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I think the example of the particules diffusing in the volume is not a good example of an entropic force since in this case there is indeed a microscopic force acting. It is the force related to the multiple collisions experienced by each particule. When integrated at the macroscopic level, it translates into partial pressure which tends to equilibrate in the volume. An other example taken from the physical review letter paper on the subject would be more precise. AlexisGiauque ( talk) 16:51, 14 March 2014 (UTC) -Alexis
I de-emphasized the new and speculative physics theories, interesting though they may be, to primarily focus on the chemistry examples which are ubiquitous and very important. See WP:UNDUE. I also deleted some explanations (like the galaxy collision and copper) that I thought were incorrect or misleading. We can put them back if there's a citation to a reliable source. (I would be surprised if there was.) The section still has citations to unpublished papers, and discussion of non-notable theories, so in my opinion it could be reduced even further. But I'll just leave it be for now. :-) -- Steve ( talk) 03:23, 3 June 2011 (UTC)
Controversial theories generally should be mentioned when external sources are available, including Wikipedia:Neutral_point_of_view/FAQ#Pseudoscience with wp:due weight, with wp:npov and wp:notcensored. "Speculative" is an inadequate description without external source claiming so, hence "Controversial" should be used instead. Before my edits this article was misrepresented and subtly ridiculed - not wp:npov. -- Asterixf2 ( talk) 18:41, 10 March 2016 (UTC)
This concept should be mentioned Special:PermanentLink/708941331#Evolutionary_origin. I agree that it is a fringe theory. If you think my previous edit has given undue weight to the theory I may rewrite it, but I am convinced that it should be mentioned on grounds of wp:npov. I'd argue it is not pseudo-science but only fringe theory. It won't be given undue weight if it is mentioned in a section named "speculative". Even if it is pseudo-science in your opinion, that I don't share, it should be mentioned, see: Wikipedia:Neutral_point_of_view/FAQ#Pseudoscience and questionable science therein. Please also see use primary/self-published sources. If you don't agree please suggest alternative page for this concept to be mentioned as it is perhaps not notable enough to have its own article. -- Asterixf2 ( talk) 10:20, 8 March 2016 (UTC)
I was clearly talking about any fringe theories. Staszek Lem ( talk) 21:15, 14 March 2016 (UTC)
I deleted This piece per Wikipedia:Fringe theories: " For a fringe view to be discussed in an article about a mainstream idea, reliable sources must discuss the relationship of the two as a serious and substantial matter.". See Wikipedia:Fringe theories#Unwarranted promotion of fringe theories for more detail. The references provided are primary sources, expressing fringe opinions of the proponents. As such they do not belong to wikipedia. Staszek Lem ( talk) 21:07, 14 March 2016 (UTC)
See the previous section for more discussion in the subject. Staszek Lem ( talk) 21:14, 14 March 2016 (UTC)
Staszek Lem have you tried looking for reliable independent sources for the statements you have deleted? Even the Matt Visser article cited in the same section already serves as a reliable independent source for the statement that people have suggested entropic descriptions of EM and other gauge forces. (Which is about all that can be reliably said on the topic. T R 10:31, 15 March 2016 (UTC)
Per WP:ONEWAY this would not be appropriate material at Coulomb's law, but as it is here under a section heading that specifically marks the results as doubtful, I think its appropriate. Someone looking for information on entropic forces could find the mathematical line of argument useful whether or not electrostatic attraction is "actually" entropic. Rhoark ( talk) 15:04, 24 March 2016 (UTC)
The lead of this article is faulty. It is not a summary of the content of the article. Instead it is an attempt to argue a case for the validity of the concept 'entropic force'. The lead is not a place to argue for the basis of an article. It is a place to summarize such argument as may be in the body of the article.
The attempt at argument in the lead is faulty as an attempt at argument, irrespective of whether such an attempt should be in the lead. Currently, the lead reads:
In physics, an entropic force acting in a system is a force resulting from the entire system's thermodynamical tendency to increase its entropy, rather than from a particular underlying microscopic force. [1]
For instance, the internal energy of an ideal gas depends only on its temperature, and not on the volume of its containing box, so it is not an energy effect that tends to increase the volume of the box as gas pressure does. This implies that the pressure of an ideal gas has an entropic origin. [2]
What is the origin of such an entropic force? The most general answer is that the effect of thermal fluctuations tends to bring a thermodynamic system toward a macroscopic state that corresponds to a maximum in the number of microscopic states (or micro-states) that are compatible with this macroscopic state. In other words, thermal fluctuations tend to bring a system toward its macroscopic state of maximum entropy. [2]
Broadly speaking, that is nonsense. In a nutshell, it puts the cart before the horse. Thermodynamics does not explain the effects of forces; it describes them. Forces explain the effects that are described by thermodynamics. The faulty argument offered in the lead seeks to explain the effects through thermodynamics.
The first sentence of the lead contains this: "the entire system's thermodynamical tendency to increase its entropy". That is nonsense. A system does not have a tendency to increase its entropy. Entropy is a state variable or state function. It is defined only for a system that is accepted as being in its own state of internal thermodynamic equilibrium. Such an equilibrium is determined by the state variables and by the walls and surrounding physical conditions. If the entropy happens to be a state variable, it is given and it is nonsense to talk of its changing. If the entropy is a function of state, it is determined by the given state variables, the walls, and the surrounding conditions. It can change if those factors are changed by an external agency, but not as a result of the agency of the system. A system in its own state of internal thermodynamic equilibrium is not an agent; it has no agency. The phrase 'tendency to increase its entropy' mistakenly attributes agency to the system.
Similar argument could be offered to impugn the rest of the lead, but I think the above sample is probably enough.
I do not intend to try to edit this article, because I think it would cause me much misery to do so. But I offer the above opinion for local editors to include in their deliberations. It will be very hard for editors to find explicit reliable sources on this topic. None of the sources offered so far is reliable for the purpose of validating a notion of 'entropic force'. Reliability of sources is not determined only by such criteria as whether they are primary or secondary, or refereed or not. A source that says black is white is not reliable, no matter by what criteria it is assessed. There is an obligation that material that is posted in articles be reliably sourced. If reliability of sources for a topic cannot be assessed by a Wikipedia editor, he should not muddle on and hope for the best; he should remain silent on that topic. There is no obligation to report on anything in Wikipedia. Chjoaygame ( talk) 20:53, 26 March 2016 (UTC)
After re-reading the 1st paragraph or two several times I realised this article is almost incomprehensible. Please make it at least readable by humans ? 178.255.168.77 ( talk) 21:05, 4 May 2016 (UTC)
Agreed, this article is basically only readable to people that already understand entropic forces at a very high statistical mechanics level. I'll write down my thoughts for improvements, and then maybe I or someone else interested can start on them.
-- Anuran ( talk) 00:14, 29 April 2021 (UTC)
I broadened the scope of the previous section on "Directional entropic forces" to discuss colloids more generally (and renamed it accordingly) because entropic forces are important there beyond just for directional entropic forces, and they weren't discussed elsewhere in the page. I migrated and edited version of the discussion of directional entropic forces to the page on depletion forces where they enter a bit more naturally. Entrophys ( talk) 15:08, 14 June 2016 (UTC)
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Lvilench, I have reverted your recent additions for five reasons:
Maproom ( talk) 20:07, 1 October 2018 (UTC)
I have worked on MERW ( Maximal entropy random walk) which is also dynamics accordingly to the (Jaynes) maximal entropy principle. I have recently found this "Causal Entropic Force" PRL paper - at first I thought it is the same, but then realized they are quite different philosophies.
It would be interesting to understand this difference, especially which one suits physics best?
If I properly understand, in this entropic force the object analyses space of future trajectories, what leads to force giving tendency to maximize this space of future trajectories?
Does it have a physical realization? Where exactly? Does it agree with quantum predictions (localization) - e.g. for [0,1] it should repel from boundaries, but is its stationary probability density exactly sin^2 as in QM? -- Jarek Duda ( talk) 13:32, 17 December 2019 (UTC)
This article is rated Start-class on Wikipedia's
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It is requested that a photograph be
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I think the example of the particules diffusing in the volume is not a good example of an entropic force since in this case there is indeed a microscopic force acting. It is the force related to the multiple collisions experienced by each particule. When integrated at the macroscopic level, it translates into partial pressure which tends to equilibrate in the volume. An other example taken from the physical review letter paper on the subject would be more precise. AlexisGiauque ( talk) 16:51, 14 March 2014 (UTC) -Alexis
I de-emphasized the new and speculative physics theories, interesting though they may be, to primarily focus on the chemistry examples which are ubiquitous and very important. See WP:UNDUE. I also deleted some explanations (like the galaxy collision and copper) that I thought were incorrect or misleading. We can put them back if there's a citation to a reliable source. (I would be surprised if there was.) The section still has citations to unpublished papers, and discussion of non-notable theories, so in my opinion it could be reduced even further. But I'll just leave it be for now. :-) -- Steve ( talk) 03:23, 3 June 2011 (UTC)
Controversial theories generally should be mentioned when external sources are available, including Wikipedia:Neutral_point_of_view/FAQ#Pseudoscience with wp:due weight, with wp:npov and wp:notcensored. "Speculative" is an inadequate description without external source claiming so, hence "Controversial" should be used instead. Before my edits this article was misrepresented and subtly ridiculed - not wp:npov. -- Asterixf2 ( talk) 18:41, 10 March 2016 (UTC)
This concept should be mentioned Special:PermanentLink/708941331#Evolutionary_origin. I agree that it is a fringe theory. If you think my previous edit has given undue weight to the theory I may rewrite it, but I am convinced that it should be mentioned on grounds of wp:npov. I'd argue it is not pseudo-science but only fringe theory. It won't be given undue weight if it is mentioned in a section named "speculative". Even if it is pseudo-science in your opinion, that I don't share, it should be mentioned, see: Wikipedia:Neutral_point_of_view/FAQ#Pseudoscience and questionable science therein. Please also see use primary/self-published sources. If you don't agree please suggest alternative page for this concept to be mentioned as it is perhaps not notable enough to have its own article. -- Asterixf2 ( talk) 10:20, 8 March 2016 (UTC)
I was clearly talking about any fringe theories. Staszek Lem ( talk) 21:15, 14 March 2016 (UTC)
I deleted This piece per Wikipedia:Fringe theories: " For a fringe view to be discussed in an article about a mainstream idea, reliable sources must discuss the relationship of the two as a serious and substantial matter.". See Wikipedia:Fringe theories#Unwarranted promotion of fringe theories for more detail. The references provided are primary sources, expressing fringe opinions of the proponents. As such they do not belong to wikipedia. Staszek Lem ( talk) 21:07, 14 March 2016 (UTC)
See the previous section for more discussion in the subject. Staszek Lem ( talk) 21:14, 14 March 2016 (UTC)
Staszek Lem have you tried looking for reliable independent sources for the statements you have deleted? Even the Matt Visser article cited in the same section already serves as a reliable independent source for the statement that people have suggested entropic descriptions of EM and other gauge forces. (Which is about all that can be reliably said on the topic. T R 10:31, 15 March 2016 (UTC)
Per WP:ONEWAY this would not be appropriate material at Coulomb's law, but as it is here under a section heading that specifically marks the results as doubtful, I think its appropriate. Someone looking for information on entropic forces could find the mathematical line of argument useful whether or not electrostatic attraction is "actually" entropic. Rhoark ( talk) 15:04, 24 March 2016 (UTC)
The lead of this article is faulty. It is not a summary of the content of the article. Instead it is an attempt to argue a case for the validity of the concept 'entropic force'. The lead is not a place to argue for the basis of an article. It is a place to summarize such argument as may be in the body of the article.
The attempt at argument in the lead is faulty as an attempt at argument, irrespective of whether such an attempt should be in the lead. Currently, the lead reads:
In physics, an entropic force acting in a system is a force resulting from the entire system's thermodynamical tendency to increase its entropy, rather than from a particular underlying microscopic force. [1]
For instance, the internal energy of an ideal gas depends only on its temperature, and not on the volume of its containing box, so it is not an energy effect that tends to increase the volume of the box as gas pressure does. This implies that the pressure of an ideal gas has an entropic origin. [2]
What is the origin of such an entropic force? The most general answer is that the effect of thermal fluctuations tends to bring a thermodynamic system toward a macroscopic state that corresponds to a maximum in the number of microscopic states (or micro-states) that are compatible with this macroscopic state. In other words, thermal fluctuations tend to bring a system toward its macroscopic state of maximum entropy. [2]
Broadly speaking, that is nonsense. In a nutshell, it puts the cart before the horse. Thermodynamics does not explain the effects of forces; it describes them. Forces explain the effects that are described by thermodynamics. The faulty argument offered in the lead seeks to explain the effects through thermodynamics.
The first sentence of the lead contains this: "the entire system's thermodynamical tendency to increase its entropy". That is nonsense. A system does not have a tendency to increase its entropy. Entropy is a state variable or state function. It is defined only for a system that is accepted as being in its own state of internal thermodynamic equilibrium. Such an equilibrium is determined by the state variables and by the walls and surrounding physical conditions. If the entropy happens to be a state variable, it is given and it is nonsense to talk of its changing. If the entropy is a function of state, it is determined by the given state variables, the walls, and the surrounding conditions. It can change if those factors are changed by an external agency, but not as a result of the agency of the system. A system in its own state of internal thermodynamic equilibrium is not an agent; it has no agency. The phrase 'tendency to increase its entropy' mistakenly attributes agency to the system.
Similar argument could be offered to impugn the rest of the lead, but I think the above sample is probably enough.
I do not intend to try to edit this article, because I think it would cause me much misery to do so. But I offer the above opinion for local editors to include in their deliberations. It will be very hard for editors to find explicit reliable sources on this topic. None of the sources offered so far is reliable for the purpose of validating a notion of 'entropic force'. Reliability of sources is not determined only by such criteria as whether they are primary or secondary, or refereed or not. A source that says black is white is not reliable, no matter by what criteria it is assessed. There is an obligation that material that is posted in articles be reliably sourced. If reliability of sources for a topic cannot be assessed by a Wikipedia editor, he should not muddle on and hope for the best; he should remain silent on that topic. There is no obligation to report on anything in Wikipedia. Chjoaygame ( talk) 20:53, 26 March 2016 (UTC)
After re-reading the 1st paragraph or two several times I realised this article is almost incomprehensible. Please make it at least readable by humans ? 178.255.168.77 ( talk) 21:05, 4 May 2016 (UTC)
Agreed, this article is basically only readable to people that already understand entropic forces at a very high statistical mechanics level. I'll write down my thoughts for improvements, and then maybe I or someone else interested can start on them.
-- Anuran ( talk) 00:14, 29 April 2021 (UTC)
I broadened the scope of the previous section on "Directional entropic forces" to discuss colloids more generally (and renamed it accordingly) because entropic forces are important there beyond just for directional entropic forces, and they weren't discussed elsewhere in the page. I migrated and edited version of the discussion of directional entropic forces to the page on depletion forces where they enter a bit more naturally. Entrophys ( talk) 15:08, 14 June 2016 (UTC)
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Cheers.— InternetArchiveBot ( Report bug) 03:41, 25 January 2018 (UTC
Lvilench, I have reverted your recent additions for five reasons:
Maproom ( talk) 20:07, 1 October 2018 (UTC)
I have worked on MERW ( Maximal entropy random walk) which is also dynamics accordingly to the (Jaynes) maximal entropy principle. I have recently found this "Causal Entropic Force" PRL paper - at first I thought it is the same, but then realized they are quite different philosophies.
It would be interesting to understand this difference, especially which one suits physics best?
If I properly understand, in this entropic force the object analyses space of future trajectories, what leads to force giving tendency to maximize this space of future trajectories?
Does it have a physical realization? Where exactly? Does it agree with quantum predictions (localization) - e.g. for [0,1] it should repel from boundaries, but is its stationary probability density exactly sin^2 as in QM? -- Jarek Duda ( talk) 13:32, 17 December 2019 (UTC)