# Smolin's Response to review by Joe Polchinski

http://www.thetroublewithphysics.com/Response%20to%20Polchinski.html" [Broken]

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turbo
Gold Member
Thanks for the link, Christine. It's important the people realize that Smolin is not trying to spike string theory, but is promoting the idea that there are viable alternative paths to approach quantum gravitation. LQG may not be the answer, either, but it is nice to know that path is being explored.

I think Smolin addresses the prime danger of group-think (consensus science) well in this reply:
The reason why string theory occupies one of four parts of the book was to give a context in which to raise some broad and fundamental questions about how science works, and how well it works in the present academic environment-compared to earlier times when there were many fewer scientists, they were far less organized and professionalized and yet, progress was faster.

josh1
It's important the people realize that Smolin is not trying to spike string theory...

Which people? People that matter? I dont think so.

turbo
Gold Member
Which people? People that matter? I dont think so.
Smolin invested a lot of years in string. Now that it appears that there may be an infinite number of "viable" variations of string, (reducing the predictive value of the approach) perhaps it is time to come at the problem from a different angle. That's all.

Chronos
Gold Member
Perhaps some feel Smolin is playing both sides against the middle. He is unabashedly disloyal to both camps. I find it refreshing.

josh1
Smolin invested a lot of years in string.

Even it this we're true, the facts don't depend on how much time smolin spent working on string theory.

...it is time to come at the problem from a different angle.

A different angle? What angle might that be? This is the question other physicists put to smolin to remind him that it's easy to say but hard to do no matter one's attitude might be. Of course, smolin already knows this so that his position is viewed quite accurately as being disingenuous at best.

You along with most people around here need to understand why physicists have so much confidence in string theory despite the challenges it currently poses and so little in alternative approaches.

Perhaps some feel Smolin is playing both sides against the middle.

What sides are those? You may care what smolin is doing, but what string theorists feel is much more annoyance then genuine concern, and for good reason: Science will advance no matter what smolin does or what you think.

He is unabashedly disloyal to both camps. I find it refreshing.

Loyalty? It may have a place in politics, but not in science.

George Jones
Staff Emeritus
Gold Member
You along with most people around here need to understand why physicists have so much confidence in string theory despite the challenges it currently poses and so little in alternative approaches.

Is this really true? The anecdotal evidence that I have accumulated seems to indicate that there is a fairly strong dichotomy in the physics community with respect to string theory.

Almost (but maybe not quite) unanimously, astrophysicists, condensed matter physicists, atomic physicists, etc. have made disparaging comments (to me) about string theory. The positive comments that I have heard about string theory have come from people in the high energy crowd (not necessarily string theorists).

josh1
Is this really true? The anecdotal evidence that I have accumulated seems to indicate that there is a fairly strong dichotomy in the physics community with respect to string theory.

But what is the origin of this division? (I assume that by "dichotomy" you meant "division".) Is it based on a detailed and accurate understanding of string theory or something else? Keep in mind that string theory is by many orders of magnitude more difficult than any other field in physics and requires much more training in both physics and mathematics before it and it's prospects can be accurately assessed.

Almost (but maybe not quite) unanimously, astrophysicists, condensed matter physicists, atomic physicists, etc. have made disparaging comments (to me) about string theory. The positive comments that I have heard about string theory have come from people in the high energy crowd (not necessarily string theorists).

It really sounds like you're basing your opinions on everything but an understanding of string theory, an understanding which is required if you want to be able to distinguish between baloney and the facts. If you want to ground your opinion in the latter, you need to learn about string theory.

So the question now is from whom would you rather learn string theory? Maybe you would prefer learning about string theory from experts on laser optics rather than string theorists, or maybe from condensed matter physicists rather than string theorists, or maybe from members of this forum rather than string theorists, or maybe from polemicists like woit/smolin who rail against string theory largely for personal reasons rather than string theorists, or maybe from anyone who has an opinion rather than string theorists.

It's very hard to deal with patients with brain tumors when for no good reason they insist that their neurosurgeon defend their choice of treatment against the opinions of the physicians of all the other specialties. Neurosurgery is a very complicated field requiring very specialized knowledge to understand and practice.

marcus
Gold Member
Dearly Missed
Perhaps some feel Smolin is playing both sides against the middle. He is unabashedly disloyal to both camps. I find it refreshing.

that's a colorful expression but could give a misleading impression. the Loop community shows little "camp" mentality.

evidence: Loops '05 conference had TWO of the 20 or so invited plenary speakers be people who normally do string.
Robbert Dijkgraaf and Stefan Theisen
http://loops05.aei.mpg.de/index_files/abstract_dijkgraaf.html
http://loops05.aei.mpg.de/index_files/abstract_theisen.html
and there were several other string participants, such as Dorothea Bahns who
gave a talk in the parallel sessions

Jan Ambjorn who has co-authored most of Loll's major papers does quite a bit of string/M and sometimes grad students and postdocs in Loll's group go over and co-author string research with him. Obviously Ambjorn is "ambidextrous". There is no code of loyalty that he is breaking.

Loops '07 has TWO of its 20-some invited plenary speakers be Moshe Rozali and Jan Ambjorn. Others of the invited speakers have notably collaborated with string theorists.

Smolin's longstanding practice of doing both string and non-string research does not seem to have caused outrage among his non-string QG associates and I think it is simply because the community is more open and less "camp"-like.

So, Chronos, your image of Smolin as disloyal to both "camps", while it might be a funny way to express the fact that he has done a dozen or more string papers (including one in 2005 and 2006 IIRC), could actually mislead people into thinking there is a "camp" mentality with standards of loyalty, so that you can be condemned and villified by fellow non-string QG if you see some string research you think worth doing and go and do it.

"Keep in mind that string theory is by many orders of magnitude more difficult than any other field in physics and requires much more training in both physics and mathematics before it and it's prospects can be accurately assessed."

God exists! I can show you the prove, if only you believed in him first!

Also neurosurgery works. String Theory doesn't.

Also it's really nice how you dismiss everyone who disagrees with your assessment as "not a physicist". And if people are not physicists they are not experts and don't have a valid opinion (because physicists *know* that String Theory is so extremely much more promising). So you are right by definition. That's cool, really facilitates open discussion.
Load of Bull. It is the most promising candidate, it's got cool stuff going for it, but get real. It's not physics yet, neither is any other approach.

Yes it's difficult to make things work and String theory has gotten more to work then any other approach, but the fact that the other stuff is even more difficult doesn't mean it's wrong. Just means it's easier to do stuff with Stringtheory and all the pretty complications it throws up (it also defers many of the really interesting (from the relativist point of view) physical questions).
And these days it's not clear that there's nice stuff to do besides the internal work within the complications of compactifications. Who knows!

marcus
Gold Member
Dearly Missed
...
Almost (but maybe not quite) unanimously, astrophysicists, condensed matter physicists, atomic physicists, etc. have made disparaging comments (to me) about string theory. The positive comments that I have heard about string theory have come from people in the high energy crowd (not necessarily string theorists).

Yes! I have noticed the same thing!

And also you can occasionally hear experimental particle physicists disparaging string.
I have never gotten the impression that there was anything like a solid majority support----more the opposite.
Again this is just more or less random anecdotal evidence of a dichotomy (in the sense of "split").

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George Jones
Staff Emeritus
Gold Member
josh1 said:
But what is the origin of this division?

This wasn't the point of my post.

josh1 said:
(I assume that by "dichotomy" you meant "division".)

From Merriam-Webster

"1 : a division into two especially mutually exclusive or contradictory groups or entities <the dichotomy between theory and practice>; also : the process or practice of making such a division <dichotomy of the population into two opposed classes>"

josh1 said:
Is it based on a detailed and accurate understanding of string theory or something else? Keep in mind that string theory is by many orders of magnitude more difficult than any other field in physics and requires much more training in both physics and mathematics before it and it's prospects can be accurately assessed.

This was not th point of my post. The point of my post was your statement

josh1 said:
... physicists have so much confidence in string theory despite the challenges it currently poses and so little in alternative approaches

josh1 said:
It really sounds like you're basing your opinions on everything but an understanding of string theory, an understanding which is required if you want to be able to distinguish between baloney and the facts. If you want to ground your opinion in the latter, you need to learn about string theory.

I didn't express my opinion about string theory, I stated the opinions that other physicists have expressed to me.

josh1 said:
So the question now is from whom would you rather learn string theory? Maybe you would prefer learning about string theory from experts on laser optics rather than string theorists, or maybe from condensed matter physicists rather than string theorists, or maybe from members of this forum rather than string theorists, or maybe from polemicists like woit/smolin who rail against string theory largely for personal reasons rather than string theorists, or maybe from anyone who has an opinion rather than string theorists.

Again, this is irrelevant to the point of my post. My point had to to with the truth value of your statement

josh1 said:
... physicists have so much confidence in string theory despite the challenges it currently poses and so little in alternative approaches

josh1 said:
It's very hard to deal with patients with brain tumors when for no good reason they insist that their neurosurgeon defend their choice of treatment against the opinions of the physicians of all the other specialties. Neurosurgery is a very complicated field requiring very specialized knowledge to understand and practice.

So, you didn't mean all physicists when you wrote

josh1 said:
... physicists have so much confidence in string theory despite the challenges it currently poses and so little in alternative approaches

Why didn't you say so in the first place?

josh1
Respectfully George,

Your preceding post is just a massive copout, and indicates that there's probably no way I would ever be able to convince you that you need to reconsider the basis of your opinion. Again, no disrespect intended.

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josh1
...you dismiss everyone who disagrees with your assessment..

And this is related to physics how? I indicate why members may want to consider more carefully the basis of their opinions. Near as I can tell, they rarely do, or at least when it comes to string theory.

In any event, I do not "dismiss" people. (Though I think we all sometimes need to do better at responding to the post and not the person, and quite frankly, based on past experience, this does indeed include you f-h. But again, this has nothing to do with physics).

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marcus
Gold Member
Dearly Missed
Respectfully George,

Your preceding post is just a massive copout, and indicates that there's probably no way I would ever be able to convince you that you need to reconsider the basis of your opinion. Again, no disrespect intended.

f-h said:
...you dismiss everyone who disagrees with your assessment..
And this is related to physics how? I indicate why members may want to consider more carefully the basis of their opinions. Near as I can tell, they rarely do, or at least when it comes to string theory.

In any event, I do not "dismiss" people. (Though I think we all sometimes need to do better at responding to the post and not the person, and quite frankly, based on past experience, this does indeed include you f-h. But again, this has nothing to do with physics).

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I was commenting about your style of arguing,so this was intentionally directed at you.

To argue that this is because they are not experts is circular logic (hence the God comment).

Maybe you didn't mean the "physicists believe in it" comment as strongly as it came across to me, in this case I apologizer. I, and many other physicists (especially thoser comming from the relativity Point of View) do not share this opinion.

It is because String Theory has no answers to the kind of physical questions people coming from GR would ask. (Similarily LQG has no answers to the kind of questions HEP theorists ask). Neither of these theories is physics yet. Not only in the sense that we can't compare them with experiment, but in the sense that the deep physical questions can not be asked within the theories, even in principle (yet), and therefore the scepticism of the non expert physics community against them is thoroughly justified IMO.

And again, by arguing for a string hegemony based soley on the opinion of people inside ST you are validating Smolins point. Which I can find nothing disingenious with.

:grumpy:

No, please, I'm quite enjoying this.

josh1
Okay, so, in his response to Polchinski, smolin says that he finds it “disappointing that Polchinski has chosen to not engage with the broader arguments of the book”. But I don't find smolin's message about the dangers of "group think" particularly alarming or interesting, and in any event, it’s clear that smolin continues to hold string theory to a different standard than he does other ideas, especially his own.

However, most of smolin’s response concentrates on disagreements with Polchinski about how he characterized string theory in his book. The issues discussed include positive cosmological constants in string theory, Ads/CFT, background independence in string theory, the role of mathematics in string theory, heavy ion physics, and cosmological applications of string theory. If anyone would like to discuss these on the same technical level that Polchinski and smolin do, I'm game if any of you are. I should say though that I really don’t think any of this matters.

turbo
Gold Member
Dear josh1, I find it enlightening that in your last post, Smolin's name is never capitalized and Polchinski's always is. Please stop with the not-so-subtle insults and games and deal with the particulars in Smolin's response. It would be a million times more entertaining than this junior-high crap.

Edit: The OP had an an open, informative, entertaining and thought-provoking blog a while back, until people with agendas and attitudes swamped it with crap and she found it too unpleasant to maintain. I miss that blog, but I respect her decision to discontinue it after being hammered by so many insensitive people that cannot tolerate a dialog that might not conform to their views. We have only one life - we're all in this together - play nice, PLEASE. Science is not WWWF.

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Chronos
Gold Member
Kea, you are such a pixie. Must be the mountain air. Marcus, it is difficult to slip a tongue in cheek remark by here with you on the prowl. LQG is like range beef, tough, but not stringy, and certainly not campy. Josh has me a bit off center with the appeal to authority approach. I agree an ST proponent cannot teach brain surgery to a neurologist, or vice versa. The point is otherwise lost on me.

Josh, how much knowledge of string theory do you belive that it is necessary to have to properly judge it´s merits?

Josh,

"it’s clear that smolin continues to hold string theory to a different standard than he does other ideas, especially his own."

How so?

josh1
Josh, how much knowledge of string theory do you belive that it is necessary to have to properly judge it´s merits?

It's not a matter of judging string theory. It's a matter of understanding why most people in quantum gravity and high energy theory have so much confidence in string theory despite the current challenges it faces. All we ever hear about here are the problems with string theory and the “successes” of lqg.

"it’s clear that smolin continues to hold string theory to a different standard than he does other ideas, especially his own."How so?

Quoting smolin from his response to Polchinski: “Of course, the key point on which good scientists differ in their judgments is precisely how long is too long to invest a large portion of our resources in fundamental theory on such a long and risky bet.”

In a radio show he did (I think with Brian Greene), smolin said that the time limit he had in mind was something like ten years. So if you haven’t produced a theory that makes predictions etc by then, you should move on. Thus smolin says that time has run out for string theory. But does he say anything about LQG? Nope. This lack of balance looks even more hypocritical when you look at the relative complexity of string theory versus lqg. Specifically, we know so little about string theory, including what it’s basic principles are, it’s easy to believe that the solutions to the current challenges it faces are there ready to be discovered. But lqg by comparison is a very simple theory so by smolin’s logic the amount of time one should spend on lqg before concluding that it’s challenges can probably never be overcome should be much less than the time allowed for a theory as complex as string theory.

josh1
I'm reposting this because it seems my invitation to discuss smolin's response has been missed for some reason:

Okay, so, in his response to Polchinski, smolin says that he finds it “disappointing that Polchinski has chosen to not engage with the broader arguments of the book”. But I don't find smolin's message about the dangers of "group think" particularly alarming or interesting, and in any event, it’s clear that smolin continues to hold string theory to a different standard than he does other ideas, especially his own.

However, most of smolin’s response concentrates on disagreements with Polchinski about how he characterized string theory in his book. The issues discussed include positive cosmological constants in string theory, Ads/CFT, background independence in string theory, the role of mathematics in string theory, heavy ion physics, and cosmological applications of string theory. If anyone would like to discuss these on the same technical level that Polchinski and smolin do, I'm game if any of you are. I should say though that I really don’t think any of this matters.