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Emergent Space-Time: a Category Mistake
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Pentcho Valev
2017-11-29 08:06:15 UTC
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Edward Witten: "I tend to assume that space-time and everything in it are in some sense emergent. By the way, you'll certainly find that that's what Wheeler expected in his essay. As you'll read, he thought the continuum was wrong in both physics and math. He did not think one's microscopic description of space-time should use a continuum of any kind - neither a continuum of space nor a continuum of time, nor even a continuum of real numbers. On the space and time, I'm sympathetic to that." https://www.quantamagazine.org/edward-witten-ponders-the-nature-of-reality-20171128/

My comment in Quanta:

"Emergent space-time" is a category mistake. Specetime has already emerged - it is a deductive consequence of Einstein's constant-speed-of-light postulate:

"Special relativity is based on the observation that the speed of light is always the same, independently of who measures it, or how fast the source of the light is moving with respect to the observer. Einstein demonstrated that as an immediate consequence, space and time can no longer be independent, but should rather be considered a new joint entity called "spacetime." http://community.bowdoin.edu/news/2015/04/professor-baumgarte-describes-100-years-of-gravity/

Anything deduced from different premises would fall in a different category and would have nothing to do with Einstein's spacetime - combining the two concepts would be absurd. For instance, bringing granularity to spacetime is equivalent to painting spacetime in yellow. If the original concept of spacetime is unacceptable and should be replaced, then the underlying premise, Einstein's constant-speed-of-light postulate, is false and should be abandoned. The step is unavoidable if logic is obeyed.

Pentcho Valev
Pentcho Valev
2017-11-29 14:13:57 UTC
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Nima Arkani-Hamed (06:09): "Almost all of us believe that space-time doesn't really exist, space-time is doomed and has to be replaced by some more primitive building blocks."


Any substitute for spacetime that emerges from "some more primitive building blocks", that is, is deduced from premises different from the principle of relativity and the constancy of the speed of light, has nothing to do with Einstein's spacetime. The two fall in different categories. The new "spacetime" could replace the old one, but then the rejection of Einstein's spacetime would entail that at least one of Einstein's 1905 postulates is false.

Pentcho Valev
Pentcho Valev
2017-11-30 08:19:08 UTC
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Marcelo Gleiser: "The challenge is to somehow bring the notion of granularity to spacetime, bring the discrete to the continuous. This is the problem that has baffled theoretical physicists for at least half a century." http://radio.wpsu.org/post/reality-not-what-we-can-see

This is insane. Spacetime is not an ab initio model that one can modify, e.g. by introducing granularity. It is a DEDUCTIVE CONSEQUENCE of Einstein's constant-speed-of-light postulate, and if the consequence is unacceptable, the postulate is false (logic forbids the combination "true postulate, unacceptable consequence"). In other words, you cannot "retire" Einstein's spacetime without declaring the postulate false:

What scientific idea is ready for retirement? Steve Giddings: "Spacetime. Physics has always been regarded as playing out on an underlying stage of space and time. Special relativity joined these into spacetime... [...] The apparent need to retire classical spacetime as a fundamental concept is profound..." https://www.edge.org/response-detail/25477

Pentcho Valev
Pentcho Valev
2017-11-30 19:30:17 UTC
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Whether spacetime is emergent or not is, in a sense, a red herring - there is an underlying "root of all the evil" that is fatal for theoretical physics as a whole. See comments here:

A Physicist's Physicist Ponders the Nature of Reality
https://www.quantamagazine.org/edward-witten-ponders-the-nature-of-reality-20171128/

jimh (comment): "...my interpretation of Special Relativity is a little different: rather than saying that the "speed" of light is constant, it says that any observer's measurement of that speed will be the same."

My reply:

Yes, special relativity does say that "any observer's measurement of that speed will be the same" but even Einstein knew that this is nonsense:

John Stachel: "But this seems to be nonsense. How can it happen that the speed of light relative to an observer cannot be increased or decreased if that observer moves towards or away from a light beam? Einstein states that he wrestled with this problem over a lengthy period of time, to the point of despair." https://history.aip.org/history/exhibits/einstein/essay-einstein-relativity.htm

When you start moving towards the light source, the wavecrests start hitting you more frequently - the frequency you measure increases. This can only mean that the speed of the light relative to you increases as well - there is no other reasonable cause for the increased frequency:

"Doppler effect - when an observer moves towards a stationary source. ...the velocity of the wave relative to the observer is faster than that when it is still."


"Let's say you, the observer, now move toward the source with velocity Vo. You encounter more waves per unit time than you did before. Relative to you, the waves travel at a higher speed: V' = V+Vo. The frequency of the waves you detect is higher, and is given by: f' = V'/λ = (V+Vo)/λ." http://physics.bu.edu/~redner/211-sp06/class19/class19_doppler.html

"Vo is the velocity of an observer moving towards the source. This velocity is independent of the motion of the source. Hence, the velocity of waves relative to the observer is c + Vo. [...] The motion of an observer does not alter the wavelength. The increase in frequency is a result of the observer encountering more wavelengths in a given time." http://a-levelphysicstutor.com/wav-doppler.php

The following quotations suggest that theoretical physics is dead because it is based on Einstein's nonsense:

"The speaker Joao Magueijo, is a Reader in Theoretical Physics at Imperial College, London and author of Faster Than the Speed of Light: The Story of a Scientific Speculation. He opened by explaining how Einstein's theory of relativity is the foundation of every other theory in modern physics and that the assumption that the speed of light is constant is the foundation of that theory. Thus a constant speed of light is embedded in all of modern physics and to propose a varying speed of light (VSL) is worse than swearing! It is like proposing a language without vowels." http://www.thegreatdebate.org.uk/VSLRevPrnt.html

"...Dr. Magueijo said. "We need to drop a postulate, perhaps the constancy of the speed of light." http://www.nytimes.com/2002/12/31/science/e-and-mc2-equality-it-seems-is-relative.html

"But the researchers said they spent a lot of time working on a theory that wouldn't destabilise our understanding of physics. "The whole of physics is predicated on the constancy of the speed of light," Joao Magueijo told Motherboard. "So we had to find ways to change the speed of light without wrecking the whole thing too much." http://www.telegraph.co.uk/technology/2016/12/06/speed-light-discovered/

Joao Magueijo, Faster Than the Speed of Light, p. 250: "Lee [Smolin] and I discussed these paradoxes at great length for many months, starting in January 2001. We would meet in cafés in South Kensington or Holland Park to mull over the problem. THE ROOT OF ALL THE EVIL WAS CLEARLY SPECIAL RELATIVITY. All these paradoxes resulted from well known effects such as length contraction, time dilation, or E=mc^2, all basic predictions of special relativity. And all denied the possibility of establishing a well-defined border, common to all observers, capable of containing new quantum gravitational effects." http://www.amazon.com/Faster-Than-Speed-Light-Speculation/dp/0738205257

Pentcho Valev
Pentcho Valev
2017-12-01 11:12:54 UTC
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Friday, December 1, 2017: The Doom of Spacetime - Why It Must Dissolve Into More Fundamental Structures. Nima Arkani-Hamed, Professor, The Institute for Advanced Study, Princeton, and A. D. White Professor-at-Large, Cornell University https://www.meetup.com/philsoc/events/244673165/

Nima Arkani-Hamed (06:09): "Almost all of us believe that space-time doesn't really exist, space-time is doomed and has to be replaced by some more primitive building blocks."x http://youtu.be/U47kyV4TMnE

That's great, breathtaking, but the nonexistent spacetime is a consequence of Einstein's constant-speed-of-light postulate:

"Special relativity is based on the observation that the speed of light is always the same, independently of who measures it, or how fast the source of the light is moving with respect to the observer. Einstein demonstrated that as an immediate consequence, space and time can no longer be independent, but should rather be considered a new joint entity called "spacetime."x http://community.bowdoin.edu/news/2015/04/professor-baumgarte-describes-100-years-of-gravity/

Logic forbids the combination

"true postulate, nonexistent consequence"

so Nima Arkani-Hamed, if he obeys logic, will have to conclude that Einstein's constant-speed-of-light postulate is false.

Another problem. There are ripples in the nonexistent spacetime gloriously discovered by LIGO conspirators. Nima Arkani-Hamed will have to declare that LIGO conspirators are fraudsters and face the retaliation of LIGO godfathers.

Pentcho Valev

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