But general relativity and quantum theory contradict each other. They cannot both be correct. Therefore at least half of physics is wrong.
Your first sentence is correct, your second is missing a qualifier, your third is plain wrong. GR and QM are valid each in their own domain. They don’t mesh together well, so something has to give in between the two domains. A modification, a wholly different model, something else we have no idea about. It’s a consensus in the field that a new revolutionary idea is needed, you are right. And that thousands of smart but “narrowly specialized postdocs” are unlikely to get us there. The five great problems are a good summary of our current views, but I suspect that to make progress in solving, say, #1, the problem itself would have to be restated completely differently. But good luck with learning more about fundamental physics. It’s a difficult and thankless task, as close to an efficient market as possible, with no profit to be made unless you have something that the likes of Witten have overlooked. You’ll need a lot of sweat and a lot of luck.
Their domain is supposed to be the universe, I think. Later people said GR is for the large scale and QM is for the small scale but nothing in the theories actually says this, AFAICT.
It could be that a straightforward extension of one or the other would solve the problem, somehow embracing or correcting the other. But all the obvious ways to do that have been explored and have failed.
Or it could be that both are fundamentally conceptually wrong, like Newtonian gravity was ‘wrong’ (though quite accurate most of the time). If that is the case the actual solution would look very different and would then be shown to approximate QM and GR in limiting cases.
String theory is not really a theory of physics; it is more like the idea that a certain type of theory, not yet identified, may work. So it is more of an approach or a program. But even if ST is successful, it would leave a lot of unanswered questions. And after decades their is not much sign of a breakthrough.
To be fair one key problem is a lack of data. If we could build accelerators 10^12 times as powerful as current ones, we may have something to work on. But there are so many possible theories given current data. Given no data, and no way to test theories, physics degenerates into a popularity contest.
Their domain is supposed to be the universe, I think. Later people said GR is for the large scale and QM is for the small scale but nothing in the theories actually says this, AFAICT.
each one was constructed for their respective domains. Not surprising that they don’t automatically keep their validity in other domains. Quantum mechanics came with their own limiter, the ad hoc Born rule without which it doesn’t predict anything. GR is too weak for small source masses, so we have no idea when and if it stops applying.
To be fair one key problem is a lack of data. If we could build accelerators 10^12 times as powerful as current ones, we may have something to work on. But there are so many possible theories given current data. Given no data, and no way to test theories, physics degenerates into a popularity contest.
Indeed we need more data, but not necessarily at high energies. If anything, measuring gravitational effects of the sources that contain 100,000 nucleons, not 10^23 nucleons would be more illuminating than a super mega LHC. Or gravitational effects of any system that can be put into spatial quantum superposition (i.e. not just a SQUID).
It’s a consensus in the field that a new revolutionary idea is needed
I disagree, I think the consensus in the field is that the fundamental laws of physics are very likely some version of string theory or something closely related to it. It’s not a unanimous consensus, but it is probably the majority position among academic theoretical physicists, even among academic theoretical physicists who are not specifically string theorists themselves. (I haven’t looked for surveys, I’m just guessing from personal experience.)
I disagree, I think the consensus in the field is that the fundamental laws of physics are very likely some version of string theory or something closely related to it.
I guess it depends on which bubble one is in. The likes of Susskind and ’t Hooft seem to acknowledge that a new paradigm is needed. And it makes sense given the herculean efforts expended on the String Theory in the last 3 decades or so, with very little to show for it. Certainly the AdS/CFT correspondence and the holographic principle in general, as well as a number of other ideas that emerged from the string theory research will have to fit into the new paradigm somewhere, but probably not in any recognizable way. I’d bet 10:1 that the next significant step in fundamental physics would not be a natural extension of the string theory.
GR and QM give correct predictions in their own domains. They also have different ontological implications, which may or may not be a problem depending on what you expect to get out of physics.
Your first sentence is correct, your second is missing a qualifier, your third is plain wrong. GR and QM are valid each in their own domain. They don’t mesh together well, so something has to give in between the two domains. A modification, a wholly different model, something else we have no idea about. It’s a consensus in the field that a new revolutionary idea is needed, you are right. And that thousands of smart but “narrowly specialized postdocs” are unlikely to get us there. The five great problems are a good summary of our current views, but I suspect that to make progress in solving, say, #1, the problem itself would have to be restated completely differently. But good luck with learning more about fundamental physics. It’s a difficult and thankless task, as close to an efficient market as possible, with no profit to be made unless you have something that the likes of Witten have overlooked. You’ll need a lot of sweat and a lot of luck.
Their domain is supposed to be the universe, I think. Later people said GR is for the large scale and QM is for the small scale but nothing in the theories actually says this, AFAICT.
It could be that a straightforward extension of one or the other would solve the problem, somehow embracing or correcting the other. But all the obvious ways to do that have been explored and have failed.
Or it could be that both are fundamentally conceptually wrong, like Newtonian gravity was ‘wrong’ (though quite accurate most of the time). If that is the case the actual solution would look very different and would then be shown to approximate QM and GR in limiting cases.
String theory is not really a theory of physics; it is more like the idea that a certain type of theory, not yet identified, may work. So it is more of an approach or a program. But even if ST is successful, it would leave a lot of unanswered questions. And after decades their is not much sign of a breakthrough.
To be fair one key problem is a lack of data. If we could build accelerators 10^12 times as powerful as current ones, we may have something to work on. But there are so many possible theories given current data. Given no data, and no way to test theories, physics degenerates into a popularity contest.
each one was constructed for their respective domains. Not surprising that they don’t automatically keep their validity in other domains. Quantum mechanics came with their own limiter, the ad hoc Born rule without which it doesn’t predict anything. GR is too weak for small source masses, so we have no idea when and if it stops applying.
Indeed we need more data, but not necessarily at high energies. If anything, measuring gravitational effects of the sources that contain 100,000 nucleons, not 10^23 nucleons would be more illuminating than a super mega LHC. Or gravitational effects of any system that can be put into spatial quantum superposition (i.e. not just a SQUID).
I disagree, I think the consensus in the field is that the fundamental laws of physics are very likely some version of string theory or something closely related to it. It’s not a unanimous consensus, but it is probably the majority position among academic theoretical physicists, even among academic theoretical physicists who are not specifically string theorists themselves. (I haven’t looked for surveys, I’m just guessing from personal experience.)
I guess it depends on which bubble one is in. The likes of Susskind and ’t Hooft seem to acknowledge that a new paradigm is needed. And it makes sense given the herculean efforts expended on the String Theory in the last 3 decades or so, with very little to show for it. Certainly the AdS/CFT correspondence and the holographic principle in general, as well as a number of other ideas that emerged from the string theory research will have to fit into the new paradigm somewhere, but probably not in any recognizable way. I’d bet 10:1 that the next significant step in fundamental physics would not be a natural extension of the string theory.
GR and QM give correct predictions in their own domains. They also have different ontological implications, which may or may not be a problem depending on what you expect to get out of physics.