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(I'm not a theoretical physicist). 20 years ago, I read "The Elegant Universe" by Brian Greene, as an introduction to string theory. I was initially impressed

• irjustin 3y ago
  Thanks for above. As Woit mentioned, the video format is great and for guys like me. PBS Spacetime is where I go for a lot of "layman-with-the-lightest-touch-of-math"[0]. [0] https://www.youtube.com/c/pbsspacetime https://www.youtube.com/c/pbsspacetime [EDIT] Phewww reading those 2004 comments on those posts. Professors getting really heated for sure.
  • Cthulhu_ 3y ago
    PBS Space Time is great but you can't just drop in with a random video, they often build on top of or expand on concepts explained in earlier videos. And that's just fine.
  • graycat 3y ago
    > PBS Spacetime I just tried that: Right away he was talking about the possibility of the universe being "infinite". Yup, in physics courses, that one word was time to lose respect for the course, f'get about it, think about some of the pretty girls on campus, and get back to math, e.g., my paper on group representations, apparently of some interest in physics.
• SiempreViernes 3y ago
  I think it's funny that Woit manages to this day sound exactly like he's some sort of underdog fighting the big corp despite having lived to see the death of string theory.
  • mcphage 3y ago
    > despite having lived to see the death of string theory Is it in fact dead?
    • pixl97 3y ago
      Mostly yes, in fact a fair number of people will tell you the killing blow was years ago. The corpse hasn't rotted away yet.
      • humansareok1 3y ago
        This would be news to every Department I know of. So dead and rotting in favor of what exactly?
        • pixl97 3y ago
          Just because grandpa is dead doesn't mean anyone has filled his job position. Nothing useful has come from string theory in a very long time. Or are you still stuck in infinite tiny dimensions that can predict anything and everything, except something testable?
          • humansareok1 3y ago
            Oh don't misunderstand I am fully against String Theory. I just was not aware anyone considered it dead as in literally no longer controlling the Theory field. I'd challenge you to find good postdocs in High Energy Theory that aren't String related as a gauge of what the field is still focused on.
• mhh__ 3y ago
  Keep in mind that a string theorist would probably just flip all of this on its head by pointing at the total lack of progress from their detractors.
  • mglz 3y ago
    ...which means nothing, especially since string theory didn't solve physics either.
  • simonh 3y ago
    That's entirely true, but the problem is ST gobbled up a large share of resources and personnel in theoretical physics for decades. Smolin in particular is arguing that other ideas should get a fair shake.
    • ryandrake 3y ago
      Disclaimer: I’m a total outsider, not in physics or even academia, so what do I know? But threads like these make me think that some entire branches of science are less and less about the search for truth, and more and more about establishing a “personal brand” made up of a bundle of research and papers, recruiting supporters, and defending that bundle from detractors. It sounds exhausting and not what comes to mind when I think “science.”
      • garaetjjte 3y ago
        "A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it" - Max Planck
      • jpm_sd 3y ago
        I think you've accurately described academia in general, and (if abstracted slightly further) the human condition. It's astonishing we've made any progress at all.
      • radioactivist 3y ago
• enopod_ 3y ago
  Given the lack of testable predictions and failure in experiments so far, string theory should be called string hypothesis.
  • onli 3y ago
    If there are no testable predictions it is not a hypothesis, it's a religion.
  • HappyPanacea 3y ago
    (I'm also not a theoretical physicist). Not entirely true, I was looking at proton decay recently and one model of string theory model apparently predicts 10^36 yr lifetime [1] which is within experimental reach. [1]: Igor R Klebanov, Edward Witten, Proton decay in intersecting D-brane models, Nuclear Physics B, Volume 664, Issues 1–2, 2003, Pages 3-20, ISSN 0550-3213, https://doi.org/10.1016/S0550-3213(03)00410-3 https://doi.org/10.1016/S0550-3213(03)00410-3. (https://www.sciencedirect.com/science/article/pii/S0550321303004103 https://www.sciencedirect.com/science/article/pii/S055032130...)
    • ogogmad 3y ago
      One model? So there may be models where it doesn't happen. Or perhaps that very same model makes other, verifiably wrong predictions.
    • CuriouslyC 3y ago
      If there are an infinite family of parameterized string theory models, it's basically guaranteed that you can pick one that predicts anomalous data. In other sciences you would adjust the P value for the probability that you can reject the null hypothesis given the number of experiments you're performing, which in the case of infinity is going to drop the probability of rejecting the null to zero.
    • graycat 3y ago
      > 10^36 yr lifetime [1] which is within experimental reach. For this might want to assume that for each proton its lifetime is a random variable that obeys a Poisson process. That's asking a LOT, might be seen as putting some severe constraints on what is going on with a proton and its internals.
• mattgperry 3y ago
  If that's the book I'm thinking of I was also initially impressed until like chapter 6 when, after spending the book talking about how simple and elegant this theory was, it opens with "what if there wasn't just one string but lots of strings, and they were n-dimensional etc etc..." and threw it all out the window. I put the book down.
• pbronez 3y ago
  From the outside, this seems to rhyme with epicycles. You’re missing a core concept, so you pile on complexity to paper over the failed predictions. The industrial organization failure is understandable. It’s all well and good to say “they should have recognized it wasn’t working and stopped” … but even if that’s true at the macro level, it’s very hard on an individual level. An established physicist working on string theory has every incentive to keep building on that line of research. They have no competitive advantage switching to a new line. The specifics about how much expertise translate how far is beyond me, but it seems that nearby better ideas would have been found given the resources poured into this. This is exactly The Innovator’s Dilemma. It’s even worse in academia than industry because the whole sector is so insular. I look forward to the reinvention of higher education and theoretical research…
  • ghaff 3y ago
    Well, and add to that the fact that it's probably not clear what all these expensively-trained and equipped physicists should be working on. That may not be totally fair but you essentially have a large subset of scientific academia that has very little idea of how to go forward.
    • nathan_compton 3y ago
      These physicists aren't that expensive, in the grand scheme.
      • ghaff 3y ago
        True. And at least some of them would probably be doing pure math if they weren't doing physics. Some of their toys are, but again probably not that much really in the grand scheme. I think there's just a generalized frustration that a cadre of mostly very bright people seem to have largely spun their wheels for 20 years.
        • RetroTechie 3y ago
          > I think there's just a generalized frustration that a cadre of mostly very bright people seem to have largely spun their wheels for 20 years. Otoh: very possible their work produced spin-offs that were useful in other fields (math advances, thought experiments, practical research tools & equipment, people in other fields having a look at their work from a different angle, etc) AND having bright people chew on a subject for decades & come up (mostly) empty, is a good hint there's nothing there. 'Unknown' vs. 'we've tried hard & not found much' is a useful result by itself. Think of it as reducing the search space.
• CuriouslyC 3y ago
  Yes. Basically you can track how physics went astray very easily. Physicists were grappling with the philosophical ramifications of some of their discoveries at the same time that experimental data was starting to get much much more expensive to generate and the success of QCD and the standard model created a culture of "shut up and calculate" where physicists put on horse blinders and just tried to make the math work without any real consideration for anything beyond fitting the data. That was fine for a while but now physics is at a crisis point where our models are elegantly accurate to a point but clearly wrong, and physicists as a group have mostly forgotten how to imagine, so the only tool left in their box is pushing numbers around.
• 7thaccount 3y ago
  I've read a couple of those. My favorite more recent video that I think also provides some good context is a rant by Angela Collier that I found to be really interesting and more condensed than a book. It is called: "string theory lied to us and now science communication is hard" It does a good job talking about the collateral damage to the public. An entire generation read Michio Kaku and Brian Greene and many others and believed this was all legit when it seems like it's been a dud for a LONG time. If you couple that with the reproducibility crisis, you have a public that is far more skeptical of what scientists say now than in years prior.
  • sockmeistr 3y ago
    I just wanted to second this recommendation - while the video is nearly an hour long, it feels much shorter and is well worth watching: https://www.youtube.com/watch?v=kya_LXa_y1E https://www.youtube.com/watch?v=kya_LXa_y1E
  • ghaff 3y ago
    You can argue that science "worked" in the case of string theory in so far as it (eventually) came to be seen as a lot of untestable mathematical games with zero experimental evidence to support it. Of course, "follow the science" is more commonly interpreted as the scientific community consensus ~= the truth. So having a generation of physics that essentially ended up as "never mind" doesn't instill a lot of public faith that scientists know what they're talking about in general.
    • thereddaikon 3y ago
      Its all very messy. The scientific method is about the best system we have. But the scientific method and academia are not the same thing. I've yet to find anyone besides some weird philosophers and contrarians who actually doubt the scientific method. But I find more and more people every day who doubt academia. And yeah. Its and industry made up of fallible people with incentives that are not aligned with the stated goals of said industry. We've had scandals. We've had falsified data. We've had falsified careers. And then there's the replication crisis where its possible an entire discipline is built on a foundation of slop. And then you have people who aren't technical themselves but chant trust the science as some kind of religious mantra. Which helps nothing frankly. And this mess leaves plenty of room for bad actors who take advantage of the situation and push their own warped agendas.
• glenstein 3y ago
  > it's about how this obsession is hogging resources and blocking other potentially groundbreaking ideas My understanding was that a unique virtue of string theory was that (for better or worse) it was playing out with pencils and paper, and not demanding billion dollar funding projects for particle colliders or other such infrastructure and thus was relatively harmless as far as competition for resources is concerned.
  • kenjackson 3y ago
    One resource could be the minds of brilliant scientists.
    • glenstein 3y ago
      Agreed, I think this is the strongest counterpoint. But it effectively requires restating the point to clarify that it's tying up minds, time, energy, which are non-trivial things; but not infrastructure.
    • oldgradstudent 3y ago
      They may be brilliant, but if they're string theorists, they aren't scientists. Or at least that's Woit's point.
  • geysersam 3y ago
    Not remotely true. The predictions theoreticians make guide what experiments are made. If the predictions are of low quality the experiments are unlikely to give us any valuable data.
    • glenstein 3y ago
      Let's say I agree to that. How does that translate into an argument that string theory is hogging resources (e.g. funds, infrastructure, colliders, space telescopes) that are now no longer available to alternative projects? Yours sounds like an argument that it's not making good or testable predictions, certainly an indictment but not (so far as I can tell) responsive to my Q.
• _sword 3y ago
  I took undergrad quantum physics with Prof Greene and it was a great time. I definitely could have chosen a better professor for the math, but the theory and his banter was fun.
• antognini 3y ago
  For those who have seen these critiques of string theory (and other issues in modern physics) and are wondering why so many physicists have bought into string theory, Sean Carroll recently presented a pretty full throated defense of the physics "orthodoxy": https://youtu.be/MTM-8memDHs https://youtu.be/MTM-8memDHs I found it a really useful overview of what led people to the current state of physics.