The 'infamous Dean Drive'...
Steve
inevitably the writer will mention Campbell's obsessions with
pseudo-science and will reference Dianetics and the Dean Drive. I know
what Dianetics is, but all I've been able to find out about the theory
of the Dean Drive is that it involved "non-directional thrust" (?).
Anyway, anyone out there able to enlighten me (or point me to a web
page) with the theory of the Dean Drive?
Thanks
Steve
MA Lloyd
It has no theory. It's probably the best known of the lunatic fringe
propulsion schemes that violate conservation of momentum and provide
reactionless thrust. As I recall Dean claimed it 'converted rotary
momentum to linear momentum', any conventional power supply turning
a rotor that provided the angular momentum miraculously converted to
thrust. Your best bet is to search the UFO related websites, it is
commonly cited as a prototype for UFO propulsion systems.
-- MA Lloyd (mall...@io.com)
Joe Slater
>Over the years, whenever I read an article about John W. Campbell,
>inevitably the writer will mention Campbell's obsessions with
>pseudo-science and will reference Dianetics and the Dean Drive. I know
>what Dianetics is, but all I've been able to find out about the theory
>of the Dean Drive is that it involved "non-directional thrust" (?).
>Anyway, anyone out there able to enlighten me (or point me to a web
>page) with the theory of the Dean Drive?
As I recall from articles in Analog, the facts are like this:
John Campbell either didn't want to or was not able to distinguish
between weird science (transistors - vacuum tubes without a vacuum!)
and pseudo-science (Dianetics - the modern science of mental health).
He naturally attracted lots of entertaining and plausible kooks, but I
presume that he rebutted most of them.
Dean presented him with a device that he said was a space drive, but
he wanted a million dollars before anyone could examine it. G Harry
Stine (I think) did get a look at it and said that it was full of
off-centre gears and springs and goodness knows what. People who saw
the demonstration agree on this: the device (which had a flat base, no
wheels) could be put down on a flat surface and would scoot along.
This apparently violates Newton's laws because the device did not
appear to be pushing against anything. The device was quite powerful -
if you put your hand down in front of it it would shove against it.
In a later (early-mid 80s?) article Stine speculated that the device
worked by stiction. The device could slowly move weights forward (the
off-balance wheels inside it) and then jerk them backwards. The
forward motion would be too little to overcome friction, but the jolt
of the backward motion would force the device forward.
Me, I want to know what happened to Russian Sleep.
jds
Dorothy J Heydt
Joe Slater <joeDEL...@yoyo.cc.monash.edu.au> wrote:
>
>As I recall from articles in Analog, the facts are like this:
[summary snipped]
And it made a cover of Analog--a nondescript cylinder with little
gadgets sticking up from it at all sides, looking vaguely like
rollers by means of which the thing might glide along overhead
tracks or cables. This picture of a strangefangled "space ship",
with the little rollers but without the explanation, got borrowed
directly into a sequence of the Dick Tracy comic strip shortly
after. I recognized it instantly and screamed with laughter, but
I don't know if anybody else did.
Dorothy J. Heydt
Albany, California
djh...@kithrup.com
http://www.kithrup.com/~djheydt
_A Point of Honor_ is out....
D E Siegel
>spar...@mindspring.com (Steve) wrote:
>>Over the years, whenever I read an article about John W. Campbell,
>>inevitably the writer will mention Campbell's obsessions with
>>pseudo-science and will reference Dianetics and the Dean Drive. I know
>>what Dianetics is, but all I've been able to find out about the theory
>>of the Dean Drive is that it involved "non-directional thrust" (?).
>>Anyway, anyone out there able to enlighten me (or point me to a web
>>page) with the theory of the Dean Drive?
>As I recall from articles in Analog, the facts are like this:
>
>John Campbell either didn't want to or was not able to distinguish
>between weird science (transistors - vacuum tubes without a vacuum!)
>and pseudo-science (Dianetics - the modern science of mental health).
>He naturally attracted lots of
>entertaining and plausible kooks, but I
>presume that he rebutted most of them.
>Dean presented him with a device that he said was a space drive, but
>he wanted a million dollars before anyone could examine it. G Harry
>Stine (I think) did get a look at it and said that it was full of
>off-centre gears and springs and goodness knows what. People who saw
>the demonstration agree on this: the device (which had a flat base,
>no
>wheels) could be put down on a flat surface and would scoot along.
>This apparently violates Newton's laws because the device did not
>appear to be pushing against anything. The device was quite powerful -
>if you put your hand down in front of it it would shove against it.
>
>In a later (early-mid 80s?) article Stine speculated that the device
>worked by stiction. The device could slowly move weights forward (the
>off-balance wheels inside it) and
>then jerk them backwards. The
>forward motion would be too little to overcome friction, but the jolt
>of the backward motion would force the device forward.
>
>
Actually there was a theory, but it seems to have been proved wrong, and it
wasn't Dean's, anyway. The "Dean drive" was sufficiently impressivve that a
read R&D company paid people for quite a while to look into it and possibly
related principles. Stine wrote about this in analog, I think that the titles
were "The Fourth Law of Motion" and "Phasors, D-testors, and the Dean Drive" --
I read these long ago and don't have copies to hand. A fictionalied version of
this research program (with the assumption that it succeeds) is found in an SF
novel by Stein, the name of which escapes me at the moment.
The basic theory was that there was a force proportional to rate of change of
acceleration, which does not agree with classical Newtonian physics, but is
exactly the sort of extension to those laws which *might* be possible, and
might not be noticed untile very high-rate processes are in use. I don't
belive that this perticular possibility checked out, but it was fringe science,
not pure kookery. (Dean, however, according to all I have read, *was* a classic
kook, constantly afraid that people would steal his invention, and therefore
unwilling to let it be tested to really demonstrate whether, and if so how, it
worked.)
Other SF reference -- The above research was run by a Dr. Davis (I don't recall
the full name) and it was in reference to this that the (otherwise not
discussed) space drive in RAH's _Podkayne of Mars_ is said to use "Davis
Mechanics"
-David E. Siegel
Sie...@ACM.ORG
Clark E Myers
Mechanics) had a story with plans to do this. Basically a sealed shoebox
that would scoot along a carpet. The story suggested home experiments such
as putting the box on a roller skate and otherwise varying the friction.
IIRC the principle was to impact the front inside wall with weights sort of
like slowly raise the weight pendulum style then turn it loose to hit the
inside front wall and give a jerky motion - just the principal not the
construction details. On carpet with the hand against the front it would
pulse against the hand.
Peter Cash
>It has no theory. It's probably the best known of the lunatic fringe
>propulsion schemes that violate conservation of momentum and provide
>reactionless thrust. As I recall Dean claimed it 'converted rotary
>momentum to linear momentum', any conventional power supply turning
>a rotor that provided the angular momentum miraculously converted to
>thrust. Your best bet is to search the UFO related websites, it is
>commonly cited as a prototype for UFO propulsion systems.
Hmm. I dimly remember reading of such a drive in a pop science mag in the
seventies. The tone of the article seemed to indicate that it worked, and
wasn't terribly controversial. As best as I can recall, it involved some
kind of weight that rotated eccentrically about a pivot; the degree of
eccentricity could be varied. I believe it was stated that this meant that
centrifugal force would be greater in one direction than all the others,
thus propelling the whole apparatus in that direction.
I haven't heard anything about it since...if the device does produce
acceleration, I doubt whether it's practical. (And yeah, I know basically
nothing about physics, so go ahead and flame...I mean correct me.)
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Die Welt ist alles, was Zerfall ist.
(apologies to Ludwig Wittgenstein)
email: cash at rsn dot hp dot com (sorry, spam prevention)
Andrew Plotkin
> Hmm. I dimly remember reading of such a drive in a pop science mag in the
> seventies. The tone of the article seemed to indicate that it worked, and
> wasn't terribly controversial.
Mm-hm. Pop science magazines, yay.
> As best as I can recall, it involved some
> kind of weight that rotated eccentrically about a pivot; the degree of
> eccentricity could be varied. I believe it was stated that this meant that
> centrifugal force would be greater in one direction than all the others,
> thus propelling the whole apparatus in that direction.
That would be controversial as hell if it worked, as it contradicts
Newtonian mechanics theory, but it doesn't work. :)
--Z
--
"And Aholibamah bare Jeush, and Jaalam, and Korah: these were the
borogoves..."
Rich Horton
>Actually there was a theory, but it seems to have been proved wrong, and it
>wasn't Dean's, anyway. The "Dean drive" was sufficiently impressivve that a
>read R&D company paid people for quite a while to look into it and possibly
>related principles. Stine wrote about this in analog, I think that the titles
>were "The Fourth Law of Motion" and "Phasors, D-testors, and the Dean Drive" --
>I read these long ago and don't have copies to hand. A fictionalied version of
>this research program (with the assumption that it succeeds) is found in an SF
>novel by Stein, the name of which escapes me at the moment.
It might be helpful to note that Stine's novels were as by "Lee
Correy". (I don't know which novel this was, either.)
--
Rich Horton | rrho...@concentric.net
"I am an excellent cook, and anyway when I am fifty I will probably
prefer the breakfast to the girl anyway." - W. M. Spackman
Christopher K Davis
> On 19 Oct 1998 16:45:38 GMT, desi...@aol.com (D E Siegel) wrote:
>> A fictionalied version of this research program (with the assumption
>> that it succeeds) is found in an SF novel by Stein, the name of which
>> escapes me at the moment.
> It might be helpful to note that Stine's novels were as by "Lee
> Correy". (I don't know which novel this was, either.)
Sounds like _Star Driver_, which I remember primarily for two things:
cover art that actually has a pretty close correspondence with a scene
in the book, and a minor plot point having to do with problems getting
time on the *one* available computer (book written in 1980 or so) and
doing the calculations with paper and calculator instead. (Lessee, 1980
minicomputer power, that's a PalmIII in 1998 technology, right?)
--
Christopher Davis * <ckd...@ckdhr.com> * <URL:http://www.ckdhr.com/ckd/>
Put location information in your DNS! <URL:http://www.ckdhr.com/dns-loc/>
D E Siegel
>Sounds like _Star Driver_, which I remember primarily for two things:
>cover art that actually has a pretty close correspondence with a scene
>in the book, and a minor plot point having to do with problems getting
>time on the *one* available computer (book written in 1980 or so) and
>doing the calculations with pape
>and calculator instead.
Yes, that is the novel I had in mind.
-David E. Siegel
Sie...@ACM.ORG
kens...@hotmail.com
> >>all I've been able to find out about the theory of the Dean Drive is
> >>that it involved "non-directional thrust" (?). Anyway, anyone out
> >>there able to enlighten me (or point me to a web page) with the theory
> >>of the Dean Drive?
>
> >As I recall from articles in Analog, the facts are like this:
> >
> >John Campbell either didn't want to or was not able to distinguish
> >between weird science (transistors - vacuum tubes without a vacuum!)
> >and pseudo-science (Dianetics - the modern science of mental health).
> >Dean presented him with a device that he said was a space drive, but
> >he wanted a million dollars before anyone could examine it.
Dean supposedly wanted both a million dollars, minimum, *and* a Nobel prize
before he'd let anyone examine the device. He was apparently a little unclear
on how Nobel prizes are handed out. Moreover, even after Dean was offered the
money he'd asked for, he didn't turn the drive over (Robert Prehoda,
representing the Rockefellers, tried to buy the drive from Dean).
> >G Harry Stine (I think) did get a look at it and said that it was full
> >of off-centre gears and springs and goodness knows what.
Stine is also someone who remained convinced for awhile that maybe Dean was on
to something, at least according to Pournelle in the late 70's. Stine
apparently changed his mind thereafter, from what I understand.
> >People who saw the demonstration agree on this: the device (which had a
> >flat base, no wheels) could be put down on a flat surface and would scoot
> >along. This apparently violates Newton's laws because the device did not
> >appear to be pushing against anything. The device was quite powerful -
> >if you put your hand down in front of it it would shove against it.
The only observers I've heard of having actually seen the drive working
(other than Dean) were Campbell, Stine, and Dave Garroway. The machine
basically jerked around and shimmied like mad. Garroway managed to shove a
piece of paper under it when it "hopped" off the floor. Stine reported that
the machine would shove against your hand with a strong push that would
vanish when the machine was turned off.
It's worth noting that the machine didn't *do* much of anything, though. It'd
meander slowly across the floor and vibrate up and down a bunch. But,
regardless of how it may have worked, it was never demonstrated to be *useful*
for anything. An out-of-balance washing machine or clothes dryer exhibits the
same behavior (and probably for the same reason, stiction).
> >In a later (early-mid 80s?) article Stine speculated that the device
> >worked by stiction. The device could slowly move weights forward (the
> >off-balance wheels inside it) and then jerk them backwards. The
> >forward motion would be too little to overcome friction, but the jolt
> >of the backward motion would force the device forward.
Yes; this depends on uneven friction. It's not any violation of anything.
You can experience the wild thrill of this "spacedrive" at home. Sit in a
swivelling chair and jerk your upper body clockwise; the chair will pivot
counterclockwise. Move your upper body back very slowly, though, and the
chair usually *won't* pivot. In this way, you can rotate 360 degrees (or
more, if you're not easily bored) without apparently pushing against anything
or throwing any reaction mass over board.
For another demonstration, stand on a piece of cloth on a nice, polished
marble floor. Without lifting your feet entirely, you can jerk them with
small hopping motions and slide the cloth along, shifting your way across the
floor. It's amusing for children, at least, but it's not going to get you to
Alpha Centauri any time soon.
> Actually there was a theory, but it seems to have been proved wrong, and it
> wasn't Dean's, anyway.
That's right; the theory was Davis's (see below).
> Other SF reference -- The above research was run by a Dr. Davis (I don't
> recall the full name) and it was in reference to this that the (otherwise
> not discussed) space drive in RAH's _Podkayne of Mars_ is said to use "Davis
> Mechanics"
That was Dr. William Davis, a colonel in the USAF and apparently a decent
inventor. Davis, who, unlike Dean, was apparently *not* a kook, wrote some
papers describing extensions of Newtonian physics which might allow something
like what Dean's drive supposedly was to work. Stine actually later worked
for Davis and built some Dean-like devices based on his and Davis's guesses
about how Dean's machine had worked.
These devices, too, did weird things, according to Pournelle, but didn't set
contemporary physics on its ear. Moreover, the current thinking seems to be
that if Davis's theories were right, then some major theories of more
mainstream physics--which are well-supported, whereas Davis's ideas are
not--would have to be wrong.
And, in any case, no one's built a working drive from either Dean or Davis's
ideas.
John Kensmark
kens...@hotmail.com
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Keith Morrison
> > As best as I can recall, it involved some
> > kind of weight that rotated eccentrically about a pivot; the degree of
> > eccentricity could be varied. I believe it was stated that this meant that
> > centrifugal force would be greater in one direction than all the others,
> > thus propelling the whole apparatus in that direction.
>
> That would be controversial as hell if it worked, as it contradicts
> Newtonian mechanics theory, but it doesn't work. :)
No, it would work. It requires friction on the outside though.
On a frictionless surface (or in space) it would be useless,
moving one way slowly and then jerking back to the original
position.
--
Keith Morrison
kei...@polarnet.ca
Andrew Plotkin
> Andrew Plotkin wrote:
> > > As best as I can recall, it involved some
> > > kind of weight that rotated eccentrically about a pivot; the degree of
> > > eccentricity could be varied. I believe it was stated that this meant that
> > > centrifugal force would be greater in one direction than all the others,
> > > thus propelling the whole apparatus in that direction.
> >
> > That would be controversial as hell if it worked, as it contradicts
> > Newtonian mechanics theory, but it doesn't work. :)
> No, it would work.
The device may work, by exploiting static friction as you (and others)
described. I was talking about the explanation given above. It doesn't
fly, metaphorically or literally.
Mike Schilling
similar method for moving a rowboat without oars: Tie a rope to one
end, sit in the other end of the boat, grab the rope, and give a series
of sharp jerks on it.
Mike
az...@my-dejanews.com
kens...@hotmail.com wrote:
> In article <19981019124538...@ng89.aol.com>,
> desi...@aol.com (D E Siegel) wrote:
> > joeDEL...@yoyo.cc.monash.edu.au (Joe Slater) wrote:
> >
> > >spar...@mindspring.com (Steve) wrote:
> [...]
> > Actually there was a theory, but it seems to have been proved wrong, and it
> > wasn't Dean's, anyway.
>
> That's right; the theory was Davis's (see below).
I believe it was called "Critical Action Theory", and was based on the fact
that the action and reaction in one of them thar Newtonian laws don't quite
happen at the same time. ;-) I believe, and this is from memory, that the
theory was that the time lag between the action and reaction would be
utilized to initiate another action which would delay or negate the reaction
from the first action. It didn't break the laws of conservation (energy,
mass, angular momentum...), only bent them really bad.
Scott Drellishak
Mike Schilling <mi...@forte.com> wrote:
)Henry Ernest Dudeny, in one of his famous puzzle books, describes a
)similar method for moving a rowboat without oars: Tie a rope to one
)end, sit in the other end of the boat, grab the rope, and give a series
)of sharp jerks on it.
Does this work? It doesn't seem to me that there'd be enough static
friction between the boat and the water. Or is some other mechanism
supposed to be operating here?
--
/ Scott Drellishak \
| "Any technology distinguishable from magic is insufficiently advanced." |
\ "Perfect paranoia is perfect awareness." /
michael a lloyd
>> > Actually there was a theory, but it seems to have been proved wrong, and it
>> > wasn't Dean's, anyway.
>>
>> That's right; the theory was Davis's (see below).
>I believe it was called "Critical Action Theory", and was based on the fact
>that the action and reaction in one of them thar Newtonian laws don't quite
>happen at the same time. ;-) I believe, and this is from memory, that the
>theory was that the time lag between the action and reaction would be
>utilized to initiate another action which would delay or negate the reaction
>from the first action. It didn't break the laws of conservation (energy,
>mass, angular momentum...), only bent them really bad.
As I recall, these theories more or less died when it was noticed they
required rotating objects in an external forcefield (say the Earth rotating
in the gravity field of the sun) to be self-exciting or self-damping
depending on the sign of the time difference. The fact the Earth wasn't
either nonrotating or rotating infinitely fast puts a big enough constraint
on the size of the effect that it couldn't be observed on the scales of
the gadgets it was supposed to explain.
--
-- MA Lloyd (mall...@mik.uky.edu)
Nancy Lebovitz
Keith Morrison <kei...@polarnet.ca> wrote:
>Andrew Plotkin wrote:
>
>> > As best as I can recall, it involved some
>> > kind of weight that rotated eccentrically about a pivot; the degree of
>> > eccentricity could be varied. I believe it was stated that this meant that
>> > centrifugal force would be greater in one direction than all the others,
>> > thus propelling the whole apparatus in that direction.
>>
>> That would be controversial as hell if it worked, as it contradicts
>> Newtonian mechanics theory, but it doesn't work. :)
>
>On a frictionless surface (or in space) it would be useless,
>moving one way slowly and then jerking back to the original
>position.
>
a very odd alternate universe.
OBexistingSF: _The Planiverse_ by Dewdney--physics, anatomy, devices,
etc. that might work in a 2-dimensional universe.
--
Nancy Lebovitz (nan...@universe.digex.net)
May '98 calligraphic button catalogue available by email!
Joe Slater
>E.E. Smith's Lensman series uses an inertialess drive. There is no
>speed of light limit. You can travel as fast as your engines can push
>you through the resistance of the interstellar gas.
>
>It's also the only place I've run into diesel powered spacecraft.
I can top that. In _Foundation_ someone (Seldon Hardin?) discovers
that the local planets threatening Terminus have lost the ability to
use atomics. He muses "So they're back to coal and oil?"
A steampowered spaceship, hurrah!
jds
Jay Random
>
> The only observers I've heard of having actually seen the drive working
> (other than Dean) were Campbell, Stine, and Dave Garroway. The machine
> basically jerked around and shimmied like mad. Garroway managed to shove a
> piece of paper under it when it "hopped" off the floor. Stine reported that
> the machine would shove against your hand with a strong push that would
> vanish when the machine was turned off.
>
> It's worth noting that the machine didn't *do* much of anything, though. It'd
> meander slowly across the floor and vibrate up and down a bunch. But,
> regardless of how it may have worked, it was never demonstrated to be *useful*
> for anything. An out-of-balance washing machine or clothes dryer exhibits the
> same behavior (and probably for the same reason, stiction).
Or an old-fashioned 14-inch hard disk: cf. the entry on `washing-machine
races' in the Hacker's Jargon File. Drives with top-loading disk packs
were naturally more subject to the effect than factory-sealed units
(what we think of as hard drives nowadays): the tolerances were just
loose enough that a disk pack could be mounted detectably off-centre.
For those of you who weren't exposed to good ole 70's mainframes,
reeeeeeally BORED operators would write seek programs to exploit the
stiction effect by, in essence, flinging the read heads of the drives
about in sync with the eccentricity, causing the drives to `walk' very
slowly across the floor. Hard-drive races seem to have been a somewhat
popular sport, though not in any installation I ever had access to 8-(,
& peculiarly unbalanced drives were capable of moving at breathtaking
speeds -- why really, an inch a minute or more.
I'm quite certain the bored techs responsible for those races never knew
that their hard drives were also Dean drives, or the term would have
passed into general computer lingo long ago.
Otzchiim
>The only observers I've heard of having actually seen the drive working
>(other than Dean) were Campbell, Stine, and Dave Garroway.
demonstrated on a coast-to-coast network hookup, when Garroway had Dean on a
couple of times. How many knew what to make of it is another question, but
that might include the physicists.
I can't answer any questions you might have. It's been almost 40 years,
and I took physics from a man who was proud of giving a barely passing grade to
the man who designed the Chesapeake Bay Bridge.
Mark Owings
Robert Pearlman
>In article <362CD289...@forte.com>,
>Mike Schilling <mi...@forte.com> wrote:
>)Henry Ernest Dudeny, in one of his famous puzzle books, describes a
>)similar method for moving a rowboat without oars: Tie a rope to one
>)end, sit in the other end of the boat, grab the rope, and give a series
>)of sharp jerks on it.
>
>Does this work? It doesn't seem to me that there'd be enough static
>friction between the boat and the water. Or is some other mechanism
>supposed to be operating here?
1. It does work. You can try it easily. And there's some town in
South America (?) where a yearly festival involves a race of these
boats.
2. When the jerk (pause for callow jokes) pulls the boat forward it
sets up a bow wave; the recoil (when the inboat momenta balance)
pushes the boat to the rear more smoothly and sets up a stern wave.
The two situations are not symmetrical and one wave will carry more
momentum than the other. Whichever wave carries more momentum will be
balanced by the boat moving in the opposite direction.
Intuition suggests (at least to me) that the stern wave carries more
because the transom is a better pusher; the bow is specifically
designed to make as little wave as possible. And that seems to be
confirmed.
Anybody done the analysis?
Pearlman
--
Pearlman
Robert Pearlman
>On 19 Oct 1998 16:45:38 GMT, desi...@aol.com (D E Siegel) wrote:
>
>>Actually there was a theory, but it seems to have been proved wrong, and it
>>wasn't Dean's, anyway. The "Dean drive" was sufficiently impressivve that a
>>read R&D company paid people for quite a while to look into it and possibly
>>related principles. Stine wrote about this in analog, I think that the titles
>>were "The Fourth Law of Motion" and "Phasors, D-testors, and the Dean Drive" --
>>I read these long ago and don't have copies to hand. A fictionalied version of
>>this research program (with the assumption that it succeeds) is found in an SF
>>novel by Stein, the name of which escapes me at the moment.
>
>It might be helpful to note that Stine's novels were as by "Lee
>Correy". (I don't know which novel this was, either.)
Select rant mode.
The awful thing about the Dean apparatus wasn't that it didn't work,
it was the drivel that Campbell pushed in the Astounding editorial
columns about it.
For example, IIRC, and I fear that I do, JWC pointed out that the
Newtonian gravitational equations had never been solved for n bodies
and voila!, thre's no need to regard their consequences as binding.
Ability to solve the equations in closed form has nothing to do with
conservation of momentum, which is what the Dean "drive" was supposed
to violate. And for that matter, conservation of momentum is an
integral of the three laws of motion and holds independently of
gravity. It's the gravitational case which (in fact) cannot be solved
in closed form, as proved by Poincare.
Looking back from here, it's sad to watch JWC descending into
crackpottery -- really fits the Greek definition of tragedy, a great
man destroyed by a single character flaw. The Dean drive was the
least harmful of his follies. I don't think it ever hurt anyone or
gulled anyone out of serious money. Psionics was a bit worse, since
it injected a corruption into SF that hasn't cleared yet.
But his whole-hearted support for Dianetcs loosed an evil on the
world. If, as seems like, the readership of Astounding, at that
time, included lots of teen-age science-lovers, JWC and Hubbard were
encouraging those kids (like me) to experiment with a kind of
psycho-analysis with other kids as subjects/analysts. I lied about my
"recalls", and no doubt my partner did too (we were no dummies!) but
there must have been some who took real harm. And look what came from
it!
Of course, Hubbard might have pushed Dianetcs/Scientology without
JWC's aid, but he might have been a lot less successful without it. I
believe that Campbell wised up and dropped out of the ranks before
much harm was done, but the harm was done later anyway.
Deselect rant mode.
Pearlman
--
Pearlman
Clark E Myers
Rick Cook
>For example, IIRC, and I fear that I do, JWC pointed out that the
>Newtonian gravitational equations had never been solved for n bodies
>and voila!, thre's no need to regard their consequences as binding.
Not exactly. What he had great fun pointing out was that scientific laws
often mask special cases. For example relativity as a special case of
Newtonian Mechanics.
Campell loved a good argument and loved nothing better than making someone
realize his or her premises weren't as air-tight as he or she had supposed.
--RC
Rick Cook
>Of course, Hubbard might have pushed Dianetcs/Scientology without
>JWC's aid, but he might have been a lot less successful without it. I
>believe that Campbell wised up and dropped out of the ranks before
>much harm was done, but the harm was done later anyway.
Actually Campbell's support of Dianetics was a pretty minor ripple in a
very large splash. IIRC the book became a bestseller and quickly attracted
a large following, most of whom had never heard of Campbell or Astounding.
(For that matter the people who did read about Dianetics in Astounding
would also have read some of Hubbard's fiction -- which should have warned
them.)
Among other things, the introduction to the book was written by one of the
leading lights in Gestalt Therapy. There's an account of this in Martin
Gardner's "Fads and Fallacies In The Name of Science" -- IIRC while Gardner
mentions Campbell and his conversion to Dianetics, he points out that
Campbell's belief was a minor part of the phenomenon.
--RC
Courtenay Footman
made to letters in ASF that he did not understand mechanics -- in
particular, he repeatedly indicated that he thought that energy was
equal to force times time, which got him into all kinds of mess.
This was not a minor point -- it was intrinsic to the plot of these
stories; he used it to create a perpetual motion machine.
(Campbell's science often irritated me; examples are one of the
Wade, Arcot, Morey stories where their solution to a villain's infernal
invention relied completely on a complete misunderstanding of partial
pressures, and another that about a humanoid race who "ate" by ignoring
the second law of thermodynamics.)
--
Courtenay Footman I have again gotten back on the net, and
c...@lightlink.com again I will never get anything done.
(All mail from non-valid addresses is automatically deleted by my system.)
Del Cotter
Rick Cook wrote:
>>For example, IIRC, and I fear that I do, JWC pointed out that the
>>Newtonian gravitational equations had never been solved for n bodies
>>and voila!, thre's no need to regard their consequences as binding.
>
>Not exactly. What he had great fun pointing out was that scientific laws
>often mask special cases. For example relativity as a special case of
>Newtonian Mechanics.
Great fun for him, but not very intelligent. Newtonian mechanics is a
special case of relativity.
Which completely reverses the point, since nothing in relativity
actually violates newtonian mechanics, as the Dean Drive does.
--
Del Cotter d...@branta.demon.co.uk
The Alien Design Bibliography
http://www.branta.demon.co.uk/alien-design/
Rick Cook
>(Campbell's science often irritated me; examples are one of the
>Wade, Arcot, Morey stories where their solution to a villain's infernal
>invention relied completely on a complete misunderstanding of partial
>pressures, and another that about a humanoid race who "ate" by ignoring
>the second law of thermodynamics.)
Which was pretty much standard for the time and place he was writing those.
Heck, EE Smith was a Phd in chemistry and the "Skylark" and "Lensman"
series are full of all sorts of things like that.
--RC
Rick Cook
>
>Which completely reverses the point, since nothing in relativity
>actually violates newtonian mechanics, as the Dean Drive does.
Oops. That was my mistake. Sorry.
And you can do things with relativity which are impossible with Newtonian
mechanics.
Remember, the main thing Campbell took scientists to task over the Dean
Drive for was their refusal to seriously look at the thing. (Somewhat
unfair in the light of what followed his publication of the article and
editorials, but still.)
--RC
Peter Cash
devices that Campbell pushed in his Analog editorials. Can anyone provide
details? I'm sorry that my recollection is so sparse, but here's what I
remember:
- hearing music by attaching wires to your temples. The wires carried an
electrical signal of some kind.
- A simple circuit that would trigger some kind of psionic effect; I
think it was called a "Hieronymous machine"
- Some remarks about color perception theory to the effect that you could
produce full-color images using only two primaries
kens...@hotmail.com
Rick Cook <rc...@BIX.com> wrote:
[...]
> Remember, the main thing Campbell took scientists to task over the Dean
> Drive for was their refusal to seriously look at the thing. (Somewhat
> unfair in the light of what followed his publication of the article and
> editorials, but still.)
Per folks like Pournelle, there were plenty who *wanted* to take a serious
look at it, but Dean wouldn't *let* them. Remember, the Rockefellers wanted
to buy the thing from Dean, and apparently offered truly substantial money,
and Dean wasn't cooperative at all. Meanwhile, Dean moaned that no one was
interested.
Eli Brandt
Peter Cash <st...@your.spam.gov> wrote:
>- Some remarks about color perception theory to the effect that you could
> produce full-color images using only two primaries
This may well be totally unrelated, but mentioning it also means maybe
somebody can fill in my memory: I once ran across some implausible work
in color perception, something about perceiving a larger gamut of hues
than ought to be there from the light present -- there was a lot of red
light involved. It sounded reputable; Edwin Land's name is floating up
to the window here, but that seems unlikely.
Clearly you're not going to get three degrees of freedom from two, but
there's no /a priori/ reason you couldn't get pseudocolor effects
spanning an unexpected range of the space. It would just make no sense.
--
Eli Brandt | el...@cs.cmu.edu | http://www.cs.cmu.edu/~eli/
JohnnyPez9
> desi...@aol.com (D E Siegel) wrote:
> > Actually there was a theory, but it seems to have been proved wrong, and it
> > wasn't Dean's, anyway.
>I believe it was called "Critical Action Theory", and was based on the fact
>that the action and reaction in one of them thar Newtonian laws don't quite
>happen at the same time. ;-) I believe, and this is from memory, that the
>theory was that the time lag between the action and reaction would be
>utilized to initiate another action which would delay or negate the reaction
>from the first action. It didn't break the laws of conservation (energy,
>mass, angular momentum...), only bent them really bad.
Isaac Asimov once pointed out that this theory was based on a misunderstanding
of the phrase "For every action, there is an equal and opposite reaction".
Actually, the action and the reaction occur simultaneously, but the common
definition of the word "react" implies a delayed response. Thus, the
theoretical basis of the Dean Drive was a semantic error.
Johnny Pez
Ethan A Merritt
I didn't see Peter Cash's original post, but you're on the wrong track
to say you can't get "3 degrees of freedom from 2". Just because the human
visual system happens to have use three distinct types of cells in the
color vision doesn't mean this is a necessary number. There is only
one degree of freedom, as you put it, in describing spectral color.
A fairly simple-minded visual detection system could get by with two
pigments - one ramping down from max sensitivity at low wavelengths to
min sensitivity at high wavelengths, and a second with the reverse
behaviour. Any spectral input would be uniquely determined by the
relative response of the two pigment types. And of course a
spectrophotometer can get by with only one sensor, albeit of a completely
different type.
You correctly remember Land demonstrating something of the sort. Land
toured extensively with a greatly entertaining stage show of colored
lights illuminating large multi-colored panels. He showed the
audience that their color perception of the true color of individual
panels was easily fooled by the setting of the illuminating lamps.
Starting with bright white light, for instance, you would see various
panels of green, yellow, red, etc. As the illumination gradually
shifted in bias toward red, say, you would continue to perceive these
colors even though the actually reflected spectrum was changing.
In the limit you might expect to retain the impression of many colors
even when illuminated purely by red light, but I don't recall that that
was what really happened.
Ethan A Merritt
mer...@u.washington.edu
Courtenay Footman
Smith made that I am aware of in the Lensmen books: He does not think
through the implications of inertialessness and he conflates negative
matter and antimatter in his negasphere. In _The Skylark of Space_ he
has the howler of a speeding spaceship being captured by a star, where
it should just be in a hyperbolic orbit. In both sets of works, Smith
ignores the implications of relativity, but one has to allow him that.
I would not be surprised at all to find out that there are others, but
compared to Campbell's routine screwups, they are negligible.
negaspheres; the
realizes that inertialessness presents all kinds of problems that Smith
igo
Del Cotter
Guy Gordon wrote:
>e...@cs.cmu.edu (Eli Brandt) wrote:
>>Clearly you're not going to get three degrees of freedom from two...
>
>Exactly. Thus it is patently obvious that human beings cannot
>perceive depth from a 2D image on the retinae.
Nitpick: that's *two* 2D images. And that's why you need two eyes for
good depth perception.
spa...@my-dejanews.com
kens...@hotmail.com wrote:
>
> Per folks like Pournelle, there were plenty who *wanted* to take a serious
> look at it, but Dean wouldn't *let* them. Remember, the Rockefellers wanted
> to buy the thing from Dean, and apparently offered truly substantial money,
> and Dean wasn't cooperative at all.
Per Pournelle et alli, Dean was the gosh-darnedest specimen of bipedal
squirrel bait who ever haunted the Patent Office. Sheesh, anyone who
deliberately fudges the patent specifications on an earth-shatteringly
important drive mechanism so that the device won't be "stolen" (insert SFX:
Woody Woodpecker laugh) ain't quite right in the haid. If it weren't for the
reports of reliable observers that *something* was going on, the whole idea
would be forgotten by now.
> Meanwhile, Dean moaned that no one was
> interested.
Any death is tragic, but somehow I'm glad that Dean died before the
popularisation of the Internet. Can anyone imagine what his Usenet posts
would be like?
*shudder*
--
-- Steve Patterson
http://www.wwdc.com/~spatterson/
email valid.sp...@wwdc.com, sans "v" word
Andrew Plotkin
> e...@cs.cmu.edu (Eli Brandt) wrote:
> >Clearly you're not going to get three degrees of freedom from two...
> Exactly. Thus it is patently obvious that human beings cannot
> perceive depth from a 2D image on the retinae.
Nope, that analogy doesn't work. Stereoscopic vision works by receiving a
point in space in *two* spots on *two* 2D retinas, which is four degrees
of freedom. One is redundant, since the Y axis on both eyes registers the
same, so you have three degrees of freedom to locate a point in space.
kens...@hotmail.com
johnn...@aol.com (JohnnyPez9) wrote:
> az...@my-dejanews.com points out:
>
> >I believe it was called "Critical Action Theory", and was based on the fact
> >that the action and reaction in one of them thar Newtonian laws don't quite
> >happen at the same time. ;-) I believe, and this is from memory, that the
> >theory was that the time lag between the action and reaction would be
> >utilized to initiate another action which would delay or negate the reaction
> >from the first action. It didn't break the laws of conservation (energy,
> >mass, angular momentum...), only bent them really bad.
>
> Isaac Asimov once pointed out that this theory was based on a misunderstanding
> of the phrase "For every action, there is an equal and opposite reaction".
> Actually, the action and the reaction occur simultaneously, but the common
> definition of the word "react" implies a delayed response. Thus, the
> theoretical basis of the Dean Drive was a semantic error.
I've always hated that phrasing; I much preferred a junior high teacher's
wording "For every action there is a corresponding equivalent
counterreaction." "Reaction", I very often find, has a definite connotation
of agency, and usually of perception and deliberation. Very
misleading--subconsciously, even if you know what's really meant.
They say "reaction", and what I think a lot of people are thinking is
something kind of close to "retaliation".
John Kensmark
kens...@hotmail.com
pa...@webnexus.com
> Exactly. Thus it is patently obvious that human beings cannot
> perceive depth from a 2D image on the retinae.
The human visual system does quite a bit of model-based processing.
Using various cues, you *do* get some depth perception from one eye.
It is easily fooled though.
model-based processing = make some assumptions about what you
are sensing to improve your perception of what you are sensing.
Simple example: expected size--you see something in the distance
that you think is a car, hence you can guess the distance assuming
the object is about a particular size.
Sam
JohnnyPez9
>johnn...@aol.com (JohnnyPez9) wrote:
>> Isaac Asimov once pointed out that this theory was based on a
>misunderstanding
>> of the phrase "For every action, there is an equal and opposite reaction".
>I've always hated that phrasing; I much preferred a junior high teacher's
>wording "For every action there is a corresponding equivalent
>counterreaction."
IIRC, Asimov himself thought "interaction" would have been better than
"reaction."
Johnny Pez
Michael S. Schiffer
Courtenay Footman <c...@adore.lightlink.com> wrote:
>In article <71d830$c...@lotho.delphi.com>, Rick Cook wrote:
>>Which was pretty much standard for the time and place he was writing those.
>>Heck, EE Smith was a Phd in chemistry and the "Skylark" and "Lensman"
>>series are full of all sorts of things like that.
>No, they are not. Here is the complete list of scientific errors that
>Smith made that I am aware of in the Lensmen books: He does not think
>through the implications of inertialessness and he conflates negative
>matter and antimatter in his negasphere. In _The Skylark of Space_ he
>has the howler of a speeding spaceship being captured by a star, where
>it should just be in a hyperbolic orbit. In both sets of works, Smith
>ignores the implications of relativity, but one has to allow him that.
Well, to be fair there's also the climate of Trenco, which
Randall Garrett gently lampooned in "Backstage Lensman":
"Trenco! That planet was, and is, unique. Its atmosphere and
its liquid are its two outstanding peculiarities. Half of the
atmosphere and almost all of the liquid of the planet is a compound
with an extremely low heat of vaporization. It has a boiling point
such that during the day it is a vapor and it condenses to a liquid at
night. The days are intensely hot, the nights intensely cold.
"The planet rotates on its axis in a little less than
twenty-six hours; during the night it rains exactly forty-seven feet,
five inches-- no more and no less, every night of every year.
"The winds are of more than hurricane velocity, rising to some
eight hundred miles per hour, accompanied by blinding, almost
continuous lighting discharges.
"What makes the planet unique, however, is that, with
compounds of such low latent heat, the energy transfer is almost nil.
Theoretically, the hot days should evaporate that liquid as quietly
and gently as a ghost evaporates in a spotlight, and during the night
it should condense as softly as dew from heaven falling upon the place
beneath. Thermodynamically speaking, the planet Trenco should be
about as turbulent as a goldfish bowl. Nobody can figure out where
those winds or the lighting come from."
(The excellent gaming supplement _GURPS Lensman_ lifts this
passage and does it one better by giving a nice Smithian handwave
explanation for the violent weather. For this and other things, like
an elegant explanation for the lack of solid state electronics in the
Lensman universe, I wholeheartedly recommend it for Smith fans whether
or not they have any interest in gaming.)
Mike
--
Michael S. Schiffer, LHN, FCS "I decline utterly to be impartial
ms...@tezcat.com as between the fire brigade and
ms...@midway.uchicago.edu the fire."
-- Winston Churchill, July 7, 1926
Del Cotter
>>>>Clearly you're not going to get three degrees of freedom from two...
>>>
>>>Exactly. Thus it is patently obvious that human beings cannot
>>>perceive depth from a 2D image on the retinae.
>>
>>Nitpick: that's *two* 2D images. And that's why you need two eyes for
>>good depth perception.
>
>I close one eye. Yep. Those trees still look farther away than the
>door. And that railing that passes behind a tree -- it still looks
>like one thing, not two separate things. Next I look at the TV. Yep.
>Still as stupid as ever, but I am able to see that the chair is behind
>the table.
>
>The perception of 3D is created in the brain using hints from the
>optical field.
Fine, but in that case the system you're using *still* has more than two
degrees of freedom.
Why is this so hard to understand? Do you know what "degrees of
freedom" means?
tomlinson
: This may well be totally unrelated, but mentioning it also means maybe
: somebody can fill in my memory: I once ran across some implausible work
: in color perception, something about perceiving a larger gamut of hues
: than ought to be there from the light present -- there was a lot of red
: light involved. It sounded reputable; Edwin Land's name is floating up
: to the window here, but that seems unlikely.
Hm. I remember the film director, John Boorman, talking about how he
would in some of his shots greatly reduce the "palette" of colors on
screen (there is, somewhere in POINT BLANK, a scene where almost
everything is in shades of green), but that this wouldn't seem un-
natural, because (now I'm really paraphrasing here because I can't
remember his exact words) "the eye sees a full spectrum where there
isn't one, and magnifies small differences in the colors that are
there." Maybe, maybe not.
Speaking of strange color perception, just how _can_ the sky be
"wine-dark", and Sirius coppery in hue?
-tomlinson
--
Ernest S. Tomlinson - San Diego State University
------------------------------------------------
Dulce et decorum est pro patria futui
Nancy Lebovitz
tomlinson <etom...@rohan.sdsu.edu> wrote:
>Eli Brandt (e...@cs.cmu.edu) wrote:
>
>: This may well be totally unrelated, but mentioning it also means maybe
>: somebody can fill in my memory: I once ran across some implausible work
>: in color perception, something about perceiving a larger gamut of hues
>: than ought to be there from the light present -- there was a lot of red
>: light involved. It sounded reputable; Edwin Land's name is floating up
>: to the window here, but that seems unlikely.
>
>Hm. I remember the film director, John Boorman, talking about how he
>would in some of his shots greatly reduce the "palette" of colors on
>screen (there is, somewhere in POINT BLANK, a scene where almost
>everything is in shades of green), but that this wouldn't seem un-
>natural, because (now I'm really paraphrasing here because I can't
>remember his exact words) "the eye sees a full spectrum where there
>isn't one, and magnifies small differences in the colors that are
>there." Maybe, maybe not.
In _How to See Color and Paint It_, the author (an art teacher) takes
students to the docks at dusk and asks them what color the brick buildings
across the bay are. The students say "red", and then are told to look
at the buildings though holes in three-by-five cards. At that hour,
the buildings are blue. The rest of the book explains how to learn
to see actual color instead of color-by-preconception.
>
--
Nancy Lebovitz (nan...@universe.digex.net)
May '98 calligraphic button catalogue available by email!
Gharlane of Eddore
>
> In addition to the Dean Drive, I dimly remember several other unorthodox
> devices that Campbell pushed in his Analog editorials. Can anyone provide
> details? I'm sorry that my recollection is so sparse, but here's what I
> remember:
>
> - hearing music by attaching wires to your temples. The wires carried an
> electrical signal of some kind.
>
> - A simple circuit that would trigger some kind of psionic effect; I
> think it was called a "Hieronymous machine"
>
> produce full-color images using only two primaries
>
Direct EM injection of audio signal is a known effect; it's not widely
used due to the field intensity necessary if you're using mag fields,
and many and varied reported side effects of sticking a human central
nervous system into an oscillating mag field. Obivously, direct electrical
signal injection is even more dubious, at least at this point. ( About
thirty years back someone came up with the idea of injecting signals
using "bipolar spikes," i.e. *two* tiny signals so close together they'd
be treated as one, but opposite in polarity; the object was to minimize
electrolysis side effects. Variations of this got used in a number of
research programs, like the BYU Med School experimental series involving
direct signal injection to the visual cortex of blind people, and I
believe we still have several research programs going on in this area. )
The Hieronymous Machine was patented, and messed with by a bunch of folks,
and various "ASTOUNDING" construction articles were printed. The problem
with things like the Hieronymous machine is that you can't entirely
trust Campbell; one of his favorite recurring themes was the storyline
where someone *apparently* invents something fabulous, and other people,
not knowing it's really impossible, find ways to do it. The man was
...besides being an obsessive loon of the most appealing variety... an
inveterate practical joker. He was more than capable of publishing a
con job aimed at getting people to "duplicate" something, in the hopes
that some real research would occur. That said, I hasten to add that
I'm certain that Campbell really believed in the Hieronymous Machine
and its variants; no one who ever heard him speak could doubt his belief
in the various aspects of "psi." It's just that, with Campbell, making
100%-certain presumptions is dangerous.
The Land color experiments, using two monochrome filters, two B&W
exposures, and melding the two monocolor images to produce something
that the human eye/brain combination sees in full color, are completely
valid. This is a standard area of research and experimentation in
perceptual physiology, and a lot of experimental psychologists and
their ilk have published papers on the subject. This would have
tremendous value in the real world, were it exploitable; after all,
an RGB monitor would only have 2/3 as much driver circuitry and
critical picture-tube componentry, if you could make do on two
colors. Unfortunately, there is a palpable percentage of the
population whose visual-apperception systems don't work quite the
right way to "generate" the missing colors, and *they* don't see
the full-color picture the rest of us do.
The "Dean Drive" articles, including Dr. William O. Davis' "THE FOURTH LAW
OF MOTION," were a minor techie-religion for a time; lots of people built
models and messed with them. The problem with the Dean Drive is that no
model I know of ever passed the free-environment test; i.e., if the device
really works, you should be able to suspend it on a wire or cable, pointed
to one side, turn it on, and measure the acceleration as it swings to one
side. Not one single demonstration device I ever heard of was able to
pass that simple and fundamental test. I remember asking Willy Ley about
his views on the Dean Drive at one of his lectures in the early sixties,
and his response was, "Dot ve gan vorgedt, gomBLETEly."
I built a couple, at the time, and yes, they did move themselves across
the floor all right, but mounted in a floating pan, just sat in the water
buzzing. The "propulsion effect" came from frictional-coefficient
variation at different points in the acceleration cycle, *NOT* from a
monodirectional thrust. ( Now, if anyone ever comes up with a way to
couple a device to space itself, to the underlying "fabric of the universe,"
we might have something we could turn into a drive, yessireee. But I'm
no more convinced of the possiblity of such a thing than I am of the idea
of epicycles in planetary orbits... )
Del Cotter
Guy Gordon wrote:
>>>The perception of 3D is created in the brain using hints from the
>>>optical field.
>>
>>Fine, but in that case the system you're using *still* has more than two
>>degrees of freedom.
>>
>>Why is this so hard to understand? Do you know what "degrees of
>>freedom" means?
>
>I have a PhD in Physical Chemistry. So no, I couldn't possibly know
>what I'm talking about.
Excellent, that's a *perfect* subject for this sort of thing (equi-
librium phase diagrams, to name just one example). So what's the
problem?
Rick Cook
>In article <71d834$c...@lotho.delphi.com>,
> Rick Cook <rc...@BIX.com> wrote:
>[...]
>> Remember, the main thing Campbell took scientists to task over the Dean
>> Drive for was their refusal to seriously look at the thing. (Somewhat
>> unfair in the light of what followed his publication of the article and
>> editorials, but still.)
>
>look at it, but Dean wouldn't *let* them. Remember, the Rockefellers
>wanted to buy the thing from Dean, and apparently offered truly
>moaned that no one was interested.
That's what I meant about "in the light of what followed". After Campbell
publicized the thing there were a number of people who tried to find out
more. Dean was by all accounts _extremely_ hard to deal with and the only
thing he had was a gadget cobbled together out of Plexiglas and powered by
an electric drill. After listening to Pournelle, G. Harry Stine and some of
the other people who were involved in discussions with Dean recount their
experiences with him, my own suspicion is that by the time he got people
interested he had come to the suspicion that the thing didn't work the way
he said it did.
Personally, I don't think Campbell cared whether the Dean Drive worked or
not (although a lot of his readers did). He hated scientific stuffed shirts
and to him refusing to even look at a potentially revolutionary new device
was the worst sort of stuffed-shirtery.
--RC
Rick Cook
>In addition to the Dean Drive, I dimly remember several other unorthodox
>devices that Campbell pushed in his Analog editorials. Can anyone provide
>details? I'm sorry that my recollection is so sparse, but here's what I
>remember:
>
>- hearing music by attaching wires to your temples. The wires carried an
> electrical signal of some kind.
The Neurophone. That one actually worked -- or seemed to, anyway. I got to
play with one.
>- A simple circuit that would trigger some kind of psionic effect; I
> think it was called a "Hieronymous machine"
That was the name of it. It used a prism to split the 'eloptic radiation'
and a metallic detector that moved in an arc around the prism. The first
one contained a fairly conventional electrical circuit. A later, modified
version only contained the schematic and was supposed to work just as well.
>- Some remarks about color perception theory to the effect that you could
> produce full-color images using only two primaries
This was something that Dr. Edwin Land (of Polaroid camera fame) came up
with. Again, it seemed to work. (Which makes a weird sort of sense when
you consider the amount of signal processing the brain does on visual
images.) However I haven't heard anything about it in years.
--RC
Rick Cook
> Thus, the
>theoretical basis of the Dean Drive was a semantic error.
Actually the Dean Drive had no theoretical basis. Dean cobbled the thing
together and patented it without ever having a theory for how it worked.
All he claimed was that it produced a unidirectional 'push'. Of course his
measuring tool was a bathroom scale, so. . .
The possible theoretical basis was worked out after Campbell publicized the
Dean Drive by a guy named Davis, a Colonel in the Air Force IIRC. Davis
said this was a possible way for the thing to produce a unidirectional
push. I don't think he ever claimed that it did.
--RC
LAL
> Actually the Dean Drive had no theoretical basis. Dean cobbled the thing
> together and patented it without ever having a theory for how it worked.
Are you sure it was patented? If so, someone should quit argueing and just
go build a working example. As I understand patent law. patent applications
must include sufficient theoretical info to reproduce the item, and
generally a working example/model or full detailed construction drawings.
Meanwhile, back in rasfw, as I recall (book not in front of me right now)
one of the later Man-Kzin Wars anthologoes (VI?) describesd the Kzinti
gravity drive as a "Dean Drive," which is interestingly illogical. If the
protagonists knew of a space drive by the name "Dean Drive" it implies
humanity would have such a drive, which it doesn't in the series's internal
history; and if the protagonists knew "Dean Drive" as an early hoax, it
implies they wouldn't call the Kzinti grav drive a "Dean Drive." Hence -
logical collapse. Cleaverness once again crumbles under its own SF
irrationality.
---------------------------------
Speaking for myself ....
Andrew Plotkin
> Personally, I don't think Campbell cared whether the Dean Drive worked or
> not (although a lot of his readers did). He hated scientific stuffed shirts
> and to him refusing to even look at a potentially revolutionary new device
> was the worst sort of stuffed-shirtery.
So, what would he have been like reading sci.physics these days? Would he
have tightened his bullshit threshold by several yards (like most of us),
or investigated everything that went by, or just picked one as the Right
Answer and become an evangelical crackpot himself?
Mary K. Kuhner
>> Personally, I don't think Campbell cared whether the Dean Drive worked or
>> not (although a lot of his readers did). He hated scientific stuffed shirts
>> and to him refusing to even look at a potentially revolutionary new device
>> was the worst sort of stuffed-shirtery.
>So, what would he have been like reading sci.physics these days? Would he
>have tightened his bullshit threshold by several yards (like most of us),
>or investigated everything that went by, or just picked one as the Right
>Answer and become an evangelical crackpot himself?
Or maybe become one of those people who hang around and flame posters
who flame crackpots? Less work than investigating, less irrational
than becoming a crackpot.
Most cohesive newsgroups I've encountered do seem to have at least one
or two posters who will jump to the defense, no matter how obnoxious
the initial posting, just on general principles.
Mary Kuhner mkku...@genetics.washington.edu
MA Lloyd
>In article <71nic3$u...@lotho.delphi.com>, Rick Cook <rc...@BIX.com> wrote:
>
>> Actually the Dean Drive had no theoretical basis. Dean cobbled the thing
>> together and patented it without ever having a theory for how it worked.
>
>Are you sure it was patented? If so, someone should quit argueing and just
>go build a working example. As I understand patent law. patent applications
>must include sufficient theoretical info to reproduce the item, and
>generally a working example/model or full detailed construction drawings.
Yes, it was. The device described in the patent doesn't work. True believers
claim that's what Dean put into the patent isn't what he had actually built
because he was afraid the idea would be stolen; which would be idiotic since
a patent only protects what is in the patent, but it's not necessarily out
of character for inhabitants of the paranoid fringe to do things like that.
-- MA Lloyd (mall...@io.com)
Matt Austern
> You want to know how many Degrees of Freedom your eyes have? Two.
> You can rotate them up&down or side-to-side. That's it.
My eyes have four mechanical degrees of freedom, because I've got two
of them. (And then another one or two if you count changing the
lenses' focus. I'm not sure whether to count that as one or two
becuase I don't know whether it's possible to focus the two lenses
independently.)
Matt Austern
> In article <71nic3$u...@lotho.delphi.com>, Rick Cook <rc...@BIX.com> wrote:
>
> > Actually the Dean Drive had no theoretical basis. Dean cobbled the thing
> > together and patented it without ever having a theory for how it worked.
>
> Are you sure it was patented? If so, someone should quit argueing and just
> go build a working example. As I understand patent law. patent applications
> must include sufficient theoretical info to reproduce the item, and
> generally a working example/model or full detailed construction drawings.
Dean's supporters say that he violated that law because he wanted to
keep his invention a secret. They say the device he patented was not
the same as the device he built and demonstrated.
Irv Koch
<snip>
> Are you sure it was patented? If so, someone should quit argueing and just
> go build a working example. As I understand patent law. patent applications
> must include sufficient theoretical info to reproduce the item, and
> generally a working example/model or full detailed construction drawings.
Yes, it was patented. No, they don't and can't insist that the thing actually
works as described, only that it meets the laws and regulations for being
patented. They quit taking models ages ago. No room. Go by the Patent Office
in Arlington, VA, some day. It's in a mixed use building (arcology) that is
nicely sf-nal. (And, BTW, I worked, back then, at the Defense Dept's
repository for all R&D Info. below Top Secret. We interfaced with the Patent
Office among others.) They require drawings and such, OK, but the "trick" is
to make them just detailed enough to get your patent but not so detailed that
it's too easy to copy in practice and "simply build a working model." One is
allowed to (or at least WAS allowed to) put in phrases like "for a suitable
value of" in ones application.
The Dean Drive PATENT only claimed to "transform rotatry motion into linear
motion." Despite claims hereabouts that "that's impossible," it is done every
day. That's what gears do, among other things. So, it worked ... as it said
... in its patent..
The kicker is that people other than his patent lawyer tried to make it out as
some sort of perpetual motion machine. They finally changed to law to make
those non-patentable, even if you flat out demonstated one that worked.
<shrug>
And, it is quite true that one of the things Dean et al had going against
them/it was that there was (past tense) no math theory behind the device.
Later, someone(s) came out with a "5th derivative of motion" theory or some
such that may or may not have had anything to do with the Dean Drive, but, at
least for SF stories, could be used to justify some sort of faster than light
space travel.
If it's been quoted here, already, sorry. Anyway, motion ... simply "going"
... straight line or not ... is a math value. "How fast." The next value in
the SERIES of values of this stuff is acceleration, IIRC (and I think I'm
skipping some stuff ... it's been ages since I worked with it). How FAST you
go FASTER. I forget all the details but think that is something like the 4th
in the series, actually.
The next whatever ("value" is probably the wrong word ... "term?") upwards, is
called "onset." It's a calculus calculation rather than "simple" math and
that's where the "derivative" comes from. Onset is how fast the accelleration
itself increases. As I understood it, but not a lot of others involved in
various "pissing contests" rather than engineering effort, the idea was that
like stomping on a tube of tooth paste. You slammed down REALY hard and the
stuff "squirted" out rather than moving out in a stream.
So, looking at what the actual patent claimed, and ignoring the jury rigged
device Dean had actually constructed, it seemed PLAUSIBLE to me that if you had
an awesome enough rotary motion, and slammed some sort of clutch into play, you
could squirt/catapult something in the direction of the "axle" that the rotary
motion was revolving about ... with whatever was revolving still attached.
Maybe. I know of no true expermentation with it. I always thought you'd need
at least an operational thermonuclear reactor ... with the plasma whirling in a
donut shape ... at near light speed ... to make it work.
My guess, BTW, has been, that it would take a 5 mile in diameter donut to
actually get a thermonuclear reactor to usefully work without slagging itself
down. Therefore, it's too expensive to do what you asked for to stop the
arguement <G>.
There's one more chunk of the puzzle I've rarely, if ever, seen interjected
into Dean Drive discussions ... where no one ever seems to give a hoot about
reality, only "who did what conspiracy to whom ... or did not do it." Go look
at your math and calculus books. There's something called a discontinuous
function. The "curve" (distance traveled) goes upwards so fast (as in "onset")
that it goes "straight up." For all practical purposes, the "spaceship" ceases
to exist for a given distance along the graph ... and then the curve comes down
again, usually symetrical to how fast it went "up."
Getting a real object to behave in a "discontinuous" manner, of course, is
where the "engineering" ... for now ... becomes Science Fiction. However, in
most cases where some weird math has existed ... maybe centuries later someone
figures out a way to make something physically behave that way or at least use
the previous "just a curiousity" math concept. So, in my not so humble
opinion, if we're ever to actually travel "faster than light," it won't be by
actually going faster than light or moving into some sort of other universe
where we can. It will be by creating some engineering effect that sends the
speed of spaceships up and down a discontinuous curve .
And meanwhile, it makes a much more fun space drive for SF stories .. which
maybe someone on here will use.
Andrea Leistra
Irv Koch <irv...@pop.a001.sprintmail.com> wrote:
>If it's been quoted here, already, sorry. Anyway, motion ... simply "going"
>... straight line or not ... is a math value. "How fast." The next value in
>the SERIES of values of this stuff is acceleration, IIRC (and I think I'm
>skipping some stuff ... it's been ages since I worked with it). How FAST you
>go FASTER. I forget all the details but think that is something like the 4th
>in the series, actually.
Fourth in what series?
Position is, well, position. Where something is. The first (time)
derivative of position is velocity, the second derivative of position is
acceleration. These are the ones that get commonly used.
>The next whatever ("value" is probably the wrong word ... "term?") upwards, is
>called "onset." It's a calculus calculation rather than "simple" math and
>that's where the "derivative" comes from.
They're *all* calculus calculations. The word I've usually heard to
denote the derivative of acceleration (the third derivative of position)
is "jerk", but generally these things just get called "a-dot", or
"r-triple-dot", or some such. ("Dot" is shorthand for "time derivative;
df/dt is commonly written as f with a dot on top, and pronounced f-dot.)
>There's one more chunk of the puzzle I've rarely, if ever, seen interjected
>into Dean Drive discussions ... where no one ever seems to give a hoot about
>reality, only "who did what conspiracy to whom ... or did not do it." Go look
>at your math and calculus books.
Would it be extremely rude to suggest you do the same?
>There's something called a discontinuous function. The "curve"
>(distance traveled) goes upwards so fast (as in "onset") that it
>goes "straight up."
That's not discontinuous, that's just infinite velocity, and has
nothing to do with acceleration or higher derivatives.
Draw your x and t axes on a piece of paper, with t horizontal and x
vertical. Now draw another vertical line. That's what you're
discussing, an infinite-velocity situation (which is physically
impossible, violating causality and causing all sorts of
unpleasantness). Nothing here is discontinuous; if you try to *connect*
this with other lines at reasonable velocities (some other trajectories
on the paper), then the *velocity* is discontinuous, but that's not
a result of the infinite velocity; you get the same sort of thing no
matter what the slope of the line is.
x ___
| | Here velocity is discontinuous, and position is not.
| | This is still the impossible, infinite-velocity case.
| --- (You can presumably *define* infinite-velocity to be
|-------t a sort of discontinuity in position, but that's not the
usual mathematical definition.)
x ___
| / The same is true here, though; velocity is discontinuous
| / and position is not, by the usual definition; but here
| --- the velocity is not infinite. The *acceleration* is,
|------t of course.
--
Andrea Leistra
Joe Slater
>The Neurophone. That one actually worked -- or seemed to, anyway. I got to
>play with one.
What about Russian Sleep? I saw this on television a few weeks ago:
apparently it is still used by Russian flight attendants. The subtitle
said it was "for relaxation"; I don't know whether they meant that it
puts people to sleep, or whether it actually doesn't work but it has a
placebo effect.
jds
Jeff Suzuki
: The perception of 3D is created in the brain using hints from the
: optical field. The stereoscopic separation of the eyes is one of
: those clues, but not the only, or even a necessary one. Parallax
: from the movement of the head, the continuation of straight lines, and
: the continuation of patterns are others.
Optical accommodation also plays a role in depth perception.
Jeffs
Del Cotter
Guy Gordon wrote:
>You want to know how many Degrees of Freedom your eyes have? Two.
>You can rotate them up&down or side-to-side. That's it. They do not
>have three degrees of freedom, unless yours are on eye-stalks (like
>Gharlane's).
Three. I can cross them as well. The more I cross them, the closer the
object I'm peering at.
Oh, and it's a bit late to start huffing about how bad the analogy is.
The time to do that was before it became obvious to everyone you were
losing it.
Andrew Plotkin
> On Tue, 3 Nov 1998, in rec.arts.sf.written
> Guy Gordon wrote:
> >You want to know how many Degrees of Freedom your eyes have? Two.
> >You can rotate them up&down or side-to-side. That's it. They do not
> >have three degrees of freedom, unless yours are on eye-stalks (like
> >Gharlane's).
> Three. I can cross them as well.
I've found that I can get a fourth, angling one eye up and the other
down. But not very much, and *only* by locking them onto identical objects
and moving one object up and the other down (or rotating my head.) The
autonomic lock causes the eyes to diverge vertically. I can't do it
voluntarily, as I can for crossing them, or (to a lesser extent) diverging
them horizontally.
None of that is relevant to depth perception, which subthread I've bailed
out of, thank you.
Eli Brandt
Ethan A Merritt <mer...@u.washington.edu> wrote:
>There is only
>one degree of freedom, as you put it, in describing spectral color.
I was thinking (unannounced) not just about hue, but about color
perception in general. Unfortunately I forgot to count the rods,
which in principle give a third axis even if you lose one primary.
But in practice they're saturated in daylight, for example.
>Any spectral input would be uniquely determined by the
>relative response of the two pigment types.
Monochromatic input: these two inputs determine intensity and hue but
can't tell white from red+blue from green.
[Land's demo:]
>As the illumination gradually
>shifted in bias toward red, say, you would continue to perceive these
>colors even though the actually reflected spectrum was changing.
Oh, drat, that's not so surprising. Maybe I'm a child of the age of
brightly-colored glasses. (Though maybe the rate or degree of
adaptation was surprising.) Thanks for the description, though.
>In the limit you might expect to retain the impression of many colors
>even when illuminated purely by red light, but I don't recall that that
>was what really happened.
I'd expect it to break at least by the time there's not enough non-red
light to drive the green and blue cones off baseline.
--
Eli Brandt | el...@cs.cmu.edu | http://www.cs.cmu.edu/~eli/
Eli Brandt
Guy Gordon <gor...@atlanta.com> wrote:
>e...@cs.cmu.edu (Eli Brandt) wrote:
>>Clearly you're not going to get three degrees of freedom from two...
>
>Exactly. Thus it is patently obvious that human beings cannot
>perceive depth from a 2D image on the retinae.
Could you explain how you're counting degrees of freedom? I don't know
how to do it here, but when I give it a handwaving try I'm not getting
your numbers.
Assume grayscale. Provisionally assume only one eye. Then you have
one input axis per photosensor? What I don't know is how you're
counting the second eye -- perhaps one shouldn't add that in since
it's covariant, but all of its contribution to stereo comes from what
independence it has. Something between N and 2N together, I guess.
On the output side, I don't know what to do with resolution. Just say
it's the same? So grayscale level is N axes. Where I'm guessing we
disagree is on depth: adjacent `pixels' are nothing like independent,
because the visual system enforces spatial coherence. So it's not
a second N here.
So I don't see the "patently obvious" in your /reductio/.
Joe Mason
>
>I've found that I can get a fourth, angling one eye up and the other
>down. But not very much, and *only* by locking them onto identical objects
>and moving one object up and the other down (or rotating my head.) The
>autonomic lock causes the eyes to diverge vertically. I can't do it
>voluntarily, as I can for crossing them, or (to a lesser extent) diverging
>them horizontally.
I just saw the Guinness World Records show, with three people who could pop
their eyes out of their sockets. How many does that give us now?
Jow
--
I think OO is great... It's no coincidence that "woohoo" contains "oo" twice.
-- GLYPH
spa...@my-dejanews.com
Matt Austern <aus...@sgi.com> wrote:
>
> gor...@atlanta.com (Guy Gordon) writes:
>
> > You want to know how many Degrees of Freedom your eyes have? Two.
> > You can rotate them up&down or side-to-side. That's it.
>
> of them.
Human eyes usually act as a coupled pair, not as independant components, and
so could be described as having only two degrees of freedom. Even if you
cross your eyes you still don't get a third degree, since the bearing of one
eye determines the bearing of the other. Chameleons can have four, though,
and sometimes I envy them for that...
(On Usenet, no one knows you're a chameleon?)
> (And then another one or two if you count changing the
> lenses' focus. I'm not sure whether to count that as one or two
> becuase I don't know whether it's possible to focus the two lenses
> independently.)
Only with brain injury, I think, and then it's not voluntary. And do we
count iris dilation as another two degrees? I think we can take this down to
absurdities pretty quickly. I'm quite happy to describe our eyes as having
two degrees of freedom.
Our colour perception, however, uses three criteria to measure a single
discrete value (the frequency of inbound photons). Using "degrees of
freedom" for that is confusing at best.
--
-- Steve Patterson
http://www.wwdc.com/~spatterson/
email valid.sp...@wwdc.com, sans "v" word
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Bertil Jonell
>Actually the Dean Drive had no theoretical basis. Dean cobbled the thing
>together and patented it without ever having a theory for how it worked.
>measuring tool was a bathroom scale, so. . .
Real springs doesn't work like ideal springs, so there are some tricks
that are possible to do with real springs that are impossible to explain
if you assume that they behave like ideal springs. Don't ask me to elaborate
because I've forgotten the math:)
>--RC
-bertil-
--
"It can be shown that for any nutty theory, beyond-the-fringe political view or
strange religion there exists a proponent on the Net. The proof is left as an
exercise for your kill-file."
Bertil Jonell
>some sort of perpetual motion machine. They finally changed to law to make
>those non-patentable, even if you flat out demonstated one that worked.
><shrug>
Before the late 1890's a nuclear reactor was a perpetual motion
machine: its a big can containing an uncommon metal treated in ways
that make no sense according to the theories accepted in those days.
Somehow this metal heats water poured into the can enough that
a steam turbine can be run. Where the heat comes from is likewise
impossible to explain using the theories accepted in those days.
MA Lloyd
>>The kicker is that people other than his patent lawyer tried to make it out as
>>some sort of perpetual motion machine. They finally changed to law to make
>>those non-patentable, even if you flat out demonstated one that worked.
>><shrug>
Got a citation for that law? Seriously. I've seen it claimed quite
often, but never backed up, and I strongly doubt it exists in any national
patent law. It's not required that your idea work to be patentable, for
the most part patent examiners are pretty overworked just checking for
excessive breadth and prior art, adding another check for functionality
would be a lot of work for no real benefit. After all there is no reason
not to grant you exclusive rights to something that doesn't work if you
are willing to pay the fees.
-- MA Lloyd (mall...@io.com)
Andrew Plotkin
> >Irv Koch <irv...@pop.a001.sprintmail.com> wrote:
> >>The kicker is that people other than his patent lawyer tried to make it out as
> >>some sort of perpetual motion machine. They finally changed to law to make
> >>those non-patentable, even if you flat out demonstated one that worked.
> >><shrug>
> Got a citation for that law? Seriously. I've seen it claimed quite
> often, but never backed up, and I strongly doubt it exists in any national
> patent law.
From the US Patent and Trademark Office web site:
http://www.uspto.gov/web/offices/pac/doc/general/models.htm
"A working model, or other physical exhibit, may be required by the Office
if deemed necessary. This is not done very often. A working model may be
requested in the case of applications for patent for alleged perpetual
motion devices."
Sounds like a department policy, not a law.
Also from that site: legally, you can only patent a device that works.
("Must be 'useful'".) But I agree that the USPTO doesn't usually check
that.
P. Wezeman
> In article <fxt67cw...@isolde.engr.sgi.com>,
> Matt Austern <aus...@sgi.com> wrote:
> >
> > gor...@atlanta.com (Guy Gordon) writes:
> >
> > > You want to know how many Degrees of Freedom your eyes have? Two.
> > > You can rotate them up&down or side-to-side. That's it.
> >
> > My eyes have four mechanical degrees of freedom, because I've got two
> > of them.
>
> Human eyes usually act as a coupled pair, not as independant components, and
> so could be described as having only two degrees of freedom. Even if you
> cross your eyes you still don't get a third degree, since the bearing of one
> eye determines the bearing of the other. Chameleons can have four, though,
> and sometimes I envy them for that...
----snip----
Two eyes, working as a coupled pair, have a total of three degrees
of freedom. One eye can point in azumith and elevation: that'a two
degrees. The second eye can then point to any point along the first
eye's line of sight: that's the third degree. Another way to look at
it, so to speak, is that the two eyes together can converge on any
point in a three dimensional space.
Focus is to some extent a fourth degree of freedom, though it
is usually coupled to convergence.
Peter Wezeman, anti-social Darwinist
"Carpe Cyprinidae"
spa...@my-dejanews.com
"P. Wezeman" <pwez...@blue.weeg.uiowa.edu> wrote:
> On Wed, 4 Nov 1998 spa...@my-dejanews.com wrote:
>
> > Human eyes usually act as a coupled pair, not as independant components, and
> > so could be described as having only two degrees of freedom.
> Two eyes, working as a coupled pair, have a total of three degrees
> of freedom. One eye can point in azumith and elevation: that'a two
> degrees. The second eye can then point to any point along the first
> eye's line of sight: that's the third degree. Another way to look at
> it, so to speak, is that the two eyes together can converge on any
> point in a three dimensional space.
> Focus is to some extent a fourth degree of freedom, though it
> is usually coupled to convergence.
I sit corrected, and am now hunting for more potent coffee blends to kindle
those mental fires a little earlier in the day.
Nancy Lebovitz
Michael Caldwell <adsu...@es.co.nz> wrote:
>
>What about when you anti-cross your eyes (focus both eyes on the far edge of
>the sockets on their respective sides)? It takes concious control,
>concentration and practice, and gives you headaches if you do it too much,
>but it is possible. I learnt to do it as the result of a silly bet (the same
>bet that gave me a fully controlable facial twitch which scares the
>begeebers out of people you want to back off).
>
What was the bet?
--
Nancy Lebovitz (nan...@universe.digex.net)
May '98 calligraphic button catalogue available by email!
Andrew Plotkin
> > Two eyes, working as a coupled pair, have a total of three degrees
> >of freedom. One eye can point in azumith and elevation: that'a two
> >degrees. The second eye can then point to any point along the first
> >eye's line of sight: that's the third degree. Another way to look at
> >it, so to speak, is that the two eyes together can converge on any
> >point in a three dimensional space.
> What about when you anti-cross your eyes (focus both eyes on the far edge of
> the sockets on their respective sides)?
Still three degrees of freedom, but you're pushing one into the negative
range now.
Technically, you're still specifying a point in 3D space, only now it's
behind you. :)
> It takes concious control,
> concentration and practice, and gives you headaches if you do it too much,
> but it is possible.
Sure. I can do it a little, probably not enough to be noticeable to
someone watching.
> > Focus is to some extent a fourth degree of freedom, though it
> >is usually coupled to convergence.
> Now that I can't figure out how to do seperately. Hmm, more practice coming
> up I see...
I can do that a little, too -- letting my eyes go unfocussed without
changing their convergence. It's a lot easier after an eight-hour hacking
session. :)
Richard Harter
>On Wed, 4 Nov 1998 spa...@my-dejanews.com wrote:
>
>> In article <fxt67cw...@isolde.engr.sgi.com>,
>> Matt Austern <aus...@sgi.com> wrote:
>> >
>> > gor...@atlanta.com (Guy Gordon) writes:
>> >
>> > > You want to know how many Degrees of Freedom your eyes have? Two.
>> > > You can rotate them up&down or side-to-side. That's it.
>> >
>> > My eyes have four mechanical degrees of freedom, because I've got two
>> > of them.
>>
>> Human eyes usually act as a coupled pair, not as independant components, and
>> so could be described as having only two degrees of freedom. Even if you
>> cross your eyes you still don't get a third degree, since the bearing of one
>> eye determines the bearing of the other. Chameleons can have four, though,
>> and sometimes I envy them for that...
> ----snip----
> Two eyes, working as a coupled pair, have a total of three degrees
>of freedom. One eye can point in azumith and elevation: that'a two
>degrees. The second eye can then point to any point along the first
>eye's line of sight: that's the third degree. Another way to look at
>it, so to speak, is that the two eyes together can converge on any
>point in a three dimensional space.
> Focus is to some extent a fourth degree of freedom, though it
>is usually coupled to convergence.
Methinks the question is ill posed; how many degrees of freedom there be
depends on what aspect of the eye you are considering. The visual
neural network has billions of degrees of freedom - necessarily so,
since one does not look at points, one looks at scenes and resolves
objects within the field of view. Mechanically each eye has two degrees
of freedom not counting alterations of shape. Since the shape of the
eye can be altered by muscular control there are a large and somewhat
indefinite number of degrees of freedom associated with focus.
Richard Harter, c...@tiac.net, The Concord Research Institute
URL = http://www.tiac.net/users/cri, phone = 1-978-369-3911
If you can laugh at something it can't hurt you.
It can kill you but it can't hurt you.
Michael Caldwell
>On Wed, 4 Nov 1998 spa...@my-dejanews.com wrote:
>> In article <fxt67cw...@isolde.engr.sgi.com>,
>> Matt Austern <aus...@sgi.com> wrote:
>> > gor...@atlanta.com (Guy Gordon) writes:
>> > > You want to know how many Degrees of Freedom your eyes have? Two.
>> > > You can rotate them up&down or side-to-side. That's it.
>> > My eyes have four mechanical degrees of freedom, because I've got two
>> > of them.
>> Human eyes usually act as a coupled pair, not as independant components,
and
>> so could be described as having only two degrees of freedom. Even if you
>> cross your eyes you still don't get a third degree, since the bearing of
one
>> eye determines the bearing of the other. Chameleons can have four,
though,
>> and sometimes I envy them for that...
> ----snip----
> Two eyes, working as a coupled pair, have a total of three degrees
>of freedom. One eye can point in azumith and elevation: that'a two
>degrees. The second eye can then point to any point along the first
>eye's line of sight: that's the third degree. Another way to look at
>it, so to speak, is that the two eyes together can converge on any
>point in a three dimensional space.
What about when you anti-cross your eyes (focus both eyes on the far edge of
the sockets on their respective sides)? It takes concious control,
concentration and practice, and gives you headaches if you do it too much,
but it is possible. I learnt to do it as the result of a silly bet (the same
bet that gave me a fully controlable facial twitch which scares the
begeebers out of people you want to back off).
> Focus is to some extent a fourth degree of freedom, though it
>is usually coupled to convergence.
Now that I can't figure out how to do seperately. Hmm, more practice coming
up I see...
--
Michael Caldwell
>>What about when you anti-cross your eyes (focus both eyes on the far edge
of
>>the sockets on their respective sides)? It takes concious control,
>>concentration and practice, and gives you headaches if you do it too much,
>>but it is possible. I learnt to do it as the result of a silly bet (the
same
>>bet that gave me a fully controlable facial twitch which scares the
>>begeebers out of people you want to back off).
>What was the bet?
Sitting around the flat with nothing better to do except the dishes (four
days worth, student flat with no clean dishes), and talk philosophy.
Discussing colour perception and for some reason started crossing eyes. Both
decided that it was probably impossible to acheive anti-crossed eyes, and I
was bet him doing the dishes that I couldn't do it. The test was two people
standing on opposite sides of the room with fingers held up, and me seeing
who was holding up what. Five minutes later I'd managed it. I can now do it
pretty much at will.
This degenerated into a face pulling contest, which in turn became a double
or nothing bet for the first person to pull a facial twitch. Ten minutes
later I won, and have since practiced to the point where I can do it at
will. The cheak to the left side of my nose twitches in what appears a
psychotic and uncontrolled manner.
--
Andrew Plotkin
> >Could you explain how you're counting degrees of freedom? I don't know
> >how to do it here, but when I give it a handwaving try I'm not getting
> >your numbers.
> >So I don't see the "patently obvious" in your /reductio/.
> I am using the example of the placement of objects in the field of
> view. Your brain has the task of determining where an object is in 3
> dimensions, (as well as *what* it is, how big it is, etc.)
> For this purpose, your eyes have only two degrees of freedom. They
> can move left-right, and up-down. But your brain easily and
> automatically assigns a depth to each object in view as well. Thus
> the brain *does* get 3D's out of 2.
For this purpose, in near-field, the brain uses stereoscopic location,
which is a third degree of freedom in eye-pointing -- or a third degree on
freedom in having two retinas. (The two descriptions are isomorphic.)
This is one of the many ways the brain guesses about location, but in some
situations it's dominant.
Farther away, as you said, stereoscopic difference is too small to be
useful.
gme...@trinity.edu
Then, guessing at the object's size, place it at the correct distance
in the model. This is a truely astounding fact when you think about
it. Recognition occurs before seeing."
Partially true but then explain the depth in random dot stereograms
or structure from motion displays.
Depth and motion can lead to form depending on the information
content.
bye
Eli Brandt
Guy Gordon <gor...@atlanta.com> wrote:
>It does not do this by *sensing* the third D. It does it by guessing.
>This is why we are subject to optical illusions. It is also why
>"degrees of freedom" is a poor analogy when drawn from physics and
>applied to perception.
Maybe a physicist's "degrees of freedom" are different than the ones
I'm using from math? Because I don't see why all the emphasis on
mechanics, at the expense of the other inputs to the visual system
(like say what comes down the optic nerve).
The (trivial) theorem is that you can't cover a higher-dimensional
space by mapping a lower onto it; the rule of thumb is you can usually
treat a continous independent parameter as a dimension. Trouble is
it's hard to know what's independent, which is what I think you're
getting at with the complicated (so possibly independent-/looking/,
but not) depth information that the visual system deduces.
Joe Slater
>For example, in a test of how well people report UFO sightings,
>scientist tethered a helium balloon in a field at night, illuminated
>by a flashlight inside the balloon.
After which, scientists measured the effects of ethanol ingestion upon
the ease by which subjects could impart angular transformation to
female bovines.
jds
Gerry Quinn
>
>Sitting around the flat with nothing better to do except the dishes (four
>days worth, student flat with no clean dishes), and talk philosophy.
>Discussing colour perception and for some reason started crossing eyes. Both
>decided that it was probably impossible to acheive anti-crossed eyes, and I
>was bet him doing the dishes that I couldn't do it. The test was two people
>standing on opposite sides of the room with fingers held up, and me seeing
>who was holding up what. Five minutes later I'd managed it. I can now do it
>pretty much at will.
>This degenerated into a face pulling contest, which in turn became a double
>or nothing bet for the first person to pull a facial twitch. Ten minutes
>later I won, and have since practiced to the point where I can do it at
>will. The cheak to the left side of my nose twitches in what appears a
>psychotic and uncontrolled manner.
>
Have you tried staring at objects and eliminating saccadic eye motion?
Eventually, your visual field starts to break up and lines and such
appear and disappear.
- Gerry
----------------------------------------------------------
ger...@indigo.ie (Gerry Quinn)
----------------------------------------------------------
David Given
Guy Gordon <gor...@atlanta.com> wrote:
[...]
>You want to know how many Degrees of Freedom your eyes have? Two.
>have three degrees of freedom, unless yours are on eye-stalks (like
>Gharlane's).
(shuffles feet) (looks embarrassed)
Three, actually. Your eyes (I'm referring here to eyeballs in the
singular --- if you start working with the pair, things get complex) can
rotate as well.
Here's a demo: stare at your monitor. Now rotate your head slowly
sideways. You should feel your eyeballs suddenly jump a small amount every
five degrees or so. This is because your eyeballs are rotating to keep the
view upright; but they can't go very far, so when they reach the limit of
their travel they jump to their opposite extreme and your brain uses
software correction instead.
--
+- David Given ----------------+
| Work: d...@tao.co.uk | Always be smarter than the people
| Play: dgi...@iname.com | who hire you. But never let them know.
+- http://wiredsoc.ml.org/~dg -+
David Given
Joe Mason <jcm...@uwaterloo.ca> wrote:
[...]
>I just saw the Guinness World Records show, with three people who could pop
>their eyes out of their sockets. How many does that give us now?
Blindness due to damage to the optic nerve, which only had a few
millimetres of slack?
BTW, since we're on the subject, I've heard quite recently about work
being done on artificial *retinas*. Has anyone else heard of this? If so,
does anyone know how they interface it the the optic nerve?
Tilman Bohn
gme...@trinity.edu wrote on Fri, 06 Nov 1998 13:29:29 -0600:
> "The best clue your brain uses, is to *first* recognize an object.
> Then, guessing at the object's size, place it at the correct distance
> in the model. This is a truely astounding fact when you think about
> it. Recognition occurs before seeing."
>
> Partially true but then explain the depth in random dot stereograms
> or structure from motion displays.
Actually, the passage you quoted shows why for some people it
is so hard to `see' RDSs. The brain already has a model of reali
ty that's working just fine, thank you, and so has to be forced
to accept another, conflicting model. This takes conscious effort
until that other model is fully in place -- as long as you only
discern part of the depicted scene and don't recognize any ob
jects in them, it is quite hard to keep it up, but once you have
a full representation of the scene, it becomes automatic. This is
what feels to people like something `snapping into place,' at
which point they just `see' the 3D scene of the RDS.
--
Cheers, Tilman
Aleph-null bottles of beer on the wall,
Aleph-null bottles of beer,
You take one down, and pass it around,
Aleph-null bottles of beer on the wall.
Tilman Bohn
Andrea Leistra wrote on 3 Nov 1998 22:16:45 GMT:
> >There's something called a discontinuous function. The "curve"
> >(distance traveled) goes upwards so fast (as in "onset") that it
> >goes "straight up."
>
> That's not discontinuous, that's just infinite velocity, and has
> nothing to do with acceleration or higher derivatives.
>
> Draw your x and t axes on a piece of paper, with t horizontal and x
> vertical. Now draw another vertical line. That's what you're
> discussing, an infinite-velocity situation (which is physically
> impossible, violating causality and causing all sorts of
> unpleasantness). Nothing here is discontinuous; if you try to *connect*
> this with other lines at reasonable velocities (some other trajectories
> on the paper), then the *velocity* is discontinuous, but that's not
> a result of the infinite velocity; you get the same sort of thing no
> matter what the slope of the line is.
Well, actually...
I'll leave the mathematical fine points out, but:
Velocity is undefined at that point, and position is discontin
uous. The function x(t), being a *function*, can only assume one
value at a given time, so no vertical lines can occur. At some
point in time, x has a certain value, and if you can't make the
difference in its value arbitrarily small for sufficiently small
time differences, then you've got a discontinuity. (A `jump' in
everyday parlance.) This, in fact, is a rigorous definition of
(dis)continuity of a f'n.
The derivative, or velocity, at the point of discontinuity it
self is not technically infinite, but undefined, although you can
in simple cases like this argue (by employing a suitable limiting
process) that it is `effectively' infinite.
> x ___
> | | Here velocity is discontinuous, and position is not.
> | | This is still the impossible, infinite-velocity case.
> | --- (You can presumably *define* infinite-velocity to be
> |-------t a sort of discontinuity in position, but that's not the
> usual mathematical definition.)
I think it's plain to see that here, position is discontinuous...
[Footnote]
> x ___
> | / The same is true here, though; velocity is discontinuous
> | / and position is not, by the usual definition; but here
> | --- the velocity is not infinite. The *acceleration* is,
> |------t of course.
..while here it is not. At the corners, if they really are cor
ners, velocity is again undefined, yielding discontinuities for
v(t) (jumping, in this example, from zero, to something finite,
to zero again) and thereby undefined accelerations. Again, using
a series of functions converging on the one you sketched, you can
show that in some sense, it is positive and negative infinity,
respectively.
[Footnote:
And that's the normal mathematical way to talk about it. I'd
phrase your parenthetical remark just the other way round: You
can presumably define discontinuities of position to be a sort
of infinite velocity, but that's not the usual mathematical def
inition. And it's only possible to do so in exceedingly simple
cases like this.]