# Gross Calls String Theory A Bizarre Science That Is A Dangerous Business

1. Jan 5, 2006

### MistyMountain

From the Woit blog:

http://www.math.columbia.edu/~woit/blog/

The only physicist quoted who recognizes that the Landscape is pseudo-science is David Gross. “It’s impossible to disprove” he says, and notes that because we can’t falsify the idea it’s not science. He sees the origin of this nonsense in string theorist’s inability to predict anything despite huge efforts over more than 20 years: “‘People in string theory are very frustrated, as am I, by our inability to be more predictive after all these years,’ he says. But that’s no excuse for using such ‘bizarre science’, he warns. ‘It is a dangerous business.’”

I continue to find it shocking that the many journalists who have been writing stories like this don’t seem to be able to locate any leading particle theorist other than Gross willing to publicly say that this is just not science.

http://www.math.columbia.edu/~woit/blog/

http://www.nature.com/nature/journal/v439/n7072/full/439010a.html

It's an intriguing idea with just one problem, says Gross: "It's impossible to disprove." Because our Universe is, almost by definition, everything we can observe, there are no apparent measurements that would confirm whether we exist within a cosmic landscape of multiple universes, or if ours is the only one. And because we can't falsify the idea, Gross says, it isn't science. Or at least, it isn't science in any conventional sense of the word. "I think Gross sees this as science taking on some of the traits of religion," says Carr. "In a sense he's correct, because things like faith and beauty are becoming a component of the discussion."

Gross believes that the emergence of multiple universes in science has its origins in theorists' 20-year struggle to explain the finely tuned numbers of the cosmos. "People in string theory are very frustrated, as am I, by our inability to be more predictive after all these years," he says. But that's no excuse for using such "bizarre science", he warns. "It is a dangerous business.

http://www.nature.com/nature/journal/v439/n7072/full/439010a.html

Should pseudo science have its own prominent forum at a place called "physics forums?"

Furthermore, if a pseudo sicence forum exists, should only pseudo sience that conforms to the pseudo-science of well-funded pseudo scienetists be discussed. Should not all pseudo science be welcomed? Do large NSF grants absolve one of having to do real physics?

And even better yet, if we are going to have forums devoted to bizarre, dangerous, pseudo science, should we not have a forum devoted to new physical theories that are based in logic and reason, in truth and beauty, in physics?

Thanks!!!

Last edited by a moderator: May 2, 2017
2. Jan 5, 2006

Staff Emeritus
First, I will quote you Clarke's first law:
When an elderly famous scientist says something is possible, he is probably correct. When he says something is impossible, he is probably wrong.

Second, the reason they can only find one particle scientist who will say such things about string theory is that most particle physicists, even those who dislike the landscape, do not believe such things about string thoery. It's important not to conflate e.g. Susskind's claims for anthropism with proper string physics; Motl and Distler are just as critical of Susskind and Gross is.

Thirdly, I don't think anyone has a right to sneer at string physics unless they have some competence in it to indicate they might know what they're talking about. I have never seen such competence in your posts.

3. Jan 5, 2006

### MistyMountain

Are you an elderly famous scientist?

For the moment I'll take David Gross's view over yours, if that's OK.

David Gross is an accomplished physicist, and we don't even know who you are nor what your publications are, if any.

David Gross speaks with logic and reason. Age has nothing to do with this, and that's a cheap shot you took at Mr. Gross. You should apologize to him on behalf of PF.

4. Jan 6, 2006

### KC9FVV

IMO, age has everything to do with it. You rarely see physicists accomplish much after their thirties (other than perhaps Richard Feynman, but even his accomplishments slowly declined in the end). I suspect it has more to do with psychology than pure reason. It is this very experience and rigidness, I believe, that makes the older physicist able to tell when a theory is correct.

It didn't exactly come out as fluent as I had hoped, but I hope you see what I am trying to say.

5. Jan 6, 2006

### Careful

**IMO, age has everything to do with it. You rarely see physicists accomplish much after their thirties (other than perhaps Richard Feynman, but even his accomplishments slowly declined in the end). **

Come on, physicists are at their best between 28 and 40 I guess, which has everything to do with the increasing knowledge one has to adsorb.

** I suspect it has more to do with psychology than pure reason. It is this very experience and rigidness, I believe, that makes the older physicist able to tell when a theory is correct.
It didn't exactly come out as fluent as I had hoped, but I hope you see what I am trying to say. **

I have a different opinion about this : as a youngster you might say well the old guy just gave up´´ but that is way too simplistic (you should realize that young string theorists also agree with him). He is certainly correct when he refers to Occam's razor in the context of the landscape, but anyway, I do not think the question is whether his overall sentiment about string theory is correct or not (one can never measure this anyway). I think the crucial aspect is that an intelligent, experienced physicist has expressed a deep concern about how things are going which certainly deserves consideration.

Cheers,

Careful

6. Jan 6, 2006

Staff Emeritus
Arthur Clarke's "law" was based on actual events in physics history, including the rejection of Relativity by the older generation of physicsts in the early 20th century, and Einstein's own rejection of the anti-realist consequences of quantum mechanics. It is no insult to any particular physicists to note that this behavior pattern continues into our own time.

Gross' logic is impressive, but no more cogent than the arguments of the defenders of string theory. I repeat that Gross is criticising the anthropic reasoning championed by Susskind and others, and that is not , nor do Susskind et al claim it is, the essence of string theory.

7. Jan 6, 2006

### Careful

**Arthur Clarke's "law" was based on actual events in physics history, including the rejection of Relativity by the older generation of physicsts in the early 20th century **

Hi, I think the situation here is rather different : Einsteins GR lead to concrete predictions and was accepted pretty much after Eddington measured the gravitational bending of light which was only *four* years after the completion of the theory (which was a one man effort which took about eight years). String theory is a massive enterprise which takes about 25 years and hasn't produced one single experimental prediction. So, the timescales involved were very different, nobody really got time to get accostumed to these ideas which btw were much more radical than the premises of string theory.

** and Einstein's own rejection of the anti-realist consequences of quantum mechanics. **

Well, I still believe that he might be right in the end (and Bell experiments haven't been really convincing so far) - that is still an open issue.

** Gross' logic is impressive, but no more cogent than the arguments of the defenders of string theory. I repeat that Gross is criticising the anthropic reasoning championed by Susskind and others, and that is not , nor do Susskind et al claim it is, the essence of string theory **

Well, I think it is very unclear for the moment what the essence of string theory is, at least I do not know for the moment. AFAIK, without the anthropic principle a serious fine tuning is necessary...

But I think the main differences are the timescales. String theory has had pleanty of time already : any other theory would have very likely been disposed of without an equivalent media circus.

Cheers,

Careful

Last edited: Jan 6, 2006
8. Feb 6, 2006

### Aridea

I believe almost any person Physicist or not with an interest in ST knows that Gross is probably the most vocal opponent of ST. It seems that his passion to see research in String Theory abandoned is equal to the passion several other Physicist have to see String Theory proven.

I do see some of the problems facing String Theory, but I also believe there is a lot of promise in the theory as well. What it boils down to is this: there have been many points throughout history when something that we know to be true now sounded ridiculous. My gosh; humans actually used to believe that Earth was the center of not only the solar system, but the entire universe. Newton believed that the force of gravity acted instantaneously, and as we all know Einstein proved that this was not true. There have been many things that mankind in the past thought impossible to prove, that have since been proven. I don't think we should abondon any theory, to do so would be an incredible loss. I believe that any unification theory is worthwhile to work on.

9. Feb 6, 2006

### marcus

**I believe almost any person Physicist or not with an interest in ST knows that [David] Gross is probably the most vocal opponent of ST. It seems that his passion to see research in String Theory abandoned is equal to the passion several other Physicist have to see String Theory proven.**

can't think of an appropriate reply
:-)

Last edited: Feb 6, 2006
10. Feb 7, 2006

### Careful

** What it boils down to is this: there have been many points throughout history when something that we know to be true now sounded ridiculous. My gosh; humans actually used to believe that Earth was the center of not only the solar system, but the entire universe. **

That is not so ridiculous at all: everything people could observe at that time was a relative motion with respect to the flat coordinate system attached to the surface of the earth, therefore it is natural to use this as a base point which you can obviously do also in Newtonian physics by making a non galileian coordinate transformation. Actually we still *do* use such ideas when making maps of the solar system and galaxy (it is rather fascinating to study the models of the old greeks based upon circular motions).

**
Newton believed that the force of gravity acted instantaneously,**

He did NOT believe in this, AFAIK Newton was a proponent of what one would call ether models.

** There have been many things that mankind in the past thought impossible to prove, that have since been proven. **

Sure, but the problem is that string theory hasn't proven anything of interest in physics at all and is by far outcasting any theoretical enterprise in history. Actually, this story is diametrically opposite to the one of the geocentrical theory : there people put forwards a too limited idea based solely upon the available data and common experience, string theory on the other hand is way too big and based upon no data/realistic experience at all

**I don't think we should abondon any theory, to do so would be an incredible loss. I believe that any unification theory is worthwhile to work on. **

You obviously have no idea at all how many different plausible ideas science counts and how very few of them are for some mysterious reason mainstream.

11. Feb 7, 2006

### arivero

But age is one of the weakness of string theory. It is a theory done in the early 1970; most of their important results, includong the D=26 y D=10 things, date from this period. Yes the scientists doing it at these times were young people, now they are old, and in nineties they were both old and influential.

12. Feb 7, 2006

### EroticNirvana

The use of the word "dangerous" maybe says everything about this dude. That sounds like a philopher speaking.
Real scientists use a more objective language.
It's always funny to hear people say that this or that cannot be proven.

Give me a single proof that something cannot be proven, given that the idea is not inconsistent!

Those tending to critisize string theory tend to be non-experts or maybe, occasionally, senile people.

If you're an expert on string theory you are able to point to a number of really sophisticated indications of its correctness as a better theory than the old ones. Here are some reasons for this:

1. String theory incorporates the standard model (even if I'm not sure that it has been shown in extreme detail)
2. String theory is consistent with the regge trajectories of hadron's
3. String theory yielded the graviton as a by-product. It was a surprise for the people producing string theory that it required the graviton. The graviton has not yet been observed, but that does not necessarily have to worry you.
4. String theory yields the first consistent QM account of gravity. (that's something big in itself)
5. String theory can incorporate all known guauge theories (at least those of the Standard model and gravity).
6. String theory exhibits new symmetries (gauge symmetries), which we already know from the standard model are important explanations for matter.

I could go on for hours. It's nonsense when people critisise string theory as a non-scientific theory that does not deserve merits as the best theory availible. The great minds of today take interest in it. Only a few dissent. There are always oddballs.

In fact, the most criticism I confront with respect to string theory is cricisism posed by people who know very little about string theory. They think that just because you have not observed gravitons there is simply no reason to embrace string theory. You could not be less wrong, but you have to be subtle to realize why. Thank God that there are a few subtle minds out there!

13. Feb 7, 2006

Staff Emeritus
The devil is in the details. String theory does NOT reproduce the Standard Model and does not really even reproduce the undemonstrated supersymmetric extension of the Standard Model, the MSSM. And no knowledgable string physicsts claims any more that it does.

Yes it is. So what?

What worries me is that the graviton is just a partial simulation of General Realtivity in flat spacetime. In fact what string theory produced was just a spin 2 boson. There's a theorem which states that ANY spin 2 boson would do what the SST one does. It still isn't generally covariant, let alone background free. And again there are detailed problems with it that have emerged in the last year or so. That last is controversial, but not definitely refuted the last I saw.

See above for the state of its "account of gravity". We'll see about logical consistency.

This is just a restatement of your previous points. I restate my demurral: it can't.

String theory is the only source of gauge symmetries? Come on! BTW the only reason that SST was able to get beyond the Standard Model is that the string model evades the Coleman-Mandula theorem that says gauge symmetries can only ever put whistles and bells on the Standard Model, not lead to really new physics. That goes for supersymmetry too. It's the reason both of them suddenly became interesting.

14. Feb 7, 2006

### EroticNirvana

wrong;)

Thx for a detailed and careful response. I apoligize that I don´t have the time to reciprocate:)

* Well I guess you´re right. String theory, thus far, has only been able to account for the most salient features of string theory (or you know, I´m not gonna get into any debate about any specific feature that is not covered which you might like); but that´s really what we need to be justified to work further on it (no one reasonable has inferred that string theory can´t do this in the future

* Oh well, the regge trajectories are pretty amazing physically. Now tell me which mathematical object is consistent with regge trajectories and you might have yourself a new physical theory; string theory was initially embarked upon because it can account for regge trajectories. Find me another math. object that does this which makes sense as an elementary particle and I´ll steel your idea and get the nobel prize;)

* Yes problems with gravity. However, just as the model of the atom was sketchy in the beginning, string theory is allowed to have some initial problems.

* YES! String theory is the most interesting source of gauge symmetries since it incorporates gravity!!!!!!!! Now compare E8xE8 and the "tiny symmetry group of the standard model! The former may even contain gauge symmetries of DARK MATTER? Exciting isnt it!!! So yes, please tell me which theory is more sexy than string theory when it comes to titilating gauge symmetries.

In summary, string theory, as most older theories, is burdened with problems, but it is really exciting from scientific point of view.

Anyhow, I´m working myself on a topological justification of string theory, and I think it might work. Yeah, don´t believe me,, I don´t care;)

Last edited: Feb 7, 2006
15. Feb 8, 2006

### Aridea

You've misinterpreted what I've said; I did not say that people in the past believing that the universe was earth centered was ridiculous. Maybe I should have added to my original post: "If you told someone years ago that the sun was the center of the solar system they'd think that was ridiculous" to further my point. Regardless, if you re-read what I wrote you'll see that I was stating that things that we know now to be true sounded ridiculous to people in the past. This is why you are correct when you say "That is not so ridiculous at all". Of course the Earth centered universe made sense to people long ago, they had been taught the Ptolemaic Theory; which asserted that the Earth was a fixed unmoving mass around which everything else in the universe moved. And this did make sense based on what their observations were, and the flat coordinate system they used. It wasn't until Copernicus completed "De Revolutionibus" in 1530 that the Earth center universe began to crumble, and that even took a while.

Yes, I am aware that Newton was proponent of ether models, but to put it in "laymans terms" it is acceptable and accepted to say that before Einstein the belief was that gravity acted instantaneously. This is what I was orignally taught in high school physics, it's how it's normally explained in books and documentaries designed for the masses, it's also how it's described in my eight year old daughters third grade science workbook. And since not everybody who visits this forum has a Phd in some area of physics, or a deep understanding of physics I felt it an acceptable, and understandable way to explain a point. The point I was trying to make was more about our knowledge of the universe and the laws of nature expanding over the years, not so much to discuss the evolution of physical theories.

One (I emphasize the word one, this isn't the only way that ST could be proven. I certainly don't want someone quoting me telling me there are others ways to possibly prove the theory) of the main reasons that String Theory can't be proven or disproven is because we lack the technology that would allow us to see at the lengths we would need to actually "see" a string. We would need tools that could probe distances as small as Planck length to actually see a string. Whether string theory has proven anything useful or not I would say is a matter of opinion, and whether it will in the future prove anything useful is not known. People often speak of the length of time that string theory has been worked on, but there haven't been hundreds of Physicists working on the theory since the late sixties. The theory has come and gone, and it's really this last time that the theory has been looked at again that most of the work has been done. String theorists have shown enough with the theory that proves it merits more work.

I also often hear opponents of string theory comparing the time it has taken in the past to prove other theories, saying that ST has been worked on for 25 years, and that other theories took much less time to prove, but I don't think they're taking into account the fact that this is a unification theory. It's a big deal, a huge all encompassing physical theory, of course it's going to take longer to unify the forces than it did to figure out each of them indivually. Just because the theory hasn't been proven yet doesn't mean it isn't correct! What if it is correct, and everyone stopped work on it, that would be a monumental disaster.

Actually, I am well aware of how many plausible ideas science counts. I'm also aware of how few of them are mainstream. I don't see how based off of that one statement you can make a determination of what idea I have about scientic theories and how many are mainstream. You make it sound as I'm saying that every single scientific theory should be worked on, that certainly is not the point I was trying to make, nor what I said. I wasn't talking about what "science counts" in general, I wasn't even speaking about physics in general; what I was talking about in particular was unification theories.

What I was saying and what I'm still saying is we shouldn't abaondon a unification theory. Yes there are other condidates besides string theory and I don't think those should be abandoned either.

One thing I've noticed is that it seems that many of the people who oppose string theory oppose it so passionately; almost more passionately than those who champion the theory defend it. And to put it simply are just plain rude when debating the whole issue. For those who oppose the theory who don't behave in this fashion I apologize, but many who do oppose it display a certain nastiness, and try to come off with a snobbish superiority to those who support the theory. I'm talking about everywhere to, is discussions, debates, articles, interviews, and forums; what is with that?

16. Feb 8, 2006

### EroticNirvana

that's because they're ignorant

Yes; the the reason for that is that they don't have any real argument to pose. They are not blessed with a scientific insight. Modern science will appear ridiculous to anyone that does not understand the reasons why modern science looks like it does.

You might also have noticed that these snobbish types tend to hide when the heat in the discussion is turned on. They run like lil' kids. They like to show off for their equally ignorant friends (who, nevertheless, are not charlatans like themselves) but when the masters enter the room they quickly run into a corner and hide.

OK OK. I don't like metadiscussions that much anyhow. But I will laugh each time an amateur disses string theory.

17. Feb 8, 2006

Staff Emeritus
No one is trying to keep you or anyone else from working on stringy approaches to the standard model. More power to you! The objection is to high profile attempts to claim SST HAS DONE more than it has.

I would appreciate it if you would tell us, perhaps in a new thread on the particle physics forum, what significance Regge trajectories have for present day theory or experiment. AFAIR they were only approximately straight for nucleons and mesons, and I don't know what has been done with them in the quark era.

Once again, if stringists were selling SST to the public as a work-in-progress, no-one could complain. If your original post that I responded to had taken that tone I would never have had a reason to respond. But you, and they, come on like SST has a string of predictive successes, and that's false. SST has more goals, and more work done on those goals, than any competitor. But it has no immediate prospect of an early closure on those goals.

If you just want to play around with gauge symmetries for their own sake, or as part of a program in pure mathematics, feel free. E8xE8 has not yet produced any real physics while the standard model has produced a bunch and is still producing new stuff. For experimentalists it remains the only game in town. Oh I will except the Witten MHV amplitude calculation method, which passses through string theory on the way to twistor space and produces calculations the experimenters can use.

I agree! It is not dissing this very interesting body of work to insist that its advocates be honest about its current achievements.

If you can do it, I'll be eager to study it. Topology of what?

18. Feb 8, 2006

### duke_nemmerle

I thought we were talking about Gross dissing string theory? Amateur?

19. Feb 8, 2006

### marcus

heh heh
it was kind of funny
David Gross applied the word dangerous to string Landscape thinking and some people reacted as follows:

Last edited: Feb 9, 2006
20. Feb 9, 2006