Since that doesn’t seem to have been auto-linkfied, here’s an actual link: https://www.scottaaronson.com/blog/?p=3975 and a few extracts to help readers judge whether they want to follow the link:
I enjoyed figuring out exactly where I get off Frauchiger and Renner’s train—since I do get off their train.
[...]
I reject an assumption that Frauchiger and Renner never formalize. That assumption is, basically: “it makes sense to chain together statements that involve superposed agents measuring each other’s brains in different incompatible bases, as if the statements still referred to a world where these measurements weren’t being done.”
[...]
The first thing to understand about Frauchiger and Renner’s argument is that, as they acknowledge, it’s not entirely new. As Preskill helped me realize, the argument can be understood as the “Wigner’s-friendification” of Hardy’s Paradox.
[...]
I don’t accept that we can take knowledge inferences that would hold in a hypothetical world where |ψ〉 remained unmeasured, with a particular “branching structure” (as a Many-Worlder might put it), and extend them to the situation where Alice performs a rather violent measurement on |ψ〉 that changes the branching structure by scrambling Charlie’s brain.
https://www.scottaaronson.com/blog/?p=3975
Since that doesn’t seem to have been auto-linkfied, here’s an actual link: https://www.scottaaronson.com/blog/?p=3975 and a few extracts to help readers judge whether they want to follow the link:
[...]
[...]
[...]