# Greene surrenders.

1. Sep 20, 2007

### arivero

Some blogs are discussing Edge dinner talk, but it is interesting to read it yourself:
http://www.edge.org/3rd_culture/einstein07/einstein07_index.html

particularly

2. Sep 20, 2007

### mathman

Most scientists would take the position that Greene is stating and I don't think it is a retreat, as Steinhardt asserts. Throughout history scientists will try to improve on existing theory or even replace it with a better one, but claiming a final theory is best described as youthful exuberence or possibly old-fogyism. Toward the end of the nineteenth century, before Planck and Einstein, the old-fogys thought that physics was almost complete - just a few loose ends.

3. Sep 21, 2007

### arivero

Where, it seems a retreat if you consider the six or seven first articles of Greene "in its early infancy in the 1980s", about some models for E8xE8 with three generations of the Standard Model.

Moreover, a selling point of string theory was uniqueness, in a physical sense, not in the mathematical sense of consistency (in this sense, every consistent mathematical theory is unique). They were not claiming sort of, "hey, I have developed a theory of non associative normed algebras, and it only has a solution". It was more of "hey, I have developed a theory of quantum gauge dynamics, and it singles out a model".

4. Sep 21, 2007

### rewebster

Greene must be writing a 'new' book

(TITLE: 'THE TROUBLE WITH' GREENE)

5. Sep 21, 2007

### BenTheMan

arivero---

Why is it a retreat? It's more or less a statement of the obvious---we thought the problem would be a lot easier than it turned out to be.

Didn't you do any Jackson problems in grad school?

Proponents of other approaches to quantum gravity claim that they don't want to detract from string theory, yet they call it the trouble with physics'', and use words like retreat'' and surrender''. A bit subversive, maybe?

6. Sep 22, 2007

### josh1

And the jihad against string theory continues.

7. Sep 22, 2007

### pelastration

Josh,

your bring string theory in a religious perspective. Is that intentional? ;-)

8. Sep 22, 2007

### Chronos

That will be an oft quoted remark, josh1. No dissent, discussion, or even a 'sigh'. If you have a point, the time is ripe.

9. Sep 22, 2007

### eendavid

String theory has gained a lot of interest (and money), partly because of this claim. Seen in this context the analogy with end-of-19th-century physics fails. One should not be surprised that proponents of other approaches have a mixed feeling about this, and see it as a retreat.

I don't see any problem in claiming the string community has 'cheated' (as in the sense of the above), while holding that string theory might be an interesting approach.

10. Sep 22, 2007

### rewebster

I bet there has been other hypotheses that have gained some favor at different points (and interest and financial support) in history that have been eventually been proven wrong, and I'm not saying with 100% certainty that string theory or everything in string theory is not right------At the 'present' time, it seems to me, that it is a mystical, magical, mathematical idea for a particle/ (whatever a string is) that is more like a genie in a bottle granting wishes (IF you CAN 'arrange' the math 'just right') to do (just about) anything you want it to do--- (talk about other people calling some questions 'philosophical'!).

11. Sep 22, 2007

### arivero

Well, I am not sure if there were proponents of other approaches. GUT was subsumed into string theory, and other models, as my beloved Non Commutative Geometry, had not traveled differently even without string theory.

12. Sep 22, 2007

### arivero

Actually I have some doubt about if the problem was thought. We had some string students in Les Houches (actually we got Greene as one of the teachers that year) and at that time (1995?) it was not easy for them to explain how particles and forces were supposed to emerge, except as I said above, by claiming contact with GUT.

Perhaps at some time it was hoped that a second uniqueness theorem could be proved about the compactification manifold. Still, it was unclear how it could drive to predictions about the CKM and masses.

THinking about, perhaps there was some hope that the compactification manifold, if unique, could predict some unique new particles and there its finding at the LHC would confirm string theory.

Hey, this is Europe. For classical fields, we proceed with handwritten lecture notes; it was conjectured that they were coming directly down from Maxwell and Onnes.

Note I started this thread in "High Energy, Nuclear, Particle Physics" subforum, and the moderator moved it here. I have not argument (others could have some) about the use of string theory to calculate quantum gravity.

Last edited: Sep 22, 2007
13. Sep 22, 2007

### nrqed

Maybe there should be two "Beyond the Standard Model" subforums on PhysicsForums.

One would be about the sociology of the field (about opinions, about the people in the field - including who did his PhD with whom, who is working on what etc etc etc) and one subforum which would be about the actual physics and maths and where loop quantum gravity, string theory, noncommutative geometry and everything else would all be treated with interest (I can't help notice how threads about actual physics are few in between and often fairly short, with string theory questions being ofetn left unanswered which is unfortunate) and the only goal would be to learn the topics and discuss them.

It seems to me that a huge fraction of the posts here are of the "sociology" type which, from the point of view of someone interested in the physics and maths of the field is quite disappointing.

I guess I have to run for cover now....the flak will be intense.

patrick

14. Sep 22, 2007

### eendavid

I too was referring to quantum gravity.
Of course it is difficult to forecast how theories would have evolved without string theory. To me it seems reasonable that LQG would've had a faster grow. At the moment string booms (mid-90's) LQG did have some results (which were negligible compared to a theory claiming to become the ultimate theory (GUT+quantum gravity)).

15. Sep 22, 2007

### josh1

I agree with every word of this.

16. Sep 22, 2007

### f-h

I'm with josh1 here. The hype for String theory is over and the statement of Greene is a welcome realistic summary of the state of the field, something that was not present in the public image of String Theory for a while, but to call it a surrender is disingenuous and mis informative.

Everybody working in QG from whatever background, agrees that ST deserves mayor investigation and funds and positions. The problem was it's claim for exclusivity, that this claim is no longer propagated or tolerated is to be welcomed but it is just as bad to now go on a ST witchhunt. And it has as little basis in physics as the original hype had.

17. Sep 22, 2007

### arivero

Perhaps the two forums should be "Beyond Standard Model" and "Beyond General Relativity".

18. Sep 23, 2007

### marcus

Arivero thanks for calling attention to this very interesting conversation! In a way it can serve as a landmark signaling a change in how the issues are thought of and discussed in future. IMHO Greene does articulate a NEW position, which may be a very usual position in Europe where nonstring approaches have been given a place at the table and live in peace with string approaches (if I can judge from some things f-h has said at various times) without claims to exclusivity on either side.

So perhaps it is only new on the US scene, where string philosophy has been hyped as the "only this" and "only that" even in recent memory. Or perhaps a non-exclusionary attitude is not really new even in the US.

In any case, the Edge conversation seems to be tending more towards a EUROPEAN mentality where each bunch of theorists realizes that theirs is not the only car on the road. This still needs to be implemented in policy in the US, where there is at present only one university with a nonstring quantum gravity group: PhDs from there normally have to emigrate to Canada, UK, the Netherlands, France (to places where nonstring is more developed).

Maybe all that is obvious and not even controversial. So I want to look at what I would call the MAIN IDEA OF THE EDGE DISCOURSE----something that was set out by Steinhardt and is deeply insightful and constructive.

If we just wanted to talk about one thing from that trialog, surely it should be this!

The flaw in inflationary theory he is highlighting only applies to scenarios which resort to exotic matter---some kind of "inflaton" field. I think the key thing in this passage is Steinhardt's critique of the prevailing notions of inflation.

Last edited: Sep 23, 2007