one program or another.
Some problems can't be solved, of course: is that red Volkswagon the
same one that I saw yesterday, or has another one been parked in the
same place?
The key to image analysis is often not in recognition of feature clusters
but in understanding how features change across space or time. The patterns
of change are themselves features that must be recognized, and that can't
be done unless you can determine the image areas over which to compute
the gradients. You can't recognize the whole from the parts because
you can't find the parts unless you know the configuration of the whole.
One of the most powerful techniques for such problems is hypothesize-
and-test. Find anything in the scene that can suggest part of the
analysis, leap to a conclusion, and see if you can make the answer
fit the scene. I suspect that this explains the object constancy that
Alan is worried about. We are so loathe to give up a previously
accepted parse that we will tolerate extreme deviations from our
expectations before abandoning the interpretation and searching for
another. Even when forced to reparse, we have great difficulty in
combining the scene entities in groupings other than those we first
locked onto (as in Cole's Law and "how to wreck a nice beach"); this
suggests that the prominent groupings form symbolic proto-objects
that remain constant even though we reevaluate the details, or "features",
within the context of the groupings.
-- Ken Laws
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End of AIList Digest
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