Talk:Laplace's demon

io ho vissuto lo stesso giorno per tre volte

Query
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)

in pop culture
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) Effilcdar

It would be more intersting if you read a fiction book, IMPROBABLE, by Adam Fawer

chaos
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) Effilcdar

Note that chaos theory is not non-determinism. The premise of Laplace's demon is that *every* particle in the universe is known. In this case, chaos is not a problem - chaos is only a problem when approximating (for example in weather simulations). — Preceding unsigned comment added by 147.188.194.245 (talk) 08:42, 4 July 2012 (UTC)

quantum m
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) Effilcdar

biased negatives and overly simplistic view of QM
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)

I also agree that the main page is biased. The arguments used against Laplace's Demon forget that this is a thought experiment. While humans are not able to measure all of the properties of an object accurately due to the Uncertainty Principle, a perfect and hypothetical thought experiment can. The question is not if such a demon could exist in reality, since the demon does not exist in reality. The question is if it could determine the state of things in the present or future given its description. The answer to that is yes, if you were able to exactly know the state of things and how they interact with the rest of the system then you could predict points at other times in the system: hypothetically. However this demon is hypothetical to begin with. 98.124.1.208 (talk) 03:28, 14 November 2010 (UTC)

Why should a thought experiment be protected from reality-based criticisms? It seems a number of counterarguments to Laplace's Demon have gone missing from the article, simply because some of the above posters were upset about critiquing a "hypothetical" concept. I would keep an eye out to make sure no more counterpoints vanish from this page. Scriblerian1 (talk) 05:47, 24 July 2017 (UTC)

arguments #4 and #5
Arguments 4 and 5 are predicated on the so-called "citation" that states it is impossible for a material mind to compute the future with sufficient knowledge and processing power because it would have to in essense compute its own computations as well. This can be overcome by theoretically computing future states NOT including the very next future state(s), but instead, 'skipping' so to speak to FUTURE future states.

equal time
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)
 * 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)


 * 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)

re: arguments against Laplace's demon
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 16:49, 11 December 2007 (UTC)

Actually, Bell's theorem just disproves the existence of any local hidden variable theory. So there could be a Laplace Demon under a global hidden variable theory. 69.248.129.79 (talk) 02:29, 9 November 2009 (UTC)

This sweeping declaration that Laplace's Demon was slain by irreversibility makes the assumption that irreversibility as a physical effect matters, but why should it, and who said it does? This one book author's conclusion is not representative, as far as I can tell, of any current or substantial past research on the matter and it does not come up in more noteworthy sources unless I'm missing something. Can we be a bit critical about this collectively? This is the kind of out of hand conclusion that makes academics crack lecture hall jokes about absurdity of relying on Wikipedia. Tomekeeper (talk) 05:49, 28 May 2015 (UTC)

Entry Paradigm Shifts Point To An Encyclopedic Gestalt Switch...
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)

About The Introduction
In the history of science, Laplace's demon is a hypothetical "demon" envisioned in 1814 by Pierre-Simon Laplace such that if it knew the precise location and momentum of every atom in the universe then it could use Newton's laws to reveal the entire course of cosmic events, past and future.

Laplace never mentioned atoms or Newton's laws. It can be viewed as a simplication of his statement, but its closer to an oversimplication, Laplace intentionally used the terms "all items of which nature is composed" and "all forces that set nature in motion".

Arguments against Laplace's demon
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)

4 May 2008:

The Smith content, while of fascinating interest and admitted relevance, is not an argument against the demon (since G*d apparently <> the completed demon in Smith's G*ddish cosmology/theology/mythology) and so should be moved elsewhere. It should also be tagged as partisan/advocative, etc., since there is so little amplificatory or critical (this is controversial territory) content in this paragraph/section. One question: Is Smith or an adherent the author of this paragraph/section? The citation [2] of Smith's mediaevalist document is faux scholarship (although it may qualify in divinity schools). Thus, while fine to attribute the sentiment to Smith, the citation should either be removed or identified as deist.

Dstlascaux —Preceding unsigned comment added by Dstlascaux (talk • contribs) 22:22, 4 May 2008 (UTC)

To me this seems to miss the point. As a thought experiment, the calculations could be thought of as occuring outside of the universe. Whether or not it is possible for the calculations to be outside the universe seems irrelevant to the thought experiment itself.

As a side point, this statement seems extremely arrogant. Even if it is correct (which I doubt everyone would be in agreement) I think using the term "slam the door" in inappropriate. In 2008, David Wolpert used Cantor diagonalization to "slam the door" on Laplace's demon.[2] 167.1.150.157 (talk) 19:03, 9 April 2009 (UTC)

Another argument against Laplace's demon
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)


 * Discussion moved there: http://en.wikipedia.org/wiki/Talk:Determinism Twipley (talk) 07:17, 9 December 2008 (UTC)


 * 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)

I know that Twipley's post is old, but I'd like to add a response to it. One response to your proposed "breaking" of Laplace's Demon is that since the location of motion of ALL particles is known it would also include those inside your brain. Movements and actions of your neurons and thus presumably your thoughts and your own reactions to your thoughts would also be known by the Demon. You're going to be somewhere in two hours and if you believe in determinism and than it can be known. 199.181.136.59 (talk) 17:50, 11 November 2013 (UTC)

Dune
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)
 * 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)
 * Yep, good call. Sebastian Garth (talk) 00:38, 10 December 2010 (UTC)

Quotation
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)
 * Oh, and what is the Essai? Myrvin (talk) 10:28, 3 August 2009 (UTC)

Billiard ball argument is false
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)
 * 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)

Laplace's Statements Taken Out of Context
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)

Heisenberg
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) "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." Well, "extrapolation", u say? For "extrapolation", you at least need some data. I can say that the statement is wrong in many ways. We cannot have the data required to know the exact position of the atoms of the future universe cause we don't even know the position of atoms in the present universe. For all we know, we don't even know how much of the universe we have ever observed! We don't know how large the universe is or how small the fundamental entities are! But thanks to Heisenberg, we do know that we cannot even observe the exact position and momentum of even an electron! That is why leptons, quarks, etc are in a domain that only quantum physicists are able to deal with. Hence, you see- "extrapolation" is definitely impossible. Moreover, a "Demon" that operates at atomic level? Newton's physics does not even yield accurate results for orbit of Mercury...how do you expect a "Demon" that operates at atomic level to predict the future state of atoms in the universe in the future?! Mehfoos (talk) 19:01, 6 March 2010 (UTC)

Sure it is. HUP basically states that either the velocity vector or the momentum component gets measured at the instant of wavefunction collapse. Moreover, the result cannot be predicted exactly, no matter how much is known about the preconditions, because it necessarily governed by cloud-like randomness. It isn't due to limitations in measurement, that is. So then HUP does indeed rule out determinism, prima facie. Sebastian Garth (talk) 00:02, 7 March 2010 (UTC)

"Randomness-governed" sounds rather like an oxymoron to me(just me, oc). But I agree, many physicists consider it that way. But that doesn't make it an absolute scientific fact. There were some who disagreed(eg: Albert Einstein). In fact it does make sense right? The whole of science is but empiricism. If i throw a dice, and knew the exact physical factors affecting its motion; I would be able to determine what number would show up. But since I don't, mathematical probability is the only tool we have. But that doesn't mean that it's a random event. I claim that randomness is relative. If I knew the number on the dice, it isn't random to me. But it would be to another person whose only knowledge about the event is the specification of the dice. I believe that HUP is but a message that attempts to define the boundary of human beings' capability of observation at the atomic level. Hence, even if it proves that Laplace's demon is impossible; determinism isn't disproved. Mehfoos (talk) 19:50, 8 March 2010 (UTC)

The question is not if humans can completely know the state of something, but if this demon could. This was one of the assumptions of the statement. To say that the statement is false would also mean that another classic thought experiment is meaningless: a frictionless ball rolling side to side in a "U" channel. Yes, from a practical perspective the ball will eventually roll to a stop since friction does exist. That is not the point of the experiment, the point is that if friction did not exist it would continue to roll forever and stop at each side at the same height the ball was originally dropped. The purpose of this experiment is not to attempt to do it in reality, but to give us a better understanding of the problem itself. 98.124.1.208 (talk) 13:44, 14 November 2010 (UTC)

Reference to Maxwell's Demon
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)

Templeton winner's argument against: dubious?

 * John Polkinghorne argues that nature is cloud-like rather than clock-like and points out that, apart from any other problems, uncertainty about the exact position of an electron on the other side of the universe would be sufficient to invalidate a calculation about the position of an O2 molecule in air after 50 collisions with its neighbours (i.e. in about 0.1 ns), even if they were solely influenced by Newton's laws. -- Quarks, Chaos and Christianity

Could someone give more detail on this example (or else a more easily accessible reference), to be included in the inline note supporting this paragraph? Based on the mention of Newton's laws (which do not cover electric forces), I assume he is modelling the atoms as rigid bodies and saying that the tiny gravitational effect of a single electron-mass even tens of light-years away would be enough to perturb this system. Since he doesn't quantify the perturbation at either end: 1) I assume he is only considering whether the effect of whether the distant electron either exists or else is entirely absent from the universe (which would of course cause far more perturbation than if it were definitely held to exist but still its exact position was merely uncertain on say the order of a metre or so); and 2) I assume his measure of "invalidate" is how long until the molecule has more than some certain probability (what, 50%?) of qualitatively rewriting the order of its collisions with other molecules (say, after identifying each molecule by its possition at time zero, how long must we wait on average until the accumulated position-perturbations are such that the one designated molecule entirely misses another molecule that it otherwise would have been destined to collide with, or vice versa, collides with one it would not otherwise have struck in that sequence), because this is obviously the mechanism for a turning point in the magnfication of quantitative uncertainty. To be correct, a note should perhaps clarify that dependency is on the status of that electron back in the primitive universe (since modern gravitational physics prohibits the system from being directly affected in such a short timescale by anything happening "now" on the other side of the universe). More importantly, it is critical that he is specifically investigating the *tidal* gravitational forces, since to first order the gravitational effect will be uniform over every molecule and thus cancel its effects out (this would be a very easy oversight to make on such a back-of-the-envelope type of calculation). Cesiumfrog (talk) 02:31, 28 April 2011 (UTC)
 * I don't have time to edit the article, but this argument appears in Chance and Chaos by David Ruelle, which predates Polkinghorne's book by 2 years. I think Ruelle gives a reference, but I don't have the book with me. I think Ruelle has the electron at the edge of the universe only blink out of existence for a Planck time-unit.
 * In any case, the argument is not due to Polkinghorne or Ruelle, so the article should be changed. 145.18.220.61 (talk) 12:09, 19 December 2011 (UTC)
 * To whom it may concern, Ruelle's description is in chapter 12. He credits M. Berry's "Regular and Irregular Motion" pages 95-96 (I found a version online, but it seems to skip a page). According to Ruelle, Berry was building on ideas by E. Borel and B.V. Chirikov. He does not specify the length of time for which the electron is absent. I think he models the molecules as elastic balls. 145.18.215.168 (talk) 14:25, 12 April 2012 (UTC)

TWIMC, the mention[] of Polkinghorne (referencing Quarks, Chaos and Christianity pp. 65–66) has now been removed by MachineElf. This is "justified" solely on the claim that Polkinghorne's argument doesn't really refer to the true Laplace's demon, since MachineElf thinks the true Laplace's demon assumes perfect knowledge. I think that claim is nonsense since 1. Polkinghorne clearly says he is describing Laplace's demon (seems to be a no-true-scotsman-fallacy in play) and 2. the argument clearly is "about" the topic of the demon regardless (i.e., it's not off-topic to include expert views on the extent to which the central premises of the thought experiment are applicable to our universe). Moreover, the paragraph has been replaced by what appears to be a paragraph of MachineElf's unverifiable original research concening implications of chaos theory. I'm leaving this note since it may help something more appropriate (e.g., using sources) to be done later. Cesiumfrog (talk) 05:55, 3 July 2012 (UTC)
 * I hadn't noticed this talk page discussion. Apparently there's prior consensus that, among several problems, the removal you're defending failed WP:V. You also fail to mention I'm not the only one who currently has a problem with it. You trivialize and dismiss the reasons I provided, as well as my attempts to address your concerns. It find it more likely than not that you know full well what Laplace's premises entail, so I won't waste my time explaining what you simply don't care to admit. Those genuinely unacquainted with the broad strokes of determinism may find this summary helpful.
 * You don't hear that the source failed WP:V... Are you seriously claiming Rev. Polkinghorne thinks I've run afoul of no-true-scotman, as detailed on pp. 65–66? Wow, right or wrong, he should get a promotion. Much less amazingly... you're claiming 1) it's explicitly about Laplace's demon and 2) it's clearly "about" Laplace's demon. In other words, everyone is wrong, except you?
 * As for my so-called WP:OR, which as I said, was lifted from Hard determinism: it does, in fact, have a named reference to the Stanford Encyclopedia of Philosophy article "Causal Determinism". I see I neglected to go back and fish it out... "thanks" for bringing it to my attention.
 * Shall I take your 180 and pugnacious rhetoric as an WP:AGF waiver? Although it would seem the "Polkinghorne" thing is what you're actually concerned about, you had only mentioned the fragment about chaos. "Clearly", you don't need my help, but as you are the only one who wants to keep it, in it's original form, without qualification... the burden falls to you to produce a citation. LOL, not for me to cite what all ain't no argument against it. Properly qualified, I have no problem with keeping something about chaos theory, and I've never said it was "undermining the article". For your information, the section title is "Arguments against Laplace's demon". Perhaps you'll indulge my editorial whimsy, but wouldn't it be a hoot if that section only contained arguments against Laplace's demon? You have a very generous notion of what constitutes a "positive contribution to the article". No one's stopping you from exercising it, sooner or later.—Machine Elf 1735  13:44, 3 July 2012 (UTC)

Is there an error in assumption in this? (No & Yes)
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)

The truth will never be known
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)

Image of the Demon?
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)

This article is bad
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)

Cantor diagonalization
"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)