As a disclaimer, my experience with physics is limited to a semester of calculus and a year of physics for biology majors in college.
Still, a theory with no empirical proof, no way of getting such, that has done nothing to advance knowledge outside of its own created confines, does not sound like solid science to me.
I wish it was either supported by evidence or else abandoned in favor of something else. I'm all for adding to the sum total of human knowledge, but if it isn't true, then the physics department across the country are writing papers to create the encyclopedia for a fantasy world.
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posted
You exaggerate. String theorists are few and far between; most particle physicists are of precisely the opinion that, until it comes up with some experimental tests, string theory is just not very interesting. (In fact, at a recent conference I attended, there was a contest for 'most unlikely finding of the LHC'. One of the entries was 'Evidence for string theory'). It's one of those theories that everybody has heard of but few people actually work with.
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And, incidentally, that article is pure media hysteria. I know any number of theorists, young and old, who have nothing but contempt for string theory; to state that you have to join the club to get anywhere in high-energy physics is sheerest bunkum.
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I'd like to hear it from someone else. Dr. Rabbit, do you know anything about this?
quote:String theory became a media obsession about 20 years ago, with one of its proponents a cover boy of a New York Times Magazine article proclaiming string theorists were super-ultra geniuses cracking the ultimate riddles of creation. Smolin's book suggests that this caused string theorists to believe their media hype and to speak of their concepts as if they were proven. For example, they talk of "branes" (short for membranes) of limited dimensions passing through realms of multitudinous dimensions and describe branes as actual physical regions. Yet after decades of attempts, no experiment has detected any hint of additional dimensions, branes, or other core elements of string theory. Meanwhile string theory failed to predict the biggest astrophysical discovery in decades, the 1998 finding that cosmic expansion is accelerating, apparently owing to powerful "dark energy" that nobody can explain. After dark energy was discovered, string theorists simply revised their equations to predict it. That's not science, The Trouble With Physics contends.
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String Bikini's are no theory. They are a glorious, well proven fact. One for which I am usually for, although there are a time or two I was interested in removing the bikinis from the situation at hand....
oh Bokum, not Bikini.
Well, excuse me, but my topic is much more interesting,
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Hmm. Well, on speaking to some other physics types, perhaps I was a little hasty in my dismissal. It seems there are 'formal theorists' who are largely string theorists, and 'phenomenologists' who are the kind of people I know; and the string theorists do in fact dominate theory departments. Still, I'm not convinced this is such a huge problem; it means some universities are paying for physics and getting pure math, but then again, pure math is quite nice too. And it's not as though there's a lack of theorists who come up with the kind of theory that does actually explain experimental results. It'll sort itself out.
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quote:And, incidentally, that article is pure media hysteria. I know any number of theorists, young and old, who have nothing but contempt for string theory; to state that you have to join the club to get anywhere in high-energy physics is sheerest bunkum.
Well, you don't need to be a string theorist to get a job, period. But if you want to do work on quantum gravity at a top department, you do basically need to be a string theorist.
Harvard/Princeton/MIT/Caltech don't really hire loop quantum gravity theorists. Ever.
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quote:Still, I'm not convinced this is such a huge problem; it means some universities are paying for physics and getting pure math, but then again, pure math is quite nice too.
Actually, this is a common misconception, that strings is pure math. The dimensional stuff is very mathematical, of course, but the core of the theory is path integral quantization, which is completely mathematically ill-defined.
Most string theory (like much of quantum field theory, to be fair) consists of doing integrals on spaces with no well-defined measure.
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There is indeed bokum. You knew what I meant, right?
quote:Main Entry: ho·kum Pronunciation: 'hO-k&m Function: noun Etymology: probably blend of hocus-pocus and bunkum 1 : a device used (as by showmen) to evoke a desired audience response 2 : pretentious nonsense : BUNKUM
Main Entry: bun·kum Variant(s): or bun·combe /'b&[ng]-k&m/ Function: noun Etymology: Buncombe county, N.C.; from a remark made by its congressman, who defended an irrelevant speech by claiming that he was speaking to Buncombe : insincere or foolish talk : NONSENSE
Clearly I needed word that included the meanings of nonsense, pretentious, and language only a small audience could understand. Neither hokum nor bunkum fit all of those, but the combined word does. Posts: 26077 | Registered: Mar 2000
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Katie, my dad (theoretical physicist) thinks much the same as KoM: the math is nice, but so far there isn't much more than to it. However, his colleague, Kip Thorne (you know, the guy who published a peer-reviewed paper on how to use a wormhole to make a time machine) works with string theory. My feeling is that Kip is an extremely intelligent guy, and I don't understand most of the stuff he does. But if he puts stock it, it's usually not hokum. Or bunkum either.
(Hmm. Can't find anything on Kip's website. But I'm pretty sure he works with string theory . . .)
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Are there any plans to test it? How long is it okay to believe in a theory without proof? Hmm...it sounds like the math supports it, but in order to make the math work, suppositions must be made like that of the other dimensions. The only proof for those suppositions is the math, but that does sound a little circular to me. That's not a reason to not believe it, but is the math sufficient? For how long? What if it never goes anywhere - the math supports it, but then it just sits there and nothing can be built on it?
---
The problem with the title is that there is a word for pretentious nonsense, and a word for foolish nonsense, but not a word for nonsense that is both foolish and pretentious. Can anyone think of one? Maybe Jonathon Swift came up with one.
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It is a bit circular. Which is why my dad says it's a nice idea, but at this point not much more.
I think those people who are working in the field are trying to come up with ways to test it, but I honestly don't really know. (Or much care.)
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Well, there are a few possible experiments that could be done, if I recall correctly, but most of them require colliders or other apparatus that we don't have the engineering ability to create.
I don't think string theory is strictly unfalsifiable, just practically unfalsifiable.
posted
Oh, Bokonon slips and and spoils the very crude funny.
Though Bokonon posting at that precise moment is pretty funny in itself. To me.
I think String Theory is a lot like the Language Acquisition Device. Satisfying, Untestable, and doomed to irrelevance.
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I don't want to charge anyone with fraud. I'm just concerned, as well as being a bit of a science groupie. I hated working in the lab and so had no desire to be a scientist myself, but I like reading about it. I think solving the mysteries of science is like delving into the mind of God.
If the string theory is true, then I want something to happen to prove it, so that things can go forward. If it isn't, then I want it to lose favor so another, more fruitful direction can emerge. But scientific advance isn't something that can be scheduled or counted on - how long did we have to wait for calculus?
pooka: Besides being crude, which I wasn't going for, I don't think that's precise enough. Posts: 26077 | Registered: Mar 2000
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"If the string theory is true, then I want something to happen to prove it, so that things can go forward. If it isn't, then I want it to lose favor so another, more fruitful direction can emerge. But scientific advance isn't something that can be scheduled or counted on - how long did we have to wait for calculus?"
String theory is likely to end up being true... at least, more likely then anything else we've got right now that does the same thing.
There are also a number of experiments that could be done to test string theory, just, as stated, none with what we can do YET.
So we are within the realm of a scientific hypothesis, but its not a theory yet.
Part of the reason that string theory is so popular with university physics departments is that further developing the math and theory of string theory, might allow us to produce experiments, or toss it aside. The thing is, there's no reason to work with any other theory that combines quantum mechanics and gravity over string theory, and there are reasons to work with string theory over, for example, loop gravity quantum theory.
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quote:Still, I'm not convinced this is such a huge problem; it means some universities are paying for physics and getting pure math, but then again, pure math is quite nice too.
Actually, this is a common misconception, that strings is pure math. The dimensional stuff is very mathematical, of course, but the core of the theory is path integral quantization, which is completely mathematically ill-defined.
Most string theory (like much of quantum field theory, to be fair) consists of doing integrals on spaces with no well-defined measure.
(begin technical question)
Could you elaborate on this? I was under the impression that QFT and string theory both take place on various manifolds. Manifolds, being homeomorphic to R^n have LOTS of (local) measures on them.
Are you saying a global measure doesn't exist? Why can't one be strung together with a partition of unity?
(if this is too off topic, I wouldn't mind another thread ;-) ) (end techincal question)
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If the LHC finds the Higgs mass is 160 billion electron volts, Alain Connes's noncommutative geometry will be all the rage.
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quote:Could you elaborate on this? I was under the impression that QFT and string theory both take place on various manifolds. Manifolds, being homeomorphic to R^n have LOTS of (local) measures on them.
The fields themselves are defined on Minkowski space, of course.
But when quantizing QCD, for instance, the method of Feynman path integrals is used. This requires you to integrate over all of the possible paths a particle can take between a source and a receptor. And in the relativistic case, no invariant measure on the space of paths has yet been discovered. (The space of paths is infinite-dimensional.)
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I asked my dad's opinion on the article. He thinks (I'm paraphrasing) that it's a tempest in a teapot -- the author is not such a big noise in physics as the article (and the author) claim, and none of his criticisms are anything new. More importantly, there is no attempt to explain the intellectual issues that lead to the current situation.
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You realize that if half of this thread were to appear on an Star Trek episode, we'd all accuse them of techno-babble.
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Rivka, if I remember correctly from another thread, your dad is Barry Simon.
He actually has an important book on the path integral approach Mathematician and I were just talking about.
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I just wanted to respond to one particular point in that article.
quote:The physics establishment reacted adversely to Smolin's cosmic natural selection because the idea implies direction:
Why? Regardless of the specifics of his natural selection theory and whether it's accurate or not, why does the idea of a cosmic natural selection imply any sort of direction? Does biological natural selection imply any sort of direction? I don't see why the "physics establishment" would react adversely to that type of theory unless it was in regards to the specific math/physics involved in forming that theory.
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The physics establishment hasn't really reacted adversely to the cosmic natural selection idea, except insofar as any theory of origins is considered too speculative to be of much interest.
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quote:Rivka, if I remember correctly from another thread, your dad is Barry Simon.
Yup.
quote:He actually has an important book on the path integral approach Mathematician and I were just talking about.
Which book is that? I can understand the acknowledgements page in most of his books. Wait, it's not the orthogonal polynomials one, is it? (See how casually I can toss off bits of titles I don't understand? )
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I agree with Destineer. Nobody's defending some sort of Holy Randomness, not that natural selection contradicts such a thing anyway; but this kind of theory is, well, 'vigorous handwaving' is a kind way to put it.
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yeah, my issue wasn't with the fact that the scientific community reacted adversely to the theory, but the authors' stated reason for the adverse reaction.
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I have finally nailed down why "bokum" sounds so wrong to me. It's because I expect the next word to be "Dano."
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Pardon me... but being the physics geek that I am...
quote:However, his colleague, Kip Thorne (you know, the guy who published a peer-reviewed paper on how to use a wormhole to make a time machine) works with string theory.
...your dad works with Kip Thorne?!
As to the actual topic. I know there are pure string theorists out there, cause one applied for a lecturer position at Skidmore last year. The talk he gave when he visited was on string theory. I don't really understand it well enough to judge it yet, but my gut sense is that if it can't be tested by experiment then it ain't science, it's math.
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quote:Originally posted by Alcon: Pardon me... but being the physics geek that I am...
quote:However, his colleague, Kip Thorne (you know, the guy who published a peer-reviewed paper on how to use a wormhole to make a time machine) works with string theory.
posted
Hi! Rivka never said I worked with Kip, only that I'm his colleague - we are both Professors of Theoretical Physics at Caltech (I'm also in Math) but our research interests are different. We do serve on committee's together.
Also, I don't think Kip has actually worked on string theory himself - because of LIGO, he has been focusing on numerical General Relativity for the past few years trying to get a handle on how to interpret what we hope LIGO will see.
The Slate article was overblown - but there was a kernel of truth. String theory does rule the roost in some parts of theoretical high energy physics and in many major departments. But it does seem at this time to be the only candidate for consistently putting together gravity and quantum theory.
While it is NOT mathematics, it has has critical spinoff in mathematics - for example the topology of 4 dimensional manifolds was revolutionized about 10 years ago by the Seiberg-Witten equations developed in the context of strings and Yang Mills theories.
I'm still shocked that you actually deleted that thread. I suppose that's what I get for pushing your buttons.
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I went to a lecture last year at SLAC by David Gross, a nobel laureate who is one of the people who came up with the string theory. I can't really repeat what he said cause, honestly, I don't remember most of it. All I remember is I was sure as hell convinced. And I think LHC WILL find evidence of the string theory.
Edit: In 08 all dicsussion will be moot anyway, LHC begins operations in November 07.
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quote:The Slate article was overblown - but there was a kernel of truth. String theory does rule the roost in some parts of theoretical high energy physics and in many major departments. But it does seem at this time to be the only candidate for consistently putting together gravity and quantum theory.
While it is NOT mathematics, it has has critical spinoff in mathematics - for example the topology of 4 dimensional manifolds was revolutionized about 10 years ago by the Seiberg-Witten equations developed in the context of strings and Yang Mills theories.
I'm glad that it isn't circling in on itself - that it's leading to breakthroughs in other areas.
Still, how long do you think a theory can be held without proof of itself? Maybe it being the only conceieved of alternative is not an argument for it but instead an indication that there isn't enough support in other areas to think of other things.
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Well certain string theory formulations have "proven themselves"... In the sense that they haven't predicted answers that conflict with known observed experiments. So it's got that going for it.
But yeah, I'd be interested in a run-down of some of the novel predictions string theory makes that would prove it versus the current models.
posted
(I wouldn't necessarily expect my dad to post again. He's like Halley's Comet -- observable once every 76 years.)
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quote:In 08 all dicsussion will be moot anyway, LHC begins operations in November 07.
Yeah, and we know what the LHC will bring, giant mutant lizards, and wierd pirate/ninja brain-eating zombie robots from alternate dimensions. What good will your theory of strings do you then? huh? when the cutlass wielding, black belted, undead cyborg comes looking for your mind to devour, huh? huh? tell me that smart guy?
OK. The nice man in the white coat says its time for my pills.
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