Entropic force
Locked
 
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I just ran across this. (Call it the "horizontal force.")
There appear to be physical explanations that are
non-causal. Suppose that a bunch of sticks are thrown into the air
with a lot of spin so that they twirl and tumble as they fall. We
freeze the scene as the sticks are in free fall and find that
appreciably more of them are near the horizontal than near the
vertical orientation. Why is this? The reason is that there are more
ways for a stick to be the horizontal than near the vertical. To see
this, consider a single stick with a fixed midpoint position. There
are many ways this stick could be horizontal (spin it around in the
horizontal plane), but only two ways it could be vertical (up or
down). This asymmetry remains for positions near horizontal and
vertical, as you can see if you think about the full shell traced out
by the stick as it takes all possible orientations. This is a
beautiful explanation for the physical distribution of the sticks, but
what is doing the explaining are broadly geometrical facts that cannot
be causes. -- Russ Abbott ______________________________________ Professor, Computer Science California State University, Los Angeles cell: 310-621-3805 Google voice: 424-2Blue2 blog: http://russabbott.blogspot.com/ vita: http://sites.google.com/site/russabbott/ ______________________________________ ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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Russ,
This seems very weird to me (as, of course, it is intended to). First off, I'm not sure it is an "explanation" any more then a "proof by definition". Second, at least in the case of a 2D snapshot, there are just as many 3D configurations that appear perfectly vertical as appear perfectly horizontal. I'll have to meditate more on the more general case. Eric On Sat, Jul 17, 2010 07:28 PM, Russ Abbott <[hidden email]> wrote: Eric Charles Professional Student and Assistant Professor of Psychology Penn State University Altoona, PA 16601 ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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On 17 Jul 2010 at 20:10, ERIC P. CHARLES wrote:
> Russ, > This seems very weird to me (as, of course, it is intended to). First off, I'm > not sure it is an "explanation" any more then a "proof by definition". If it's an "explanation" of any thing, I think it's an explanation of the manner in which we (or some of us) come to give an account of the situation. I'd rather call it a description of the situation, coupled with a description (not particularly explanatory) of our manner of coming to that account (e.g., how we assign labels "vertical" and "horizontal"). > Second, > at least in the case of a 2D snapshot, there are just as many 3D configurations > that appear perfectly vertical as appear perfectly horizontal. That depends on how the definition of "appears" appears. (And makes my point, above, about the us-ness of the how-ness of it all.) Sticks that lie in the (assumed horizontal) plane of the monocular viewer will have a distribution of apparent lengths (defined in some purely optical, non-perceptual, way: e.g., in terms of measurements taken with a pair of dividers on a 2D snapshot) that may be (and very likely is) markedly different from the distribution of apparent lengths of all the sticks; the viewer's assumptions (conscious or unconscious) about what is seen will play a large part in determining what conclusions (conscious or unconscious) the viewer draws about the distribution of attitudes of the sticks. (Affordances must come up here, eh?) If we had a 2D photo such as you suggest, Eric, it would be an interesting experiment to show it to various people turned at various angles. My prediction is that (absent clues about "true vertical") "appreciably more" of the sticks would be perceived as being "near the horizontal than near the vertical orientation" in every case (assuming, as I just realized I have been, that the 2D photo is viewed in a vertical plane, rather than lying on a desk or in one's lap or on the floor; in *those* cases, I'll now predict that ascriptions of verticality will be quite variable). Shephard points out (in his paper speculating on why humans have a 3D color space) that for terrestrial animals (at least, ones that live above the scale where things like surface tension of water and viscosity of the atmosphere are big deals in daily life), the vertical axis defined by gravity is highly salient. What, we may ask, would a porpoise or a porgy make of your photo? Lee Rudolph > I'll have to meditate more on the more general case. > > Eric > > On Sat, Jul 17, 2010 07:28 PM, Russ Abbott <[hidden email]> wrote: > >> > >I just ran across > <http://plato.stanford.edu/entries/mathematics-explanation/>. (Call it the > "horizontal force.") > > > >> > >There appear to be physical explanations that are > >non-causal. Suppose that a bunch of sticks are thrown into the air > >with a lot of spin so that they twirl and tumble as they fall. We > >freeze the scene as the sticks are in free fall and find that > >appreciably more of them are near the horizontal than near the > >vertical orientation. Why is this? The reason is that there are more > >ways for a stick to be the horizontal than near the vertical. To see > >this, consider a single stick with a fixed midpoint position. There > >are many ways this stick could be horizontal (spin it around in the > >horizontal plane), but only two ways it could be vertical (up or > >down). This asymmetry remains for positions near horizontal and > >vertical, as you can see if you think about the full shell traced out > >by the stick as it takes all possible orientations. This is a > >beautiful explanation for the physical distribution of the sticks, but > >what is doing the explaining are broadly geometrical facts that cannot > >be causes. > > > > > >> > > > >-- Russ Abbott > >______________________________________ > > > > Professor, Computer Science > > California State University, Los Angeles > > > > cell: 310-621-3805 > > Google voice: 424-2Blue2 > > blog: <a style="font-family: trebuchet ms,sans-serif;" > href="http://russabbott.blogspot.com/" target="" > onclick="window.open('http://russabbott.blogspot.com/');return > false;">http://russabbott.blogspot.com/</a> > > vita: <a style="font-family: trebuchet ms,sans-serif;" > href="http://sites.google.com/site/russabbott/" target="" > onclick="window.open('http://sites.google.com/site/russabbott/');return > false;">http://sites.google.com/site/russabbott/</a> > >______________________________________ > > > > > > > > > ============================================================ > >FRIAM Applied Complexity Group listserv > >Meets Fridays 9a-11:30 at cafe at St. John's College > >lectures, archives, unsubscribe, maps at http://www.friam.org > > > > Eric Charles > > Professional Student and > Assistant Professor of Psychology > Penn State University > Altoona, PA 16601 > > > ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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On Sat, Jul 17, 2010 at 08:57:42PM -0400, [hidden email] wrote:
> > Shephard points out (in his paper speculating on why > humans have a 3D color space) that for terrestrial > animals (at least, ones that live above the scale > where things like surface tension of water and > viscosity of the atmosphere are big deals in daily > life), the vertical axis defined by gravity is > highly salient. What, we may ask, would a porpoise > or a porgy make of your photo? > > Lee Rudolph > This seems to be a non-sequitur. Most mammals have a 2D colour space. Many birds (and a few rare humans, so called "tetrachromats") have a 4D colour space. What possible connection could it have with the spatial dimension? -- ---------------------------------------------------------------------------- Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [hidden email] Australia http://www.hpcoders.com.au ---------------------------------------------------------------------------- ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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> On Sat, Jul 17, 2010 at 08:57:42PM -0400, [hidden email] wrote:
> > > > Shephard points out (in his paper speculating on why > > humans have a 3D color space) that for terrestrial > > animals (at least, ones that live above the scale > > where things like surface tension of water and > > viscosity of the atmosphere are big deals in daily > > life), the vertical axis defined by gravity is > > highly salient. What, we may ask, would a porpoise > > or a porgy make of your photo? > > > > Lee Rudolph > > > > This seems to be a non-sequitur. Most mammals have a 2D colour > space. Many birds (and a few rare humans, so called "tetrachromats") > have a 4D colour space. What possible connection could it have with > the spatial dimension? I was referencing where I read it. I don't recall that it was part of his color-space argument; it was (probably) an interesting digression. (Thank goodness discussions on mailing lists never include digressions!) If I can find my copy (originally Nick's spare copy...) of the book it's in, I'll check later and try to get back with whatever I find. ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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In reply to this post by Eric Charles
Russ, I don't get this at all. Two points:
1) There are an infinite number of ways that a line can be parallel to a plane; there is exactly one way it can be perpendicular to the plane. Is that the point?
2) The degree of orientation around the X and the Y axises don't have anything to do with each other. As far as the random distribution is concerned, you just pick a random number out of 360 degrees for the X axis orientation (the horizontal plane), then pick another random number of 360 for the Y axis orientation (the vertical plane).
The random orientation out of the vertical plane determines to what degree the stick is parallel / perpendicular to the "ground," while the random orientation of the horizontal plane determines how short or long the stick appears, when viewed from the side. But there is absolutely no relationship between one orientation and the other.
With both accounted for, you can have your stick pointing in any direction within a sphere. In other words, we won't see more oriented towards the horizontal. I suppose I could prove this to you with a few digital photos, but that just seems silly. (Maybe this image will help visualize it.)
Also, to comment further on the source material, I'm pretty sure the only regularity in terms of which face is up (R or S) when I flip a tennis racket is determined by the bias of whatever spin I apply. There is no physical principle here - at least not relating the vertical and horizontal spin in a vacuum - and I can end up with either face pointing up. Or neither.
It is harder to do flip without spin of course, due to air resistance, but it is still quite possible. I could also apply more spin to get one or the other. I can assure you that I have done this many times with a ping-pong racket.
If Ashbaugh, Chicone, & Cushman 1991 are properly summarized here, then I would say they are full of it. Perhaps we should write a paper and call them silly buggers? (Perhaps it was intended for the April Fool's edition of the Journal of Dynamics and Differential Equations? I know math guys tend to have a pretty good sense of humor.)
Cheers, Ted On Sat, Jul 17, 2010 at 8:10 PM, ERIC P. CHARLES <[hidden email]> wrote:
--
Ted Carmichael, PhD Complex Systems Institute Department of Software and Information Systems College of Computing and Informatics 343-A Woodward Hall UNC Charlotte
Charlotte, NC 28223 Phone: 704-492-4902
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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On Sun, Jul 18, 2010 at 8:41 AM, Ted Carmichael <[hidden email]> wrote:
Russ, I don't get this at all. Two points: Actually, that is the point, at least so I thought. A uniform distribution of orientations in 3D, which is equivalent to a uniform distribution of points on a sphere, has a uniform distribution in azimuth, but a biased distribution in elevation. Elevations are chosen so that the density comes out proportional to cosine(elevation) which corrects for the different areas of the latitudinal rings as elevation moves away from the equator.
At first I thought that this explained the "horizontal force", but then I realized that the uniform distribution is a uniform distribution no matter which direction is designated as up. So no matter which bisecting plane through the sphere we examine, it will always have more sticks parallel to it than to the orthogonal pole. So this actually explains a "planar force". There more horizontal sticks than up/down sticks, but there are also more meridional sticks than left/right sticks.
-- rec -- ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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In reply to this post by Eric Charles
Lee, True, but I was thinking projective geometry rather than a psychology of appearances. Grant the arbitrariness of "horizontal" and "vertical", let us assume the ground is a flat plane that is easy to reference these terms to. If we fix a midpoint on the stick, there there will be a plane that we can rotate the stick in for which all angles will appear perfectly "horizontal" in a 2D projection, and a perpendicular plane for which all angles will appear "vertical" in a 2D projection (minus the intersection of the plains, where the stick will appear head on). By "appear" I mean only that they will be either parallel with or perpendicular to the ground plane. Of course, you also bring up lots of other interesting hypotheses regarding perceptual biases. Agreeing with what I take to be your main thrust: I imagine that if we had people rapidly and repeatedly mark a variety of lines as either "horizontal", "vertical", or "other", we would find that they allow higher variability in horizontal lines. Eric On Sat, Jul 17, 2010 08:57 PM, [hidden email] wrote: Eric CharlesOn 17 Jul 2010 at 20:10, ERIC P. CHARLES wrote: > Russ, > This seems very weird to me (as, of course, it is intended to). First off, I'm > not sure it is an "explanation" any more then a "proof by definition". If it's an "explanation" of any thing, I think it's an explanation of the manner in which we (or some of us) come to give an account of the situation. I'd rather call it a description of the situation, coupled with a description (not particularly explanatory) of our manner of coming to that account (e.g., how we assign labels "vertical" and "horizontal"). > Second, > at least in the case of a 2D snapshot, there are just as many 3D configurations > that appear perfectly vertical as appear perfectly horizontal. That depends on how the definition of "appears" appears. (And makes my point, above, about the us-ness of the how-ness of it all.) Sticks that lie in the (assumed horizontal) plane of the monocular viewer will have a distribution of apparent lengths (defined in some purely optical, non-perceptual, way: e.g., in terms of measurements taken with a pair of dividers on a 2D snapshot) that may be (and very likely is) markedly different from the distribution of apparent lengths of all the sticks; the viewer's assumptions (conscious or unconscious) about what is seen will play a large part in determining what conclusions (conscious or unconscious) the viewer draws about the distribution of attitudes of the sticks. (Affordances must come up here, eh?) If we had a 2D photo such as you suggest, Eric, it would be an interesting experiment to show it to various people turned at various angles. My prediction is that (absent clues about "true vertical") "appreciably more" of the sticks would be perceived as being "near the horizontal than near the vertical orientation" in every case (assuming, as I just realized I have been, that the 2D photo is viewed in a vertical plane, rather than lying on a desk or in one's lap or on the floor; in *those* cases, I'll now predict that ascriptions of verticality will be quite variable). Shephard points out (in his paper speculating on why humans have a 3D color space) that for terrestrial animals (at least, ones that live above the scale where things like surface tension of water and viscosity of the atmosphere are big deals in daily life), the vertical axis defined by gravity is highly salient. What, we may ask, would a porpoise or a porgy make of your photo? Lee Rudolph > I'll have to meditate more on the more general case. > > Eric > > On Sat, Jul 17, 2010 07:28 PM, Russ Abbott <[hidden email]> wrote: > > > >I just ran across > <http://plato.stanford.edu/entries/mathematics-explanation/>. (Call it the > "horizontal force.") > > > > > >There appear to be physical explanations that are > >non-causal. Suppose that a bunch of sticks are thrown into the air > >with a lot of spin so that they twirl and tumble as they fall. We > >freeze the scene as the sticks are in free fall and find that > >appreciably more of them are near the horizontal than near the > >vertical orientation. Why is this? The reason is that there are more > >ways for a stick to be the horizontal than near the vertical. To see > >this, consider a single stick with a fixed midpoint position. There > >are many ways this stick could be horizontal (spin it around in the > >horizontal plane), but only two ways it could be vertical (up or > >down). This asymmetry remains for positions near horizontal and > >vertical, as you can see if you think about the full shell traced out > >by the stick as it takes all possible orientations. This is a > >beautiful explanation for the physical distribution of the sticks, but > >what is doing the explaining are broadly geometrical facts that cannot > >be causes. > > > > > > > > > >-- Russ Abbott > >______________________________________ > > > > Professor, Computer Science > > California State University, Los Angeles > > > > cell: 310-621-3805 > > Google voice: 424-2Blue2 > > blog: <a style="font-family: trebuchet ms,sans-serif;" > href="http://russabbott.blogspot.com/" target=" > onclick="window.open('http://russabbott.blogspot.com/');return > false;">http://russabbott.blogspot.com/</a> > > vita: <a style="font-family: trebuchet ms,sans-serif;" > href="http://sites.google.com/site/russabbott/" target=" > onclick="window.open('http://sites.google.com/site/russabbott/');return > false;">http://sites.google.com/site/russabbott/</a> > >______________________________________ > > > > > > > > > ============================================================ > >FRIAM Applied Complexity Group listserv > >Meets Fridays 9a-11:30 at cafe at St. John's College > >lectures, archives, unsubscribe, maps at http://www.friam.org > > > > Eric Charles > > Professional Student and > Assistant Professor of Psychology > Penn State University > Altoona, PA 16601 > > > ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org Professional Student and Assistant Professor of Psychology Penn State University Altoona, PA 16601 ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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I agree with the comments on the psychology/perception issue. But I don't agree with this:
"So no matter which bisecting plane through the sphere we examine, it will always have more sticks parallel to it than to the orthogonal pole. So this actually explains a "planar force". There more horizontal sticks than up/down sticks...."
I just don't think that is possible. All you have to do is consider one case (that supposedly has more sticks parallel), and then freeze the sticks in place, and rotate the plane through the sphere so that it is now perpendicular to the original plane. Clearly now the "parallel" sticks are "perpendicular," so if there were more parallel before, now there are more perpendicular.
The plane is simply a place of reference. It makes no difference on the number of sticks oriented one way or another. Cheers, -Ted
On Sun, Jul 18, 2010 at 12:08 PM, ERIC P. CHARLES <[hidden email]> wrote:
--
Ted Carmichael, PhD Complex Systems Institute Department of Software and Information Systems College of Computing and Informatics 343-A Woodward Hall UNC Charlotte
Charlotte, NC 28223 Phone: 704-492-4902
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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On Sun, Jul 18, 2010 at 10:53 AM, Ted Carmichael <[hidden email]> wrote:
I agree with the comments on the psychology/perception issue. But I don't agree with this: There is no one plane perpendicular to a given plane in three dimensional space, that only becomes a possibility in four dimensions. When you rotate a plane through 90 degrees in 3D you end up with a plane that intersects the original plane along a line. Some of the sticks parallel to the first plane are still parallel to the rotated plane.
-- rec -- ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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Hey Roger, Your posts inspired me to track you down a bit. Nice website (The Entropy Liberation Front). Not many posts, though. You should post more. I like your Puzzle Earth. Very nice--except that the cursor doesn't always grab what it should.
-- Russ
On Sun, Jul 18, 2010 at 10:14 AM, Roger Critchlow <[hidden email]> wrote:
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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On Sun, Jul 18, 2010 at 12:27 PM, Russ Abbott <[hidden email]> wrote:
Thanks. Sigh, so little time, so many web pages to fill. Keep playing puzzle earth and you'll find the pieces with the clipping boundary problem, too, they leave behind a smear of image detritus when you move them. Two things which I could never get java to do right.
-- rec -- ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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In reply to this post by Russ Abbott
On Sun, Jul 18, 2010 at 10:53 AM, Ted Carmichael <[hidden email]> wrote: I agree with the comments on the psychology/perception issue. But I don't agree with this:
"So no matter which bisecting plane through the sphere we examine, it will always have more sticks parallel to it than to the orthogonal pole. So this actually explains a "planar force". There more horizontal sticks than up/down sticks...."
I just don't think that is possible. All you have to do is consider one case (that supposedly has more sticks parallel), and then freeze the sticks in place, and rotate the plane through the sphere so that it is now perpendicular to the original plane. Clearly now the "parallel" sticks are "perpendicular," so if there were more parallel before, now there are more perpendicular.
That seems reminiscent of the vision trick of Bumps(or Hollows) with shadows. In some sense our brains are wired (Hard or Soft?) to prefer certain short cuts of reasoning based on gravity or the assumption that the sun is overhead and shadows always fall in a particular way. If the sticks were oriented perpendicular to a plane it strikes me that most viewers would inevitable prefer to say the sticks are lying in some other orthogonal plane. It is striking that this discussion can not disentangle itself from Human perception for very long before exposing it again. Perhaps the reason we find difficulty accepting Gravity in this new form is that our brains themselves are stuck using a short cut approach. In spite of most human beings accepting a roundish earth, day to day we still assume it to be flat.!
We automatically orient to a level flat plane with our bodies upright. Our plane of reference is preferred over all others.
Vladimyr Ivan Burachynsky Ph.D.(Civil Eng.), M.Sc.(Mech.Eng.), M.Sc.(Biology)
120-1053 Beaverhill Blvd. Winnipeg, Manitoba CANADA R2J 3R2 (204) 2548321 Phone/Fax
-----Original Message-----
Hey Roger, Your posts inspired me to track you down a bit.
Nice website (The Entropy Liberation Front).
Not many posts, though. You should post more. I like your Puzzle Earth. Very nice--except that the
cursor doesn't always grab what it should.
On Sun, Jul 18, 2010 at 10:14 AM, Roger Critchlow <[hidden email]> wrote:
On Sun, Jul 18, 2010 at 10:53 AM, Ted Carmichael <[hidden email]> wrote: I agree with the comments on the psychology/perception issue. But I don't agree with this:
"So no matter which bisecting plane through the sphere we examine, it will always have more sticks parallel to it than to the orthogonal pole. So this actually explains a "planar force". There more horizontal sticks than up/down sticks...."
I just don't think that is possible. All you have to do is consider one case (that supposedly has more sticks parallel), and then freeze the sticks in place, and rotate the plane through the sphere so that it is now perpendicular to the original plane. Clearly now the "parallel" sticks are "perpendicular," so if there were more parallel before, now there are more perpendicular.
The plane is simply a place of reference. It makes no difference on the number of sticks oriented one way or another.
There is no one plane perpendicular to a given plane in three dimensional space, that only becomes a possibility in four dimensions. When you rotate a plane through 90 degrees in 3D you end up with a plane that intersects the original plane along a line. Some of the sticks parallel to the first plane are still parallel to the rotated plane.
-- rec --
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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Imagine that you have a single stick. It is flat on a table and pointing directly away from you--like a knife when sitting down to dinner. Now rotate the table about the axis of that stick. The table now intersect the original plane of the table at a right angle. But the original stick will still be parallel to the original plane. (Since you rotated the table about it using it as an axis it won't have moved.)
As a first generalization imagine that instead of a single stick one had an array or parallel sticks, e.g., a knife, a spoon, a couple of forks, etc. (No utensils at the top of the plate perpendicular to the side utensils, though.) Rotate the table again, and all the sticks will still be parallel to the original table plane. Some will now be above the original table and some will now be below, But none will be perpendicular to the original table plane. -- Russ On Sun, Jul 18, 2010 at 2:09 PM, Vladimyr Ivan Burachynsky <[hidden email]> wrote:
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In reply to this post by Russ Abbott
It's in Cosmides and Tooby, THE ADAPTED MIND. When you find my damned copy, send it back to me. Nick -----Original Message----- >From: [hidden email] >Sent: Jul 18, 2010 6:21 AM >To: Russell Standish <[hidden email]>, [hidden email] >Subject: Re: [FRIAM] Entropic force > >> On Sat, Jul 17, 2010 at 08:57:42PM -0400, [hidden email] wrote: >> > >> > Shephard points out (in his paper speculating on why >> > humans have a 3D color space) that for terrestrial >> > animals (at least, ones that live above the scale >> > where things like surface tension of water and >> > viscosity of the atmosphere are big deals in daily >> > life), the vertical axis defined by gravity is >> > highly salient. What, we may ask, would a porpoise >> > or a porgy make of your photo? >> > >> > Lee Rudolph >> > >> >> This seems to be a non-sequitur. Most mammals have a 2D colour >> space. Many birds (and a few rare humans, so called "tetrachromats") >> have a 4D colour space. What possible connection could it have with >> the spatial dimension? > >I was referencing where I read it. I don't recall that >it was part of his color-space argument; it was (probably) >an interesting digression. (Thank goodness discussions >on mailing lists never include digressions!) If I can >find my copy (originally Nick's spare copy...) of the >book it's in, I'll check later and try to get back with >whatever I find. > >============================================================ >FRIAM Applied Complexity Group listserv >Meets Fridays 9a-11:30 at cafe at St. John's College >lectures, archives, unsubscribe, maps at http://www.friam.org PS --Please if using the address [hidden email] to reply, cc your message to [hidden email]. Thanks. ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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In reply to this post by Russ Abbott
Russ Abbott wrote circa 10-07-17 04:28 PM:
> I just ran across this > <http://plato.stanford.edu/entries/mathematics-explanation/>. (Call it > the "horizontal force.") I think this is a categorical error. This measurement bias is distinct from an "entropic force". Again admitting that I'm ignorant and don't really know what I'm talking about, it seems to me that entropic forces are _causal_, at least to some extent. Imagine a network of arroyos. It may be true that a non-causal description of those arroyos does not specifically identify the "cause" of the flooding of one particular region of land. The "cause" would intuitively be rain and the water that pools in the flooded part.... as well as gravity, climate, microclimate, weather, soil qualities, etc. But the description of the network of arroyos _does_ address some of that cause. Hence, it makes some sense to talk of the density or sparsity of the network when talking of the causes of flooding. The network is, I think, analogous to degrees of freedom on a holographic screen. In fact, if we are largely ignorant of all the bazillions of causal factors involved, then imputing ontological salience on something like a network of arroyos or an entropic force may well help us design particular hypotheses that then help us discover the other causal factors. So, we can't just write the whole shebang off as "non-causal". Cause is complex despite our persistent desire to make it simple. Identifying or even analogizing entropic forces to this planar bias (or the diff. eq. description of the spinning tennis racket's phenotype) is suspiciously pat and too easy. My inner skeptic insists that Verlinde and the others that talk about entropic forces really are studying real forces, even if they lack complete, pat, easy answers to any questions we may ask about their target. -- glen e. p. ropella, 971-222-9095, http://agent-based-modeling.com ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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