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#53966 - 06/07/15 02:43 AM How about Quantum Gravity
Bill Offline
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Ethan Siegel has a review of some of the current contenders for a theory of Quantum Gravity on his blog Starts With A Bang. The review is found at Ask Ethan #91: Does Quantum Gravity Need String Theory?. I'm not going to try to interpret what he says. He gives a quick overview of 5 different ideas which are currently being investigated. Interesting for any body interested in the subject.

Bill Gill
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#53969 - 06/08/15 02:50 PM Re: How about Quantum Gravity [Re: Bill]
Orac Offline
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Ethan just proved he is completely out of his depth and has just written an what can only be described as a typical glossy science media garbage that is at it's heart completely wrong in almost every way possible. It wasn't just bad on one thing it was bad on everything smile

You might want to read just one analysis of Ethan's masterpiece
http://motls.blogspot.com.au/2015/06/ethan-siegels-misconceptions-on-quantum.html

LM was actually uncharacteristically kind I know a few who went well beyond that.

Dilaton's posted comment about what Ethan did is about exactly spot on. Ethan's work on cosmology is first class his work on theoretical physics not so much laugh


Edited by Orac (06/08/15 02:56 PM)
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#53970 - 06/08/15 05:23 PM Re: How about Quantum Gravity [Re: Bill]
pokey Offline
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This article had the word "gravity" in it:

http://www.scienceagogo.com/news/20150428025743.shtml

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#53971 - 06/08/15 05:53 PM Re: How about Quantum Gravity [Re: Orac]
Bill Offline
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My Motl sure got carried away. A relatively short article by Ethan Siegel requires a huge article to rebut it line by line. He seems to be totally dedicated to String Theory. He reacts to any suggestion that String Theory might not be right as if it was an attack on his god. It is kind of like a religious authority (RA) who has had some small part of his belief system questioned. An RA in that condition will respond to a small question with an impassioned sermon about the absolute correctness of his/her belief. A brief statement to address the question is not deemed to be sufficient. For example consider the Catholic Churche's response to Martin Luther's questions about Church doctrine.

Then of course he completely denies that any of the other areas of investigation into a theory of Quantum Gravity have any value. This seems to be in complete disagreement with what I have been seeing more and more often. That a scientist should always entertain the idea that she/he might be wrong. A real scientist should always doubt her/his beliefs. If he/she doesn't look for things that would disprove what she/he knows to be right then he/she can easily lead her/him self down the wrong path. I'm afraid a lot of String Theorists have fallen down in this respect. Of course the fact that string theorists seem to have gotten a lock on the physics departments of many American universities can lead to this sort of an attitude. It doesn't leave much place for other ideas to be considered.

Bill Gill
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C is not the speed of light in a vacuum.
C is the universal speed limit.

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#53972 - 06/09/15 07:09 AM Re: How about Quantum Gravity [Re: Bill]
Orac Offline
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And for once I almost agree with you Bill smile

Personally I like to consider all options but then there a experimental results which rule things in and out.

As I said I don't think LM gets everything right but his understanding is lets just say a hell of a lot better than Ethan's. What I will say is at least LM got the basics facts and experiment results right.

You like your consensus in science well it's definitely closer to LM's than Ethan but cooler on the string's. Ethan's article could have been written in the seventies that is how out of date it is. There were a few comments that the founder of Asymptotic safe gravity Steven Weiberg conceded the idea was dead but I have not personally seen it, last I knew he was still beating it up and if I get time I will follow that up.

As I said it was just a really bad article I was expecting Matt Strassler to raise a few eyebrow's over it as well.


Edited by Orac (06/09/15 08:00 AM)
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#53973 - 06/09/15 10:29 AM Re: How about Quantum Gravity [Re: Orac]
Orac Offline
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One of the funnier postings about the whole issue and tone of the article

"Some prefer actually correct to political and/or attitude correct. Those who prefer not thinking but like polite, wrong and dumb have so many choices. Those who feel a nicer tone is needed probably should go to those sites because the wrong included is more offensive than the attitude expressed"
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#53974 - 06/09/15 01:03 PM Re: How about Quantum Gravity [Re: Orac]
Bill Offline
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Originally Posted By: Orac
As I said it was just a really bad article I was expecting Matt Strassler to raise a few eyebrow's over it as well.

As I recall Matt has some doubts about String Theory as well. He did say that they had developed some wonderful mathematical tools for use in other aspects of QM.

Bill Gill
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C is not the speed of light in a vacuum.
C is the universal speed limit.

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#53975 - 06/10/15 02:57 AM Re: How about Quantum Gravity [Re: Bill]
Bill Offline
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And another country heard from. Sabine Hossenfelder has an interview with Lee Smolin on Ethan's Starts With a Bang blog.
The Road Less TraveledÖ To Quantum Gravity
An interview with theoretical physicist Lee Smolin.


I assume that Lee Smolin, who has been active in research on Quantum Gravity for many years, is not an acceptable spokesman for your taste Orac?

Bill Gill
_________________________
C is not the speed of light in a vacuum.
C is the universal speed limit.

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#53976 - 06/10/15 08:40 PM Re: How about Quantum Gravity [Re: Bill]
Bill S. Offline
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To the uninitiated, i.e. me, Smolin's responses seem well balanced and interesting, even if I don't understand all of them.

I recently came across an Einstein quote which seems relevant.

"Because of the intra-atomic movement of electrons, the atom must radiate not only electromagnetic but also gravitational energy, if only in minute amounts. Since, in reality, this cannot be the case in nature, then it appears that the quantum theory must modify not only Maxwell's electrodynamics but also the new theory of gravitation. (Einstein 1916).

I wonder if the informed view of intra-atomic movement is the same now as it was in 1916.
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#53980 - 06/11/15 12:43 PM Re: How about Quantum Gravity [Re: Bill]
Orac Offline
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Originally Posted By: Bill
I assume that Lee Smolin, who has been active in research on Quantum Gravity for many years, is not an acceptable spokesman for your taste Orac?

Bill Gill


You would be correct Bill G he is a first class crackpot and don't get me started about his last book. That may be too harsh, maybe he just found the good drugs in his studies as his early work was semi ok. He hasn't quite reached the Sean Carroll levels but running fast and hard to get there.

Hey but he can put a good article together for the the glossy science magazines so it must be science worthy .. right smile

Oh BTW in the amazon reviews of his last book it most gets 1 star which is 1 more than I give it.

http://www.amazon.com/Time-Reborn-Crisis...howViewpoints=0

The most accurate customer review of his last book was this one

Quote:
Reading this tedious tome, which is distinguished only by its utter worthlessness, one cannot help but be struck by the fact that Lee Smolin actually has the credentials of a legitimate physicist.

This lamentable affront cannot even claim the dignity of masquerading as an understandably failed attempt at explaining modern physics to laymen. Instead, all we have is a disconnected, rambling discourse combining equal measures of dreary doubletalk and philosophical twaddle. The only coherent notion, that the laws of physics might actually change with time, is not only one that has been expressed far better by many previous authors but one that is almost completely obscured by the morass of metaphysical gibberish.

This book should have been published on a perforated roll.

What exceeded my expectation is the number in the reviewers who realize the guy is a crackpot and the book complete dribble which I guess means education is improving on these things.

Interesting Sabine interviewed him on his 2001 book not his latest smile

The question that springs to my mind is how many drugs were taken in the period between the books.

So I guess I should ask is Lee Smolin a good scientist on the science of Quantum Gravity to you Bill G? You seem to intimate that people including me should respect this guy smile


Edited by Orac (06/11/15 02:05 PM)
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#53981 - 06/11/15 05:03 PM Re: How about Quantum Gravity [Re: Bill]
Bill S. Offline
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Orac, your quote in red says two things to me:

This chap didn't like the book.

If the book has upset someone that much, it might be worth a look.
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#53982 - 06/12/15 01:56 AM Re: How about Quantum Gravity [Re: Orac]
Bill Offline
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Well, you don't give an attribution for the quote. Was the review by a String Theory True Believer? The fact that Smolin is a professor of physics does seem to give him some credibility. Particularly when he is just giving a short overview of a number of different ideas which are being investigated. Please note: I said "which are being investigated". If a proposal is being investigated you have to provide some proof that it is wrong before you start running off about its total lack of credibility. I expect that some or all of them are wrong. Until somebody comes up with a theory that can be fully tested I am certainly not going to accept any body's word that any of them is junk.

String Theory may be a really beautiful theory, but beauty in physical theories is not a clear indication of truth. The Ptolemaic model is a beautiful theory that describes the motion of the planets in good detail. It is wrong. So String Theory may be wrong, no matter how beautiful it is. I personally have very little faith in it, but that doesn't mean it is wrong, it just means that I don't like it.

Personally I think that both space and time are probably quantized. That isn't based on any great knowledge, just a feeling that since everything else seems to be quantized then space and time should match.

Bill Gill
_________________________
C is not the speed of light in a vacuum.
C is the universal speed limit.

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#53984 - 06/12/15 07:54 AM Re: How about Quantum Gravity [Re: Bill]
Orac Offline
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The quote comes from number 35

http://www.amazon.com/Time-Reborn-Crisis...howViewpoints=0

It is attributed to William R. Franklin "Illuminatus" VINE VOICE on February 26, 2013

I have no idea what the guy believes or who is is but he is spot on the money IMO ... you probably see it very different smile


Edited by Orac (06/12/15 07:55 AM)
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#53986 - 06/12/15 01:28 PM Re: How about Quantum Gravity [Re: Orac]
Bill Offline
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Yes I see it very differently, at least in regard to attacks on lists of possible areas of research into quantum gravity. As long as there is no approach that provides an adequate and tested theory then just declaring that all theories except the most studied one are junk is unjustified. If String Theory really provided testable results then it might be more favored among people who are not True Believers, but it doesn't. So until it can then people should be encouraged to try to come up with new ideas that may provide a better description of how the universe works.

So the lists of areas of research into quantum gravity are completely valid. The approaches may not wind up going any where, but listing them is a completely valid exercise and can be useful to people who are not actively working in the field. I assume people who are working in the field already know about the different approaches. Those people can do a better job of evaluating the value of those approaches, and while they are doing it they should always keep in mind that their preferred approach may be wrong. Most scientists at least give lip service to the idea that even settled areas of research may be wrong. In an area that isn't settled they should admit that there is a strong likelihood that they are wrong.

Bill Gill
_________________________
C is not the speed of light in a vacuum.
C is the universal speed limit.

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#53987 - 06/12/15 02:45 PM Re: How about Quantum Gravity [Re: Bill]
Orac Offline
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So people should keep investigating crackpot ideas that can be shown to be trivially false by a number of experiments .... hmmmm interesting concept.

Calling Marosz .... explain your idea to Bill again ... he needs pages and pages of drawings please and lots on new experiments you built out of lego on the kitchen table smile

Originally Posted By: Bill G
the approaches may not wind up going any where, but listing them is a completely valid exercise and can be useful to people who are not actively working in the field.

The real answer is even with greats like Einstein we trivially ignore some of there theories and ideas because we know they are trivially wrong due to later results.

Lee Smolin may once have had valid ideas but all his ideas are long washed up on the scrapheap of experimental results, you may care to do some reading. He has one last theory still standing that inflation is caused by the simplest field and what he is short on is what this field is. I would argue that it is not even really a unique idea because I have seen it suggested indirectly by many. Every other theory and idea he has contributed is dead like a Norwegian Blue.

Unfortunately getting Lee Smolin to explain the current state of physics seems a bit to me like asking Einstein to explain Quantum Mechanics back in his day ... given what they believe you might get some half truths and it will be entertaining smile

For what it's worth at the level you are prepared to read I stick with Prof Matt Strassler.


Edited by Orac (06/12/15 03:29 PM)
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

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#53989 - 06/12/15 06:08 PM Re: How about Quantum Gravity [Re: Orac]
Bill Offline
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Ok, let's take this one step at a time. Please answer the following question.

Do you believe that String Theory is correct?

Bill Gill
_________________________
C is not the speed of light in a vacuum.
C is the universal speed limit.

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#53990 - 06/12/15 11:22 PM Re: How about Quantum Gravity [Re: Bill]
Bill Offline
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And another item from Sabine Hossenfelder. She has a post on her BackReaction blog Where are we on the road to quantum gravity?

Bill Gill
_________________________
C is not the speed of light in a vacuum.
C is the universal speed limit.

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#53991 - 06/13/15 02:53 AM Re: How about Quantum Gravity [Re: Bill]
Orac Offline
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Originally Posted By: Bill
Ok, let's take this one step at a time. Please answer the following question.

Do you believe that String Theory is correct?

Bill Gill

Nope I don't think it is correct but nor do I think it is dead and possibly it will kick on for years yet and that is fine as it isn't definitively dead. Again that is a personal view nothing more, nothing less. I liked the ideas a few years ago but would have expected different results and so have cooled on the idea.

An interesting question to ask is when does a scientist become what I call a crackpot. My answer would be when they refuse to accept results because they don't like them or they are at odds with there theory yet they have no alternative answer.

Einstein did not like the implications of QM, his objections were fine in the 1920's but by the late 1930's and then the 40's I probably would have called him a crackpot. It's hard historically because I wasn't there to see what he said and you always wonder how accurately the media got his views.

You don't like Lubos but he is operating in a small window that is still valid and hasn't moved yet into the crackpot status. I haven't ever seen him say he won't or doesn't believe something and he accepts results and as long as he does that he is fine with me. He operates in that area you sort of discussed legitimate alternative ideas.

I actually am quite interested in this idea at the moment
https://www.quantamagazine.org/20150527-a-new-theory-to-explain-the-higgs-mass/

Not saying it is correct or anything remotely like that but it's an interesting new approach.


Edited by Orac (06/13/15 02:54 AM)
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

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#53992 - 06/13/15 03:04 AM Re: How about Quantum Gravity [Re: Bill]
Orac Offline
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Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
Originally Posted By: Bill
And another item from Sabine Hossenfelder. She has a post on her BackReaction blog

I love her honesty she hasn't a clue what to do with Quantum Gravity next but just not string theory please smile

Interesting she actually is thinking along lines I once posed to you and got a certain reaction from
Quote:
For me the most interesting theoretical developments in quantum gravity are the ones Lee hasnít mentioned. There are various emergent gravity scenarios and though I donít find any of them too convincing, there might be something to the idea that gravity is a statistical effect.

That is techno speak for the the fact gravity isn't a quantum effect at all and so you better go set her straight Bill G, Quantum Gravity has to exist doesn't it because it's in Bill's box laugh
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I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

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#53993 - 06/13/15 01:05 PM Re: How about Quantum Gravity [Re: Bill]
Bill Offline
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Registered: 12/31/10
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I keep being absolutely astounded by Orac. Whatever I say I am wrong. I can even recall a couple of years ago when I said that I had just realized that the 'magic' in the quantum entanglement was based on conservation laws. Orac immediately pointed out that I was an idiot and didn't understand anything. We went on for several pages of back and forth until he explained it clearly for me. He explained that it is based on conservation laws. I'm glad he finally got me set straight on that. I might otherwise have gone on thinking it was based on conservation laws.

He apparently is setting out to do it again. I provided a link to a brief discussion of various areas of research into quantum gravity. And now I don't know anything about the subject. I didn't claim to be an expert. I was just trying to provide some insight into what is going on in the field, using information from somebody who is more familiar. When I provide more links he jumps all over those as being totally worthless. Well, I guess he gave a qualified approval to Sabine's article. But the only thing that I saw in that article was a couple of references to more extremely poorly supported research efforts.

It also seems that Orac only believes in non-quantum gravity. I hope he figures out how it works before long.

Bill Gill
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C is not the speed of light in a vacuum.
C is the universal speed limit.

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