Is string theory bad science or just bad for science?

Friday night I went, as usual, to the monthly meeting of my local astronomy club, of which I have been a member for many years. A friend of mine, for some inexplicable reason, had brought in a supposed psychic to speak about this whole 2012 thing. I’ll spare the gory details but I will note that she kept saying science was starting to prove her right (though she never elaborated). At one point someone asked a question about multiple dimensions and string theory and paranormal stuff or something like that – I had tuned out by that point (Note: I am somewhat open-minded about such things, but only with hard scientific evidence).

In any case, it nonetheless got me thinking that string theory has taken on a life of its own and become something that is bad for science – or is it just bad science period? String theory’s major problem is that, because it has never been tested in a laboratory (at least directly), no one really knows which of its crazy predictions is true. And many aspects of the theory are, in fact, not directly testable by definition! Now, there are plenty of theories out there that haven’t been tested yet including this stuff on closed time-like curves (i.e. wormholes) some of us have working on. But there are several differences.

First, our work is intended, primarily, to investigate some side problems in quantum information and quantum computing and we explicitly make it clear that the concept of a closed time-like curve is highly speculative. In other words, it’s a nice theoretical laboratory for testing some more mainstream ideas, but we realize that, in itself, it’s out there a bit. String theorists, on the other hand, thing their wackaloon ideas are Gospel.

Second, we’re not media hounds (at least in relation to this stuff). The string theorists (e.g. Brian Greene) have done such a good job selling their theory that over the past 15 years or so it has become the face of theoretical physics (which is utterly absurd since it is only a small portion of it). They then have no trouble appearing on TV and radio shows whose sole purpose seems to be an improved Nielsen rating and will happily let their imaginations run wild on the air while unsuspecting viewers and listeners start to think this is more than just speculation.

In the end the media blitz perpetrated by the string theorists over the past 15 years has done little or nothing to help the public understand the scientific method since the public is left (or even guided, in some cases?) to think that things like ghosts and paranormal experiences are evidence in support of string theory. Even if string theory turns out to be correct, the media blitz it has triggered has only muddied the notion of what science is and how it operates. In that sense, string theory has been very bad for science.

But is it bad science itself? I say, at least in part, yes, since aspects of it are not testable by definition (i.e. if the strings really are smaller than a Planck length there should be no way to ever confirm their existence). Developing a theory that is impossible to test, one way or another, smacks of religion in my book and, to me, that’s bad science.

Let’s hope, then, that people like Lee Smolin continue to challenge its supremacy in the mainstream media. Unfortunately, the best way to battle this would be to find an anti-string theorist who was as big a media hound as Brian Greene. Hey, CNN, I’m available!

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17 Responses to “Is string theory bad science or just bad for science?”

  1. “Developing a theory that is impossible to test, one way or another, smacks of religion in my book and, to me, that’s bad science”

    *Standing ovation for one*

  2. I can’t say that I entirely agree with you about whether string theory is bad science or not. I see it as more comparable to various interpretations of quantum mechanics. The Copenhagen interpretation for example is completely untestable in its entirety, but makes correct predictions for the things we can observe. In the same way it is meaningless to ask whether a particular interpretation is correct, I think it is meaning less to ask whether string theory is correct. What we need to do is ask if the predictions it makes about things we can observe are correct, and if it is distinguishable from other theories through physically realisable observations.

  3. quantummoxie Says:

    Despite being a theorist, I have come to believe that some (most?) of the ‘interpretations’ of quantum mechanics are as equally bad for science. The same wackaloons that cite string theory to support odd events, do the same with QM.

    You make a good point about predictions and the meaninglessness of our asking if a particular interpretation or theory is correct. But that was partly my point as well when I talk about it being ‘testable.’ String theory, to my knowledge, hasn’t successfully predicted any new phenomena. Since it is so much more complicated than anything else, Ockham’s (Occam’s) Razor suggests the other theories are at least more useful to work with, if not ‘correct.’

    Now, again despite being a theorist, I have absorbed some of my friend Dave Guerra’s outlook (Dave’s a colleague here at Saint Anselm). He’s an experimentalist and thinks physics essentially models physical phenomena as best it can, but that’s all it is – a model (or rather a collection of them that don’t always work well together). But there are ways to roughly determine is a theory is ‘good’ or not (e.g. the predictions).

    In any case, my beef with string theory is primarily that it has not been balanced by experiment. Historically, theory and experiment go hand in hand, in fact much like two hands climbing a rope – one leap-frogging the other, back and forth. String theory is ‘one-handed’ in that sense. That is the sense in which I think it is bad science, but that is an opinion and I could be entirely wrong about that.

    However, regardless of that, I still maintain that, even if it turns out to be correct, it has been (and continues to be) bad for science. This may be the fault of its practitioners and/or the media and entertainment industry, but it has nonetheless given a very false impression to the public. Many of the interpretations of quantum mechanics have done the same thing and I feel the same way about them (I have always disliked the many-worlds interpretation). Perhaps we simply need to do a better job of educating the public, but people like Brian Greene haven’t helped matters. Plus, at least in the US, the string theorists seemed for a long time to have hogged a disproportionately large chunk of the funding for theoretical physics, particularly for a theory that hasn’t seen any of its novel predictions proven yet, despite nearly thirty years of research.

  4. The atomic hypothesis was formulated 2500 years before it was validated by experiment. Was it bad science?

  5. quantummoxie Says:

    That’s only partly true. The Greek atomic hypothesis was very different from our modern understanding of atoms. In truth all the Greeks really did was a little bit of reasoning to assume that if you start chopping things up you’d eventually reach tiny pieces you couldn’t chop up anymore. That’s almost a trivial idea, particularly for a culture with no notion of infinity or zero. Note also that our modern day atoms, named after the Greek idea, have since turned out to not be the smallest things around since they can be sub-divided and even some of their components can be further sub-divided.

    In addition, the testability of the Greek idea was not considered logically impossible (even if they thought it may ave been practically impossible). Due to the fact that strings are supposed to be sub-Planckian objects, in theory there will be no way to ever tell if they really are strings or if they are, in fact, tiny gnomes all running around in a frenzy.

    So, in short, I don’t think your analogy works.

  6. “The Greek atomic hypothesis was very different from our modern understanding of atoms”

    The same we can say about Newtonian gravitation, is very different from general relativity, but you cannot say that the starting point of GR is Newtonian gravity.

    “In truth all the Greeks really did was a little bit of reasoning to assume that if you start chopping things up you’d eventually reach tiny pieces you couldn’t chop up anymore. That’s almost a trivial idea, particularly for a culture with no notion of infinity or zero.”

    That is not at all correct, Democritus reasoned for example that if matter were continuous then we cannot cut it, and other ingenious ideas that you can see, for example in an episode of “Cosmos” by Carl Sagan. The basic idea of atoms like the basic constituents of matter is the idea that lead to the modern concept of atoms.

    This idea of atoms was inherited by the first chemicals, by Newton and in the XIX century by Boltzmann to build Statistical Physics, but atoms at that time were seen by many physicists as only abstracts objects. For example the criticisms of Mach to Boltzmann lead to this one to the depression. Even Einstein complained that their professors did not want to teach anything regarding atoms. Atoms were seen in all this time, by the people that belived in them, as the basic constituents of matter, that is, basically the Greek idea.

    “Due to the fact that strings are supposed to be sub-Planckian objects, in theory there will be no way to ever tell if they really are strings or if they are, in fact, tiny gnomes all running around in a frenzy”

    Who supposes that strings are sub-Planckian objects?, all the books I have read about string theory say that the length of the strigs is of the order of Plack length, in fact there exists string theories in which the string length is grater that the Planck one, for example the posibility that fundamental strings exist as cosmic strings.

  7. quantummoxie Says:

    “The same we can say about Newtonian gravitation, is very different from general relativity, but you cannot say that the starting point of GR is Newtonian gravity.”

    But Newtonian gravity can be derived from GR. You can’t derive the Greek atomic theory from modern atomic physics.

    “That is not at all correct, Democritus reasoned for example that if matter were continuous then we cannot cut it,…”

    Indeed I stand corrected here. I was confusing the Eleatics with the Atomists.

    “This idea of atoms was inherited by the first chemicals, by Newton and in the XIX century by Boltzmann to build Statistical Physics, but atoms at that time were seen by many physicists as only abstracts objects.”

    You are correct here as well, but I think there’s a philosophical difference. So, for instance, Newtonian gravity is mathematically derivable from GR whereas what you’re talking about is more of a philosophical link since the exact nature of these theories is not derivable from modern atomic physics in that same sense. In other words, these older theories inspired the modern ones but did not hold up to the tests of time themselves (unlike Newtonian gravity – which, by the way, just demonstrates how amazing Newton was – I never thought about that before in quite that way).

    “Who supposes that strings are sub-Planckian objects?, all the books I have read about string theory say that the length of the strigs is of the order of Plack length,…”

    Well, even if they are exactly the Planck length, that’s right on the edge of testability – a nudge in the wrong direction and we’ll never find them. It was also my impression that cosmic strings were not related to the strings of string and M-theory. See Peebles’ book on physical cosmology.

  8. In the limit of low energies atoms are elementary particles, and can be identifyed, at least, with the atoms of John Dalton. (“New System of Chemical Philosophy” (1808).)

    And what if the atoms of the Greeks are not exactly what we know, the important thing is the idea, in words of Feynman “If, in some cataclysm, all of scientfic knowledge were to be destroyed” and only one sentence could be passed to the next generation, then the most important one would be the atomic hypothesis “all things are made of atoms -little particles that move around in perpetual motion,…” (from The Feynman Lectures on Physics).

    In the review “Cosmic Superstrings Revisited” by Joseph Polchinski, http://arxiv.org/abs/hep-th/0410082, you can see that there is a possibility that fundamental strings, not solitonic ones, grow up to cosmic size.

    In the last years there are many papers studying cosmologies derivables of string theory, and perhaps we can obtain testable consequences.

    Finally I love the freedom of research, the capacity of human beings to adventure themselves in the intrincacies of fundamental Physics. Planck scale is so far away…, really do you think that a theory describing the world at such energy would be immediately testable? What if string theory is, at least, the correct direction? Today I am very impressed by the derivable consequences of the simple sentence: “all things are made of strings -little strings that move around in perpetual motion,…”

    P.D.: I also respect very much others approaches to the ultimate theory, such as Loop Quantum Gravity and even the heroic Hardy’s approach. All these people are giving the best of their capacities. Thanks to all of them, I will never say that they are doing bad science.

  9. quantummoxie Says:

    Your quote of Feynman refers to the modern atomic hypothesis. The Greeks, from my understanding, did not include the notion of constant motion of these fundamental particles.

    In any case, philosophically I do see your point and perhaps I, myself, am having trouble drawing a line between ‘bad science’ and ‘bad for science.’ But as someone who is very involved in trying to educate non-scientists about science, I have big problems with the manner in which string theory, as a field, has conducted itself in the past decade or two.

    As a note, my PhD thesis was on Eddington’s Fundamental Theory, often derisively referred to as ‘numerology’ or ‘cosmonumerology’ (neither of which is true) so I don’t take these things lightly.

    Are there good things to be found in string theory? Sure, and it may even turn out to be correct (personally, I have no particular preference when it comes to any theory and will, in the face of evidence, happily pursue something new). But the seeming self-engrandizement practiced by its leading authorities – the monopolization of research funds, the nearly mystical manner in which it is presented to the public, and the often snobbish claims of its infallibility by many of its practitioners – is proving difficult to deal with when it comes to the public. For instance, as in the example that prompted this post, little old non-famous me can’t talk sense into these people because, well, Brian Greene said ‘this’ and, well, string theory is the leading area of theoretical physics, you know.

    And, while I may sound bitter, I don’t generally apply for much external funding (so I’ve never been burned by string theory in that department) and I even considered string theory as my primary area of research when I was in grad school. My work with Eddington, which I thought would take me in that direction (since Fundamental Theory was essentially an early attempt at a unified theory), instead, unexpectedly, moved me in the direction of foundational theories in quantum and statistical mechanics. In short, I’m not bitter about anything and am surprisingly open-minded. But I require evidence like any good scientist should.

  10. This constant chauvinism on the part of non-string theorists towards string theorists is what’s bad for science. By all means, study your own field. Just be aware that string theorists sitting in their departments aren’t wasting their time complaining about how much they can’t stand people who work on quantum information and quantum computing.

    Is string theory bad science? Well, *all* the leading ideas for physics beyond the Standard Model were generated by string theory, from supersymmetry to extra-dimensions and brane-world scenarios. Not to mention some of the SUSY-breaking scenarios. The glue-ball was first posited by string theorists in their old string model of the strong force. All these ideas are on the cutting edge of experimental physics, and the people working on them have high hopes that they will be observed at the LHC very soon. Their discovery would not confirm string theory of course, but the mere fact that string theory generated so many of the most powerful ideas used by phenomenologists today belies any claim that string theory has been bad for science. String theory has spat out matrix theory and provided the first explicit calculation of the Bekenstein-Hawking entropy of black holes in terms of microstates, and the result miraculously agrees. String theory has also generated countless new kinds of dualities, and opened up enormously many new insights into field theory. There’s also the great many string theorists hard at work trying to determine how cosmic inflation can fit into string theory, if it can, and what observable consequences that might have. (After all, the very early universe was hot enough to be sensitive to string theory, and the effects could be visible on the sky today.) Finally, the AdS/CFT correspondence, yet one more of string theory’s most important direct scions, has provided the first methods for explicitly calculating quantities in strongly-coupled non-Abelian gauge theories. AdS/CFT provides the first and only known nonperturbative definition of quantum gravity, albeit only in AdS backgrounds. AdS/CFT was used to finally settle the black hole information loss paradox. I personally know CM theorists who actually use string theory to compute numerous things that they say they’d never be able to do the old-fashioned way. And AdS/CFT has been a boon for RHIC physics. Nuclear theorists use string theory to study quark gluon plasmas, and they get results that agree with experiment. AdS/CFT has also been used to compute properties of *actual* black holes in our galaxy, those with large angular momenta and near-horizon limits that approximate a slice of AdS space. Then there’s the amazing ongoing work that uses AdS/CFT to study superconductivity. And I haven’t even mentioned the vast contributions string theory has made to mathematics.

    So, were some of the people who went on TV to promote string theory doing harm? Maybe. But you can’t judge a whole subject by the unwise behavior of some of its members. We all have misbehaving members. And the bitter tirades by non-string theorists are petty and infantile, and they *do* turn off bright young students who don’t know any better and who might otherwise grow up to make important contributions to physics. You don’t need to poison someone else’s subject just because you don’t like it—that’s childish. If you don’t like string theory, come up with a better idea. None of the other prominent ideas for quantum gravity have generated experimentally testable results (simple and general arguments, after all, show that in a 4D universe, the first quantum corrections to gravity are 10^-70 effects, which is hardly string theory’s fault), nor have they generated nearly as many by-products (such as the non-exhaustive list above) as string theory has.

    So stop the hatred already. Most string theorists respect greatly the work done by physicists in other fields—heck, much work in string theory lately has consisted of finding stringy tools that physicists in other fields can add to their toolboxes. They deserve exactly the same respect. Just as string theorists should avoid over-hyping their theories in the public, so should people like you stop spreading bile about fellow physicists.

  11. I know that I’m not going to change your mind about string theory, by the way. I’m sure that’s set too deep in stone. I’m only asking you, as one human being to another, not to waste your precious time attacking and demonizing other physicists in front of the public just because you don’t agree with the work they’re doing. I do hope that I can at least change your mind on that. I’m just asking for a little civility here. Is that really so much to ask? I know you wouldn’t like it if, I don’t know, cosmologists spent their time groaning to the public about how much they think you’re subject is going nowhere and is a waste of time. I know you’d be worried that young students might get turned off of a field that you care about.

  12. quantummoxie Says:

    Matt,

    Thanks for your comments. I think some of the language is a little harsh, but I will admit you have a point. My point wasn’t necessarily to demonize the subject, though I’ll admit it comes off that way. Part of me is definitely frustrated by the whole thing. But I’m also an historian of science (and cosmologist, by the way – I drifted into quantum information by way of foundational work) and string theory is unusual historically in that the theory has so outpaced the experiment. From that standpoint it does raise legitimate questions about ‘good science.’ On the other hand, you make a good point about how it has introduced methods that have proven useful in other areas of physics.

  13. I really appreciate your response. String theorists have no problem with the fact that others in the physics community are skeptical and even critical of their work. Skepticism is what makes science work. But I greatly appreciate that you agree with my larger point that we shouldn’t turn that healthy skepticism into demonization in front of the public. It turns off young students, and its overall effect on physics as a whole tends to be negative.

    We can also agree that string theory has so far outspaced experiments. But we might disagree on the reason why. In my opinion, it’s because, like I mentioned, the first perturbative quantum-mechanical corrections to general relativity can be computed without knowing the final theory beforehand, and these corrections are order 10^-70 effects. (See, for example, some of the papers by Donoghue.) So any theory of quantum gravity is going to have exactly the same sort of experimental difficulties as string theory, unless the theory is interesting enough that it can also spin off much larger effects indirectly, and indeed that’s one thing string theory is good at doing, as the list I gave you will indicate. The problem is that these very low-energy phenomenon are then decoupled from telling us whether string theory, the high-energy theory, is correct. There’s the challenge.

  14. I should also mention something else, by the way. I know a lot of string theorists, and while some are tough as nails, there are quite a few (as you’d find in any academic discipline) who are kind, and sometimes brilliant, but are nonetheless sensitive people. This isn’t the rough-and-tumble world of finance or politics. These are grad students and researchers, not all of whom have developed thick shells. It’s one thing to challenge their ideas, and quite another to talk about them in front of the public like they’re destroying all of science as we know it. When you read blogs like those by Woit, for example, it’s easy to get that sense. It should really go without saying that science itself, the discipline, is a robust enterprise that will not be destroyed by string theory, and to say otherwise in public is just mean and spiteful.

  15. “…is completely untestable in its entirety, but makes correct predictions for the things we can observe…”

    So does attributing gravity & other phenomena to angels, or leprechauns, or voodoo, or any other number of things that would get you laughed out of a room.

    I hate string theory, and I hate people who take string theorists seriously and give them money. These people don’t belong in academia and research – they belong in a seminary.

  16. Since the time of Maxwell, electric charge has been treated as a mathematical point. Quantum Mechanics and Special Relativity were invented to facilitate this mindset, and attempt to explain phenomena that could have been explained otherwise if electric charges were treated as spatially extended, as opposed to being points. As every Physicist knows, electric charges confined to a point have infinite self energy and no physical means to explain angular momentum, magnetic spin or energy exchange (radiation).

    All String Theory does is extend this point to a Plank scale Calabi Yau manifold of several dimensions, which is even more non physical. String Theory has been around for over 30 years, and it still has no field equations, has never been experimentally verified, and there are millions of potential Calabi Yau manifolds that could act as the fundamental String. It is great if you wish to garner grant money, because it has no solution.

    Actually, even the “straight” Grand Unified Theory requires non visible Dark Energy and Matter, Higg’s Bosons to explain mass, no unification of Gravity and Electromagnetism, 20+ fudge factors and truncated asymptotic series, plus arbitrary subtraction of annoying infinities just to explain a small group of experiments, where the data was probably massaged as well. Only until the electron and proton are properly treated as spatially extended charged entities, will Physics be back on the right track, because it resembles a comic book these daze.

    • quantummoxie Says:

      Well, I’m not so sure it’s necessary to treat them as spatially extended. I think we’re simply thinking about these things in all the wrong ways.

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