Jamesian Philosophy Refreshed

I discussed Quantum Bayesian theory here about three weeks ago. But now that I know what to look for, it has become easier to find more about it, so I come back to it. Early this year, the William & Mary blog ran an interview with Hans Christian von Baeyer, who believes that QB-ism (which he pronounces "cubism" as in Picasso) is nothing less than the "future of physics." He regrets that advocates of QBism have yet to get it into physics textbooks. But there are "hundreds of articles and conference proceedings" that deal with it, so he is hoping admission into the canon, with the dozen or so older interpretations of quantum mechanics, will come soon. Von Baeyer also makes reference to "an excellent article" that was added to the Stanford Encyclopedia of Philosophy in December 2016. So, after finishing up the interview, I went there. The actual title of that article is evidence that this is an appropriate thing to be discussing in a blo...

We discussed quantum theory yesterday. Now it is time to remind ourselves of the other half of our proposed mash-up. 'Bayesianism' is an approach to probability theory that begins with subjectivity, with somebody's guess about what  is the likelihood of an event. It then discusses how an individual having certain circumstances may change his beliefs rationally, and (assuming he has beliefs on more than one question) may keep them consistent with one another -- or, in other words, how he may keep his view of the world coherent. The chief rival of Bayesianism is "frequentism." This treats probability as an objective fact in the world, another name for the frequency of some outcomes vis-a-vis others. I've discussed this difference before. But ... what does it have to do with quantum theory? Collapse the Function for your own Damned Self With a Bayesian approach we get a take on quantum theory that doesn't shrug its shoulders at the "what is rea...