Talk:Boltzmann brain

Tags require talk page comment

I wish people who tag articles with reference to the talk page would put a comment on the talk page saying what they were about. For the record, this article accurately describes its subject as far as I can see. Remove tags, anyone? PaddyLeahy 09:52, 9 May 2007 (UTC)

Exactly what was this guy smoking?

I know, not a very eloquent question; one clearly indicating a lack of enlightenment. But I know some of you were thinking it too! — Preceding unsigned comment added by 68.156.83.135 (talk) 12:51, 13 June 2011 (UTC)

Actually, this article makes perfect sense to me, as opposed to the inaccuracies or failures of explanation in more technical articles. 178.38.152.228 (talk) 23:48, 20 November 2014 (UTC)

Well, so we have Boltzmann Brains - what about much simpler things, like Boltzmann Bananas? Boltzman Cheeze Puffs? Boltzmann Ballpoint Pens? These things are many, many orders of magnitude simpler - we should be awash in them, and all manner of other Boltzmann "products", one would think... 2601:195:C102:D940:B428:F646:B938:66E8 (talk) 21:36, 15 June 2022 (UTC)

Shouldn't Darwinian evolution come into this?

Surely the probability of an environment in which evolution could occur coming into existence it much lower than any of the produces of evolution coming into existence by chance? Wouldn't this mean that any where a 'brain' had come in to existence, it would surely have happened this way? —The preceding unsigned comment was added by 62.232.221.61 (talk) 16:20, August 22, 2007 (UTC)

Evolution requires a continuing flow of energy, which is happening now but won't be when any Boltzmann brain might appear in our cosmos. If you're arguing that the "Big Bang" is less likely than the spontaneous appearance of a god-like Boltzmann brain, you might be right. --Wfaxon 20:35, 22 August 2007 (UTC)

New Scientist

New Scientist did a cover on Boltzmann Brains. It can be found here.

http://www.newscientist.com/channel/fundamentals/mg19526171.100-spooks-in-space.html

It is from the 17 August Magazine. 203.98.31.34 23:01, 30 August 2007 (UTC)

I also added that link to the Manifestation article, since the article discusses objects popping into existence as a result of Boltzman brains. 5Q5 (talk) 22:49, 20 December 2007 (UTC)

Is it appropriate - or necessary/desirable - to add some indication that this article can only be viewed in full with a subscription to New Scientist (as seems to be the case for most if not all their items)? - Irdwrwyn (talk) 01:14, 31 August 2012 (UTC)

I don't think it's a good idea to link to a PAYwalled article, unless there are no free articles available. It just generates frustration. 84.117.18.221 (talk) — Preceding undated comment added 03:46, 27 August 2014 (UTC)

Descartes

Doesn't this whole notion seem like a modern reformulation of Descartian dualism? —Preceding unsigned comment added by 128.6.78.31 (talk) 16:05, 16 January 2008 (UTC)

Interesting comparison. One obvious difference is that Descartes envisaged a "separate but equal" dualism between mind and body. What would the duality be here? It wouldn't be much of a reformulation if it didn't retain the yin-yang character of Cartesian dualism, which seems more naturally related to the bra-ket notation of quantum mechanics than to Boltzmann brains. --Vaughan Pratt (talk) 19:37, 14 April 2008 (UTC)

It certainly brings to mind the "malicious demon" and other (universal?) belief falsifiers Jep1203 (talk) 00:53, 2 October 2023 (UTC)

references

The article asserts that Boltzmann advanced an idea: "that the known universe arose as a random fluctuation". I looked through the cited references that I could access and did not find a Boltzmann reference cited. I requested a citation to a published source that constitutes Boltzmann's idea, "that the known universe arose as a random fluctuation". KesheR removed my request for such a citation with the edit summary "request for facts makes no sense". It seems a simple matter of fact checking to find a citation to Boltzmann's works where he made this proposal. I'd like to see a direct quote from Boltzmann. Can anyone explain why "Disturbing Implications of a Cosmological Constant" is listed as a reference? I suggest that this Wikipedia article use numbered references and that the references be cited in the text of the article. Also, the sentence, "The idea is named for physicist Ludwig Boltzmann (1844 - 1906), who had advanced an idea that the known universe arose as a random fluctuation, similar to process through which Boltzmann brains might arise," does not seem grammatically correct, although I'm not sure what "similar to process through which Boltzmann brains might arise" is trying to say. Can a "random fluctuation" constitute a "process"? --JWSchmidt (talk) 17:04, 26 January 2008 (UTC)

I second this. Until someone produces some convincing documentation for the attribution to Boltzmann (which has been repeated so often that no one doubts it any more) it would be better if the article phrased the origin of the idea as "commonly attributed to Boltzmann." (Not to say that the original idea was necessarily bad, but the form repeated retelling has given it might make Boltzmann turn in his grave.) Secondly the originator of the supposed paradox also needs to be cited, particularly given that it is hard to see how such a statistical comparison can be justified without an assumption of independence similar to that made by EPR to support their paradox. Like the EPR paradox, this alleged BB paradox goes away as soon as one allows for the possibility of correlation (entanglement or otherwise) between widely separated parts of the universe. Thirdly the article speaks of entropy as though it were an absolute quantity, in the segue from "increasing entropy" to "low entropy". Entropy is defined by the formula dS = dQ/T, which expresses a differential relationship between energy Q and entropy S mediated by temperature T---one can think of temperature as diluting the impact of energy change (power) on entropy change (bit rate), much as noise dilutes bit rate in an information channel for a given transmitter power (clearer when both sides are divided by dt as the time differential to give dS/dt = (dQ/dt)/T). One can measure changes in entropy by integrating over time, so one can speak of increasing or decreasing entropy, but there is no formula for the constant of integration, whence there is no sensible notion of high entropy or low entropy, only higher or lower entropy. --Vaughan Pratt (talk) 17:55, 14 April 2008 (UTC)

ORLY? Entropy may be 'defined' as dS=dQ/T in classical (macroscopic) thermodynamics, but, as the best of my recollection goes, it was originally defined in a statistical mechanics framework (by Boltzmann himself) as S=k*log(Z), where Z is the number of microstates compatible with the observed macrostate, and k is a known constant, named, appropriately enough, 'Boltzmann's constant'. This is the actual definition of entropy, which can therefore be computed precisely, in absolute terms, at least for finite systems. By the way, the origin of the paradox's name is probably due to the concept of stochastic fluctuation in equilibrium systems, originally analyzed by Boltzmann with his distribution; it's not meant to imply he actually thought this up. —Preceding unsigned comment added by 89.214.196.69 (talk) 05:08, 27 November 2008 (UTC)

Badly written?

This doesn't make much sense that I can see. It seems far too verbose and vague. Surely the argument presented is not so complex that it cannot be summarized in a sentence or two? The introduction completely fails to present the argument. Is it about the likelihood of the existence of highly ordered regions (brains presumably being chosen solely for their alliterative properties, a choice with the dubious odour of a preacher's corny OHP slides)? What has that to do with physics? I'm not sure the argument is being correctly represented here either.

This article debunks one interpretation http://startswithabang.com/?p=12 and gives a reference to papers on the subject. I doubt the version currently is circulation has much to do with anything Boltzmann actually said or thought.

This poster seems to get to grips with the concept more effectively, though the OP seems a bit clueless, viewing the notion like a Star Trek plot element: http://www.bautforum.com/questions-answers/63924-boltzmann-brains-question.html#post1057956

Another reference to a paper, maybe one of the same ones http://motls.blogspot.com/2007/01/boltzmanns-brain-and-low-entropy.html The discussion is mistaken on some points (e.g. he imagines something that is not a Boltzmann's brain as he initially describes it). The ref mentions "the Boltzmann-Penrose question of why the initial conditions for cosmology have low entropy.

Mr. Jones (talk) 19:46, 13 June 2008 (UTC)

• I agree, especially the closing sentence. I don't mean to sound offensive, but it reads as though it were written by a high-schooler. Msanford  T  02:28, 30 June 2008 (UTC)

matrix reality ?

Neo

• how close it this to a universe based on the Matrix movie?, there is no reality no individual just one big simulation.

Strange as it might sound i think a lot of budhisms might not find this whole concept that strange, no individual, no reality as we observe it, reality as a lie from which one needs to get free (enlighten).. —Preceding unsigned comment added by 82.217.253.26 (talk) 11:41, 27 April 2009 (UTC)

Cultural reference

The "Boltzmann Brain Hypothesis" is referred to in this Dilbert cartoon strip. I can't quite make it relevant enough to include, but add it here for the record. Earthlyreason (talk) 07:54, 27 April 2009 (UTC)

It certainly had an imapct on the hits for this page - 9,400 against a background daily average of about 70-80 ([1]). However I agree that a reference in one cartoon doesn't justify an "in popular culture" section. —  Tivedshambo  (t/c) 07:38, 28 April 2009 (UTC)

Yes, we shold be careful. --94.79.152.113 (talk) 22:39, 1 September 2009 (UTC)

Never heard of "Boltzman Brains" but in a big 'aha" moment for me, I just realized that it is the origin of the famous whale appearing out of the quantum vacuum (with help from the infinite improbability drive) in the atmosphere of the planet in Douglas Adams' "The Hitchhikers Guide to the Galaxy". — Preceding unsigned comment added by 98.111.255.217 (talk) 02:15, 5 September 2013 (UTC)

I wish to add my weight to the argument that Dilbert is significant enough to include a cultural section, for example Ego the Living Planet links to this page.

Signed - someone with a 9.9×10^49 to 1 chance of having a single vote. — Preceding unsigned comment added by 49.184.195.195 (talk) 00:06, 6 May 2022 (UTC)

See WP:CULTURALREFS. If a review is found that says the comic is significant, then we can add it. But it needs to be a mainstream citation, not just someone's blog or reddit post. Richard-of-Earth (talk) 17:21, 8 May 2022 (UTC)

Star Trek Strange New Worlds Season 1 Episode 8 from June 23, 2022 discusses the antagonist as a Boltzmann brain when the protagonists' spaceship, enterprise, is trapped in an apparently conscious nebula. — Preceding unsigned comment added by Renegadesci (talk • contribs) 00:44, 24 June 2022 (UTC)

Hmm, I found a ref. Also Star Trek: Strange New Worlds#Episodes links to this article. We need to confirm that Screenrant.com is suitable as an WP:RS and write some prose. Richard-of-Earth (talk) 05:06, 24 June 2022 (UTC)

References

What's So Paradoxical 'bout That?

"[I]t is more likely that a brain randomly forms out of the chaos with false memories of its life than that the universe around us would have billions of self-aware brains." To me this nowhere approaches a statement that existence of a population of self aware entities, being highly improbable, must be the result of non-stochastic phenomenon. From "we seem to be unlikely" to "we must have been created" is a nonsequiter of order far beyond the watchmaker hypothesis. The logical conclusion I can derive follows thusly;

1. A population of brains (say humanity) has been observed by a brain (say the reader of this text). 2. A single brain with false memories is more likely to form than a population of brains. Therefore 3. It is more likely the observed brains were false memories of the observing brain than that the observed brains ever existed.

Under this formalism the Boltzmann brain theory presents no paradoxical contradiction, and is nothing but a statistical argument for solipsism. So what am I missing?97.83.161.77 (talk) —Preceding undated comment added 22:37, 17 June 2009 (UTC).

My question is why "solipsism" isn't even mentioned anywhere in this article?? At the very least it should be in the See Also section, it's more relevant than many of the things there. 71.238.12.254 (talk) 18:46, 17 January 2024 (UTC)

Yes it is not a paradox and no useful source calls it so. I removed it today from the category of paradoxes but some guys undo that without saying why.

I will remove that category once more. If you think it should be called paradox in that category maybe say why instead of just putting it back with not saying anything.

— Preceding unsigned comment added by 14.20*.*.* (talk)

Paradox could theoretically be sourced to [2] or maybe [3], but I'm personally fine with leaving the category out, as I don't personally think 'paradox' is a WP:CATDEFINING characteristic of this article. Rolf H Nelson (talk) 01:38, 19 June 2020 (UTC)

That would be quite theoretically indeed, using those sources. Neither article is presenting an argument for the existence of a paradox.

The author of the second article has a later, more substantial work on the topic ([4] Carroll. 2017. Why Boltzmann brains are bad) which lacks the term and makes no case for paradox either. Rather, the author invites the reader to believe it is 'cognitively unstable' and 'disturbing.'

Thanks for the comment and confirming. — Preceding unsigned comment added by 14.201.171.126 (talk) 11:42, 20 June 2020 (UTC)

Last paragraph misses probability of initial conditions

This ignores the possibility that the probability of a universe in which a brain pops into existence, without any prior mechanism driving towards its creation, may be dwarfed by the probability of a universe in which there are active mechanisms which lead to processes of development [...]

This misses the prohability of the initial condiditions. Because the entropy was extremly lower in the past (say, Big Bang) than it is today where all those brains exists, the initial conditions are extremly unlikely, in fact more unlikely than at any later point in time. The prior mechanism is just shaking some elementary particles. If you do this, it is more likely that some form of "brain" pops out than the extremly unlikely initial conditions of the big bang. Only if you get the initial conditions "for free" the cited argument holds, which may be true for the physic of the future. —Preceding unsigned comment added by 92.72.94.97 (talk) 01:25, 30 August 2009 (UTC)

The Big Bang is a lot more than "shaking some elementary particles." I don't even know where to start with that. Also, you assume the Big Bang only happened once, and is not something that keeps happening in separate universes. And you seem to think a brain could exist without a universe existing first? That doesn't make any sense: both situations require a universe existing first. A brain is a highly organized, complex, very low entropy configuration, where the brain that eventually results from natural selection requires starting conditions that do not really need to be all that low in entropy as long as a nice energy source is present. We can already see that stars and planets are not that uncommon, but we have yet to observe anything brain-like. Note: I say "the" brain because the multitude of brains produced is part of the process and thus should not be considered as decreasing the probability. Honestly the whole argument is very silly: if you know how brains work, which requires complex interactions on a fairly large scale, and you are familiar with particle physics which relies on small scale forces, than you know that the mechanism to create some sort of large connected and long-distance-reacting brain out of a cloud of loose, rarely interacting matter is impossible. unless you want to make consciousness without matter??? 141.214.192.96 (talk) 15:27, 28 October 2009 (UTC)

Not the OP, but I think you misunderstand the OP's point. The "shaking some elementary particles" is a reference to what people believed before the notion of a Big Bang was invented. Before the Hubble Constant was observed many people believed that the universe had existed in roughly the same form forever, and that we were currently in a low-entropy fluctuation. If this were the case, though, then the entropy-reversal involved in creating a floating brain out of gas is far smaller (much, much, much smaller) than the entropy-reversal involved in creating a planet orbiting a sun, and so we should expect the former to be much more frequent in the history of the universe. Luckily, current cosmology suggests we ad a Big Bang at some point in the past, and the observed low-entropy state of the universe is a result of that rather than random fluctuations. Current cosmology also suggests a Big Crunch within a mere 100 Billion years last I checked, far less time than we would expect it to take for a Boltzmann Brain to arise due to random fluctuations. It doesn't matter whether there was only one Big Bang or many of them, as long as _a_ Big Bang is responsible for there being stars and planets around instead of just gas (or a big black hole, using more modern science).

To render the whole argument a bit more technical, if you posit that the universe can be adequately described as a Canonical Ensemble that cannot exchange energy with any external source, then Boltzmann Brains are unavoidable. The incompressibility of phase space combined with infinite time mean that every point in phase space will be explored and that every point in phase space will be explored with equal frequency. This means that in infinite time every configuration of particles will occur, and since more configurations of particles correspond to "a brain" than to "a brain and a body" or "a brain and a body and an livable environment" by a huge factor we should expect that Boltzmann Brains will outnumber human brains by a similar factor. All the above totally ignores and might be invalidated by relativity, quantum physics, or nuclear physics - but none of those were around when Boltzmann was creating statistical mechanics, which the idea of a Boltzmann Brain presumably dates back to even if Boltzmann didn't create them. 129.55.200.20 (talk) 19:14, 1 July 2011 (UTC)

References and Criticisms

The article is interesting and useful, though rather speculative, and I further second the above requests for a reference to Boltzmann himself. Also, the main argument is probably incorrect, since it assumes that a selfaware brain could emerge without social interaction. Since all certainly selfaware animals (i.e. humans) have language, selfawareness probably arises only socially. In other words, the intelligence that is needed for selfawareness may only be possible via social interaction (especially, linguistic). Indeed, until we understand what intelligence is, the matter remains obscure. 174.141.81.106 (talk) 12:37, 3 January 2011 (UTC)

You are employing common-sense psychology in a thought experiment that turns on accepting a one-shot thermodynamic counterfactual at the very base of the physics, namely the low-entropy initial condition or fluctuation. But an ambient nebular plasmic Kaspar Hauser, like a typing monkey, might learn English by accident. Say 10^{-1000000000000000000}. The thesis is that this is vastly more likely than the entire low entropy state of solar system, earth, water, iron and rivers that you require for the education of your African village child. The latter process unfolds in a more thermodynamically plausible way once it starts, but its initial condition is far less likely than a single nebular coincidence brain. That is the thesis anyway.178.38.152.228 (talk) 00:14, 21 November 2014 (UTC)

Would the Boltzmann brain be able to be aware of its own existence?

I've always thought that quantum fluctuations, being consequences of the uncertainty principle, have to give back their energy to the vacuum a split second. If quantum mind has scepticisms about anything quantum lasting long enough to effect human cognition, then how is it posited that I might be a Boltzmann brain? In fact exceedingly more likely than not? But anything can form from quantum fluctuations, right? Even so isn't it inevitable that given enough time into the future (if it hasn't happened already, a running and fully operational: human brain, input/output leads for the human brain, pretty self-consistent virtual reality hypercomputer, nuclear reactor for the hypercomputer, Big Tank O' Hydrogen/Fuel Rods/Antimatter ® for the reactor, and a feeding mechanism for the Big Tank O' Hydrogen/Fuel Rods/Antimatter ® pop into existance right next to it's own micro black hole, which strips away every unneeded antiparticle preventing anihilation, making the virtual particles real, and then decays into Hawking radiation to leave behind all of the previous equipment running and that this might be more likely than a whole universe popping up at random? As evidence for this I propose the photo I glanced in the New Yorker of a woman traveling by airplane, purchasing from a hot dog stand etc. completely naked with the caption that nobody seemed to care as proof of this. Sagittarian Milky Way (talk) 00:34, 6 January 2012 (UTC)

the photo I glanced in the New Yorker of a woman traveling by airplane, purchasing from a hot dog stand etc. completely naked with the caption that nobody seemed to care

Please give a link! Or it doesn't exist. 178.38.152.228 (talk) 00:55, 21 November 2014 (UTC)

In answer to the question: Yes, the brain/hypercomputer is more likely than a whole universe, but less likely than a Boltzmann brain. ··gracefool💬 07:12, 29 November 2014 (UTC)

Illogical statements

"The usual resolution of the Boltzmann brain paradox is that we and our environment are the products of a long process of natural selection, which can produce complex and improbable outcomes without violating the laws of thermodynamics." How exactly does evolution theory "resolve" this "paradox" ? How does it prevent these "brains" to come to existence? If there is no logical counter-argument to existence of these brains it should be noted, also it should be pointed out that if universe expansion is accelerating then the occurence of these brains is increasing and chance of concious beings to be Boltzmann's brain rather than anything else is increasing with it. — Preceding unsigned comment added by Mentospech (talk • contribs) 09:58, 13 September 2013 (UTC)

Dubious Claims

"The idea is named for the physicist Ludwig Boltzmann (1844–1906), who advanced an idea that the known universe arose as a random fluctuation in the process of inflation, similar to a process through which Boltzmann brains might arise."

This seems like a pretty dubious claim. In the linked article on inflation, inflation proper was postulated by Alan Guth in the 1980s, and the earliest inflation-like models came about in the 1930s. Boltzmann died in 1906, long before any of this came to fruition. In the (6 year old) discussion below, no sources for this were located

--Necroforest (talk) 04:24, 7 March 2014 (UTC)

Actual counter-argument

If no-one objects, I think we should remove the counter-argument paragraphs. Not only is it uncited, it doesn't actually counter the argument at all. It just states the process of evolution, which is beside the point: The Boltzmann brain is a counter to the anthropic principle, showing that selection bias means we should expect a Boltzmann brain universe rather than our vastly more complex universe. ··gracefool☺ 13:44, 30 May 2014 (UTC)

Sean Carroll resolution

I propose to delete or shorten it since it is not just linked to many-worlds but also makes dubious claims like that quantum fluctuations don't exist without observers (many-worlds is observer independant as far as I know) I that nothing happen inside the wavefunction. It is also heavily criticized by Lubos Motl.Thundergodz (talk) 00:58, 29 April 2015 (UTC)

What is it?

Is it a theory about the origin of God? That should be discussed, and as such this idea should be topic-boxed categorically along with other arguments for the existence of God. Does the term which is the title of this article apply just to Boltzmann's conception, or is there some allowance for expansion as such which keeps the idea alive, to include re-conceiving in the context of string theory, which is the highly validated theory of the fundamental quantum object being something elongated that constitutes everything including spacetime, but wasn't available to Boltzmann. The term "fatal flaw" in the introduction is biased form. -Inowen (nlfte) 09:12, 18 August 2018 (UTC)

responsible use of tags

An IP contributor added a lot of {{cn}} tags. Another contributor removed them all, calling them "ridiculous cn tag bombing". IP contributors can be irresponsible, or simply too inexperienced to do effective editing.

But I think this IP contributor had a valid point. These paragraphs were without references. This IP made a valid point. How many {{cn}} tags did they need? Well, some, at least. Geo Swan (talk) 00:49, 23 June 2019 (UTC)

Mnmh. Well, these were in the lede section. there's a template for tagging entire sections: {{More citations needed section}}, or {{Unreferenced section}} if there're no refs at all. But you wouldn't use those for the lede section: lede sections don't need references (usually), they are supposed to summarize stuff in the body of that article. If the lede does summarize material from the body of the article, but there aren't refs there (in the article body), it is there that you'd tag, using either the inline tags or section tags.

If, on the other hand, the lede says stuff that's not even in the article body, that's a different problem, and there's a tag for that: {{Citation needed lead}} (it says "[not verified in body]", and it's inline, not a section header, so it's used for each statement of fact or each sentence, I suppose. (I suppose you could also use it even if the fact is supported in the body, if the supporting material has no refs and is so tagged)).

And then there's {{More citations needed}}, which goes at the top of the article and tags the entire article as being insufficiently ref'd generally.

Which are needed here, I haven't studied the article, but maybe one of these. Herostratus (talk) 03:35, 23 June 2019 (UTC)

Modern Boltzmann brain problems?

The section with this title does not state what "problems" there are. This renders the text puzzling, at least to some readers (like me). It would be helpful to know what the section is talking about. That should be stated clearly. Zaslav (talk) 05:39, 3 September 2019 (UTC)

I agree. It is never established how this is supposed to present a problem for science and the article loses neutrality and quality around that point. There is not much to extract from Carroll's paper. By page 21 of the paper he makes this admission, complete with real adjectives:

 We can’t claim to have empirical evidence against this disturbing possibility.

Chilly. I had to grab my blankie. The next sentence we get the pie:

 What we can do, however, is recognize that it’s no way to go through life.

So a Boltzmann+ universe is too grimdark for itself. Solid. I would be more concerned over the evil demon they added to the most recent simulation of Carroll's mother.

After reviewing the sources used in this section I can't see that the case is really well made for "the problem", regardless of how passionate and fired up a small group of authors are. Carroll 2017 is probably the most relevant source here. A lot of this article is pulling from commercial media or, you know, a book that has the word CONTROVERSIES in its title.

In the interests of presenting a more neutral view, I have trimmed this particular section and changed the heading to deemphasize that its considered "a problem" generally. Some writers are apparently concerned, that's a more accurate heading. I have digested yarns and most babble is either Carrollesq "too disturbing" or Lloydian "too absurd". Cited both and presented succinctly and plainly exactly their own adjectives as the "reason".

I further add in some mentions comparing this to the basically identical concepts of evil demon, simulation hypothesis, etc. With citation to Carroll who makes this connection himself.

— Preceding unsigned comment added by 14.20*.*.* (talk)

Perceived inconsistency with the simulation hypothesis

I spot a serious inconsistency between the Boltzmann brain concept with the simulation hypothesis.

Assuming a highly compressed (== minimal entropy dip) universe implies the need for a "decompression process" to be "spawned". And identifying that "decompression process" with the "program" in the simulation hypothesis (program = boundary conditions plus generating function - bootstrap compressed - maybe more like an observation consistent equivalence class of programs). That "decompression program" that spawns the whole universe may well require an enormously smaller entropy dip than a single human brain (with all its lifelong experiences) totally cropped out of context from the rest of the universe or any other nontrivial crop-out.

Given that:

• even a few lines of code can generate something as complex as the mandelbrot set and
• even a few hundred MB of DNA can generate something as complex as a human being (looking aside epigenetics the microbiome and other stuff)

This shouldn't be all too surprising.

I think without examples like the two above most people will perceive statements like "the lifelong experiences of a single human may be much more complex than the essence of the whole universe" as illogical, stupid and paradox because of the false human bias of "size equates to complexity".

I could discuss my deeper thoughts on this in more detail here but Wikipedia is not the place for hyper speculative essays. So since I doubt I'm the first one to notice this, maybe someone knows of existing literature that is discussing this topic or has time to look it up and integrate these thoughts plus references into the article.

Login Mechadense (talk) 13:32, 4 December 2019 (UTC)

Identifying oneself as a Boltzmann brain

This content recently rewritten, to be more useful for a reader that has not grasped fully the implications from the technical and dense descriptions given earlier in the article. It has been removed several times now without critical comment or consideration.

The previous content used loaded terminology such as "normal" and "abnormal" observers, especially in a counterfactual and deceptive way. Such content included its sources present that under the conditions of the theory an exceptionally rare experience (that of an actually biological human having a non-spontaneous existence) is a "normal observer" whereas the stastistically probably, far more typical experience (Boltzmann brain) is "abnormal." This is a gross abuse of terminology and only put forth by a very few "writers" on the topic. If anything, the "normal observer" is that which is more common and expected under the supposed conditions.

It is more transparent to just avoid such terms. The reworked content is avoiding using these loaded terms altogether and using instead meaningful terms like "Boltzmann brain" and "non-Boltzmann brain" and "other spontaneously formed entities" which are plain and precise terms for the subject matter.

The previous content in this section is technical and dense, talks about statistics and probabilities, and does not directly address the section topic. It could probably go back in a new section under "Probability" or some such, but itself doesnt add much only rehashing the same statistical analysis that are presented earlier.

The rewrite is less technical, and more pedagogy. It is presented in three sections, using smaller paragraphs and more step-wise flow. None of the material contained therein is not implicit in the technical discussion presented earlier in the article or otherwise the cited material used. It is specifically focused on educated the reader to be able to answer for himself the question whether the subject matter can self-identify, and also points to some relevant edge case and similar concepts implied by the technical-dense content (which may not be apparently obvious) such as: spontaneously formed brains that are not delusional in the way of Boltzmann brains. The inclusion and brief discussion of these similar concepts serves to delineate the subject at hand.

Carroll 2017 is used quite centrally in the replaced material and all over this article, as he is one of the main writers on this topic. It is in this source that we find the claim that Boltzmann brains are "disturbing". The presentation in the cited material implicitly assumes that the reader agrees--that is to say--it is implied that Carroll believes it is already accepted as a given that Boltzmann brains are "disturbing" or similar emotion. Maybe you don't like the funny equating this to "sadder than wet kittens" but its a matter of taste how you want to rephrase and present Carroll's presumptions about the general acceptance here.

Maybe you got a survey where people took a vote on how emotions they feel about being a Boltzmann brain?

— Preceding unsigned comment added by 14.20*.*.* (talk)

"Creation'"

Please don't continue calling the section like "creation" and using this word. Boltzmann brain are not created by anyone, it is proposed that they arise spontaneously by fluctuation or similar mechanism. This is not the same as an act of creation or something and I mentioned that several times in the "edits summary" when I change it recently which people are renaming it back.

Like, if a person keeps renaming something back to use a loaded term like "creation" and not say why then it makes you look like you are using prejudice terms and inserting them deliberately to push a special agenda. At least say why you dont think the reasons which I wrote in my own edit summary.

Seriously

This is not called creation in English because this is a verb which has a subject person or agent that is to do the creating. I dont think any consensus that a universe is something which could do creating (you have sources?) just like a bucket doesnt do that either. Sorry, am I wrong? Why do you keep changing this to say creation again I just do not understand.

I change it back once more. If you think it should be called creation maybe you can write on the talk page why you think that. Then everyone can see what your reasons are and they can see also my reasons because I already wrote them.

Actually I will create a place for you to write your reasons write here:

YOUR_REASONS_PLEASE

— Preceding unsigned comment added by 14.20*.*.* (talk)

Are/aren't and other problems in the last paragraph

The last paragraph/sentence currently states "in a Boltzmann-dominated Universe, most Boltzmann brains have "abnormal" experiences, but most observers with only "normal" experiences are Boltzmann brains". This doesn't make a lot of sense. I couldn't read the full source, but the abstract puts it in the terms "most Fs are Gs, this is an F, so it’s probably a G; because I also know this F is an FH, and most FHs are not Gs..." (shortened a bit). I thought this could be fixed by replacing "are" with "aren't", but the follow up also seems oversimplified to the point of being simply wrong (the amount of Boltzmann brains with "abnormal" experiences and their ratio to brains with "normal" experiences supports the argument, the overall number still works in the opposite direction). Personuser (talk) 06:13, 3 June 2021 (UTC)

"... remain only long enough to have a single coherent thought or observation, and then disappear into the vacuum as suddenly as it appeared"

No, it would not have any coherent thought, it would disappear in $10^{-23}$ seconds, right? Zalán Hári (talk) 10:50, 7 April 2023 (UTC)

The citation abstract says "last at least long enough to think a few thoughts". Do you have some citation that says otherwise? The whole thing is theoretical anyways, is it not? Richard-of-Earth (talk) 02:39, 9 April 2023 (UTC)

There is a formula: https://math.ucr.edu/home/baez/uncertainty.html. Δ$H$ should be greater than 938 MeV, because the brain must contain protons, and the energy from mass of a proton is 938 MeV . It is approximately $1.5\cdot 10^{-10}$ joule. The half of the Planck constant is approximately $3.313\cdot 10^{-34}$ .${\frac {3.313\cdot 10^{-34}}{1.5\cdot 10^{-10}}}$. Its order is $10^{-23}$. Zalán Hári (talk) 04:17, 10 April 2023 (UTC)

Okay, well thanks for bringing it to our attention, however, you need to look at WP:OR. Someone needs to write a paper about that and get it published in a peer-reviewed journal and then we might consider adding it to the article. Until then, we should stick to what the already published reference says. That said, it looks like the cited article is a pre-print that was not peer-reviewed nor published in a journal, so we could be justified in removing the whole section, That is, if you feel the section is misinformation. I do not mind it being there, myself. Richard-of-Earth (talk) 07:15, 10 April 2023 (UTC)

Sorry, the original resource rule of the Hungarian Wikipedia (where I mostly edit) is a less strict rule, I did not know it. Zalán Hári (talk) 08:03, 10 April 2023 (UTC)

References

Modern reactions to the Boltzmann brain problem

I was confused by the possible error referred to in the first sentence of this section. An error in what exactly? Our model of the universe, I assume, but could this be made less vague? Apologies if this the wrong forum or format. DCT667 (talk) 09:08, 8 July 2023 (UTC)

Fallacy?

The concept of a Boltzmann Brain as usually presented has, in my opinion, as serious shortcoming. Suppose that a human brain fluctuates into existence in a void, viz. in the vacuum of space. An implicit assumption is that it is indeed only a brain; there is no supporting mechanism for perfusion (like the human heart) or protection (like the human skull). Assume furthermore that the brain i) is at normal body temperature (37°C), ii) is perfused with normally oxygenated blood, and iii) has no open blood vessels through which blood could leak out. While such a brain would be 'alive' and able to think, and would not instantly freeze upon materializing, it would, in the absence of blood circulation, very soon run out of oxygen; the Wikipedia article on Brain ischemia mentions that consciousness would be lost after 10 seconds. The conscious entity associated with the brain would therefore barely be able to think "Huh?" before going extinct. Since the entity would have no time for any contemplation of significance, the statement, mentioned in this article, that 'statistically, humans are likely to be wrong about their memories of the past and in fact are Boltzmann brains' cannot be correct. A somewhat more interesting concept would be a Boltzmann Astronaut - a spontaneously materialized living human being inside a space suit equipped with a life support system; such an unenviable astronaut would at least have some time to live and contemplate their circumstances. Kees van Zon (talk) 19:49, 18 March 2024 (UTC)

@Kees van Zon: Perhaps, but this talk page is not a forum. See WP:NOTAFORUM. Can any of this be supported by a citation? Would adding it improve that article? If so, what change to the article would you make? Richard-of-Earth (talk) 01:14, 22 March 2024 (UTC)

@Richard-of-Earth:: the key fact is the brain running out of oxygen, mentioned in the linked Brain ischemia page (which has citations). The rest follows logically, except for the Boltzmann astronaut, which is an opinion/suggestion. Adding this remark may indeed improve the article. It could e.g, be phrased as follows. "If a brain were to fluctuate into existence in the vacuum of space, it could not survive for long if it is indeed only a brain, i.e., if there is no supporting mechanism for perfusion (like the human heart) or protection (like the human skull). Assuming that the brain i) is at normal body temperature (37°C), ii) is perfused with normally oxygenated blood, and iii) has no open blood vessels through which blood could leak out, the brain would be 'alive' and able to think. While it would not instantly freeze upon materializing, it would, in the absence of blood circulation, very soon run out of oxygen; the article on Brain ischemia mentions that consciousness would be lost after 10 seconds. The conscious entity associated with the brain would therefore barely be able to start thinking before going extinct. Since the entity would have no time for any contemplation of significance, the view that 'statistically, humans are likely to be wrong about their memories of the past and in fact are Boltzmann brains' can therefore not be correct."

Kees van Zon (talk) 00:46, 3 April 2024 (UTC)

Again, perhaps what you say is true, however we will not be adding this to the article without you first presenting a reliable source that mentions these conclusions. Please see WP:OR and WP:V and WP:RS. Any information in Wikipedia articles is suppose to be derived from published sources and presented from a neutral point of view. We also avoid presenting a synthesis of published material to imply a new conclusion, because that is original research. See WP:SYNTH. Even if you found some obscure article that explored this reasoning, it would be considered a WP:FRINGE view and most likely not be suitable to include in the article. If you wish to find someone to discuss yours, theirs, or anyone's ideas about Boltzmann brains, you should find a forum orientated site like Reddit. Richard-of-Earth (talk) 03:22, 3 April 2024 (UTC)