The discussion at Scott Aaronson's blog[1] has some fascinating to-and-fro in the extensive comments, including claimed refutations and detailed responses to them from one of the paper's authors.
If I understand correctly, the paper asks us to imagine Alice's friend making a 'classical' coin flip, and Alice modeling and measuring her friend's lab as if the coin flip were a quantum superposition of coin heads/coin tails.
But this is simply wrong. The error creeps in in the second assumption:
> An agent can analyze another system, even a complex one including other agents, using quantum mechanics
This is likely a good assumption, but quantum physics would tell Alice that the coin's atoms are all firmly in a state corresponding to either 'heads' or 'tails'. The author is actually making the following assumption:
> What we classically think of as chance is completely interchangeable with the unpredictability of quantum superpositions.
This notion has already been proven wrong many times over.
After reading a lot of comments about this, several of which said "there must be something to this if there are so many different views on why it is wrong", I think a better title would be "New Quantum Paradox Gratuitously Confuses Where Our Views of Reality Go Wrong".
I can't say anything about physics, but when people disagree on why something is inconsistent, that does not mean it's consistent and correct, it just means they are choosing different fixed points to reason from.
When someone (an author of the paper) keeps going "oh, you keep changing your view of why I am inconsistent", I think they are just trolling. The attitude seems to be, "if I confuse you, I win, and if I claim to be confused then you lose".
From the comments on Aaronson's blog analogizing why the paper is wrong: “I have just enough money for one beer. I have just enough money for a sandwich. So tonight, I will dine on a beer and sandwich”
It makes me wonder whether quantum computers can actually solve problems... Does this mean that each person can get a different result from the same calculation done by the same quantum computer?
Doesn't this make quantum computers completely useless?
https://news.ycombinator.com/item?id=18666392
https://news.ycombinator.com/item?id=18023452
I think there might have been others too.