Talk:Boltzmann brain

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Contents 1 Tags require talk page comment 2 Shouldn't Darwinian evolution come into this? 3 New Scientist 4 Decartes 5 references

[edit] 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)

[edit] 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)

[edit] 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)

[edit] Decartes

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)

[edit] 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)