Dax discussions of Beyond SM theories/including newcomer questions

[Kevin_Axion]

That's exactly the points I was trying to address, surprised, you're a string theorist, correct?

 

[Lt_Dax]

Well what one calls theory is semantics, there is eg in mathematics also the theory of modular forms and countless other "theories", so the string phyisicists just don't care how their field of research is called and go on. It is the self-declared critics who are obsessed with this kind of questions, in particular with falsifiability.

Semantics (meaning) really does matter! It's unfair of you to call me a self-declared and obsessed critic because of that. The meaning of things really does matter, because if words can mean anything, then the discussion becomes meaningless. (And as I've said, I don't care about falsifiability because all ideas are "in principle" falsifiable).

Your comment about parts of mathematics which are called "theories" illustrates the point. I'm not talking about those parts of mathematics which can be called "formal theories" - where the word formal is used because we adhere to mathematical standards of proof. I am talking about "empirical theories" - which is what we mean when we call something a scientific theory. "Proof" in what scientists call a theory means something different.

Maybe the problem is that many string theorists trained as mathematicians, so they think that the only thing that matters is proof in mathematical sense?

The string physicists are more interested in positive questions, like what can be learned from the results and how to make further progress.

Again, your semantics are unclear to me. What do you mean by "results"? Part of the whole problem seems to be that people involved with speculative models feel comfortable with building upon results which haven't been rubber stamped by experiment yet. In the past, you could only build such a house of cards if you know that the foundations are correct.

In real science, contact with experiment is not a "goal", it is part of the enterprise. Right up until the 1980s it was always very close by.

Here's the problem: even for very high energy physics which might require something like a string theory, the cry of being devoid of experiments is false. Cosmological or even some condensed matter physics results may be capable of showing things which we can't do in a super accelerator (again some of these reports have been prominent lately). The point is that you develop a theory from these results, not in anticipation of them. This is what the creationism cartoon was mocking.

(And I believe there is a lot to be learned about how science works from the evolution/creation debate).

By the way, I'm beginning to wonder if string theorists often find no further recourse than a personal attack of some form. I realize that some of what I say is uncomfortable, but I'd prefer a crystal clear answer to some of my questions than accusations about personal character.

 

[negru]

@suprised, you make some interesting points, but I'm not convinced that what makes a scientific theory is falsifiability - as I've said before, I think this is given greater importance than it deserves.

So who exactly gives it greater importance than it deserves? The people who work on it? It's their business what they're interested in. The people who fund it? See my post above.

 

[Lt_Dax]

So who exactly gives it greater importance than it deserves? The people who work on it?

No, the usual low-quality critics of string theory who haven't really thought about it. The problem is that string theorists then spend too much time trying to claim that string theory is in principle falsifiable, even though it is irrelevant either way.

And I have to say, if someone's career is publicly funded, then the public has a say in what they work on. It's our job to explain to people how we're advancing physics. If they're self funded, then that's different.

 

[negru]

By the way, I'm beginning to wonder if string theorists often find no further recourse than a personal attack of some form. I realize that some of what I say is uncomfortable, but I'd prefer a crystal clear answer to some of my questions than accusations about personal character.

What you're saying is neither uncomfortable nor new, just usually uninformed, if you don't know what kind of results surprised is referring to. There have been a great deal of results coming out of string theory which apply to day-to-day physics, like scattering amplitudes in qcd. Today the easiest way to compute scattering amplitudes is via string theory.
Not to mention things like the klt relations. This has all been discussed hundreds of times on this forum. Just these applications to scattering amplitudes means that string theory will never go away, because it is directly intertwined with gauge theory and gravity. If there's any other qg theory out there, it will either be eaten by string theory, or eat it itself.


But of course, if string theory only says new things about old stuff, it wasn't actually needed in the first place, and if it says something completely new it's out of touch with reality.

 

[negru]

No, the usual low-quality critics of string theory who haven't really thought about it. The problem is that string theorists then spend too much time trying to claim that string theory is in principle falsifiable, even though it is irrelevant either way.

And I have to say, if someone's career is publicly funded, then the public has a say in what they work on. It's our job to explain to people how we're advancing physics. If they're self funded, then that's different.

You have good intentions, but seriously, the public doesn't know the difference between quantum physics and teleportation. Most people who come to this forum don't know this, despite having a greater than average interest in physics.

This isn't to say that whoever gives the money shouldn't have the last say, but the say will always be uniformed. The public will want to continue research in QM because they want teleportation, and they will want research in string theory because they want wormholes.

 

[Lt_Dax]

There have been a great deal of results coming out of string theory which apply to day-to-day physics, like scattering amplitudes in qcd. Today the easiest way to compute scattering amplitudes is via string theory.

Why reinvent the wheel? I'm not uninformed about these "results", so please don't make uncalled for accusations, I just don't view them as necessary. If they are just a calculational device, then are you saying that you don't really believe strings exist? Is this just like using complex plane integration to simplify tricky integrals in the real plane?

Just these applications to scattering amplitudes means that string theory will never go away, because it is directly intertwined with gauge theory and gravity.

Has this "calculational device" approach ever explained things which the standard model could never explain? Has it made new predictions beyond the standard model which we can search for soon? If the answer to both is no, then was it a waste of time?

 

[friend]

Maybe it would help to think in more general terms what a theory of everything would accomplish and what issues it would raise.

It might be with experiment we can discover smaller and smaller particles, and with time we can discover more interesting mathematical structures that describe them. But just because we can measure the properties of these smaller particles doesn't mean that we have an explanation for them. And just because we can predict their rate of occurance doesn't mean we understand why they exist.

We will always be asking why things are as they are until we can derive physics from the principles of reason alone. I think that's the ideal for a theory of everything, to be derived from logic alone. Such a theory would explain where the principles of QM and GR come from to begin with and why the SM has the constants it has. And I'm not so sure we're far off from that goal.

Then what becomes of the questions of falsifiability? Can you falsify a mathematical equation? Can you falsify a logical deduction? If the logic is impecible that give the physical prediction, then what are we to think if measurements are contrary? What are we to question, our sight or our reason? Perhaps that delemma is one reason many may be uncomfortable with supporting such efforts. Yet, isn't it the ultimate goal of science to "explain" everything - to prove that the universe is perfectly logical - to derive physics from logic?

 

[Lt_Dax]

This isn't to say that whoever gives the money shouldn't have the last say, but the say will always be uniformed. The public will want to continue research in QM because they want teleportation, and they will want research in string theory because they want wormholes.

Are you saying that we can just work on what we want, with a loose definition of how to build a scientific theory, because the unwashed plebians won't be able to tell the difference either way? I'm not comfortable with that view of the public.

 

[negru]

Has multiplication explained anything that addition could never explain?

Has QFT ever explained anything SR and QM could never explain?

 

[negru]

Are you saying that we can just work on what we want, with a loose definition of how to build a scientific theory, because the unwashed plebians won't be able to tell the difference either way? I'm not comfortable with that view of the public.

Well I'm not comfortable with publicly funded research in the first place. But if you're going to have it, it's not practical to ask the public what they want. I'm not comfortable with democracy either, but if you're going to have it, it's not going to be practical to ask the public to vote on every law itself. See what I mean?

 

[Lt_Dax]

Has multiplication explained anything that addition could never explain?

Has QFT ever explained anything SR and QM could never explain?

Answer to first question no, answer to second question yes.

 

[suprised]

It's unfair of you to call me a self-declared and obsessed critic because of that.

Oh I didn't mean you, be assured - there were plenty of other threads here over the years which is what I was referring to. With obession I mean that the same claims are made over and over again, by the same people, despite explanations to the contrary. With self-declared I mean people who don't understand the issues but nevertheless behave in a way as if they would be experts.

Maybe the problem is that many string theorists trained as mathematicians, so they think that the only thing that matters is proof in mathematical sense?

I don't quite understand what you mean here; why would there be a problem.

Again, your semantics are unclear to me. What do you mean by "results"?

Results like the successful count of microscopic quantum states in blach holes, and the AdS/CFT correspondence. The latter relates gauge to string theories, which is obviously of great importance.

Part of the whole problem seems to be that people involved with speculative models feel comfortable with building upon results which haven't been rubber stamped by experiment yet.
In the past, you could only build such a house of cards if you know that the foundations are correct.

Yes...that's true also today. That's why people are working very hard to understand the foundations of quantum gravity etc. Do you want to criticize this?

"Speculative" is often used misleadingly. Many results (eg see the above) are not speculative but just plainly follow from, or are strongly suggested by computations. That's why we don't talk about religion here. What is speculative is to build models and claim these describe nature.

In real science, contact with experiment is not a "goal", it is part of the enterprise. Right up until the 1980s it was always very close by.

What do you mean by "real science". You you realize how biased already your language is?

The point is that you develop a theory from these results, not in anticipation of them. .
..
(And I believe there is a lot to be learned about how science works from the evolution/creation debate).

I doubt it, theoretical physics is different. Again an example: there IS an apparent clash between GR and QM. This is likely the deepest basic questions in physics. Do you view it as a "problem" if a few people sit down and try to resolve it? Is it "purely mathematical" or "non-scientific"?

By the way, I'm beginning to wonder if string theorists often find no further recourse than a personal attack of some form.

There wasn't any attack. And apart from that, string physicists have quite good arguments, so your "no further recourse" is not appropriate.

 

[Kevin_Axion]

There is no need to be nihilistic towards a certain theory just because you may not understand the implications of String Theory or it doesn't conform to your idealization of what physics should be. If everyone had favoured your opinion in the 1970s theoretical physics, as suprised stated, would be absolutely bare of richness and beauty that has been discovered recently, particularly in the context of String Theory. Once again, I'll state that some people need to fully understand what something has done before ultimately stating that it's effects on physics have been minimal. Again, if everyone had said this about Superstring Theory SUSY wouldn't exist and SUSY appears to be a vital component to extending the Standard Model, Gauge/gravity duality wouldn't exist, String Dualities wouldn't exist, Holographic Principle wouldn't exist and unique approaches to understanding high-temperature superconductors wouldn't exist. String Theory has actually become unavoidable because its ability to explain certain aspects of reality is unprecedented.

 

[Lt_Dax]

Me: Maybe the problem is that many string theorists trained as mathematicians, so they think that the only thing that matters is proof in mathematical sense?

You: I don't quite understand what you mean here; why would there be a problem.

I'm tiring of this. If you actually believe that the criterion for accepting an idea in science is mathematical proof, whereas I believe it is experimental validation, then it is no wonder we are talking past each other.

Same goes for your conveniently loose definition of a "result". In my view the only kind of result that matters is an experimental one: either a result that calls for a new theory, or one which confirms a recent one. You talk about things such as AdS/CFT, which are new ways of thinking about QFT, as a result, but in a discussion like this, coffee break language doesn't cut it.

A conversation where we don't agree on the meanings of simple words can only descend into farce. Unfortunately, I assumed from the outset that these terms were so well established in science that we took them for granted.

I sought some clarification of why it is justified to claim that in BTSM theories we are discovering new physics rather than merely hypothesizing. People have made some interesting points but there has been no clear response to this question - I suspect that many string theorists actually disagree with it. Same goes for the theory issue - some of you guys have been claiming string theory is a theory, even though many string theorists accept that it isn't. With inconsistency like this within the same discipline, we can only ever descend into conversational farce.

So here it is: some people think I'm talking sense, others think I'm talking nonsense, and my initial criticisms have not been addressed, mainly because we are wasting time arguing about the meaning of words. Since I have to keep repeating points I made in my original post, I'm not particularly motivated to carry on with this discussion.

 

[marcus]

Dax, it puzzles me that although you stress the importance of physics being guided by phenomena (observation/experiment) you play down the value of nearterm falsifiability.

Falsifiability is one form of testability (a particularly strong form) which could include weaker forms such as constraint of parameters and other types of guidance as well. There is, I think you would agree, special value in near term testability.

The judgment as to whether something is legitimate empirical science, or abstract math, or crackpot, or pseudoscience must surely be a subjective consensus-type judgment by the scientific community involving some imprecision and perceived differences of degree. Can't ever be perfectly clear cut black-or-white. Science is an aristocratic community and a tradition, not a computer program.

I suppose that is why people find it necessary to get defensive, argue interminably, and engage in special pleading and occasional propaganda. These are community functions.

Anyway, I urge you not to deprecate the value of nearterm falsifiability. And note that it's important when the phenomenologists themselves (whose professional job is to identify and delineate testability) determine that a theory is falsifiable.

When they decide, that is, while the theoreticians have not asked for it and may even be a little reluctant to accept the idea.

 

[negru]

Well you keep arguing about the meaning of words, what is a real vs unreal theory, when string theorists couldn't care less about any of this and are busy finding interesting results, in whatever form they appear. You say people are focusing too much on reaching a particular conclusion, when in fact it's you doing that. String theorists don't care what they need to find. They just look for what's interesting. But we also had this discussion when we were arguing about the significance of the scattering amplitudes developments.

 

[Lt_Dax]

@marcus I agree that near-term falsifiability is practically important and you can't really make progress without it. I just think that it doesn't go into what makes something a theory or not. However on both counts, the case for pursuing string theory is weakened. Unfortunately, it's practically impossible to have a conversation about this with clever people who will play mental gymnastics with the meaning of words in order to accommodate their view.

It is a sad indictment on people's reasoning ability that I was accused of using biased language for claiming there is such a thing as real science. This is the reason I don't feel like carrying on with this discussion.

 

[marcus]

@marcus I agree that near-term falsifiability is practically important and you can't really make progress without it. I just think that it doesn't go into what makes something a theory or not. However on both counts, the case for pursuing string theory is weakened. Unfortunately, it's practically impossible to have a conversation about this with clever people who will play mental gymnastics with the meaning of words in order to accommodate their view.

It is a sad indictment on the current state of the physics community that I was accused of using biased language for claiming there is such a thing as real science. This is the reason I don't feel like carrying on with this discussion.

Please don't be offended or disheartened. This is your first thread here at PF and you have caused a very lively active one. We learn from observing what people get defensive about and become heated and impassioned over. The issues are not to be settled but we learn a lot by noting what arguments are employed. Bravo. (Now I am applying the masculine case as I think of you, perhaps it is the symbiont who is a he.)

I am not too concerned with stringery---I think that in practical terms like new jobs the interest in it is moderating in the physics community. People have to say a lot of things just to keep their morale up. Like trumpeting black hole entropy and taking credit for holographic principle.

We are not obliged to show reverence or devotion---we can ignore the hat-on-the-stick symbol if we choose.

 

[Lt_Dax]

Yes the symbiont has been a he on several occasions.

 

[petergreat]

Imagine Schrodinger, Bohr, Heisenberg et. al. developing QM before there was even a shred of proof that energy was quantized. Not only would it have been rather silly (c.f. my creationism cartoon), but I doubt it would even have been possible. How much more so is this true for far more complex modern physics?

If these people were smart enough, they could have developed quantum mechanics in 1870, when Mendeleev had already published his periodic table but well before the discovery of electrons, atomic nuclei, photoelectric effect, Balmer series and so on. After all, the periodic table encodes many elements of quantum mechanics, i.e. quantized nuclear charge, gradual filling of electron energy levels, fermi statistics restricting 2 electron per orbit, and existence of neutrons to make up missing atomic weights etc. Certainly the periodic table was a better hint towards new physics than today's dark energy.

So Even if experimental physics halted in 1870, these people could have worked out a theory compatible with all the features of the periodic table. If they were as clever as string theorists, they might even come up with a beautiful theory explaining these elements as Kaluza-Klein multiplets, or obtain a whole landscape of periodic tables!

 

[Lt_Dax]

The periodic table is an experimental result, and indirect evidence of quantization, isn't it?

 

[Kevin_Axion]

Ok, this will continue ad infinitum, let's just settle our differences and realize that they won't change by a mild debate amongst conflicting views.

 

[marcus]

... let's just settle our differences and realize that they won't change ...

I think we will choose not to, at this point, Kevin. Because the topic in Dax opener is the role of phenomena (observation, experiment, measurement, prediction...) in the development of physical theory. It is a general issue, more interesting than stringy specifics.

And some phenomenologists, possibly to the dismay of some Loop theorists, have recently determined LQG to be falsifiable by observation of the polarization in ancient light.

Some of these phenomenologists (whose past work has involved several other theories besides Loop) are Aurelien Barrau, Julien Grain, Wen Zhao. There are a half-dozen others who have co-authored with one or more of these in a series of papers.
https://www.physicsforums.com/showthread.php?p=2983268#post2983268
http://www.math.columbia.edu/~woit/wordpress/?p=3262&cpage=1#comment-67952

Zhao is at Cardiff, Barrau is at Grenoble (sometime CERN), Grain is at Paris.

What happened is kind of intriguing. The work of Ashtekar's Penn State group, and many others, has confirmed since 2006 that the bounce is a highly robust conclusion from Loop cosmology. Meanwhile a lot of bridges have been built between the full (spinfoam) LQG theory and the application to cosmology. One can even start with a simple spinfoam version of LQG and derive a bounce.

Possibly to some Loop theorists' surprise, Barrau and friends have determined that a Loop bounce must have a particular signature in the B-mode polarization of ancient light. It puts LQG at risk and is either interesting or exciting depending on one's moral character and point of view.

This may put several persons' noses out of joint and they may have nasty things to say about it ---scorn denial etc. We can't predict but it will be instructive to see the reaction. Someone will probably mention Lee Smolin, but this whole thing has nothing to do with Smolin or any of his current research. It is basically on Ashtekar and Rovelli's plate and you need to know their recent work to comment intelligently.

To summarize: The conservative Baconian stance taken in Dax opening post is pragmatically correct. And quantum gravity theory is going to move ahead in concert with experiment/observation whether you like it or not.

 

[marcus]

I have to go out for a while but will continue later.
Loop QG space is tending to become the space we use to talk about the early universe. You can see that with a simple keyword search of the Stanford/SLAC database of physics research papers. Recent "quantum cosmology"

There's a simple reason for this. I'll try to explain when I get back. It won't always necessarily be the quantum geometric framework for early universe---could be replaced by an improved version or something different! But that's the current trend and there's a reason to point out.
Back later.
============
I'm back.
The reason has to do with what Dax said in the first post. But this may not be immediately obvious. It's not because of presumed "rightness or wrongness"----we only have superstitions about that, can't presume to know future.

The reason is that LQG gives a mathematical representation of the geometry of the whole universe, that you can calculate with.
It has a Hilbert space of quantum states of geometry and a pathintegral or spinfoam way for them to evolve---simple enough to calculate with. And this is what cosmologists need.

It is what General Relativity gives you, a dynamic geometry instead of a fixed pre-determined one. You have to have this to do cosmology. Cosmology is the key to observation here (because our image of the early universe is enormously magnified by expansion.) The only trouble with GR being that it fails at the bang---it does not allow time-evolution to proceed back before the start of expansion. The spacetime geometry of GR is the basis for cosmology, so to go back into the very early you need a quantum geometry to take its place.

LQG is experiencing rapid growth now precisely because it provides a simple tractable model of the geometry of the early universe. One you can try out your ideas with. To a first approximation for practical purposes it doesn't matter whether right or wrong. The competition currently offers dubious handwave, or fixed pre-determined geometries, or ones based on GR that blow up at the start. Whatever they offer it seems not to be what the cosmologists are used to or find convenient to work with.

=======================

A rival approach could get in on this action by offering an appropriate quantum dynamical model of the geometry of the whole universe, to compete for some of LQG cosmology business. But I didn't hear of any competition yet, in practical terms that you can get your hands on and play around with.

=======================

The reason this is a valuable stimulus for Loop progress goes back to what Dax said. Early universe is our window on extreme physics. Theory needs to progress in concert with observation/experiment. Quantum gravity MEANS QUANTUM GEOMETRY and to connect to quantum geometry phenomena you need to provide a spacetime geometric home for the early universe.

This may seem roundabout but contemporary experience bears it out and if you listen to the chain of reasoning you will hear Empiricism talking and giving you her advice.

If you do a search of Spires HEP archive with keyword "quantum cosmology" for consecutive years you will see this rapid growth I am talking about. Loop gives the observational people a quantum geometry they can use.

Or so I think. That's how I interpret the past 4 or 5 years changes. You may have different explanations and understanding.
http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=dk+quantum+cosmology+and+date+%3E2006&FORMAT=WWW&SEQUENCE=citecount%28d%29

 

[Fra]

(I've been troubleshooting intermittently failing RAM modules for the last days and now finally found the bad one)

I sought some clarification of why it is justified to claim that in BTSM theories we are discovering new physics rather than merely hypothesizing.

I missed out the whole discussion and I'm not sure what the key question really was, but I too certainly wouldn't label "discovering" dualities in ambigously created theory spaces as "new physics". That's not to say it won't lead anywhere, but I think theoretical speculation is a better word.

It's more like a exploration of a specific theory space, construction and transformations of theories, where we find mathematical patterns and relations. Wether this has any physical significance is still an open question IMO, beucase the logic of inference applied when doing this is NOT unique. It's perhaps almost unique given certain premises; but that's the same thing. The basic premises and abstractions of ST (for example; although I agree this discussion isn't specific to ST) aren't objectively justified.

I don't think it's not necessarily bad with speculations, mathematical or philosophical - they are needed - but one must still be fair and not confuse these things with the physics content.

/Fredrik

 

[suprised]

I'm tiring of this. If you actually believe that the criterion for accepting an idea in science is mathematical proof, whereas I believe it is experimental validation, then it is no wonder we are talking past each other.

No I didnt mean that. What I meant is that the problem you allude to isn’t one. Only very few string theorists have were trained as mathematicians, and they think as physicists and not mathematicians. And they are smart enough to not confuse a mathematical proof with physical reality.

It is you who has a prejudice how poeple think and work, and this is sneaks in all the time. Like your “real science”…this expresses your doubts that string theory is real science. Or your “Same goes for your conveniently loose definition of a “result” below. Sorry, a result is a result! For example, that certain correlations functions in Yang-Mills theory and string theory coincide. This is a mathematical fact, and NOT a “conveniently loose definition”.

Same goes for your conveniently loose definition of a "result". In my view the only kind of result that matters is an experimental one:...

Well that’s your point of view. Fine. Many don’t share this point of view.

A conversation where we don't agree on the meanings of simple words can only descend into farce. Unfortunately, I assumed from the outset that these terms were so well established in science that we took them for granted.

Frankly I begin to doubt that you really know how science works.

I sought some clarification of why it is justified to claim that in BTSM theories we are discovering new physics rather than merely hypothesizing. People have made some interesting points but there has been no clear response to this question - I suspect that many string theorists actually disagree with it.

Again deriding: “merely hypothesizing”. Sorry, things are a bit more intricate than coffe table talk. Take for example, black holes. No one has yet seen one by naked eye (perhaps fortunately). Still they exist as solutions of Einsteins equations and people have been starting investigating them theoretically, even without initial experimantel evidence. You may call this “merely hypothesizing” but this is viewed by many as an important line of reasearch; and indeed, just because of the theoretical investigations which lead to understanding various properties of black holes, indirect evidence for their existence has been found, and I guess almost no serious astrophysicist would doubt their existence. If science would be done like you advocate it, namely starting from experimantal obervations, we wouldn’t be there where we are (as you need precise clues for what you look for, otherwise you may never notice it).

Same goes for the theory issue - some of you guys have been claiming string theory is a theory, even though many string theorists accept that it isn't. With inconsistency like this within the same discipline, we can only ever descend into conversational farce.

Because there is no absolute definition what a “theory” is. Every one may have a slightly different idea about this, that’s why you get different answers. And that’s also why this is an irrelevant point to discuss about. What matters are results, not names. It is you who brought up this irrelevant discussion, and now you complain.

 

[Fra]

You may call this “merely hypothesizing” but this is viewed by many as an important line of reasearch

I agree with that. Hypothesis generation - the precursor of any theory, is of course an important part of a scientific process. And the logic of hypothesis formation is extremely interesting. Something that is sometimes completely lost is simplistic analysis when one only focusys on the falsification/corroboration part, which is the easy part of the process.

I think one can simultaneously acknowledge the importance of thel logic of hypothesis generation (which relates to theory spaces) and still admitt that there is a difference between this and physics contents, although there may be some deeper ways in which they are related (but I don't think that's the main focus here).

/Fredrik

 

[Lt_Dax]

Frankly I begin to doubt that you really know how science works.

You smug and arrogant individual. People who resort to hubris usually do so when they feel threatened. (and it's not surprising that you didn't elaborate on the above point, because it was merely an ad hominem attack).

If I've learned one thing in this whole conversation, it's that it's other people who are apparently unclear about science works, not myself. You claim that the concept of a theory hasn't been well defined, which is ridiculous. If a "theory" can mean anything you like, or a "result" can mean anything you like, then you may as well be working on the perfect barm cake recipe.

This is why I will not choose to stay in academia: science is wonderful, but the people are ugly, petty and have muddled thinking, and there is too much of a tendency to "feather the nest". When people have decades-long careers to defend, they will change the meaning of words which have been well established through four centuries of history in order to squeeze in their pet project.

 

[Lt_Dax]

The google ads currently generated for my page about evolution being only a theory are somewhat amusing in the context. Hold that thought, I may come back to it in a few moments.

 

[MTd2]

This is why I will not choose to stay in academia: science is wonderful, but the people are ugly, petty and have muddled thinking, and there is too much of a tendency to "feather the nest".

That is not a reason for you not to stay in academia. In fact, you can make yourself quite comfortable given that the vast majority is the very attached to science as you and me (I agree 100% with you) see it. Besides, it is a wonderful source of models to high energy physics.

 

[Lt_Dax]

I actually enjoy models, we can learn from them, they're just not oracles of physical reality. Hold that thought for now...

 

[Lt_Dax]

About the silly claim that the term "theory" is ill defined. It's not. Its meaning was not established through dogma (that is agreed) - it was established through centuries of experience. This generally agreed definition is accepted because it works (pragmatism).

Bear in mind that if this wasn't true, we wouldn't be able to respond to creationists who claim that evolution is "only a theory".

(Note that dictionaries also report colloquial definitions of theory, like hunch, and mathematical theories - I ignore those).

Webster's dictionary:
From the primary entry:
theory: ""a scientific hypothesis that survives experimental testing becomes a scientific theory".

Webster's dictionary (secondary entry):
theory (science): "An explanation for some phenomenon that is based on observation, experimentation, and reasoning."

theory (geology) "...but in science, something is not called a theory until it has been confirmed over the course of many independent experiments. Theories are more certain than hypotheses, but less certain than laws."

Webster's wiktionary:
theory (sciences) "A coherent statement or set of statements that attempts to explain observed phenomena. There is now a well-developed theory of electrical charge."

Wikipedia:
Scientific theory: "A scientific theory is constructed to conform to available empirical data about such observations, and is put forth as a principle or body of principles for explaining a class of phenomena."

Wikipedia:
Same entry, pedagogical definition, USNAS: "The formal scientific definition of theory is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence." and "One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observed."

(Wikipedia distinguishes an empirical theory, which is a scientific theory, from a formal theory, which means mathematical proof not scientific proof).

Oxford dictionary:
theory, noun: "a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained: Darwin's theory of evolution".

TheFreeDictionary.com:
theory:"A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena."

Don't believe a string theorist who claims that there is no generally accepted view of the word theory. Evolutionary biologists, chemists, other physicists, geologists, etc., who are all professional scientists to be respected, and who all engaged in building scientific theories, all agree with the above definitions. You can't do careful work unless the basic principles of your subject are established.

 

[suprised]

Look, this discussion is completely irrelevant. It should be about the scientific content and not the name. While the many hundreds of people working on the subject of strings happily call this string theory, you are welcome to call it different. I don't mind if you call it "string $#$*#$", it won't make any difference. But I doubt you can convince the people in the field to call it "string $#$*#$".

Let me rethink what I said about obsession.

 

[MTd2]

I actually enjoy models, we can learn from them, they're just not oracles of physical reality. Hold that thought for now...

I was just giving you a reason not to give up academia.

 

[Lt_Dax]

Look, this discussion is completely irrelevant. It should be about the scientific content and not the name. While the many hundreds of people working on the subject of strings happily call this string theory, you are welcome to call it different. I don't mind if you call it "string $#$*#$", it won't make any difference. But I doubt you can convince the people in the field to call it "string $#$*#$".

Let me rethink what I said about obsession.

No, the discussion is not irrelevant, you just want it to be, because you find it uncomfortable.

You also make it sound like string theorists secretly know that it's just a model (or to use a cringeworthy term favoured by others, a "framework"), but I know this is not the case. If anything, the highest practitioners in the field (such as Green, Witten and others) talk in more grandiose terms than others. They not only think it is a theory, they think it is a theory of everything (!) and that the reason it is correct is because it is beautiful. Well beauty doesn't cut it. People who follow the Koran claim that its beauty is an indicator of truth , but obviously this argument is easily ignored.

I'll ignore the comment about obsession.

 

[Lt_Dax]

I was just giving you a reason not to give up academia.

I appreciate your support

 

[Lt_Dax]

It should be about the scientific content and not the name.

If any content is "scientific" then it can be, and should be, described in terms of meaningful words. Language, communication, really does matter. How can it not?

I've noticed that you are no longer challenging my point about what a theory is, now you've changed your argument to claiming that string theory is a theory, they just don't call it one by name - even though they actually do (huh? This is severely muddled up thinking). Both points are manifestly incorrect, and I have addressed both of these points in previous posts so there's no point in repeating what I've said before.

I think my original question about why we call progress in string theory discovery of new physics has been answered: string theorists don't even know. They contradict each other, and even an individual string theorist contradicts himself/herself!

 

[Lt_Dax]

Hypothesis generation - the precursor of any theory, is of course an important part of a scientific process. And the logic of hypothesis formation is extremely interesting. Something that is sometimes completely lost is simplistic analysis when one only focusys on the falsification/corroboration part, which is the easy part of the process.

I just want to pick up on this if I may. I never said that hypothesizing is not part of science. I said that engaging in hypothesizing alone, and claiming it is progress, or even discovery, as your hypothesis becomes more and more complex, is meaningless. Hypothesizing and testing the hypothesis to see if it can be accepted into a theory go hand in hand, like bangers and mash.

This is why it is absurd when people say that we don't understand string theory yet, using language as though we're actually slowly unveiling physical reality. You don't understand your own hypothesis which you seek to test? Ridiculous! The whole point of generating a hypothesis is that it is well understood so it can be tested. It certainly should not morph into some sort of pseudotheoretical collection of hypotheses (I'm sorry, a "framework" ). The claim made by Witten that string theory is 21st century physics discovered in the 20th century shows you the hubristic mentality of the people involved, in my opinion.

 

[negru]

I'm surprised no one brought up the "but membranes aren't 1d why do people still call it string theory" discussion.

Dax, honestly, no one cares and will never care what exactly is a "theory" and if string theory qualifies as one. People only care about results. If you think the name of string theory should be changed...I don't know, try writing to your congressman.

And for the love of god (pun intended) do stop already with creationist vs evolutionist argument. It's childish, getting old, and you're misusing it.

 

[Lt_Dax]

Dax, honestly, no one cares and will never care what exactly is a "theory" and if string theory qualifies as one.

Correction, some string theorists don't care. Many thinking people do care. I'm not alone. You have a nerve accusing me of childishness, when you try to dismiss an entire thread with "nobody cares"! That's school playground language!

People only care about results.

And what makes something a "result"? Is something a result because it gets accepted for publication? This viewpoint stinks. Just because an idea is published, doesn't mean it represents physical reality. Maybe it's true that people only care about the number of publications and citations they get. Publish or perish?

And for the love of god (pun intended) do stop already with creationist vs evolutionist argument. It's childish, getting old, and you're misusing it.

In what way am I misusing it (care to explain)? It's highly relevant. There isn't one definition of science in evolutionary biology, and another in physics. The methods of science are universal. We only divide science into separate subjects to make it easier to understand. Nature doesn't have clean dividing lines.

You can't conveniently dismiss the discussion about evolution/creation just because it comes from a different subject. It illustrates the point perfectly about what a theory is. Need I repeat that it means something much more precise than just an idea? This really matters, whether you think it does or not.

I repeat that it's quite amusing of you to accuse me of being childish, when your concluding argument seems to be merely "it doesn't matter, nobody cares, stop whining". Is that the best you can do?

 

[Haelfix]

I just want to pick up on this if I may. I never said that hypothesizing is not part of science. I said that engaging in hypothesizing alone, and claiming it is progress, or even discovery, as your hypothesis becomes more and more complex, is meaningless.

Suffice it to say, I think you'll find that most proffessionals will disagree with this statement. I certainly do, and I suspect most others will as well.

Sometimes progress can be made in pure theory, without the need for experiment. Its particularly true that you can falsify most ideas, long before you ever test them.

When a statement is inconsistent with logic, then that's all there is too it. I don't need experiment to tell me that the collision between two gravitons does not output pink elephants.

The reason so many people believe in string theory, is that there aren't many (arguably any) viable alternatives and you are very much bootstrapped into this way of thinking through a rather tight network of highly plausible inferences (for instance, the existence of black holes as being 'real').

In some ways, it is the theory with the minimal set of assumptions necessary that also simultaneously explains the bewildering array of modern physics that is observed.

This is not supposed to be *obvious* to a layman! They see complicated mathematics, extra dimensions and a bunch of structure that looks many steps removed from the laboratory and immediately complain. Well, until one actually does the math and see's that the arguments for each step are actually pretty tame and natural, be sure that the person will stay hostile to the idea.

 

[Lt_Dax]

Suffice it to say, I think you'll find that most proffessionals will disagree with this statement. I certainly do, and I suspect most others will as well.

Hypothesizing is not discovery, no matter how sound or simple the step of logic used to achieve your hypothesis. It still needs to be tested to become a theory - a description of reality. A "professional" is not correct just because they have authority.

Sometimes progress can be made in pure theory, without the need for experiment.

The word progress could mean anything here. What do you mean? Lots of publications? By the way, the concept of "pure theory" is a contradiction in terms. A theory is linked to experiment by definition.

Its particularly true that you can falsify most ideas, long before you ever test them.

You can't falsify a hypothesis without testing it, by definition. However, if something is logically flawed, then it never gets called up for testing in the first place. It's not even a hypothesis, it's trash, surely.

The reason so many people believe in string theory, is that there aren't many (arguably any) viable alternatives

Alternatives in doing what? You're going to have to be more clear than this.

In some ways, it is the theory with the minimal set of assumptions necessary that also simultaneously explains the bewildering array of modern physics that is observed.

Most of observed modern physics is explained with the standard model, and the rest of the unsolved observations are not explained by string theory, otherwise we wouldn't even be having this conversation. So what are you talking about?

This is not supposed to be *obvious* to a layman! They see complicated mathematics, extra dimensions and a bunch of structure that looks many steps removed from the laboratory and immediately complain. Well, until one actually does the math and see's that the arguments for each step are actually pretty tame and natural, be sure that the person will stay hostile to the idea.

Well, I'm not a layman (although I'm not a string theorist), so I don't know how this applies in this case. I resent the implication that I'm too stupid to see how wonderful and beautiful string theory is. This sounds a lot like when religious people say that a person just doesn't have god's spirit and therefore couldn't possibly appreciate the beauty and truth of said belief. It's a bogus argument and a fallacy.

 

[Haelfix]

When I say progress, I mean discovery about how the real world works (tm). When I say alternatives, I mean alternatives about the nature of the Planckian world.

"Most of observed modern physics is explained with the standard model, and the rest of the unsolved observations are not explained by string theory, otherwise we wouldn't even be having this conversation"

Umm, String theory contains the standard model as a low energy limit, and I don't know which 'unsolved observations' you are referring too? B/c in principle, it does contain the explanation! That's what it means to be a possible theory of everything! If you can find an observation about the real world that string theory does not contain, then by definition you have falsified the theory.

"You can't falsify a hypothesis without testing it, by definition. However, if something is logically flawed, then it never gets called up for testing in the first place. It's not even a hypothesis, it's trash, surely."

Now you are playing with semantics and besides, this is wrong! You *can* falsify theories without testing them. Most of the time a Gedanken is all that is required.

For instance, I don't need to test the nature and predictions of creationism. I know its wrong, b/c it is logically inconsistent and absurd and clashes with many known phenomenon that have been tested.

 

[Lt_Dax]

When I say progress, I mean discovery about how the real world works

To find out how the real world works you have to interrogate nature. There is simply no alternative - even if your ideas are wonderful, they have to be tested.

When I say alternatives, I mean alternatives about the nature of the Planckian world.

We bring up alternatives as and when they are needed. Special relativity was proposed because there were unexplainable experimental observations. We do currently have unexplainable experimental observations, but string theory doesn't explain them, it purports to do something different (I assure you that if string theory explained these things we don't understand, it would be all over the world's media).

Umm, String theory contains the standard model as a low energy limit, and I don't know which 'unsolved observations' you are referring too?

String theory contains the standard model, so what? Why reinvent the wheel? Some people have suggested that ST is merely a calculational device for amplitudes. In that case then, it doesn't even qualify as a hypothesis, it's just a tool. Some unsolved observations: Dark energy/matter, the arrow of time, the origin of mass, explaining confinement, neutrinos etc. etc. Has string theory had explained these things? If it had we'd have heard about it.

Now you are playing with semantics and besides, this is wrong! You *can* falsify theories without testing them. Most of the time a Gedanken is all that is required.

No, my semantics (meaning) are clear. I have been crystal clear about what I mean by "theory", "result", "hypothesis" - on the other hand, you contradict yourself within the same sentence even! You've already changed from "hypothesis" to "theory" in your response! So who's playing games with meaning? Not only that, but you merely made an assertion (that you can falsify a theory without experiment) without explanation. And I don't know what a Gedanken is...

For instance, I don't need to test the nature and predictions of creationism. I know its wrong, b/c it is logically inconsistent and absurd and clashes with many known phenomenon that have been tested.

Creationism does not qualify as a hypothesis because the existence of god, for example, can neither be proved or disproved and is therefore not a scientific question. This proves my point, not yours.

 

[marcus]

... String theory contains the standard model as a low energy limit, ...

Haelfix I don't think it is true that any version of SST contains the SM and its 20-some mass etc parameters (correct me if I'm wrong) but I would be interested if you would give me an arxiv reference to some paper which documents a version of SST which comes closest to that desirable goal. If you have a favorite amonst the many alternatives, I'd be delighted to read about it.

...String theory contains the standard model, so what? Why reinvent the wheel?...

But Lieutenant, where did you hear that SST contains the standard model of particle physics? I have always heard the contrary, from sources I consider reliable. They have made great efforts, trying various ways to roll up and stabilize the extra dimensions, in the attempt to get standard particle physics with its various particle masses, coupling constants and so forth. I think it would be great news if those efforts had succeeded!

Let's see what journal article preprint (online arxiv source) Haelfix offers us.

 

[Lt_Dax]

But Lieutenant, where did you hear that SST contains the standard model of particle physics? I have always heard the contrary, from sources I consider reliable.

I was just taking his word for it really - although since I've not seen any publication which shows this myself, I share your skepticism.

 

[Kevin_Axion]

Lt_Dax do you think you can tell me what exactly everyone is arguing about, is it the merits and faults of String Theory? This has become very unclear to me.

 

[Lt_Dax]

Kevin_Axion, my primary point of contention has been about why it is justified to claim physics discovery and what it means to discover anything in science - my viewpoint has somewhat hardened from asking a question to making an assertion - mainly because it has become clear that many practicing string theorists have never sat down to think about what all these words we chuck around actually mean (I no longer feel like an inexperienced student asking a question - I overestimated the wisdom of the people I was asking.)

But as I've said in the distant past, this is not about questioning the interesting nature of string theory or its usefulness in model building - but I've never been able to have a decent conversation about this because some string theorists have been using words like theory, hypothesis, model, framework, result, progress interchangeably. Others are dismissive and say it doesn't even matter and that I should stop "complaining". So I agree with you that it is confusing, but this is not your fault or mine.

 

[samalkhaiat]

If this was 1954, this thread would have been about Yang-Mill’s theory! Back then, some people (mostly non-professionals) called it “fancy mathematics”, others (including some professionals) said: “it is worthless” because it disagreed with the observed short-range nuclear force. But, a class of good physicists saw Yang-Mill’s as a “beautiful and logical next step in theoretical physics”.
It took those good physicists 20 years of hard work to realize that nature is indeed fundamentally Yang-Mill’s. They, deservedly, got Nobel prizes and we (thanks to them and to Yang and Mill) got the electro-weak and QCD.
So, people work on string theory because they see it as “the one and only logical next step in theoretical physics". Those who can't see this, well they just can't!

Regards

sam