Talk:Maximum entropy thermodynamics

message: To do:
* technical note that strictly the entropy should be relative to a prior measure.  -> Principle of minimum cross-entropy  (Kullback-Leibler distance).  In thermodynamics we usually assume the "principle of equal a-priori probability" over phase space, so the two are then equivalent.
* section on philosophical implications regarding the conceptual problems of statistical mechanics, second law, etc.
:: -- (?) DONE Jheald 22:07, 2 November 2005 (UTC)
thread_title:  From stub to article 

message: * I think the title of the article is not a correct and wide-accepted term.  Meanwhile, its content have been covered by these articles: Entropy, Principle of maximum entropy, and Edwin_Thompson_Jaynes.  Actually, this article seems an layman version of Principle of maximum entropy, stuffing too much discussion of Entropy.  Biohuang (talk) 13:20, 16 March 2017 (UTC)
thread_title:  Deletion? 

message: I have done a fair bit of reading and writing of Wiki entries on math and science, and this entry strikes me as one of the hardest to follow out of all those I've read. This entry badly needs to be turned around, but I don't quite know where to begin. If anyone conjectures that I am incompetent to form an opinion of this nature, let me point out that my education included Bayesian statistics and Shannon information.
This entry is important simply because E.T. Jaynes founded its subject with his 1957 Princeton Ph.D. thesis written under Eugene Wigner; Wigner was a worthy fellow, and Jaynes became one himself. In fact, I first encountered his name while learning Bayesian statistics. I think of Jaynes as having advanced the legacy of Gibbs and Boltzmann. In any event, this entry should also include a paragraph giving the history of its subject.
Another reason why this topic is a worthy one is that subjective probability and Bayesian statistics can be a powerful tool in the philosophy of science; see, for example, the work of Nick Bostrom. If the data can be adequately summarized via a likelihood function, then Bayes Rule is a powerful way of reasoning inductively from those data. Hence I am surprised that this entry does not mention Bayes's Rule.123.255.63.50 (talk) 06:25, 25 December 2008 (UTC)
thread_title: This entry is hard to follow

message: At the moment the article isn't very clear as to when it's talking about expectations (either as a constraint, or a prediction), and actual measurements.  For example, in the discussion of the 2nd law, the measured macroscopic quantities probably won't come in bang on the nose of the predicted -- instead (we assume) they will be within the margin of predicted uncertainty.
This especially needs to be much cleaned up in the context of entropy, particularly if we're going to discuss the fluctuation theorem.
Also, the new measurements will therefore contain (a little) new information, over and beyond the predicted distribution.   So it's not quite true that SI is unchanged.   It will still be a constant, but strictly speaking it will become a different contstant, as we propagate back the new information, sharpening up our phase-space distribution for each instant back in time.
-- Jheald 15:51, 1 November 2005 (UTC)
replies: text: -- DONE Jheald 22:07, 2 November 2005 (UTC)
thread_title:  Average entropy, measured entropy and entropy fluctuations 

message: The article at present, in a section called 'The nature of probabilities in statistical mechanics', writes: "According to the MaxEnt viewpoint, the probabilities in statistical mechanics are subjective (epistemic, personal), to the extent that they are conditioned on a particular model for the underlying state space (e.g. Liouvillian phase space). They are also conditioned on a particular partial description of the system (the macroscopic description of the system used to constrain the MaxEnt probability assignment). The probabilities are objective to the extent that given these inputs, a uniquely defined probability distribution will result." [bold type by present talk page writer here]
I think this is not quite right. It is true that critics of the MaxEnt viewpoint view the MaxEnt viewpoint as dealing with 'subjective (personal) probabilities', but the holders of the MaxEnt viewpoint do not do so. The holders of the MaxEnt viewpoint hold that the probabilities are simply objective and epistemic. They hold that being epistemic logically precludes them from being subjective or personal. The root of the word epistemic, used by Aristotle, is usually translated as "scientfic knowledge", in direct and explicit contrast with "opinion", which is regarded as essentially subjective and personal. In view of this tradition of thinking and language, it is self-contradictory to say that something is both epistemic and subjective/personal. I think all will agree that in science, to label something as 'subjective/personal' is pejorative. That the probabilities are conditioned on a particular model does not make them subjective or personal unless one hides or conceals or fails to state the model. The MaxEnt people are keen to put the model upfront and explicit, and not to hide it. Indeed, "the probabilities are objective because given these inputs, as is the case in a properly stated proposition, a uniquely defined probability distribution will result." It is according only to the opponents of the MaxEnt viewopoint that the MaxEnt viewpoint deals with "subjective/personal" probabilities. The sentence in the article that says otherwise is not an accurate statement, and should be deleted. Perhaps it could be replaced, if one was keen, by a sentence like "According to the opponents of the MaxEnt viewpoint, it deals with subjective or personal probabilities, but the holders of the MaxEnt viewpoint categorically deny this pejorative mischaracterization."
The article at present continues: "At a trivial level, the probabilities cannot be entirely objective, because in reality there is only one system, and (assuming determinism) a single unknown trajectory it will evolve through. The probabilities therefore represent a lack of information in the analyst's macroscopic description of the system, not a property of the underlying reality itself." This is not an argument that the probabilities are not objective. It is an objective fact that the analyst is stating that he has a lack of information. Objectivity is not about direct contact with the underlying reality itself: it is is about how the situation is conceived and described: objectivity is an epistemic notion not an ontological one. The two quoted sentences are inaccurate, misleading, and should be deleted. Chjoaygame (talk) 05:54, 17 October 2009 (UTC)
thread_title:  meaning of the words 'subjective' and 'objective' 

message: I have above proposed to make some edits to the effect that 'subjective' is not the right word to label the epistemic meaning of probability. The word 'subjective' is used by opponents of MaxEnt theory as a politely pejorative epithet, but that something is epistemic does not make it subjective. MaxEnt people do not think that probability is subjective. So far, no replies to my above remarks that are preliminary to my efforts at editing to this effect. Anyone with a comment?Chjoaygame (talk) 07:00, 23 October 2009 (UTC)
thread_title: note of intention to edit

message: On page 44 of Probability Theory, Jaynes writes, in a slightly uncharacterisitic appeasement of critics, that "any probability assignment is necessarily 'subjective' in the sense that it describes only a state of knowledge, and not anything that could be measured in a physical experiment." Jaynes puts single quote marks ' ' on the word subjective. This indicates that he is not using the word in its natural sense, but is exhibiting it in the strained sense of his critics. In its  natural sense, the word is opposite to the word objective. Jaynes goes on on page 45 to say that the probability assignments that he regards as valid are objective. Jaynes here puts ' ' marks on the word objective, to indicate that he is critically examining it, as distinct from merely using it. There are things objective that cannot be demonstrated in a physical experiment. That 0 = 0 and exp(i pi) = - 1 are objective facts of mathematics that cannot be demonstrated in an empirical experiment. True, they are not empirical facts; they are only analytic or logical facts, but they are still objective. So it is with the objective character of Jaynes' probabilities. As mentioned above, the real distinction here can be traced back further back than Plato and Aristotle; the distinction is as valid today as it was in the old days. It is between doxa, meaning reputation, expectation, or opinion, and episteme, meaning scientific knowledge. The opposition is fundamental. Doxa is subjective, episteme is objective. Jaynes intended his probabilities as objective and not subjective. The Wikipedia article should make that clear, and make it clear that it is the opponents of Jaynes who like to call his probabilities subjective.Chjoaygame (talk) 10:05, 23 October 2009 (UTC)
thread_title: more argument about opinion versus scientific knowledge

message: I have made an edit to focus on Jaynes' view that probability is not a matter of personal opinion, but is a matter of impersonal scientific logic.Chjoaygame (talk) 21:59, 1 November 2009 (UTC)
thread_title: edit to focus on Jaynes' view that probability is epistemic and impersonal

message: The new edit did not make clear that it refers to a transient non-equilibrium situation, in which the system is started far from equilibrium, or is watched until it eventually, after a time comparable with the age of the universe, if such exists, fluctuates back to a transient state far from equilibrium. The edit distracted from the point that was being made where the edit was inserted. If the editor wants to discuss this kind of situation, he should state his concern clearly, not just as an unexplained interruption to an account of a different matter, which referred to an all-time average.Chjoaygame (talk) 00:11, 27 December 2011 (UTC)
thread_title:  increase of thermodynamic entropy 

message: The editor who made the edit that I have undone was writing in good faith. But he is writing from his perspective of thinking of things along Kantian lines, not from the perspective of maximum entropy thermodynamics. The problem that he sees with the terms objective and subjective is not present when things are considered from the perspective of maximum entropy thermodynamics. That is not to say that the problem is not important for Kantian theory. The paragraph of the article that leads that editor to write his "however" explains why his "however" is irrelevant for the present page. The edit was an advertisement to Kantian theory but did not actually say anything useful for this page. I am not criticizing Kantian theory by these remarks. I am saying that the edit did not contribute to the value of this page. I hope that the editor may read again the paragraph that he thinks needs his "however", and come to agree that his "however" was non-contributory to this page.Chjoaygame (talk) 16:20, 19 January 2013 (UTC)
thread_title:  epistemic and objective 

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