I'll take the statements out of order from your original post.
QM is internally inconsistent in it's definition of a measurement. What is a measurement? What happens when a measurement occurs?
This is not true. It's fairly clear in the theory what happens when a measurement occurs. There's a mathematical operation to describe how a measurement affects the state of the system.
The technical name for this mathematical structure is a Kraus operator, although when students take their first course in quantum mechanics we usually simplify it to something called a projection operator. The technical details don't matter so much for a forum post here, the point is more that it's fairly clear what happens when a measurement occurs, I've taught it several times and it pops up usually the first three chapters of an undegraduate QM book. If the theory couldn't describe how to deal with measurements it wouldn't be empirically valid.
Furthermore QM can be derived as a set of statements about measurements, i.e. its rules for describing measurements are in fact the core of the theory from which the rest can be derived. This is covered in recent books like Jochen Rau's "Quantum Theory: An Information processing approach" and D'Ariano's "Quantum Theory from First principles". It's even covered in detail in older books like Julian Schwinger's "Quantum Mechanics: Symbolism of Atomic Measurement" and Asher Peres' "Quantum Theory: Concepts and Methods".
So quantum theory has a very clear notion of what occurs upon a measurement and nobody has ever shown an actual internal inconsistency.
Some people don't like measurement being a primitive, but that's different from a mathematical inconsistency.
Copenhagen
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But it is not a solid consensus of the discipline
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Objective reality has been "interpreted" to be incorrect by one school of QM
You said phrases like this a few times in your post.
"Copenhagen" usually refers to the specific approach to quantum theory discussed by Heisenberg, Bohr, Peierls, Pauli, von Weisacker, Ludwig, Born, etc. Essentially the understanding of the theory by the people who discovered it, as well as others after them such as Julian Schwinger.
I never specifically referred to this. In fact my favourite way of looking at the theory is that of the French physicist Roland Omnès called Consistent Histories. It doesn't really matter because although there might not be an exact consensus on whether literally every aspect of Copenhagen is correct, there is very little debate about a return to objective reality by people who discuss the fundamentals of quantum theory. It's not just one school that comes away from objective reality, it's virtually all of them. It's really impossible to understand how somebody could maintain it when you know the theory well due to results like the Kochen-Specker theorem, the Unruh effect and so on. That's why most people, even if they don't completely agree with Bohr, rarely argue for objective reality or measurement independent values.
Added to this is that the people that advocate a return to an objective reality
have no working theory that actually matches observations.
In fact most of the people who disagree with Copenhagen think Bohr wasn't subjective enough.
The internal inconsistency shows the theory in not complete and needs to be adjusted
Again I have never seen this "internal inconsistency".
Fundamental levels? I submit we aren't there yet. We can make QM/QFT work so very well, exceptional accuracy, modern magic, but we don't know how measurement works or why it works. One view is to say hang the lot of it, reality doesn't matter, just shut up and calculate. Very productive but very inane.
I expect more. The smart guys have a lot more study to do.
Sorry AZPaul3 but I honestly view this as somewhat anti-scientific.
We physicists don't just think "reality doesn't matter". It's that we have seen a theory that jettisons objective reality, quantum theory, matches experimental results and there is no working theory that retains objective reality. Further as physics has advanced since Heisenberg's rejection of objective reality we have had to remove more and more elements of objectivity from our theories.
The realisation that reality lacks an objective description is an advancement in our understanding of reality. Going on about how a theory and the people who use it are "inane", have "more study to do" and you personally "expect more" is just anti-scientific rhetoric about a theory being poor because it doesn't match your metaphysical predilections regardless of how empirically successful it is.
Here is a video with a much better explanation of the issue involved. It is not a settled matter in the discipline.
I know both Hossenfelder, I have met her, and the experiment she is discussing. I'll only say:
(a) I don't see any reason why she is focusing on this experiment when the hundreds of experiments on the Kochen-Specker theorem, GHZ theorem, etc already show the existence of an objective description of reality is untenable. I don't think she analyses this experiment correctly. Ultimately her objection just amounts to that the experiment doesn't show a lack of objectivity at the human level. All of us know this. As I said above large scale features of the world are known to support an objective description. That's why Classical Mechanics works. The experiment does show however the lack of an objective description at the atomic level. One of hundreds that does so.
(b) She herself has started advocating nonsense like superdeterminism, an idea that involves rejecting basic aspects of scientific thinking. Again just because quantum theory doesn't fit her metaphysical preconceptions.
Again all I can say to you is look at the actual literature. Roland Omnes, Asher Peres, Bernard d'Espagnat, Werner Heisenberg, Rudolf Haag, all of them and several others have highly cited (thousands of citations) monographs explaining why you have to give up objective reality. To me it is a settled matter scientifically. It's only unsettled under the trivial criterion of "there exists some people saying otherwise in youtube videos and some pop science books". I mean then we could say evolution is not a settled matter in the discipline of biology due to the presence of creationist academics.
Edited by Son Goku, : TyposEdited by Son Goku, : Details