Gravity as an emergent phenomenon
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Gravity as an emergent phenomenon
 
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Great food for thought. Gravity might be no more than an emergent phenomenon:
http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&emc=rss "God keep me from ever completing anything. This whole book is but a draft--nay, but the draft of a draft. Oh, Time, Strength, Cash, and Patience!" Melville, "Moby Dick" ============================================================ 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 |
Re: Gravity as an emergent phenomenon
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And if you want to see if the argument confuses you as much as it confuses the physicists:
-- rec --
On Tue, Jul 13, 2010 at 10:39 AM, Pamela McCorduck <[hidden email]> wrote: Great food for thought. Gravity might be no more than an emergent phenomenon: ============================================================ 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 Pamela McCorduck
Pamela McCorduck wrote circa 10-07-13 09:39 AM:
> http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&emc=rss “The end result was that everyone else didn’t understand it either, including people who initially thought that did make some sense to them,” he [Bousso] said in an e-mail message. Sounds a lot like the end result of our discussions of "emergence". ;-) -- 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 |
Re: Gravity as an emergent phenomenon
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In reply to this post by Pamela McCorduck
Stephen G will be glad to know too that the physicist featured in the
article thinks it might be all thermodynamics. (or should that be quantum thermodynamics?) Robert C On 7/13/10 10:39 AM, Pamela McCorduck wrote: > Great food for thought. Gravity might be no more than an emergent phenomenon: > > > http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&emc=rss > > > > > > "God keep me from ever completing anything. This whole book is but a draft--nay, but the draft of a draft. Oh, Time, Strength, Cash, and Patience!" > > Melville, "Moby Dick" > > > ============================================================ > 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 > > > ============================================================ 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 |
Re: Gravity as an emergent phenomenon
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In reply to this post by Pamela McCorduck
Pamela,
I got all ready to be huffy about the article, but then found it really interesting. At risk of going all professorial on you, I want to examine your expression, "no more than a". The most important phenomena that we experience are all emergents. If you hit me with a rock, the hardness and edginess of the rock that collapses my skull, are all emergents. So, then what the dickens is meant by "no more than"? I think it means SOMETHING and would like to explore it further with you (and others on the list.) "Reduction" means to some to account for a phenomenon n terms of events or objects that are smaller than the phenomenon itself. Reduction is always to break a process or an object into its parts. To others, "reduction" means to explain a phenomenon by reference to a more familiar or well understood phenomenon. This latter understanding of reduction opens the possibility for a reduction to refer to a process that is larger or more inclusive than the process it reduces, what I would call an up-reduction, to distinguish it from the "breaking-into-parts" sort of reduction. It sounds to me that the account of gravity being offered in this article is a case of up reduction in that sense. I hope others will read the article and comment, because i wasnt sure I understood it. All the best, Nick Nicholas S. Thompson Emeritus Professor of Psychology and Ethology, Clark University ([hidden email]) http://home.earthlink.net/~nickthompson/naturaldesigns/ http://www.cusf.org [City University of Santa Fe] > [Original Message] > From: Pamela McCorduck <[hidden email]> > To: The Friday Morning Applied Complexity Coffee Group <[hidden email]> > Date: 7/13/2010 12:39:41 PM > Subject: [FRIAM] Gravity as an emergent phenomenon > > Great food for thought. Gravity might be no more than an emergent phenomenon: > > > http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&em c=rss > > > > > > "God keep me from ever completing anything. This whole book is but a draft--nay, but the draft of a draft. Oh, Time, Strength, Cash, and Patience!" > > Melville, "Moby Dick" > > > ============================================================ > 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 ============================================================ 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 always find myself confused about how to think about entropy. The article says that gravity is an entropic force. I understand that to mean that it not reducible to lower level forces but to be reducible (if that term applies) to statistical thermodynamics.
Just as there are a lot more ways that a gas can be more or less uniformly distributed in a closed area than the ways it could be bunched up in a corner -- and hence we tend to find it more or less uniformly distributed -- gravity according to this analysis is like the universe in a more uniformly distributed state rather than a more unusual state. There is no force that causes it. It is a statistical phenomenon. In other words, gravitational attraction is like whatever it is that pushes a gas bunched up in a corner to become more uniformly distributed. But the whatever-it-is in the case of a gas is nothing but statistical phenomena. There are no forces involved even though from a naive point of view it may appear that there is a force that is pushing the gas to be spread out. -- Russ On Tue, Jul 13, 2010 at 10:36 AM, Nicholas Thompson <[hidden email]> wrote: Pamela, ============================================================ 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 |
Re: Gravity as an emergent phenomenon
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Administrator
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In reply to this post by Pamela McCorduck
Great catch, thanks.
Time for a new book? :) -- Owen On Jul 13, 2010, at 10:39 AM, Pamela McCorduck wrote: > Great food for thought. Gravity might be no more than an emergent phenomenon: > > http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&emc=rss > > "God keep me from ever completing anything. This whole book is but a draft--nay, but the draft of a draft. Oh, Time, Strength, Cash, and Patience!" > > Melville, "Moby Dick" ============================================================ 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 Roger Critchlow-2
Roger Critchlow wrote circa 10-07-13 09:55 AM:
> And if you want to see if the argument confuses you as much as it > confuses the physicists: > > http://arxiv.org/abs/1001.0785 So far (section 3.2), I'm getting that same tickle in my lizard brain that I get when I play numerologist. "Do you see? When I take this number and add it to that one, then shift them around, add the digits together, fold in the position of the moon, and say a prayer to Satan, we end up with the magic number 22! Do you see!?!?" -- 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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In reply to this post by Pamela McCorduck
Then for something really complicated (complex?) this article on
microbiology/micobiomes made me think I'm just a host for all the millions of symbiotes? Literally your right hand might not know what your left hand is doing. http://www.nytimes.com/2010/07/13/science/13micro.html?ref=science Persons with a sensitive nature may get grossed out about references to certain emergent phenomenon and other procedures. Thanks Robert C On 7/13/10 10:39 AM, Pamela McCorduck wrote: > Great food for thought. Gravity might be no more than an emergent phenomenon: > > > http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&emc=rss > > > > > > "God keep me from ever completing anything. This whole book is but a draft--nay, but the draft of a draft. Oh, Time, Strength, Cash, and Patience!" > > Melville, "Moby Dick" > > > ============================================================ > 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 > > > ============================================================ 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 glen e. p. ropella-2
Sabine Hossenfelder's summations are fun and interesting and, alas more
informative than the nyt article: http://backreaction.blogspot.com/2010/03/gravity-is-entropy-is-gravity-is.html http://backreaction.blogspot.com/2010/07/in-praise-of-black-holes.html Carl On 7/13/10 10:55 AM, glen e. p. ropella wrote: > Pamela McCorduck wrote circa 10-07-13 09:39 AM: >> http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&emc=rss >> > > > “The end result was that everyone else didn’t understand it either, > including people who initially thought that did make some sense to > them,” he [Bousso] said in an e-mail message. > > Sounds a lot like the end result of our discussions of "emergence". ;-) > ============================================================ 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 |
Re: Gravity as an emergent phenomenon
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In reply to this post by Robert J. Cordingley
Herr Prof. Thompson,
Would you "reductionally posit that our personalities are emergent?
Paul
-----Original Message-----
From: Robert J. Cordingley <[hidden email]> To: The Friday Morning Applied Complexity Coffee Group <[hidden email]> Sent: Tue, Jul 13, 2010 1:11 pm Subject: Re: [FRIAM] Gravity as an emergent phenomenon
Then for something really complicated (complex?) this article on
microbiology/micobiomes made me think I'm just a host for all the
millions of symbiotes? Literally your right hand might not know what
your left hand is doing.
http://www.nytimes.com/2010/07/13/science/13micro.html?ref=science Persons with a sensitive nature may get grossed out about references to certain emergent phenomenon and other procedures. Thanks Robert C On 7/13/10 10:39 AM, Pamela McCorduck wrote: > Great food for thought. Gravity might be no more than an emergent phenomenon: > > > http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&emc=rss > > > > > > "God keep me from ever completing anything. This whole book is but a draft--nay, but the draft of a draft. Oh, Time, Strength, Cash, and Patience!" > > Melville, "Moby Dick" > > > ============================================================ > 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 > > > ============================================================ 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 ============================================================ 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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Nick, I love it when you talk professor-ese to me.
"No more than" = well, I dunno what. I found the article provocative, but if the best physicists don't quite understand what the guy is on about, I needn't feel bad for myself. Pamela "God keep me from ever completing anything. This whole book is but a draft--nay, but the draft of a draft. Oh, Time, Strength, Cash, and Patience!" Melville, "Moby Dick" ============================================================ 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 |
Re: Gravity as an emergent phenomenon
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Administrator
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In reply to this post by Pamela McCorduck
From Carl's post's post (backreaction):
In this case however one finds that the "temperature" can be negative and that the "entropy" can decrease without having to do work. Whoa! Definitely relates to complexity babble! -- Owen ============================================================ 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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So, Verlinde lost me in section 4. But I usually try to continue reading even if I don't understand (just like I continue talking about stuff I don't understand ;-). And equation 5.35 (attached) had a surprise for me. What is that ^ symbol between dx^a and dx^b? -- 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 |
eq-5.35.png (9K)
Re: Gravity as an emergent phenomenon
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Working from the context, I'd guess: the tensor product between the components <i>dx<sup>a</sup></i> and <i>dx<sup>b</sup></i>of the stress energy tensor <i>T<sub>ab</sub></i>, but I've never been too sure about tensors.
I was lost in the introduction. The proposition of entropy causing action at a distance reminded me of a notorious demonstration. A beaker of water and a beaker of sugar dissolved in water are sealed together inside a bell jar. Over time the level of liquid in the beaker of water will drop and the level of liquid in the beaker of sugar water will rise.
-- rec --
On Tue, Jul 13, 2010 at 7:30 PM, glen e. p. ropella <[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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Wonderful! I love the water/sugar example.
-- Russ On Tue, Jul 13, 2010 at 9:07 PM, Roger Critchlow <[hidden email]> wrote: Working from the context, I'd guess: the tensor product between the components <i>dx<sup>a</sup></i> and <i>dx<sup>b</sup></i>of the stress energy tensor <i>T<sub>ab</sub></i>, but I've never been too sure about tensors. ============================================================ 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 |
Re: Gravity as an emergent phenomenon
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In reply to this post by Roger Critchlow-2
On Tue, Jul 13, 2010 at 10:07:14PM -0600, Roger Critchlow wrote:
> Working from the context, I'd guess: the tensor product between the > components <i>dx<sup>a</sup></i> and <i>dx<sup>b</sup></i>of the stress > energy tensor <i>T<sub>ab</sub></i>, but I've never been too sure about > tensors. > Not a tensor product, but an exterior product. It's somewhat related to a cross product of two 3D vectors. Cheers -- ---------------------------------------------------------------------------- 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 |
Re: Gravity as an emergent phenomenon
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In reply to this post by Pamela McCorduck
Verlinde makes the same unfortunate argument that is made by scores of
scientists - even noted thermodynamicsists - about so-called
"disorder": namely that certain permutations are "disordered", while
other permutations are not. To wit:
"Think of the universe as a box of scrabble letters. There is only one way to have the letters arranged to spell out the Gettysburg Address, but an astronomical number of ways to have them spell nonsense. Shake the box and it will tend toward nonsense, disorder will increase and information will be lost as the letters shuffle toward their most probable configurations. Could this be gravity?" I find this argument specious. Just because, from an anthropomorphic, English-speaking bias, he finds the Gettysburg address "more ordered" than any other permutation of the same length - it is not. They are all permutation of the same number of letters. Each is as well-defined, and well-ordered, as the other. Anyway, "order" is an ill-defined, conflated term within the discussion of thermodynamics. It enjoys two distinct usages that get oft-conflated in the conversation regarding entropy. One usage is that it means "disorganization", "absence of arrangement", "dispersed", etc. This is approximately the meaning had originally by R. Clausius. The other usage is that of "uncertainty" or "unpredictability". This is the meaning had by Shannon. "Disorganized" and "uncertain" do not mean the same thing. I can prove this because they can vary independently - and, the same phenomenon can exhibit one without the other - the Organized state can sometimes be Uncertain... In between the meanings of Clausius and Shannon are the meanings of entropy put forth by Boltzmann and Gibbs. Those meanings are often taken to be about "disorganization", but they are actually about "uncertainty". They involve probabilities. So, there is much confusion within statistical thermodynamics about "entropy", because the conversation often assumes that "disorder" is about "disorganization", when it is actually about "unpredictability". Certainly, it is confusing since Clausius was all about "dispersion", "disorganization", while these other two physicists, Boltzmann and Gibbs, were actually about "uncertainty". On the other hand, Shannon was not behaving as a physicist, when he "borrowed" the word "entropy" (upon the insistence of von Neumann) for his measure of uncertainty. Indeed, he even "borrowed" most of his formula from Gibbs. However, with his definition of entropy, Gibbs ( and Boltzmann before him) was doing physics - he was describing a specific physical phenomenon. On the other hand, Shannon was not doing physics. Rather he was doing mathematical statistics. His definition of entropy is a mathematical function whose domain space is probability distributions (to use the term loosely). With Shannon's entropy, any probability distribution now has a "measure of unpredictability". Some PDFs have more unpredictability built into them than others, and he measures it. Harold Morowitz also makes this point: [Shannon’s entropy] is a meaningful measure
over
any probability distribution, while [Gibb’s thermodynamic entropy] has
meaning
only if the pi are the probabilities of a system being in
the ith
quantum state when the system is at equilibrium, as rigorously
defined
for thermodynamics….[Shannon’s entropy] is a measure on a probability
distribution; it is not a physical quantity.” [Morowitz 1992] Grant Pamela McCorduck wrote: Great food for thought. Gravity might be no more than an emergent phenomenon: http://www.nytimes.com/2010/07/13/science/13gravity.html?_r=1&partner=rss&emc=rss "God keep me from ever completing anything. This whole book is but a draft--nay, but the draft of a draft. Oh, Time, Strength, Cash, and Patience!" Melville, "Moby Dick" ============================================================ 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 -- Grant Holland VP, Product Development and Software Engineering NuTech Solutions 404.427.4759 ============================================================ 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 |
Re: Gravity as an emergent phenomenon
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In reply to this post by glen e. p. ropella-2
Hi Glen,
I believe it's also called a "wedge product". Mike Spivak's tiny but frustrating but elegant book Calculus on Manifolds, if I remember correctly, defines these things and explains what they mean in geometric terms. Eric On Jul 13, 2010, at 7:30 PM, glen e. p. ropella wrote: > > So, Verlinde lost me in section 4. But I usually try to continue > reading even if I don't understand (just like I continue talking > about stuff I don't understand ;-). And equation 5.35 (attached) > had a surprise for me. What is that ^ symbol between dx^a and dx^b? > > -- > glen e. p. ropella, 971-222-9095, http://agent-based-modeling.com > > <eq-5.35.png>========================================================= > === > 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 ============================================================ 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 |
Re: Gravity as an emergent phenomenon
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In reply to this post by Pamela McCorduck
Roger,
Some how that seems less mysterious if you say, seal a beaker of SUGAR and a beaker of water in a bell jar. In time the sugar will become damp. By the way, help me out with the technology, here. Initially, what is the atmosphere in the bell jar composed of?
Nick
Nicholas S. Thompson
Emeritus Professor of Psychology and Ethology,
Clark University ([hidden email])
http://www.cusf.org [City University of Santa Fe]
============================================================ 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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