Blog Wars: Woit and Smolin vs Motl

  • Thread starter Thread starter Bohr_Wars
  • Start date Start date
  • Tags Tags
    Blog
  • #61
Josh,
The way you put it, no it's not odd at all. As you say, the theory/theories with claims to be the TOE are going to be of interest because they'll provide the foundation on which everything else is built. How much we understand of those theories is another matter.
 
Physics news on Phys.org
  • #62
turbo-1 said:
This is an important concept IMO, that is often overlooked. The universe does what it does regardless of whether we are here or not, and just because we humans overlay coordinate systems on it in order to try to express what it does in mathematical terms, that should not imply that the coordinate system has some sort of independent reality or importance, apart from the theory that requires its implementation in order to be predictive.
You have to be very careful here : (a) when we do observations, we always endow coordinates with a *physical* meaning, that is we image our x,y,z axis to be *straight* lines with respect to an imaginary Minkowskian geometry, we can also put a priori restrictions upon the conformal factor (e.g. put it = 1 in these coordinates) of the ``real geometry'' for example ...
(b) Of course, the relational laws expressing our *observations* should be the same no matter which coordinate system has been chosen (but this invariance does not need to be *manifestly* present). However this does not preclude one from considering one coordinate system more real than another one (and rebuild the theory from there).

The whole ``quarrel'' is about wheter general covariance is something trivial or whether it is not : it goes between a worldpicture of spacetime atoms carrying non local relations amongst themselves and a picture of atoms traveling on a continuous background geometry. The thing is that the only more or less rigorous *classical* proposal for space time atoms that I am aware of and which recovers GR (at low energies) in a convincing way comes out of condensed matter physics (which uses a background).
 
Last edited:
  • #63
Long as it works, any coordinate system is fine. If they can't be interchanged, the problem is with the coordinate system, not physical reality.
 
  • #64
Chronos said:
Long as it works, any coordinate system is fine. If they can't be interchanged, the problem is with the coordinate system, not physical reality.

The point is that any theory can be made manifestly covariant, manifest covariance simply requires extra ``gauge degrees of freedom'' which results into constraints and into people wondering whether it is impossible to give an objective status to the evolution of the universe and whether the theory only allows for expressing relations between partial observables. On the other hand, the funny thing is that LQG as it stands now, does not even make proper work of the spacelike diffeomorphisms : although one does not meet the difficulty here that the constraints only generate diffeomorphisms on shell (such as is the case for the H constraint) and therefore diffeo invariance can be implemented at the kinematical level, one still needs implement the constraint itself (which is impossible since the action of the diffeo group is discontinuous).
 
  • #65
Careful said:
The point is that any theory can be made manifestly covariant, manifest covariance simply requires extra ``gauge degrees of freedom'' (...)

Dear Careful,

I have read recently this paper by Weinstein

http://philsci-archive.pitt.edu/archive/00000834/

What do you think of his interpretation? He makes an interesting point, but it seems like there could be some contra-argumentation. I`m not sure. I appreciate any inputs.

(Perhaps we should start a new thread on this?)


Christine
 
  • #66
ccdantas said:
Dear Careful,

I have read recently this paper by Weinstein

http://philsci-archive.pitt.edu/archive/00000834/

What do you think of his interpretation? He makes an interesting point, but it seems like there could be some contra-argumentation. I`m not sure. I appreciate any inputs.

(Perhaps we should start a new thread on this?)


Christine

Dear Christine,

I just gave one brief look so I might be wrong here : but I suppose the main criticism will be that gravity is not a gauge theory in the sense of what we usually mean with this (defined through fibre bundles). If I am correct, you should know that I agree here (all strict gauge theoretical attempts require the introduction of torsion - arriving therefore at Einstein Cartan theory which is not a bad thing btw), that is why I put ``gauge degrees of freedom'' between brakets. If you want to know what I actually was talking about, you might want to study the paper of Doran, Gull and Lasenby : ``Gravity, gauge theories and geometric algebra'' gr-qc/0405033.
 
Last edited:
  • #67
Careful said:
If you want to know what I actually was talking about, you might want to study the paper of Doran, Gull and Lasenby : ``Gravity, gauge theories and geometric algebra'' gr-qc/0405033.

Thanks for the reference, I'll read it.


Christine
 
  • #68
Last edited by a moderator:
  • #69
George Jones said:
You might want to look at https://www.physicsforums.com/showthread.php?t=164352".

Indeed, in the Doran, Gull and Lasenby paper, there is a clear separation between the usual local rotation symmetry and the nonlocal ``translation symmetry''. However, there is a large number of other benefits to it which are not mentioned in the post you refer to.
 
Last edited by a moderator:
  • #70
ccdantas said:
One thing that I find obvious, but it is my personal view of course, is that the debate is not about winners and losers. It's mostly about a fight for limited resources, and how the scientific activity is conducted in our era.

This is certainly part of the story. But, I think some of the anger surrounding the string wars comes from the desperation many theoretical physicists feel when it comes to making progress on big issues like the unification of forces and the quantization of gravity.

People have invested their whole careers in string theory and loop quantum gravity. Decades have gone by without any clear payoff in experimental results. Lots of good math, but no experimental confirmation! This makes people scared, and unhappy... and now, I think, it's making them fight.

Note how little fighting of this sort we see in cosmology, where people are making wonderful discoveries left and right: dark matter, dark energy, hints of inflation in the cosmic microwave background radiation.

I ran a blog during one year and I felt myself suddenly in the middle of war that made no sense to me and I got tired, bored, and lost sleep. Yes, blogs amplify things.

Blogs provide a brand new forum for uninhibited and often anonymous fighting, just at a time when a bunch of physicists are getting desperate and miserable... it's a flammable combination.

Like you, I got sick of these fights. They helped convince me it was time to stop working on quantum gravity and focus on math.

For a long time these fights also kept me from starting a blog. But then, thanks to Urs Schreiber, I realized it's possible to have a pleasant and interesting blog, by keeping it technical and avoiding controversy.

It's a pity I have to avoid writing about controversial topics just to avoid fights. But, it's worth it.
 
  • #72
john baez said:
This is certainly part of the story. But, I think some of the anger surrounding the string wars comes from the desperation many theoretical physicists feel when it comes to making progress on big issues like the unification of forces and the quantization of gravity.

People have invested their whole careers in string theory and loop quantum gravity. Decades have gone by without any clear payoff in experimental results. Lots of good math, but no experimental confirmation! This makes people scared, and unhappy... and now, I think, it's making them fight.

Note how little fighting of this sort we see in cosmology, where people are making wonderful discoveries left and right: dark matter, dark energy, hints of inflation in the cosmic microwave background radiation.



Blogs provide a brand new forum for uninhibited and often anonymous fighting, just at a time when a bunch of physicists are getting desperate and miserable... it's a flammable combination.

Like you, I got sick of these fights. They helped convince me it was time to stop working on quantum gravity and focus on math.

For a long time these fights also kept me from starting a blog. But then, thanks to Urs Schreiber, I realized it's possible to have a pleasant and interesting blog, by keeping it technical and avoiding controversy.

It's a pity I have to avoid writing about controversial topics just to avoid fights. But, it's worth it.

Isn't it just the behavior of just of couple of obnoxious stingy theorists (including a famous one from Harvard)?

I thought of it more as the result of the business success that string theorists like Kaku, Randall, SUskind and Greene have made even Hawking, and the lucrative business model is being challenged.
 
  • #73
john baez said:
This is certainly part of the story. But, I think some of the anger surrounding the string wars comes from the desperation many theoretical physicists feel when it comes to making progress on big issues like the unification of forces and the quantization of gravity.

Anger ? never seen such thing :bugeye:; the large majority seems pretty pragmatic waiting for something better to come.

john baez said:
People have invested their whole careers in string theory and loop quantum gravity.

Hum, you forget to mention that the large majority got a career in the first place because they were doing ST or LQG. You can hardly call that an investment, mostly it is career opportunism.

john baez said:
Decades have gone by without any clear payoff in experimental results. Lots of good math, but no experimental confirmation! This makes people scared, and unhappy... and now, I think, it's making them fight.

Me think that most people are realistic enough to know that more or less convincing experimental indications for Planck scale physics (unless you are very quickly content) won't come before they die.

john baez said:
Like you, I got sick of these fights. They helped convince me it was time to stop working on quantum gravity and focus on math.

Really ? :bugeye: I mean if you are really passionate about something, nothing will stop you to do what it is you like.

john baez said:
It's a pity I have to avoid writing about controversial topics just to avoid fights. But, it's worth it.

And you feel the compelling need to stress that each time :smile:
 
  • #74
Care, you really are insufferable :biggrin:
JB is a sweet guy and you should just let him do what he wants and not bug him:approve:
 
  • #75
Careful said:
... the large majority seems pretty pragmatic waiting for something better to come.
...
this is something I would like to agree with (if I had a wide enough statistical sample to be sure)

so maybe I share your attitude somewhat here.

It seems to me that the RANCOROUS VITUPERATION is confined to the minor figures.

I don't see Smolin or Witten as rancorous squabblers at all, or David Gross...or JB for that matter. They all seem to be above the squabble.

Smolin had some serious points about policy and science in general, which he made politely and respectfully (I thought)

Other people like Witten, Rovelli etc. have interesting research to work on and seem hardly to pay attention. Anybody who has anything interesting to work on is peacefully working on it. That's how it looks to me as outsider observer.

If you were a kind of centaur-like half media-journalist half theoretician then maybe it cramps your journalistic half. Because you can't get involved in the issues of the day without getting embroiled. So only half of you is getting to live fully (the theoretician part) and that cramping may hurt.

But look at what KITP did in January. Major bridge-build and olivebranch offering. Or? Gary Horowitz and Martin Bojowald organized a 3 week workshop on Singularities with a major Loop component---Ashtekar, Thiemann, Pullin, Gambini, Dittrich, of course Bojowald. that is not "war" or even anger. it was a remarkable and constructive step to take. BTW lovely halfhour performance by Ted Jacobson at blackboard.

(at end after most participants were gone there was a hand-wave vague put-down "were still the best" kind of face-save gesture by G.H. which only to be expected---but looking overall it was extremely positive and friendly, even hopeful---or so comes thru in the videos)

Am I missing something? It seems to me that at most we've got a squabble in the lower-echelons.
 
Last edited:
  • #76
marcus said:
Anybody who has anything interesting to work on is peacefully working on it. That's how it looks to me as outsider observer.
Sure, so what is the hype you are constantly making ?
 
  • #77
marcus said:
Care, you really are insufferable :biggrin:
JB is a sweet guy and you should just let him do what he wants and not bug him:approve:
You should not bug anyone either and neither should you express what you consider bugging or not, nor assess anyone's posting unless it is on a scientific (factual) basis. :approve:
 
  • #78
Last edited by a moderator:
  • #79
john baez said:
Like you, I got sick of these fights. They helped convince me it was time to stop working on quantum gravity and focus on math.

It is a pity indeed, specially to hear from someone who contributed significantly to the field. :cry: (It's no news of course, I recall you said that last year or so). But in any case, I'm sure you are motivated and happy with your current interests.

The blog experience made me certain of two things: I continue more than ever curious about quantum gravity and also I do enjoy blogging (I'm back to it after all). It can be interesting and educative -- as far as you manage to keep out of things that bother you.

Christine
 
  • #81
I have a question about these "string vs loops" war.
I have got from a library the Brain Green´s book "teh fabric of the cosmos" (the spanish edition), and I was very surprised to see that in his last chapter he has a words for Smollin and the LQG.

He says that the LQG is a valid road of investigation, he recomends the reading of "the threed roads to quantum gravity". He also claims that the idea of an discrete space time is a valid one (Lubos has denosted it many times). He finally says that probably the future of the string gravity field could come from some kind of fussion betwen the ideas of string theory and loop quantum gravity.

That is doubly surprising as Lubos has repeteadly mentioned Brian Green as an "antiloop" guy.

have readed that the engish version of the book os from 2005 (in Spain it has been published very recently) so maybe that is the cause of the disagreement. But if so, how could it be such a drastic change of viewpoint about LQG of the string comunity?
 
  • #82
Sauron said:
... how could it be such a drastic change of viewpoint about LQG of the string comunity?

one possible explanation was offered a few posts back:
...Note how little fighting of this sort we see in cosmology, where people are making wonderful discoveries left and right: dark matter, dark energy, hints of inflation in the cosmic microwave background radiation.

...Blogs provide a brand new forum for uninhibited and often anonymous fighting, just at a time when a bunch of physicists are getting desperate and miserable... it's a flammable combination.

talking about these things requires gentleness and tact. one can't put one's finger on the source of trouble without someone saying "ouch"

in some sense, less said the better. most of us tend not to talk about the more bitter altercations, I think, most of the time. I rarely even pay attention (don't visit rage blogs, etc.)

I think it is helpful to keep reporting the news, which is why I follow things like the Loop Quantum Cosmology presentations at the KITP workshop. LQC is not an area which has been experiencing frustration---it was invented in 2001 and has made a lot of progress in areas that people are interested in (BB, BH). When you listen to those folks you don't hear "desperation and misery"----and you don't hear them quarreling either AFAIK.

if anyone hasn't watched the LQC KITP videos and wants to, you can google "KITP spacetime singularities" which gets you here:
http://online.kitp.ucsb.edu/online/singular_m07/
and scroll down to Ashtekar or Bojowald or Thiemann talks.
Here's a direct link to e.g. Bojowald slides and video
http://online.kitp.ucsb.edu/online/singular_m07/bojowald/
 
Last edited:
  • #83
Careful said:
You should not bug anyone either and neither should you express what you consider bugging or not, nor assess anyone's posting unless it is on a scientific (factual) basis. :approve:

Careful, I feel that you are mostly wasting your breath here, but your input is much appreciated. It is quite amazing to see people walk past an elephant and not even see it.

:smile:
 
  • #84
Kea said:
Careful, I feel that you are mostly wasting your breath here, but your input is much appreciated. It is quite amazing to see people walk past an elephant and not even see it.

I don't want to misinterpret this Kea. What did you mean by it? Who or what is the elephant?
 
Last edited by a moderator:
  • #85
josh1 said:
Who or what is the elephant?

The Elephant is a very large creature with floppy ears, a trunk and cute eyes that anybody can see is in the room.

:smile:
 
  • #86
Kea said:
Careful, I feel that you are mostly wasting your breath here, but your input is much appreciated.

Whether I waste my breath or not depends upon the personal ``weight'' I attach to my posting here (and unlike what some want to imply, no ``deep'' feelings are involved at all, haha), but on the other hand I haven't noticed (since one year or so :rolleyes:) that anyone appreciates my input (although I am rather factual and open for discussion).

Kea said:
It is quite amazing to see people walk past an elephant and not even see it.
:smile:

Could you for once not speak in sentences which can at least be interpreted in a threefold way (like you would have to do in real life) ?

Careful
 
Last edited:
  • #87
Hi Careful,

If you know what Kea meant, would you mind telling me?
 
  • #88
josh1 said:
Hi Careful,

If you know what Kea meant, would you mind telling me?

Ohw, I suspect that she was referring to my sentence

``Me think that most people are realistic enough to know that more or less convincing experimental indications for Planck scale physics (unless you are very quickly content) won't come before they die.''

In another thread, some very cheerful people are already ``unifying'' the entire gamma of models revealing a shortest length scale (which should be confirmed by experiments at CERN). :biggrin: For some ``funny'' reasons, Kea baptized it ``elephant theory'' (although whale theory might even be more impressive). I am sure she knows how to argue why the conclusion that a shortest quantum length scale has been confirmed isn't like the famous needle in the haystack.
 
Last edited:
  • #89
Careful said:
...but on the other hand I haven't noticed (since one year or so) that anyone appreciates my input (although I am rather factual and open for discussion).

Sigh. Yes, it really is a great shame that selfAdjoint has left us. He had a quiet way of encouraging interesting discussions.

:smile:
 
  • #90
Kea said:
Sigh. Yes, it really is a great shame that selfAdjoint has left us. He had a quiet way of encouraging interesting discussions.

Why did he stop posting?
 

Similar threads

Review in Nature by Geoff Brumfiel
  • · Replies 0 ·
Replies
0
Views
3K
Against Symmetry Smolin in Paris June 14
  • · Replies 21 ·
Replies
21
Views
6K
Foot-trap rage and spanking the messenger
  • · Replies 15 ·
Replies
15
Views
3K
Non-string QG positions in US (some data)
  • · Replies 16 ·
Replies
16
Views
4K
Who Are String Theory's Top Hypsters & Con Artists?
  • · Replies 6 ·
Replies
6
Views
5K
Max Tegmark, Lee Smolin-polite conversation at Peter's
  • · Replies 20 ·
Replies
20
Views
8K