"Political scientist" L David Raub reports a poll of 72 of the "leading cosmologists and other quantum field theorists" about the "Many-Worlds Interpretation" and gives the following response breakdown [T].However, I believe that this is incorrect. Hawking, Gell-Mann, Feynman, and Weinberg do not favor MWI in their latest opinions on the subject. Eg, this recent paper of Gell-Mann on the subject mentions MWI only in a footnote without any endorsement.
1) "Yes, I think MWI is true" 58%
2) "No, I don't accept MWI" 18%
3) "Maybe it's true but I'm not yet convinced" 13%
4) "I have no opinion one way or the other" 11%
Amongst the "Yes, I think MWI is true" crowd listed are Stephen Hawking and Nobel Laureates Murray Gell-Mann and Richard Feynman. Gell-Mann and Hawking recorded reservations with the name "many-worlds", but not with the theory's content. Nobel Laureate Steven Weinberg is also mentioned as a many-worlder, although the suggestion is not when the poll was conducted, presumably before 1988 (when Feynman died). The only "No, I don't accept MWI" named is Penrose.
Hawking's recent book on the subject, The Grand Design, talks a lot about the multiverse, but does not mention MWI at all. Weinberg's recent paper on the subject has only negative comments about MWI. Also, PBS says:
[Physicist Richard] Feynman went on record as saying, in essence, "Well, this is not possible because there can't be multiple universes."Apparently some of these physicists have discussed MWI in the context of the other worlds being mathematical fictions that are not real. That makes MWI trivial. The MWI advocates use the term to mean that the other worlds are real. While there are experiments that would convince me of quantum computing, supersymmetry, global warming, etc, there are no experiments that would convince me of MWI. The concept is incoherent and untestable.