Is string theory a theory?

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Here to read an article of Richard Dawid about the T duality and S duality as equivalence principle for ontology and scientific realism
Richard Dawid is the conference CEO in Munich on monday. He is theoretical physicist and philosopher at the mathematical philosophy institute in munich

http://homepage.univie.ac.at/richard.dawid/Eigene Texte/10.pdf
 
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From the end of section 3

"Scientific theories in general cannot be expected to fit all possible empirical evidence. The
specific status of string theory changes this situation in two respects. First, string theory offers
a number of reasons for being called a final theory. (see e.g. (Witten 1996), (Dawid 2004).)
Therefore, the assertion that string theory, if fully understood, could fit all possible empirical
evidence, has a certain degree of plausibility. Second, in the context of string theory the claim
of Quinean underdetermination is not based on the accidental occurrence of several
empirically equivalent theoretical schemes but on a physical principle, the principle of
duality, which represents a deep characteristic of the involved theories and may be expected
to be a stable feature of future fundamental physics. It seems plausible to assume that the
duality principle will continue to play an important role even if string theory changed
substantially in the course of future research."

Parts of "string theory" are stepping stones regardless...
 
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yes but nevertheless it is like a war, what happens right now.

Here a capital out of a book from the same author but only in german, which describes both positions and what is underlying in this war against String physicists
very good analysis. From the book: Wenn Naturwissenschaftler über Naturwissenschaftlichkeit streiten, in Pseudowissenschaft. Konzeptionen von Nicht-/Wissenschaftlichkeit in der Wissenschaftsgeschichte , D. Rupnow, V. Lipphardt, J. Thiel und C. Wessely (eds.): 395-416, Suhrkamp 2008.

http://homepage.univie.ac.at/richard.dawid/Eigene Texte/14.pdf
 
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The only German word I know is Zitterbewegung, laugh out loud...
 

fresh_42

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The only German word I know is Zitterbewegung, laugh out loud...
I've recently read "Ansatz" in an English scientific article!
 
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The only German word I know is Zitterbewegung, laugh out loud...
oh you will know a lot more, when you studied physics or mathematics. Most words in mathematics and physics are german words. Eigenvector, Ansatz, Gedankenexperiment and much more. All german words.

;-)

but to come back to the theme: The war. Actually there was an experiment which should prove holographic principle in spacetime. This is a speculation of Stringphysicist Lenni Susskind that there is such a principle. But Hogan is against stringtheory and wanted to show how absurd all these theories are. Hogan is not everyone. but read by yourself what it was about.

http://backreaction.blogspot.de/2015/12/what-fermilabs-holometer-experiment.html
 
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or ansatzes is an educated guess that is verified later by its results.

This should sum it up: String theory nor any other might ever be able to predict random quantum interference (zitterbewegung?) when the ansatz of an atom causing physical action is only half the non-local (eigen?) value?
 
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or ansatzes is an educated guess that is verified later by its results.

This should sum it up: String theory nor any other might ever be able to predict random quantum interference (zitterbewegung?) when the ansatz of an atom causing physical action is only half the non-local (eigen?) value?
random quantum interference should be Zitterbewegung? Never heard before.
 

fresh_42

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Even no result is a result! For how long do they search gravitational waves now? For how long have black holes been regarded as a mathematical peculiarity? But remember this if those "too far" galaxies won't be found.

Seemingly this kind of war you are talking about belongs to physics. I just hoped it had been kept in the 20th century when fundamental concepts of as well physics as mathematics have been challenged. Things have changed a lot since Hilbert and Bohr. Judging content by publications, reputation or fields of research obviously not. I'd wish scientific staff would live a lot more without prejudices and Vanity Fairs.
Not everyone with an unusual idea or a new point of view is automatically a trisectionist. (Those people writing letters to faculties "proving" they can divide angels into three parts or in former times claimed to have solved FLT.)
 
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Even no result is a result! For how long do they search gravitational waves now? For how long have black holes been regarded as a mathematical peculiarity? But remember this if those "too far" galaxies won't be found.

Seemingly this kind of war you are talking about belongs to physics. I just hoped it had been kept in the 20th century when fundamental concepts of as well physics as mathematics have been challenged. Things have changed a lot since Hilbert and Bohr. Judging content by publications, reputation or fields of research obviously not. I'd wish scientific staff would live a lot more without prejudices and Vanity Fairs.
Not everyone with an unusual idea or a new point of view is automatically a trisectionist. (Those people writing letters to faculties "proving" they can divide angels into three parts or in former times claimed to have solved FLT.)
We had this war often in the 20th century. first when Einstein came out with his GR. Later with Kopenhagen definition/interpretation of QT. In the scientific community is often a war. Mostly it is about groupthinking, reputation and financial support. The first time and phase in history where we had some kind of peace was between the 1970s to about 1995 (Dawid says 2002 but gave the latence time after Witten showed M Theory and where some people get aware, what it meant for them) This was the time where we had really a free open research and no scientific wars.
 

haushofer

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I can understand why physicists don't want speculations because all the last 70 years we had much speculations about quantumtheory and their interpretation. Heisenberg saw this long before and said that we only should calculate and don't want to see in the black box (although he was much more afraid of the positivistic lame middleintelligent physicists who only take all for granted what he was talking about without thinking by themself) . But you cannot forbid to look in the black box and then a lot of esoteric religions, believing systems developed over the time. Evene the religions itselves are now argueing with quantumtheory for their believing system (free will, probability etc.)
And now we have a lot of physicists who are religious in some kind also and want to defend this established physics for their believing system too. Big bang with creator, Quantumtheory for free will etc.
We have now similar situation as it was in old greek before Platon.

On the other hand we have now the first possibility with string theory to get a theory which cannot be misused for religious believing system because it is explicitely without a creator, without indeterministic interpretations. This makes a lot people afraid.

Freud explained this behaviour and thinking behind of such physicists and religious people psychologically that it is a narzistic violation. We had it all the time in science history.
It was with the end of ptolomaic worldview. With darwins evolutiontheory and now we get it with modern physics of multiverses especially which makes most afraid.
Well, for me the issue is not religion. It is about interpretation. We should not only calculate, but also interpret. Sometimes I have the feeling that there is an attitute that concepts and interpretations are left over for philosophy. And when philosophers do talk about these issues, it is not seldomly being regarded as irrelevant by physicists. I can e.g. understand that with the history of QM people people have become reluctant and suspicious to talk about interpretations of QM, but as far as I can see it's a valid debate. Somehow it seems a bit odd to me that we have developed string theory and still have interpretation-issues with QM. I rarely see the question being adressed whether the interpretation-issue of QM can affect the quantum gravity debate.

For me the reason why the interpretation-issue of QM doesn't get more attention is more a matter of sociology than rationality.
 

marcus

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Speaking of the Munich conference "Why trust a theory?" a philosopher of science named Massimo Pigliucci (MP)provided an extensive account of the first day's talks.
Here are excerpts of his summary of the first two talks of the day---by David Gross and Carlo Rovelli:
==quote from MP==
...
...
So, let us get started with David Gross, talking on “What is a theory?” Gross began by noticing that philosophy and physics have, ahem, “grown apart” over the years — citing the now classic quote by Richard Feynman about philosophy, birds, and ornithology. Gross himself said, however, that he envies the pioneers of quantum mechanics and relativity, who were well versed in philosophy, and he still thinks there is much the two fields can say to each other.
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The crucial issue is strategy, not ideology: we shouldn’t be discussing what science is or is not — since the scientific method itself evolves continuously — but rather what works and what doesn’t. One of the reasons for this meeting is that physics makes predictions that are far out of the current limits of experimentation, around the energy level at which all forces, including gravity, unify (10^28 eV, the Planck scale).
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Theorists may give up, or they may play with extrapolation, or toy models (i.e., thought experiments). They could also adopt strategies from other fields, like mathematics, where beauty is a criterion for success. [Uhm, that’s pretty dangerous territory…]

String “theory” (framework, really) started about 47 years ago out of a data fitting problem, and it didn’t even feature strings at the time, as it initially was a theory of the behavior of gauge mesons. Then people immediately realized that string theory “must” contain gravity, and it is this sort of unexpected theoretical consequences that have kept the excitement going.

But string theory isn’t really a theory — you can’t write its equations on a t-shirt, after all! String theory and quantum field theory are, according to Gross, part of a larger framework. The problem is that we don’t have any idea of how the framework in question picks the Standard Model, hence connecting to experimentally based physics. Here, Gross also thinks, is perhaps where philosophers — who are used to think carefully — may help.
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Gross thinks that the “no alternatives argument” introduced by Dawid (see below) is a powerful one in favor of string theory, as it is not easy to change a framework. [I guess Kuhn would call these paradigms?] There is also an “unexpected explanatory power” argument based on the fact that the string framework connects elegantly with a number of other known notions in physics. Finally, there is the “meta-inductive argument,” according to which past speculative but strongly supported (by the physics community) theories have turned out to be correct. As I said, these are the argument actually advanced by the conference organizer, Richard Dawid, so I’ll return to them shortly below.

[Some of the testiness underlying the conference became briefly evident during an exchange between the next speaker, Rovelli, and Gross. Rovelli pointed out that Gross had gone way over time, and asked whether the organizers would take time out of his talk or from dinner. To which Gross replied that he will surely interrupt Rovelli’s talk too. And he did, somewhat rudely I must say, follow up on his threat. Ouch.]

Next was Carlo Rovelli, on “Non-empirical confirmation: just a cover-up for the failures of string theory?” He started out by saying that Dawid makes good points in his paper on non-empirical confirmation, about the analyzability of the context of discovery, for instance. But also that Dawid confuses the context of discovery with the context of validation. [Smells of Popper here.] He also confuses descriptive and normative philosophy of science, misreading the history of string theory, since the latter has failed by the lights of its own stated criteria for validation.

Rovelli traced the distinction between context of discovery and of validation to Reichenbach (1938). The time between the two can be very long, as for instance between the publication of Copernicus and Galileo’s books on the structure of the solar system (1543 vs 1610).

[Rovelli has a good general point, though I must also signal that modern philosophers of science do not make a sharp distinction between the two contexts, as discovery and validation are continuously interacting processes.]

Theoretical work is guided by preliminary appraisal, i.e. weak evaluation. This aids the decision of whether to take the theory seriously enough to develop it and test it further. Dawid’s criteria are good as preliminary, weak evaluations of string theory. But they fail as validations.

Rovelli, amusingly, quotes Lakatos [an influential student of Popper]: “It is no success of Newtonian theory that stones, when dropped, fall towards the Earth.” The speaker then listed a good number of past theories that seemed very promising, and yet turned out to be very clearly wrong.

String theory itself set out validation criteria early on in its history: computing the parameters of the Standard Model from first principles, for instance, or deriving the existence of three families (of particles) from first principles, or predicting the sign of the cosmological constant, or predicting new particles to be discovered at LHC energy levels, or low energy supersymmetry, and so forth. According to Rovelli, all of these failed, turning string theorists into the mythical fox who argued she didn’t really like the grapes, once it was clear that she couldn’t reach them… [Nice classical reference to Aesop!]

There are alternatives, like loop quantum gravity (which actually can be written on a t-shirt!). For Rovelli this is just as not yet validated as string theory, but at the least its existence rejects the oft-made claim that string theory is the only game in town. He also cautioned about confusing “tenure in major universities with consensus of the scientific community,” pointing out that Gross won the Nobel and has a position at a major university because of his non-string work.

Rovelli concluded by pointing out that claiming that a theory is valid even though no experiment has confirmed it destroys the confidence that society has in science, and it also misleads young scientists into embracing sterile research programs. [Lakatos would have called them “degenerate.”]

After coffee break it was Dawid’s turn with “Non-empirical Confirmation.” Though his focus is on string theory, his ideas are applicable to other frameworks as well. He began by acknowledging that the theory hasn’t found empirical confirmation for quite some time, and moreover that this state of affairs may continue long into the future. Nevertheless, ...
===quote===
https://platofootnote.wordpress.com/2015/12/08/why-trust-a-theory-part-i/
http://www.whytrustatheory2015.philosophie.uni-muenchen.de/index.html
http://www.whytrustatheory2015.philosophie.uni-muenchen.de/program/index.html
http://www.whytrustatheory2015.philosophie.uni-muenchen.de/media/index.html
 
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Fra

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I apologize for my quite intermittent prescence on the forums, life is just keeping me too busy. Good to see some of the old users still here!

The crucial issue is strategy, not ideology: we shouldn’t be discussing what science is or is not — since the scientific method itself evolves continuously — but rather what works and what doesn’t.
The problem is that we don’t have any idea of how the framework in question picks the Standard Model, hence connecting to experimentally based physics.
I think these two lines sums is up well. To me it also means that wether a scientist thinks that string theory (here I mean the framework, and "way of thinking") is the most rational way to make things work or not, to a certain extent mirrors their preferred logic of reasoning about fundamental physics.

So - if we have no idea how ST framework "picks" the SM, the quesion is if it can still be a viable strategy? I think not even those that are not fans of ST, will deny that the ST framework has decent flexibility as framework for adapting theories. But the question is, if the core problem is variability or selectivity? IMO an evolutionary model, and evolving framworks such as evolution of life, or learning, needs both. Of course some of the "selections" takes place against interactions with the environment of the host systems (scienticsts making experiments in this case) but a viable strategy should imo still _at each stage of evolution_ be well balanced between options and guidance, otherwise the host system risks destabilize and be deselected.

The idea that a microstructure such as a multidimensional strong encodes interactsion is perfectly rational and sound IMO. This is not at all the problem. The problem is that it is not as sound, to postulate the details in such a complex model from nothing. There is something missing in the strategy here. To make this complete me need a still missing guiding principle, for how to connect these non-observable microstructures. I think these principles exists, but they aren't found yet. And as far as I see it, most string papers I have seen are using a way of reasoning that makes me thing it will NOT be found from that side.

/Fredrik
 

marcus

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Hi Fredrik, your post #65 makes it look as if I said those two things. You write that "marcus said" but of course I did not say those things. Just to be clear: they are not my words, they are quotes from Massimo Pigliucci one of the speakers at the conference, who took notes on what the other speakers said.
 

Fra

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Ah you're right Marcus, sorry for beeing carless about quotations! I used the quote button but forgot to edit it to make it clearer that you quoted someone else.

/Fredrik
 
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String theory is certainly not more "untestable" or more "religion" than, e.g., loop quantum gravity (LQG).
big bang quote " I guess I prefer my space stringy instead of loopy " :smile:
 
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So, let us get started with David Gross, talking on “What is a theory?” Gross began by noticing that philosophy and physics have, ahem, “grown apart” over the years — citing the now classic quote by Richard Feynman about philosophy, birds, and ornithology. Gross himself said, however, that he envies the pioneers of quantum mechanics and relativity, who were well versed in philosophy, and he still thinks there is much the two fields can say to each other.
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In your following part you have left out, what Gross was really saying on the congress. Here the more important footnote:

"Gross proposed to distinguish among frameworks, theories, and models. Classical mechanics, quantum mechanics and string “theory” are not theories, but rather frameworks. Theories are something like Newton’s or Einstein’s theory of gravity, or the unfortunately named Standard “Model.” Theories can be tested, frameworks not so much. Models include the BCS model of superconductivity, or BSM (Beyond Standard Model) models.

According to Gross, quantum mechanics, for instance, cannot really be tested directly. But the Standard “Model” can. Also, theories (at the least in physics), are compact enough that they can apparently be written on a t-shirt. Not so for frameworks."

I think this is the best description, what Gross had to say and was as introduction to the congress a very important hint for further discussions.
 

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