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The Dangerous Irrelevance of String Theory

188 points by seycombi 9y ago

PhantomGremlin 9y ago
It's very sad how so many bright physicists have made this their life's work, and yet: the problem with string theory is that, in its landscape version, it has a hugely complicated and poorly understood high energy scale behavior, seemingly capable of producing a very wide range of possible observable effects, none of which have been seen
- coldtea 9y ago
  Sad that many bright theoretical physicists have been doing science? Because, even if a theory doesn't pan out, it' s still science: you've researched an avenue and came to certain conclusions. And perhaps this is most of science work -- not the "found a new theory" but "checked whether this theory works" (and same for experimental science).
  - kobeya 9y ago
    The problem, as talked about in the article, is that it is NOT science. Science involves experimentation, which string theory so far has eschewed. It more resembles mathematics in that sense (which is ostensibly not a science either).
    - coldtea 9y ago
      That's just a not very well thought out definition of science, and is wrong on several counts. 1) Science does not necessarily involve experimentation. 2) String theory has attempted many times at experimental verification. 3) Math are more experimental than most people think.
      - dhimes 9y ago
        A scientific hypothesis must be falsifiable, by definition. Some have tried unsuccessfully to argue this away, but it is still the majority opinion. And it's for this reason: once you open the "scientific" world to unfalsifiable hypotheses, you open it up to a bunch of bullshit. That is not to say, however, that all important work must be scientific. There is a certain value to exploratory work, which can guide the direction of experiments in such a way as "if we could get experiment X then we could turn hypothesis Y into a testable hypothesis." In my opinion that is important work. You can see this in fields like psychology and such where the systems are just too complex to be easily testable (even medicine to some degree). But if we don't keep pursuing we will never get there.
        yulaow 9y ago
        We have this problem in general in science at this point of time, probably because of the big scope of our modern theories. EG: We already consider "Dark Energy" a sort of made-up assumption to justify a model which, after recent observations was considered falsified. So, instead of focusing on others we decided to keep using it, we created a not-falsifiable nor testable assumption (dark energy indeed) and kept going with it, even if it violates everything Popper teach us. Honestly it seems to me that, especially in physics, too many people are just too much mentally involved in their own theory that they have an hard time just dropping it when it doesn't seem to work anymore.
        dhimes 9y ago
        Perhaps, but science is a human endeavor like any other and thus subject to human biases. I think a great example is the discovery of the neutrino. Particle tracks showed a clear violation of energy, momentum and angular momentum, but Pauli and others believed in these fundamental properties of the universe so strongly that he (they?) proposed a particle that was virtually undetectable to keep those properties. This was a non-scientific hypothesis at the time, but it told scientists the direction they needed to pursue in order to get to the point where the hypothesis could become scientific. Most argue that the discovery of the neutrino saved the fundamental conservation laws, but we should never lose sight of the fact that we still don't detect them in a very large percentage of events we record (we say simply that they are there, but interact weakly). One important measure of whether a hypothesis is likely going to be accepted as true in the future is that as we build better and more sensitive detectors we detect more outcomes favorable to the hypothesis. This is the way smart money bets when data are still hard to come by (see 'climate change').
      - rotorblade 9y ago
        Indeed. To emphasize '1)' you could mention most astro- related fields: astronomy, astrophysics, etc, which are almost purely observational.
        kobeya 9y ago
        Observational and experimental are not opposed attributes. For astronomers the universe is the laboratory, and that is fine. An astronomer can say "I predict binary black holes to emit gravitational waves of a certain sort" and then go and find a binary black hole system and see if it does. That is experimentation.
        rotorblade 9y ago
        I can possibly agree with that notion of experiment. My point, in the context of the discussion, was that just because we do not have a an idea for an experiment that would test string theory, in some definite way, does not exclude that there is some possible observation within reach.
        kobeya 9y ago
        Sure, but it becomes troublesome when they stop bothering to look.
- reikonomusha 9y ago
  If you look at string theory as a piece of mathematics, which may provide a language for physicists to use and generate hypotheses, it doesn't seem so bad. I suspect this is closer to the motivation of the theoretical physicists working on it (including folks like Ed Witten, who are really mathematicians in disguise).
  - AstralStorm 9y ago
    Hopefully to be replaced with something far less cumbersome soon. And providing testable hypotheses.
  - noobermin 9y ago
    String theory might occupy a different space perhaps, this is kind of like changing the underlying domain so now your function is "continuous" somewhere, although String theory and HEP theory in general isn't quite rigorous enough to be considered mathematics proper.
- Animats 9y ago
  Like "expert systems". (Anyone remember those?) I went through Stanford CS in the mid-1980s, just as it was becoming clear that expert systems didn't do very much. But there were many faculty heavily invested in the technology. Feigenbaum was running around telling Congress that the US would "become an agrarian nation" unless they funded a big national knowledge system lab headed by him. Strong AI was supposed to work Real Soon Now. What actually happened was the "AI Winter" - for about two decades, not much happened. The AI startups from the 1980s went bust.
  - zer0tonin 9y ago
    > Like "expert systems". (Anyone remember those?) Yes, my university still has a class were you build some using CLIPS...
  - dhimes 9y ago
    Feigenbaum was running around telling Congress that the US would "become an agrarian nation" unless they funded a big national knowledge system lab headed by him. At about the same time somebody was running around telling people we were going to be in a whole lot of trouble if we didn't train a bunch more physicists. A few years later we entered the era of the 40 yr old post-doc.
  - fusiongyro 9y ago
    Some of that technology is actually used today. Systems like JBoss Drools, IBM Operational Decision Manager. Government agencies sometimes use modern versions of these things to ensure that policies are followed. Eligibility for medicaid, for instance, is often decided by rules systems that are descended from systems like CLIPS. This technology isn't super-sexy compared to deep learning but there are application areas where it is still relevant.
Sniffnoy 9y ago
This is just a link to Peter Woit's blog. I'm assuming you meant to link to the most recent entry (as per the title): https://www.math.columbia.edu/~woit/wordpress/?p=9375 https://www.math.columbia.edu/~woit/wordpress/?p=9375 (Could we get a mod to fix this? Thank you!)
- dang 9y ago
  Sure. Changed from https://www.math.columbia.edu/~woit/wordpress/ https://www.math.columbia.edu/~woit/wordpress/.
vorg 9y ago
> The significance of these negative results is not that they disconfirm a strong prediction of string theory, but that they pull the plug on the last remaining hope for connecting standard string theory unification scenarios to anything observable. The reason String Theory first became so popular in the mid-1980's was because of its prediction of a massless chargeless spin-2 particle (the graviton) which behaves like gravity in a quantum setting. Surely this could be called a proven observation of String Theory?
- gaius 9y ago
  The reason String Theory first became so popular in the mid-1980's was because of its prediction of a massless chargeless... Barry explains this quite succinctly in The Big Bang Theory: "I'm not a string theorist; I'm a string realist".
- Chronos 9y ago
  As I understand it (not being a physicist): the graviton, if it exists at all, would have to be a massless chargeless spin-2 boson for it to fit our understanding of what particles are. But the graviton has never been observed, nor has any quantized behavior of gravity or its General Relativistic effects, so it doesn't count as an observation by String Theory; there are other models that also give rise to gravity-as-we've-observed-it, up to and including just gluing the Standard Model to General Relativity and calling it a day.
  - evanb 9y ago
    While it's true that the graviton has never been observed, the point is that string theory was not, originally, a "theory of everything" candidate! It was originally a way of trying to understand QCD and strong dynamics. In 1974 people discovered that the massless chargeless spin-2 boson "popped out" of the theory accidentally! Since people knew that such a particle behaves like a graviton, and is manifestly quantum-mechanical, suddenly it occurred to them that string theory might be a theory of quantum gravity. In fact, General Relativity can be viewed simply as the low-energy effective theory of massless chargeless spin-2 bosons, as emphasized in Feynman's Lectures of Gravitation, where he derives GR from a particle-physicist point of view, rather than a differential-geometry point of view. This led to the tongue-in-cheek saying that string theory post-dicted the existence of gravity at all---since it isn't built into the foundational assumptions of the theory at all (which is more than a lot of the other models, such as the "gluing" you propose, can say). And since string theory is guaranteed to be quantum-mechanical, a lot of interest developed towards understanding it as a theory of quantum gravity (most other models fail to account for how GR can be made compatible with quantization and how the renormalization works sensibly).
deleted 9y ago
[deleted]
noobermin 9y ago
I hate to do it but I have to do it, the "String" phenomenon is an out-growth of the academic (industrial?) complex. When you have a group of closely knit scientists from a handful of universities who have a steady stream of cheap labor and fed by a media that bedazzles their untestable hypotheses, when you're propped up by that hype and prestige, the fumes that academics at the top feed off, then you can plunge further into the deep, while offsetting the externalities and opportunity costs onto governments and broken graduate students who eventually find themselves unemployable after about 5 to 6 years. I smelled the stink early on when a project at the LHC I was joining found 6 (plus or minus 4!) possible supersymmetry events in the two years of PBs of LHC data(!) in their specific search. I made the bet against supersymmetry and went for a less hyped field, and now that their funding is drying up, I'm happily taking almost double (or more) the salary compared to other graduate students since I'm in another field. Haven't regretted since. The hype behind string theory and HEP in general needs to die. There are so many interesting problems worthy of investigation that are not High Energy or Quantum Gravity. Yes, few things beat the fun math of HEP and string theory (although there are close contenders in the condensed matter world), few things--except perhaps validation in experiment...you know, the entire point of science in the first place.
- ejolto 9y ago
  Just curious, what field did you go into? I'll be spending the next year at CERN, as an electronics engineer though not a physicist.
- the6threplicant 9y ago
  I like https://www.youtube.com/watch?v=Q8ccXzM3x8A https://www.youtube.com/watch?v=Q8ccXzM3x8A (The case for String Theory). It shows that there is a natural progression to String Theory that very few other theories have.
  - ajnin 9y ago
    I'm not a physicist but after watching this I'm utterly unconvinced. Inconceivably large number of possible Universes cited as evidence because our own might well be in there somewhere ? A casual passing mention that there are not 4 but 10 dimensions, and the fact that we can't see them is not proof that the theory is wrong but simply dismissed because they might be very well hidden. To the casual observer that I am it looks like formula-tweaking to fit some mathematical framework better, but with no regard with compatibility with reality.
paulpauper 9y ago
I think the comparison to EM or GR is pretty much absurd. For one thing it’s comparing two completely different things: tests of a particular prediction of a theory (EM or GR) that made lots of other testable, confirmed predictions to the case of string theory, where there are no predictions at all. More relevant to the argument over how long to wait for an idea to pay off is that the real question is not the absolute value of the amount of progress, but the derivative: as you study the idea more carefully, do you get closer to testable progress or farther away? I don’t think anybody can serious claim that, 33 years on, we’re closer to a successful string theory unification proposal than we were at the start, back in 1985. I’d argue that the situation is the complete opposite: we have been steadily moving away from such success (and thus entered the realm of failure). The problems string theory are attempting to answer are many magnitudes more complicated than general relativity and electromagnetism and hence require tests many magnitudes more precise and complicated. It's possible such tests may never be developed and that there may be many competing theories of everything with no way to ever ascertain which one is correct. New theories take not just decades, but centuries to develop. There was at least a three-hundred year gap between the development of Newtonian gravity and general relativity. Much of string theory is only a couple decades old. If physicists and mathematicians decide that string theory is untenable, they will gradually abandon it, similar to how in capitalism products become obsoleted in favor of newer, better ones. There is no need for someone to determine which theories are worth pursuing or or not; the ‘marketplace’ of ideas does that automatically, gradually nudging the natural progression of research towards better ideas as old ones are discarded or modified. For example, 120 years ago aether theories were conjectured the propagation of light and gravitation, but these theories were later were supplanted by special relativity. http://greyenlightenment.com/falsifiability-string-theory-and-policy/ http://greyenlightenment.com/falsifiability-string-theory-an... String Theory succeeds because it offers a means that is logically consistent to bridge gravity and quantum mechanics, and the strings themselves are building blocks for all particles. If someone can come up with a logically consistent theory that is as encompassing as string theory and can be tested and verified with existing technology, the physics community is all ears. The tyranny of verificationism impedes scientific progress. Let string theorists do their thing/string.
- appleflaxen 9y ago
snarfy 9y ago
The case for string theory https://www.youtube.com/watch?v=Q8ccXzM3x8A https://www.youtube.com/watch?v=Q8ccXzM3x8A tl;dr - Nobody theorized strings. They were trying to solve the scattering problem of w-bosons and came up with a solution. The interpretation of the solution is strings.
- euyyn 9y ago
  Thanks for the link; TIL. He answers "But is it falsifiable?" with "Of course it is! If special relativity is false, so is string theory." Which misses the point completely. Is it actually falsifiable?
  - woodandsteel 9y ago
    You know there is something wrong with an idea when someone feels compelled to argue for it by giving a word a different meaning than it usually has, but not explaining he is doing that.
    - posterboy 9y ago
      falsifiable literally has fals~ in it.
dataphyte 9y ago
Why doesn't pure math get similarly attacked? Clearly math has generated lots of economic and scientific value, but it seems to me that there isn't much difference between string theory and, say, math work on the Monster Moonshine group or whatever.
- liberte82 9y ago
  Because pure math doesn't make a claim to be anything other than it is. String theory supposedly describes real things in the real universe, and as such it's a valid criticism to say it can't be tested. Maybe it's a marketing problem. If string theory would move outside of the realm of physics and into that of mathematics I don't think it would have these issues.
  - dataphyte 9y ago
    That's my thinking as well: just re-brand string theory as math. It's not as though string theory will be testable anytime soon, so the criteria of verification is just hurting the field.
- ajnin 9y ago
  Pure math does not pretend to be a theory explaining the natural world. String theory does, and that's why it must be subject to the standards that describe what is, and what is not, a scientific theory.
woodandsteel 9y ago
If I understand the post correctly, it is not just that ST has not been verified, but that the way the theory has developed over time has made it harder to verify.
woodandsteel 9y ago
One reason why theories need to be testable is for checking out which of two theories is correct. If both theories fit with what has been observed so far, you think of a situation where they make different predictions, and then collect some new data and then see which theory turns out to be correct. String theorists seem to think their theory is so beautiful that there is no need for it to be able to pass this sort of test.
- dragonwriter 9y ago
  > String theorists seem to think their theory is so beautiful that there is no need for it to be able to pass this sort of test. I don't see any evidence that string theorists don't believe that having practically-testable predictions is desirable. IIRC, actually, there was quite a bit of noise a few years back when string theory was the basis for in-principle-testable predictions regarding quantum entanglement, but I don't know if any practical tests have been constructed.
  - woodandsteel 9y ago
    The blog post in question is about how at least some string theorists think that string theory has been proven true, in spite of the fact that no one knows how to test it empirically. The post includes a link to an article that argues against this https://www.nature.com/news/scientific-method-defend-the-integrity-of-physics-1.16535 https://www.nature.com/news/scientific-method-defend-the-int... So yes, they would like it if there were practical tests, but no, they don't think they are necessary.

188 points by seycombi 9y ago

It's very sad how so many bright physicists have made this their life's work, and yet: the problem with string theory is that, in its landscape version, it has a hugely complicated and poorly understood high energy scale behavior, seemingly capable of producing a very wide range of possible observable effects, none of which have been seen

coldtea 9y ago
Sad that many bright theoretical physicists have been doing science? Because, even if a theory doesn't pan out, it' s still science: you've researched an avenue and came to certain conclusions. And perhaps this is most of science work -- not the "found a new theory" but "checked whether this theory works" (and same for experimental science).
- kobeya 9y ago
  The problem, as talked about in the article, is that it is NOT science. Science involves experimentation, which string theory so far has eschewed. It more resembles mathematics in that sense (which is ostensibly not a science either).
  - coldtea 9y ago
    That's just a not very well thought out definition of science, and is wrong on several counts. 1) Science does not necessarily involve experimentation. 2) String theory has attempted many times at experimental verification. 3) Math are more experimental than most people think.
    - dhimes 9y ago
      A scientific hypothesis must be falsifiable, by definition. Some have tried unsuccessfully to argue this away, but it is still the majority opinion. And it's for this reason: once you open the "scientific" world to unfalsifiable hypotheses, you open it up to a bunch of bullshit. That is not to say, however, that all important work must be scientific. There is a certain value to exploratory work, which can guide the direction of experiments in such a way as "if we could get experiment X then we could turn hypothesis Y into a testable hypothesis." In my opinion that is important work. You can see this in fields like psychology and such where the systems are just too complex to be easily testable (even medicine to some degree). But if we don't keep pursuing we will never get there.
      - yulaow 9y ago
        We have this problem in general in science at this point of time, probably because of the big scope of our modern theories. EG: We already consider "Dark Energy" a sort of made-up assumption to justify a model which, after recent observations was considered falsified. So, instead of focusing on others we decided to keep using it, we created a not-falsifiable nor testable assumption (dark energy indeed) and kept going with it, even if it violates everything Popper teach us. Honestly it seems to me that, especially in physics, too many people are just too much mentally involved in their own theory that they have an hard time just dropping it when it doesn't seem to work anymore.
        dhimes 9y ago
        Perhaps, but science is a human endeavor like any other and thus subject to human biases. I think a great example is the discovery of the neutrino. Particle tracks showed a clear violation of energy, momentum and angular momentum, but Pauli and others believed in these fundamental properties of the universe so strongly that he (they?) proposed a particle that was virtually undetectable to keep those properties. This was a non-scientific hypothesis at the time, but it told scientists the direction they needed to pursue in order to get to the point where the hypothesis could become scientific. Most argue that the discovery of the neutrino saved the fundamental conservation laws, but we should never lose sight of the fact that we still don't detect them in a very large percentage of events we record (we say simply that they are there, but interact weakly). One important measure of whether a hypothesis is likely going to be accepted as true in the future is that as we build better and more sensitive detectors we detect more outcomes favorable to the hypothesis. This is the way smart money bets when data are still hard to come by (see 'climate change').
    - rotorblade 9y ago
      Indeed. To emphasize '1)' you could mention most astro- related fields: astronomy, astrophysics, etc, which are almost purely observational.
      - kobeya 9y ago
        Observational and experimental are not opposed attributes. For astronomers the universe is the laboratory, and that is fine. An astronomer can say "I predict binary black holes to emit gravitational waves of a certain sort" and then go and find a binary black hole system and see if it does. That is experimentation.
        rotorblade 9y ago
        I can possibly agree with that notion of experiment. My point, in the context of the discussion, was that just because we do not have a an idea for an experiment that would test string theory, in some definite way, does not exclude that there is some possible observation within reach.
        kobeya 9y ago
        Sure, but it becomes troublesome when they stop bothering to look.
reikonomusha 9y ago
If you look at string theory as a piece of mathematics, which may provide a language for physicists to use and generate hypotheses, it doesn't seem so bad. I suspect this is closer to the motivation of the theoretical physicists working on it (including folks like Ed Witten, who are really mathematicians in disguise).
- AstralStorm 9y ago
  Hopefully to be replaced with something far less cumbersome soon. And providing testable hypotheses.
- noobermin 9y ago
  String theory might occupy a different space perhaps, this is kind of like changing the underlying domain so now your function is "continuous" somewhere, although String theory and HEP theory in general isn't quite rigorous enough to be considered mathematics proper.
Animats 9y ago
Like "expert systems". (Anyone remember those?) I went through Stanford CS in the mid-1980s, just as it was becoming clear that expert systems didn't do very much. But there were many faculty heavily invested in the technology. Feigenbaum was running around telling Congress that the US would "become an agrarian nation" unless they funded a big national knowledge system lab headed by him. Strong AI was supposed to work Real Soon Now. What actually happened was the "AI Winter" - for about two decades, not much happened. The AI startups from the 1980s went bust.
- zer0tonin 9y ago
  > Like "expert systems". (Anyone remember those?) Yes, my university still has a class were you build some using CLIPS...
- dhimes 9y ago
  Feigenbaum was running around telling Congress that the US would "become an agrarian nation" unless they funded a big national knowledge system lab headed by him. At about the same time somebody was running around telling people we were going to be in a whole lot of trouble if we didn't train a bunch more physicists. A few years later we entered the era of the 40 yr old post-doc.
- fusiongyro 9y ago
  Some of that technology is actually used today. Systems like JBoss Drools, IBM Operational Decision Manager. Government agencies sometimes use modern versions of these things to ensure that policies are followed. Eligibility for medicaid, for instance, is often decided by rules systems that are descended from systems like CLIPS. This technology isn't super-sexy compared to deep learning but there are application areas where it is still relevant.

Sniffnoy 9y ago

This is just a link to Peter Woit's blog. I'm assuming you meant to link to the most recent entry (as per the title): https://www.math.columbia.edu/~woit/wordpress/?p=9375 https://www.math.columbia.edu/~woit/wordpress/?p=9375 (Could we get a mod to fix this? Thank you!)

dang 9y ago
Sure. Changed from https://www.math.columbia.edu/~woit/wordpress/ https://www.math.columbia.edu/~woit/wordpress/.

vorg 9y ago

> The significance of these negative results is not that they disconfirm a strong prediction of string theory, but that they pull the plug on the last remaining hope for connecting standard string theory unification scenarios to anything observable. The reason String Theory first became so popular in the mid-1980's was because of its prediction of a massless chargeless spin-2 particle (the graviton) which behaves like gravity in a quantum setting. Surely this could be called a proven observation of String Theory?

gaius 9y ago
The reason String Theory first became so popular in the mid-1980's was because of its prediction of a massless chargeless... Barry explains this quite succinctly in The Big Bang Theory: "I'm not a string theorist; I'm a string realist".
Chronos 9y ago
As I understand it (not being a physicist): the graviton, if it exists at all, would have to be a massless chargeless spin-2 boson for it to fit our understanding of what particles are. But the graviton has never been observed, nor has any quantized behavior of gravity or its General Relativistic effects, so it doesn't count as an observation by String Theory; there are other models that also give rise to gravity-as-we've-observed-it, up to and including just gluing the Standard Model to General Relativity and calling it a day.
- evanb 9y ago
  While it's true that the graviton has never been observed, the point is that string theory was not, originally, a "theory of everything" candidate! It was originally a way of trying to understand QCD and strong dynamics. In 1974 people discovered that the massless chargeless spin-2 boson "popped out" of the theory accidentally! Since people knew that such a particle behaves like a graviton, and is manifestly quantum-mechanical, suddenly it occurred to them that string theory might be a theory of quantum gravity. In fact, General Relativity can be viewed simply as the low-energy effective theory of massless chargeless spin-2 bosons, as emphasized in Feynman's Lectures of Gravitation, where he derives GR from a particle-physicist point of view, rather than a differential-geometry point of view. This led to the tongue-in-cheek saying that string theory post-dicted the existence of gravity at all---since it isn't built into the foundational assumptions of the theory at all (which is more than a lot of the other models, such as the "gluing" you propose, can say). And since string theory is guaranteed to be quantum-mechanical, a lot of interest developed towards understanding it as a theory of quantum gravity (most other models fail to account for how GR can be made compatible with quantization and how the renormalization works sensibly).

deleted 9y ago

[deleted]

noobermin 9y ago

I hate to do it but I have to do it, the "String" phenomenon is an out-growth of the academic (industrial?) complex. When you have a group of closely knit scientists from a handful of universities who have a steady stream of cheap labor and fed by a media that bedazzles their untestable hypotheses, when you're propped up by that hype and prestige, the fumes that academics at the top feed off, then you can plunge further into the deep, while offsetting the externalities and opportunity costs onto governments and broken graduate students who eventually find themselves unemployable after about 5 to 6 years. I smelled the stink early on when a project at the LHC I was joining found 6 (plus or minus 4!) possible supersymmetry events in the two years of PBs of LHC data(!) in their specific search. I made the bet against supersymmetry and went for a less hyped field, and now that their funding is drying up, I'm happily taking almost double (or more) the salary compared to other graduate students since I'm in another field. Haven't regretted since. The hype behind string theory and HEP in general needs to die. There are so many interesting problems worthy of investigation that are not High Energy or Quantum Gravity. Yes, few things beat the fun math of HEP and string theory (although there are close contenders in the condensed matter world), few things--except perhaps validation in experiment...you know, the entire point of science in the first place.

ejolto 9y ago
Just curious, what field did you go into? I'll be spending the next year at CERN, as an electronics engineer though not a physicist.
the6threplicant 9y ago
I like https://www.youtube.com/watch?v=Q8ccXzM3x8A https://www.youtube.com/watch?v=Q8ccXzM3x8A (The case for String Theory). It shows that there is a natural progression to String Theory that very few other theories have.
- ajnin 9y ago
  I'm not a physicist but after watching this I'm utterly unconvinced. Inconceivably large number of possible Universes cited as evidence because our own might well be in there somewhere ? A casual passing mention that there are not 4 but 10 dimensions, and the fact that we can't see them is not proof that the theory is wrong but simply dismissed because they might be very well hidden. To the casual observer that I am it looks like formula-tweaking to fit some mathematical framework better, but with no regard with compatibility with reality.

paulpauper 9y ago

I think the comparison to EM or GR is pretty much absurd. For one thing it’s comparing two completely different things: tests of a particular prediction of a theory (EM or GR) that made lots of other testable, confirmed predictions to the case of string theory, where there are no predictions at all. More relevant to the argument over how long to wait for an idea to pay off is that the real question is not the absolute value of the amount of progress, but the derivative: as you study the idea more carefully, do you get closer to testable progress or farther away? I don’t think anybody can serious claim that, 33 years on, we’re closer to a successful string theory unification proposal than we were at the start, back in 1985. I’d argue that the situation is the complete opposite: we have been steadily moving away from such success (and thus entered the realm of failure). The problems string theory are attempting to answer are many magnitudes more complicated than general relativity and electromagnetism and hence require tests many magnitudes more precise and complicated. It's possible such tests may never be developed and that there may be many competing theories of everything with no way to ever ascertain which one is correct. New theories take not just decades, but centuries to develop. There was at least a three-hundred year gap between the development of Newtonian gravity and general relativity. Much of string theory is only a couple decades old. If physicists and mathematicians decide that string theory is untenable, they will gradually abandon it, similar to how in capitalism products become obsoleted in favor of newer, better ones. There is no need for someone to determine which theories are worth pursuing or or not; the ‘marketplace’ of ideas does that automatically, gradually nudging the natural progression of research towards better ideas as old ones are discarded or modified. For example, 120 years ago aether theories were conjectured the propagation of light and gravitation, but these theories were later were supplanted by special relativity. http://greyenlightenment.com/falsifiability-string-theory-and-policy/ http://greyenlightenment.com/falsifiability-string-theory-an... String Theory succeeds because it offers a means that is logically consistent to bridge gravity and quantum mechanics, and the strings themselves are building blocks for all particles. If someone can come up with a logically consistent theory that is as encompassing as string theory and can be tested and verified with existing technology, the physics community is all ears. The tyranny of verificationism impedes scientific progress. Let string theorists do their thing/string.

appleflaxen 9y ago

snarfy 9y ago

The case for string theory https://www.youtube.com/watch?v=Q8ccXzM3x8A https://www.youtube.com/watch?v=Q8ccXzM3x8A tl;dr - Nobody theorized strings. They were trying to solve the scattering problem of w-bosons and came up with a solution. The interpretation of the solution is strings.

euyyn 9y ago
Thanks for the link; TIL. He answers "But is it falsifiable?" with "Of course it is! If special relativity is false, so is string theory." Which misses the point completely. Is it actually falsifiable?
- woodandsteel 9y ago
  You know there is something wrong with an idea when someone feels compelled to argue for it by giving a word a different meaning than it usually has, but not explaining he is doing that.
  - posterboy 9y ago
    falsifiable literally has fals~ in it.

dataphyte 9y ago

Why doesn't pure math get similarly attacked? Clearly math has generated lots of economic and scientific value, but it seems to me that there isn't much difference between string theory and, say, math work on the Monster Moonshine group or whatever.

liberte82 9y ago
Because pure math doesn't make a claim to be anything other than it is. String theory supposedly describes real things in the real universe, and as such it's a valid criticism to say it can't be tested. Maybe it's a marketing problem. If string theory would move outside of the realm of physics and into that of mathematics I don't think it would have these issues.
- dataphyte 9y ago
  That's my thinking as well: just re-brand string theory as math. It's not as though string theory will be testable anytime soon, so the criteria of verification is just hurting the field.
ajnin 9y ago
Pure math does not pretend to be a theory explaining the natural world. String theory does, and that's why it must be subject to the standards that describe what is, and what is not, a scientific theory.

woodandsteel 9y ago

If I understand the post correctly, it is not just that ST has not been verified, but that the way the theory has developed over time has made it harder to verify.

woodandsteel 9y ago

One reason why theories need to be testable is for checking out which of two theories is correct. If both theories fit with what has been observed so far, you think of a situation where they make different predictions, and then collect some new data and then see which theory turns out to be correct. String theorists seem to think their theory is so beautiful that there is no need for it to be able to pass this sort of test.

dragonwriter 9y ago
> String theorists seem to think their theory is so beautiful that there is no need for it to be able to pass this sort of test. I don't see any evidence that string theorists don't believe that having practically-testable predictions is desirable. IIRC, actually, there was quite a bit of noise a few years back when string theory was the basis for in-principle-testable predictions regarding quantum entanglement, but I don't know if any practical tests have been constructed.
- woodandsteel 9y ago
  The blog post in question is about how at least some string theorists think that string theory has been proven true, in spite of the fact that no one knows how to test it empirically. The post includes a link to an article that argues against this https://www.nature.com/news/scientific-method-defend-the-integrity-of-physics-1.16535 https://www.nature.com/news/scientific-method-defend-the-int... So yes, they would like it if there were practical tests, but no, they don't think they are necessary.