alt Hacker News"sensational style" is one part but another is that it is hard to extract truth from Sabine's videos, at least for me, not without doing some serious research as someone with a PhD in physics.
Example starting at ~1:00 "Carlo Rovelli is fine with the theory being untestable for practical purposes. So now the situation is that either the theory is falsified or its not falsifiable..."
Is Carlo Rovelli fine with it not being testable, in that he is fine with research continuing even though it can not be tested with up coming experimental set ups? That is reasonable lots of research goes on for long periods of time with out experimental verification. From a funding point of view it makes sense to allocate more money to things that have a tighter feedback loop though. If Sabine was going to expose howe much money was going to these topics and where it could be better spent that would be worth watching.
Or is Carlo Rovelli ok with the theory being unfalsifiable in the sense that that he is ok with the research not being science? This is the straight forward meaning of Sabine's words, but are a negative attack, and one that would come off as a personal attack to many scientists I have known, one that she does not back up with anything immediately and then goes on to make more negative comments like "and Carlo complains to me because he thinks I do not understand his genius".
Ok if Sabine was going to expose Carlo Rovelli as someone who was not really practice science but was getting paid to be a scientist that would be awesome to watch and learn about. That does not happen.
"everyone who works on this just repeats arguments that they all know to be wrong to keep the money coming" - accusation of scientific fraud and defrauding the government.
Ok what percentage and total amount of founding is going to this? Is there anyone who has come forward? It would be awesome to watch something that exposed something like this. That does not happen either.
~3:19 - Arguments saying loop quantum gravity require space to be quantized, but they can not be lorentz invariant without having the quantization go to zero volume, according to Sabine, and no one has done that and extracted back out loop quantum gravity.
I am experimentalist and this is not my area. I would want to see a link to a paper/book etc. The analogy to the angular momentum operator comes off as a good place to start investigation/research but is treated dismissively, anologies like this often do not apply in the end but can still be useful.
3:53 ~ "length contraction should make that minimal area smaller than minimal proof by contradiction"
Ok that does not seem like the gottcha that it is laid out to be. Interesting stuff happens where their are apparent contradictions in physics. If experimental/observational evidence about A produces theory TA and experimental/observational evidence about B produces theory TB and they contradict each other in conditions C that is an interesting point to study look in to etc. This may not be interesting for other reasons, but the apparent contradiction does not make it obviously non interesting.
~4:27 ~ "this can't work because these deviations would inevitably so large we'd have seen them already" -
Why did Sabine talk about it being a mathematical contradiction if you can make the theory work, but it leads to physical phenomenon that we do not observe?
I can not make those two arguments jive in to a cohesive whole. Not that it can not happen, but I can not from this video and that is the conclusion, or similar, I normally reach when watching Sabine's videos and why I do not watch or recommend them generally.
I do not see any of the interesting things I mentioned above being discussed or dug into in comments so far or other new interesting takes. The issue for Sabine's videos, at least for me, is not the "sensational style".
Well, if you want a simple argument from authority, John Carlos Baez's confirmation that she's right is pretty good. If you want a better one, she very rarely gets any of her facts wrong.
Now let's go point by point.
Is Carlo Rovelli fine with it not being testable, in that he is fine with research continuing even though it can not be tested with up coming experimental set ups? He is arguing for a version of the theory that can't be tested, is continuing to do research on it, and presumably thinks that he is doing science.
If Sabine was going to expose howe much money was going to these topics and where it could be better spent that would be worth watching. Discussing how these things wind up getting funded would be a very different video. And would not likely be interesting to most of her audience.
Or is Carlo Rovelli ok with the theory being unfalsifiable in the sense that that he is ok with the research not being science? Presumably he thinks that he is doing science. Sabine's opinion clearly is that this isn't really science. However she only claims her opinion as her opinion, not established fact.
Ok what percentage and total amount of founding is going to this? Again, that would be a very different video. In 10 minutes for a general audience, you have to make decisions about what you will and will not cover. It's not a valid criticism of her that she made a choice. Particularly in a video that she disclaims as a personal rant.
Arguments saying loop quantum gravity require space to be quantized, but they can not be lorentz invariant without having the quantization go to zero volume, according to Sabine, and no one has done that and extracted back out loop quantum gravity. This is not according to her, this is according to an argument that comes from Lee Smolin. A region of space that has a specific amount of area will, according to special relativity, have a smaller area according to an observer that is traveling fast enough. By having the velocity as close as you want to C, you can make the area arbitrarily small. So your choice is to violate Lorentz invariance, or have arbitrarily small areas. If you violate Lorentz invariance, the speed for light will depend on the wavelength.
As her previous video at https://www.youtube.com/watch?v=ZlHvW6k2bcM said, this prediction of Lee Smolin has been tested to extremely high precision, and the predicted effect was not seen. That version of LQG has been falsified. The alternative supported by Carlo Rovelli is that you need to average out over quantum areas in all reference frames. This is a neat idea, but in several decades, nobody has made it work. Until someone can make it work, LQG can't produce any testable predictions.
Please note that John Baez, who worked on LQG for 10 years, specifically complimented her presentation of this particular issue. Her description of where research stands is accurate.
I am experimentalist and this is not my area. I would want to see a link to a paper/book etc. Rants generally do not come with properly cited references. That said, the previous video that this refers back to is based on https://arxiv.org/abs/2402.06009?utm_source=substack&utm_med..., which is one of the experimental tests showing that Lee Smolin's prediction is false.
The analogy to the angular momentum operator comes off as a good place to start investigation/research but is treated dismissively, anologies like this often do not apply in the end but can still be useful. It was a good place to start. After 20 years of research that has failed to turn that idea into anything workable, most people would conclude that this is an analogy that will not apply in the end. But apparently Rovelli gets mad at anyone who doubts that it will work out. One of the triggers for this rant was whatever Rovelli said to her in private. Personally, I excuse her for being human here in her reaction.
Ok that does not seem like the gottcha that it is laid out to be. Interesting stuff happens where their are apparent contradictions in physics. No, it really is the gotcha it claims to be. It's directly inside of the math. This demonstration is no different than, say, proving that sqrt(2) is irrational by proving that if you start with the smallest fraction that equals it, you can find a smaller one.
The conclusion of that gotcha is exactly what she said: if there's a minimal area then you can't have Lorentz invariance. And conversely, if you have Lorentz invariance, then you can't have a minimal area. Experimentally, we have tested for the Lorentz invariance to be expected from a minimum area based on the Planck length. It does not exist. And therefore there isn't Lorentz invariance.
Why did Sabine talk about it being a mathematical contradiction if you can make the theory work, but it leads to physical phenomenon that we do not observe? Her previous video (that triggered the nasty emails)_made this point more clearly. She's saying that there is a mathematical contradiction between having minimal areas and Lorentz invariance. This forces us to choose to have one or the other. Minimal areas leads to a testable and now falsified theory. Lorentz invariance has yet to lead to a theory that doesn't blow up with unnormalizable infinities, let alone one which can produce a testable prediction.
I can not make those two arguments jive in to a cohesive whole. Not that it can not happen, but I can not from this video and that is the conclusion, or similar, I normally reach when watching Sabine's videos and why I do not watch or recommend them generally. Is that Sabine's fault, or yours? This video is much lower quality than her normal ones. And yet absolutely none of what you think are flaws, do I think is one. Every one of your objections has an answer that jives. And the conclusion is agreed with by John Baez, whose background on this specific topic is much stronger than yours.
Perhaps, rather than looking for things to complain, you should try figuring out what she actually said. In my experience it is logically internally consistent. Even though it skewers some sacred cows.