Back before Bell's Theorem ruled out local hidden variables, it seemed possible that (as Einstein thought) there was some more complete description of reality which we didn't have, and the quantum theory summarized incomplete knowledge of this more complete description.
EY seems a big fan of Jaynes. Has he ever specifically confronted Jayne's arguments against Bell?
Jaynes paper on EPR and Bell's Theorem: http://bayes.wustl.edu/etj/articles/cmystery.pdf
Eliezer is definitely a big fan of Jaynes. I've never seen him write anything like a whole post or essay on that particular topic, but he has touched on it a few times. In general, Jaynes seems to have considered and rejected all the various interpretations of QM that were floating around in his day, on probability theoretic grounds. I did see EY in one place imply that he thinks Jaynes would have gone for the MWI, if Jaynes had ever heard about it. To the best of my knowledge, he never did.
Jaynes died in 1998. How did he never hear of MWI? I'd heard of MWI in 1998, and I was just a kid.
EDIT: Google Books turns up the following snippet in The Many Worlds of Hugh Everett III:
All possibilities 'actually realized,' with corresp. observer states.15 In May 1957, Everett wrote a critical letter to ET Jaynes, a physicist at Stanford University who was pioneering the use of von Neumann-Shannontype information...
I have been unable to find any copies online, Amazon wants $30 for any copy, and neither my local library nor university nor county catalog hold it. Man!
EDITEDIT: Google Books gives more access to The Everett Interpretation of Quantum Mechanics: Collected Works 1955-1980, which gives an entire chapter 18 to 'Correspondence: Everett and Jaynes (1957)': http://books.google.com/books?id=dowpli7i6TgC&pg=PA261&dq=jaynes+everett&hl=en&sa=X&ei=N9CdT9PSIcLOgAf-3vTxDg&ved=0CDYQ6AEwAQ#v=onepage&q&f=false
I'm not sure what they are discussing, and many-worlds doesn't seem to come up (at least under that name) and most of the chapter is inaccessible, but it's clear from the chapter summary Jaynes doesn't think much of Everett's position.
EDIT: they are both on Libgen now. The Many Worlds of Hugh Everett III's mention of Jaynes is just about statistics, not MWI. (The book is worth reading for other reasons.) Jaynes's view of MWI remains a mystery.
The correspondence mentioned is available online. http://ucispace.lib.uci.edu/handle/10575/1158
They seem to be talking more about Jaynes work in probability theory and statistical mechanics. Didn't see relevant comments on quantum theory, but mainly scanned the docs.
Given Jayne's interest in the foundations of quantum theory, it seems extremely unlikely to me that he was unaware of MWI. I've read most of his papers since around 1980, and can't recall a mention anywhere. Surely he was aware, and surely he had an opinion.
Ditto [edit: responding to gwern's first paragraph] but in the mid-1980s. The many-worlds interpretation and the Copenhagen interpretation are contrasted in the pop-science books The Tao of Physics and The Dancing Wu Li Masters, published respectively in 1975 and 1979.
You're right, that should have been obvious. Hmm. I'm going to have to see if I can track down where I heard that and didn't question it.
Shut up an calculate brings up two points.
Knowledge is not necessarily representational. It may just be algorithmic. You may know that performing a certain calculation gives the right answer, but be unable to map all elements of the calculation to real entities.
We'd rather be able to do white box testing than black box testing, but I'll take a useful black box.
Today's post, Quantum Non-Realism was originally published on 08 May 2008. A summary (taken from the LW wiki):
Discuss the post here (rather than in the comments to the original post).
This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was Decoherence is Falsifiable and Testable, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.
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