I have a few questions regarding Many Worlds Interpretation (MWI) Terminology: QM is just the math, doubted by none; MWI and CI (Copenhagen Interpretation) are ontological interpretations. David Deutsch believes MWI with certainty. He even says that it's "proven" experimentally. How many theoretical physicists go along with that? How is Deutsch's attitude viewed, generally, in the community? Do any theoretical physicists disbelieve MWI with certainty? Stephen Hawking has used MWI model for some theoretical work (right?). He's in situations where (arguably) no "collapse of the wave function" would occur, like Big Bang or Black Holes. In that case CI is equivalent to MWI anyway, isn't it? He puts special emphasis on reversibility of physical laws: no information is ever lost. MWI fits this requirement, but "collapsed" wave function violates it. Is that why he uses MWI? How prevalent is this approach in theoretical cosmology generally? Does MWI facilitate the attempt to unify GR and QM? I think that experimental physicists ignore MWI and work with CI by default. Is that true? These questions are not about physics per se but the culture of physicists, so aren't ideal for this forum. In defense of them, let me make the following points. - The overall issue is important in terms of the relation of physicists to society - They concern mainstream physics or at least close to that - They are not speculative or argumentative - There's nowhere else to ask them, to get authoritative answers without impassioned argument (I have experimentally proven that, elsewhere on the net and at local universities) Take these questions as merely guidelines, no need to go through them "bullet by bullet". Most important, please correct any misunderstandings evident in the questions.