I think I just became a QBist ?

[atyy]

I recall that the "updating" idea arose our discussion of the Rovelli Smerlak paper some time ago. Each observer has his own Hilbertspace to keep track of his information and updating is not something catastrophic that the world does, it is just something he does in his own file system to stay au courant.

You are on a different schedule from me, Atyy. You already understand QB interpretation and are starting to critique it and consider antecedents alternatives and improvements. I basically want to understand better, especially what Mermin is saying.

We have these two recent papers that Rep mentioned:
November FMS http://arxiv.org/abs/1311.5253
December Mermin http://arxiv.org/abs/1312.7825
That defines what QB is, for me, and what I want to concentrate on.

When Mermin talks about probability he refers to Bruno de Finetti:
[[That probabilities are personal judgments was put most forcibly by Bruno de Finetti, and if “B” has to stand for anything I would expand “QBism” to “Quantum Brunoism.”]]
I believe in this case it is the personal judgements of a rational bettor. What wagers would an ideal rational Bookie consider fair? He mentions is the concept of a "Dutch Book" which I suspect is where a good bookie writes down the odds at which to buy and sell bets.

No, if you read my post #89 it is my summary of QBism you asked for. I simply dislike Mermin's writing about it. I believe the review by Fuchs and Schack I linked to is a far better exposition of QBism. The statistical method of Bayesian inference I mentioned is based in large part on de Finetti's work, and the formal notion of Bayesian coherence I mentioned is de Finetti's. The Dutch Book example is a famous example illustrating Bayesian coherence.

 

[Dale]

It has been recommended that we close all the threads about QM interpretations in order to be coherent with the closure of the spawned thread.