Talk:Laplace's demon

message: Why is Laplace's demon based on the premise of reversibility?
If the demon knows that a->b and c->d, and there are 100 a and 100 c, it can thus predict there will be 100 b and 100 d eventually. 
I don't know anything of Laplace's demon besides this Wikipedia entry, but I simply didn't understand it so if someone knows the answer, please add to the article :) 19:06, 14 October 2006 User:82.168.228.248 (Talk)
I deleted a section entitled Simplistic Downfall that claimed to be an encapsulation of the paragraph "The downfall of Laplace Demon".  It was in fact not an encapsulation of that graf (which focuses on philosophical and information theory concerns, and was to my eyes either grossly incorrect or gave a ridiculously superficial treatment of a highly complex section of the foundational issues of QM.
Robert Ulanowicz's claim that Laplace's Demon is invalidated by the second law of thermodynamics is incorrect to my eyes. Thermodynamics doesnt have anything to do with it, since it is based on the average over many particle states owing to a lack of information on microscopic states.  The microscopic states (to which the demon has by assumption has complete knowledge) are still governed by reversible laws, (measurement process in copenhagen QM excluded).  I'm therefore demoting it and putting a note questioning its validity.
QuantumSage 06:10, 7 February 2007 (UTC)
thread_title: Query

message: This would be the same concept as the precognition of the dune series wouldn't it. Could someone who understands both better put somthing in about it.71.112.27.85 06:15, 7 April 2007 (UTC)
thread_title: in pop culture

message: Should some mention of chaos theory be made and how that is integral to the problems with such awareness. 71.112.27.85 06:15, 7 April 2007 (UTC)
thread_title: chaos

message: Should mention be made in this article of hizenberg's uncertenty principal. Acordning to it alone such a demon qould be imposible in that it couldn't predict the location of even a single electron. 71.112.27.85 06:15, 7 April 2007 (UTC)
thread_title: quantum m

message: The negative arguments in this article are overstated.  They paint the picture that no intelligent being believes in the theoretical possibility of such a demon/intellect.  It seems to state that every interpretation of quantum mechanics DISPROVES the intellect.  Such people would be advised to read the many views on the interpretations of QM page, or elsewhere that are just as deterministic as Laplace.  There are far too many unqualified and uncited claims that need to be deleted or at least modified to create a more Non-biased POV.  —Preceding unsigned comment added by Mcb142 (talk • contribs) 22:41, August 25, 2007 (UTC) 
Determinism cannot be disproved by quantum mechanics. True. My proof would be this: the heisenberg's principle ultimately points out that the human limitation in observing reaches it's significant limit at the stage when u'r not able to determine the location and momentum of an electron. This doesn't prove that randomness exists from the bigger picture. It proves that since it borders on human limitation, anything beyond that is surely random from our perspective. Of course, considering the fact that most of us are humans, determinism can be ignored...but mind you- never "disproved".
The laplace's demon, however is completely irrational because such a machine, for one- doesn't exist. I could call it an end of argument, but since it's hypothetical: The machine, having the power to predict the future, should at least be able to picture the universe at the present. Now if it cannot even determine the position of the electron's position and momentum, it is definitely not possible for it to predict the future universe by calculation, because, it can never obtain the data required to observe the present and past so that it can predict the future. Hence the hypothetical machine's existence in itself cannot be explained "hypothetically". Therefore it is irrational. Once again, let me remind you- it is not determinism or fatalism that is disproved- it is the notion that one can predict the future. Mehfoos (talk) 18:26, 6 March 2010 (UTC)
thread_title:  biased negatives and overly simplistic view of QM 

message: It would also be helpful to have Quantum Physics and Philosophy of Science experts quoted in favor of Laplace's deterministic theory to balance with the non-deterministic quotes. —Preceding unsigned comment added by Mcb142 (talk • contribs) 22:59, August 25, 2007 (UTC) 
:Well that would seem more appropriate for an article on determinism. In fact, I think that Laplace's demon should really be a redirect to determinism.Cutler 14:08, 27 August 2007 (UTC)
replies: text: While it isn't an article on determinism, it is an article on a deterministic thought experiment.  Therefore, the non-deterministic POV should be removed by at the very least, matching each non-deterministic argument with a deterministic argument.  And in the realm of original research by contributors, philosophical arguments should obviously be removed entirely according to Wikipedia standards.Mcb142 03:34, 16 November 2007 (UTC)

text: Sorry but I have to say that there's nothing to tell in favour of the Laplace daemon, at least not in a scientific way, since quantum theory explicitly disallows the existence of such a daemon. Although Heisenberg's uncertainty principle in itself doesn't fully disapprove Laplace's idea about this daemon (as theoretically one could think about some hidden parameters that we can't detect, but would describe nature's behaviour), Bell's theorem expicitly says that there can't be any hidden parameters, not even in a theoretical sense. Also one must mention that this isn't really something that falls under Wikipedia's "no original research" guideline (as somebody mentioned below), since these statements could be find in whatever graduate textbook about quantum physics (I'd gladly cite any of mine, but since they are not written in English, they would not pass Wikipedia's policy about favouring English citations). Besides, as you won't quote a textbook just to mention Newton's laws or the Lagrange formalism, you don't need to cite a source for self-evident statements (at least in my opinion). AdamSiska (talk) 02:02, 29 January 2009 (UTC)
thread_title:  equal time 

message: This section of the article starts off with six assumptions that Laplace's demon allegedly rest upon. Putting aside for a moment the question of whether in fact Laplace's theory depended on those six assumptions (I don't think they do), unless that specific argument can be attributed to a reliable source who makes that specific argument, it appears that it is in violation of the No original research policy. Unless a reliable source making that argument can be provided, I'll go ahead and remove the argument from the article. - Walkiped (T | C) 16:49, 11 December 2007 (UTC)
thread_title: re: arguments against Laplace's demon

message: This entry should point somewhere within it to Technological Singularity... which itself should be broken down into 4 parts, but isn't. A small reminder to those writing both, don't forget an introduction and a conclusion, for good measure. 
Met4foR (talk) 08:44, 9 March 2008 (UTC)
thread_title:  Entry Paradigm Shifts Point To An Encyclopedic Gestalt Switch... 

message: I don't know any sources to back this up, but I'm sure the main argument against Laplace's demon is the fact that if the demon existed within the universe, then the information gathered would have to be stored using part of the universe. The demon would then have to store the information about the information about the universe. This would require an infinite amount of information stored within a finite universe, which is, of course, impossible.
I notice this is vaguely mentioned in "Recent views", but it should be expanded more thoroughly, because to me it seems like an important aspect of Laplace's demon.  —Preceding unsigned comment added by 130.216.30.233 (talk) 10:31, 29 April 2008 (UTC)
thread_title:  Arguments against Laplace's demon 

message: Chances are I'm not the first person on the planet to think about this argument. If anybody is aware of references pointing to what I'm going to say, it'd be appreciated, because it would be freaky to learn I'm the first one to get this thing out.
The argument goes as follow: given you have access to a powerful-enough computer (presuming that such a thing could exist), that could tell you where you are going to be in two hours. It calculates, then it says: "you'll be at your friend's." Knowing that information, what could possibly prevent you from fooling the pre-determined future and not being at your friend's in two hours?
From that moment on, I knew free-will had to exist.
I've told a few friends about it back then, but none seemed to understand. Several years later, I'm falling on this very  page, learning with relief that I'm not the first to have imagined the concept of Laplace's demon, but I've yet to fall on somebody holding the same argument.
Does the reasoning seem logical to you? what do you think about all this?
Twipley (talk) 06:45, 9 December 2008 (UTC)
replies: text: Discussion moved there: http://en.wikipedia.org/wiki/Talk:Determinism Twipley (talk) 07:17, 9 December 2008 (UTC)

text: This is a extremely low quality circular argument ... you have to assume free will in order to assert that you could choose to do other than what was predicted. Also, the argument falls through if the demon simply doesn't tell you what it predicted. -- Jibal (talk) 21:45, 14 January 2022 (UTC)
thread_title:  Another argument against Laplace's demon 

message: From the article at present:
"For example, in Frank Herbert's Dune, certain highly trained people are capable of prescience. The ability of these people, prescients, is limited by their knowledge and focus (in the Dune franchise, this focus is aided by the use of drugs). Prescients see time as a nexus of causality, and as such, recognize the presumed fallacy of free will. Powerful prescients with greater focus and knowledge can see further into the future, and the presence or attention of other prescients increases the amount of focus required for to predict the actions of the other prescient. Presumably a certain amount of recursion due to the other prescients and their knowledge results in this demand for extra focus on the part of those making a prediction."
This doesn't really seem like an accurate description. In Dune, prescience can't be "taught" but is more of an inherent ability, only available to a very small number of people... primarily the Kwisatz Haderach and his offspring, and guild navigators under the spice trance.
I also got the very strong impression that Paul's visions and Leto II's "golden path" both represented not an abject lack of free will, but rather an apparent lack of free will. By looking into the future Paul is seeing all possible ways that things could go and all the different choices he could make. He then lacks free will in the sense that every action and choice he makes leads him down a path he already knows, but that doesn't come from a deterministic worldview, simply from seeing all possible outcomes of his free will.
Likewise Leto II's "golden path" represents his choice to become the tyrant and take a very specific set of actions. Within that path, he has absolutely no free will, but it's precisely because he's seen the whole path and decided already that he must take it - if he were to make other choices humanity would no longer be on his golden path.
So prescience in the Dune series isn't about seeing the outcomes of a deterministic universe but rather about gaining knowledge of the possible futures, which then gives you a deterministic, un-free path to the outcome you desire.
Finally, there is no "extra focus" required because of other prescient beings or recursion - there's simply a hard barrier - it's not possible to see the future where other prescient beings are at work. No amount of concentration or focus can get around it. This is why the group conspiring against Paul includes a guild navigator. This is also the logic behind Leto II's program to breed a whole line of humans who are "invisible" to prescience - taking away the ability of any future prescients to have that position of total power. It's also the purpose of the "no-chamber" and "no-ship" technology. 152.91.9.219 (talk) 03:09, 24 February 2009 (UTC)
replies: text: I've removed the references to Dune, because although the book is partly about prescience, there's no mention of Laplace's demon, and as commented above has a rather different take on predicting the future. I've also removed a couple of other mentions of works that don't seem to have any explicit connection to Laplace's demon. 4u1e (talk) 22:41, 9 December 2010 (UTC)
replies: text:  Yep, good call. Sebastian Garth (talk) 00:38, 10 December 2010 (UTC)
thread_title:  Dune 

message: The text says: "Note, however, that the description of the hypothetical intellect described above by Laplace as a demon does not come from Laplace, but from later biographers". The quote doesn't say 'demon'. Also, who are these 'later biographers'? Myrvin (talk) 10:26, 3 August 2009 (UTC)
replies: text: Oh, and what is the Essai? Myrvin (talk) 10:28, 3 August 2009 (UTC)
thread_title:  Quotation 

message: Additionally, the existence of Laplace's demon is impossible because such an algorithm could predict the future state of a billiard-ball computer and effectively solve the halting problem.
It is trivial to predict the future state of a billiard-ball computer, even a human could probably do it. This only affects the demon if it could predict the future after infinite time, which it doesn't.--83.50.139.110 (talk) 19:09, 21 September 2009 (UTC)
replies: text: I agree; Laplace's demon is essentially just a computer running the program (as part of a larger program), and is no more "solving" the halting problem than any normal computer is. Wiml (talk) 05:45, 3 October 2009 (UTC)
thread_title:  Billiard ball argument is false 

message: The original quote comes from a paper describing methods for calculating probabilities. At the time that it was written there were basically two camps: those who considered outcomes a matter of pure chance and those who favored a deterministic viewpoint. Laplace's statement was simply an attempt to illustrate that the need for probabilistic analysis stems from our uncertainty of preconditions rather than the mere randomness of a system. Nowhere in his statements are there any allusions to the effect that this would ever be computable or if there was even an entity capable of doing so. Neither determinism nor non-determinism can be either proven or disproven, thus the assertion that his statement is somehow flawed is nothing more than a matter of opinion. Sebastian Garth (talk) 13:38, 17 October 2009 (UTC)
thread_title:  Laplace's Statements Taken Out of Context 

message: Use of Heisenberg's Uncertainty Principle as an argument against the Demon is invalid. The HUP is only applicable at the quantum level whereas the Demon, by definition, operates at the atomic level where Newtonian physics apply. The state - position and velocity - of an electron somewhere in the universe is not part of the problem and is immaterial. If the state of every atom can be computed as hypothesized, uncertainty does not exist and chance never occurs. It follows that two such Demons, working independently, would produce exactly the same results and would never disagree. 
Humans are doing to a very limited degree what the Demon is hypothesized to do. We have algorithms that can compute the orbital trajectory of the Earth relative to the Sun to a very high degree of precision for centuries in advance. We can do the same for everything from satellites in orbit around the Earth and space probes orbiting other planets to any of the planets and their moons in the Solar system. By extrapolation, therefore, an omniscient computer with unlimited capability would be able to predict the exact future state of any atom in the universe given an exact initial state for each atom. --Virgil H. Soule (talk) 09:33, 20 October 2009 (UTC)
thread_title:  Heisenberg 

message: This link to Maxwell's Demon is trivial as they perform completely different functions.  The only similarity is that they are both called demons and hypothetically perform a function. 98.124.1.208 (talk) 13:44, 14 November 2010 (UTC)
thread_title:  Reference to Maxwell's Demon 

message: No: The statement is correct due it´s openness.
Yes: Irrational numbers, ratio´s, can not be calculated out to an infinite number of decimal places within a finite time limit, therefore there is allways an indeterminant IN CALCULATIONS, equivalent to 1/infinity, where infinity is in relation to the smallest differencial within the totality [allways placed within the range [0,1].
It is therefore hightly recommended to not ignore those demons whose seat of pants prowers are within negative log factor differencials from the stability criterea of the mid section of reality.  — Preceding unsigned comment added by 186.94.185.159 (talk) 13:37, 28 April 2013 (UTC)
thread_title:  Is there an error in assumption in this? (No & Yes) 

message: In order for a Laplace-demon computer-program to figure the future and show the results to a human, who would then know the future but could not change it, it is necessary that the action of building this computer-program has been predetermined in history (just as this post I'm writing here is). The chances that building such a computer-program has been predetermined are very close to zero, wouldn't you say?  Actually you wouldn't, because you sadly but randomly have not been predisposed to respond to this...  
On the other hand, when looking at a slice of toast falling off the end of the table, I can, without having all the knowledge of the universe, 42 and everything, still be able to predict with quite a good estimate, that it will reach the floor and not stop in mid-air. 
So using the two facts detrimentally predestined to be formulated in the way they are above this proposition, I can, using my brain, predict with a good amount of accuracy, and seeing the current state of computer programming, machine learning and information processing methods, that such a program with a limited ability will actually be developed as a scientific experiment, with a Drosophila Manogaster house fly in mind, before moving on to rats and humans. The Laplace-demon computer program will be nicknamed Lapsy.
The experimenters will realize that before moving on to In-Vivo experiments, they can actually compose a computer-program Drosophila simulator to test Lapsy - the Laplace-demon computer-program. They'll call the simulator Droso. Droso will be programmed to be in a certain state of a real fly, with all the fly's effect-response mechanisms, up to a reasonable accuracy and given a not-too-small area within which to fly and a few different surfaces to land on, each with different conditions - smell, light, wind, food, texture etc. One of these surfaces, nicknamed the Spider Surface will lead to the death of Droso. A means of communication will be available to Droso, so that knowledge of the lethal surface will lead it to avoid landing there. This warning will be available to Droso, only if it intended to land on the lethal service according to Lapsy's first stage predictions, and only enough time in advance for Droso to "change its mind" in accordance with the new information.   
Lapsy meanwhile will receive all the knowledge about Droso and its set-up environment. It will work in two stages. First it will calculate several "predictions" of Droso's location in time given the known conditions and changes in the environment over time, and calculating Droso's reactions faster than Droso itself, using approximations and noticing predetermined patterns which take time for Droso to accomplish, but can be determined in advance by Lapsy the demon program. 
In the second stage Lapsy will take into account its own communication of results to Droso, and then re-calculate the predictions about Droso's location. 
If successful, it would prove that IF the world is causally predetermined, a Laplace-demon program COULD be built, and more importantly, that it could be built in a way that does not change the future, so that no paradoxes are created, and the fate of the experiment could then be actually and finally determined. 
The expected good and statistically aligned results will bring much joy to the deterministic scientists, but (I predict) they will then find a problem, and begin arguing about it. This will cause much agony and in some cases even depression. They will have realized that for all practical reasons, they will not be able to focus on everything everywhere and at any time. This means that not all Drosophilas can be warned, and more importantly that it has been historically predetermined that not everyone - even those who have knowledge of Lapsy - will know everything about their future. Even before developing it further, the deterministic scientists will have realized that Lapsy can only inform a small amount of people and only about a limited amount of knowledge. Sadly, the rest of the community will have to decide on their actions alone, as determined by their history.פשוט pashute ♫ (talk) 12:36, 11 June 2015 (UTC)
thread_title:  The truth will never be known 

message: I have added two images symbolizing the Demon. The images can be found in the Wikimedia Commons Category "Demons". If they are appropriate to the article please feel free to use them.
Rhetos (talk) 16:53, 8 September 2019 (UTC)
thread_title:  Image of the Demon? 

message: The article misrepresents the thought experiment, ignores the context it is originally framed in, and fires many sloppy arguments against silly interpretations. I think the concept deserves a Wikipedia entry, as part of the philosophy of science and a cultural reference. I do, however, not think that the current entry is useful. Arguments against determinism belong in Determinism. Arguments regarding physical/computational realisability of the "demon" should be marked clearly as violating the thought experiment nature. The best part, actually the only good part, of the current entry, is the quote of Laplace himself. A remarkably clear and beautiful explanation of the idea of determinism.Elias (talk) 10:44, 17 August 2020 (UTC)
thread_title:  This article is bad 

message: "In 2014 in a paper of Josef Rukavicka, where a significantly simpler argument is presented that disproves Laplace's demon using Turing machines, under the assumption of free will.[12]"  - sorry, but if the assumption upon which the paper was founded was free will, then it is already irrelevant to a discussion of whether free will or determinism are principle to the operation of the universe. It has already discounted one of them and no valid investigation can ensue. 2.28.151.187 (talk) 23:41, 22 November 2021 (UTC)
thread_title:  Cantor diagonalization