One thing that frustrates me about discussions of the crisis in fundamental physics is the lack of (good) suggestion for what researchers ought to be doing instead of putting out more string theory papers etc. (I realize that Hossenfelder includes a list of suggestions at the end of her book, but I certainly do not find them compelling).
The problem is that there is essentially no data pointing to an alternative to the null hypothesis (the standard model + Lambda CDM). No experiment has returned a really surprising result that held up to scrutiny in decades (the Higgs and gravitational waves were each predicted decades ago, and failure to find them would have been more surprising). Perhaps then, we should accept the conclusion that the null hypothesis is simply true, and that it's time to close up shop and do something else. And perhaps the second part of that conclusion is correct. But the problem with the first part is that the standard model + general relativity is not renormalizable, and thus is very likely mathematically inconsistent as a quantum theory (of course the same could be said about general relativity on it's own).
If we are to do something other than close up shop, it seems the best way out of the issues pointed out by Hossenfelder and Grimstrup is to go all in on experiment in a way that is as hypothesis agnostic as possible, in the hopes of getting some clue. However, critics like Hossenfelder consistently oppose such experiments on the grounds that there is no good theoretical reason to expect a non-null result!
I should point out that, at least to my mind, there is a perfectly reasonable framework in which to look for extensions to the standard model in a very broad (hypothesis agnostic) way, given by the standard model effective field theory (and there is likewise an effective field theory approach to characterizing corrections to general relativity).
Thank you for this. It's a compelling read and I agree there should be good suggestions about how to behave not just how not to behave. I don't think it's a requirement for critics but it makes critique more convincing.
My high level version of a path forward (and by high level, I also mean superficial) is that everyone needs to take their lumps. If it turns out at the end, after string theorists have admitted all the non-empirical aspects of string theory and the non-empirical attempts to bolster string theory, that string theory is still the best theory then so be it. I agree nobody has a plan to end the drought of empirical results. I think the critics don't admit that readily enough, that there is a drought that is likely the root cause of the dysfunction.
The problem that we see over and over in science is a prisoner's dilemma where you have to convince a lot of people to simultaneously risk the thing most precious to them (usually their careers) to achieve peace. Everyone has to admit they're a little bit wrong in front of their intellectual enemies and it rarely happens.
Failing that, and I expect that will fail, we have to argue and maybe come up with a definitive falsification of any theory that doesn't deserve attention. The problem there is that nowadays everything gets more and more meta. It once was that empiricism was the final word. Sure there was denial of reality and patching up failed theories, but there was certainty that empiricism would win. (I'm thinking particularly of Popper who saw that there was a way out of falsification by denying the whole system of testability but it didn't preoccupy him.) Now I think we have bold anti-empiricism and we have to point it out.
I'm surprised Leonard Susskind's turn from string theory hasn't entered into every debate since. One would think it's on everyone's mind, particularly since the popularity among physicists is a major pillar of the string camp.
One thing that frustrates me about discussions of the crisis in fundamental physics is the lack of (good) suggestion for what researchers ought to be doing instead of putting out more string theory papers etc. (I realize that Hossenfelder includes a list of suggestions at the end of her book, but I certainly do not find them compelling).
The problem is that there is essentially no data pointing to an alternative to the null hypothesis (the standard model + Lambda CDM). No experiment has returned a really surprising result that held up to scrutiny in decades (the Higgs and gravitational waves were each predicted decades ago, and failure to find them would have been more surprising). Perhaps then, we should accept the conclusion that the null hypothesis is simply true, and that it's time to close up shop and do something else. And perhaps the second part of that conclusion is correct. But the problem with the first part is that the standard model + general relativity is not renormalizable, and thus is very likely mathematically inconsistent as a quantum theory (of course the same could be said about general relativity on it's own).
If we are to do something other than close up shop, it seems the best way out of the issues pointed out by Hossenfelder and Grimstrup is to go all in on experiment in a way that is as hypothesis agnostic as possible, in the hopes of getting some clue. However, critics like Hossenfelder consistently oppose such experiments on the grounds that there is no good theoretical reason to expect a non-null result!
I should point out that, at least to my mind, there is a perfectly reasonable framework in which to look for extensions to the standard model in a very broad (hypothesis agnostic) way, given by the standard model effective field theory (and there is likewise an effective field theory approach to characterizing corrections to general relativity).
Thank you for this. It's a compelling read and I agree there should be good suggestions about how to behave not just how not to behave. I don't think it's a requirement for critics but it makes critique more convincing.
My high level version of a path forward (and by high level, I also mean superficial) is that everyone needs to take their lumps. If it turns out at the end, after string theorists have admitted all the non-empirical aspects of string theory and the non-empirical attempts to bolster string theory, that string theory is still the best theory then so be it. I agree nobody has a plan to end the drought of empirical results. I think the critics don't admit that readily enough, that there is a drought that is likely the root cause of the dysfunction.
The problem that we see over and over in science is a prisoner's dilemma where you have to convince a lot of people to simultaneously risk the thing most precious to them (usually their careers) to achieve peace. Everyone has to admit they're a little bit wrong in front of their intellectual enemies and it rarely happens.
Failing that, and I expect that will fail, we have to argue and maybe come up with a definitive falsification of any theory that doesn't deserve attention. The problem there is that nowadays everything gets more and more meta. It once was that empiricism was the final word. Sure there was denial of reality and patching up failed theories, but there was certainty that empiricism would win. (I'm thinking particularly of Popper who saw that there was a way out of falsification by denying the whole system of testability but it didn't preoccupy him.) Now I think we have bold anti-empiricism and we have to point it out.
I'm surprised Leonard Susskind's turn from string theory hasn't entered into every debate since. One would think it's on everyone's mind, particularly since the popularity among physicists is a major pillar of the string camp.
https://www.youtube.com/shorts/Jm9rEyNtB7A
Love your posts!
Thank you, Michael. Very nice to hear.