I will apply the same cavaet here that I did to my earlier thread. I have only started taking an introductory QM course, and am still grappling with the subject matter(which is exceptionally counter-intuitive, as I'm sure everyone here would agree) so forgive me if the question seems inane to you experts. A person in my class, the TA as a matter of fact, keeps insisting that all interpretations of QM amount to multiverse interpretation involving alternate universes and such. He is an exceptionally strong advocate for MWI, and keeps backing up his claims with random quotes from David Deutsch. I thought MWI was the only multiverse interpretation of QM, and keep on saying the Bohmian mechanics, Copenhagen,and GRW, for example, are single universe views(at least in terms of quantum mechanics is concerned...I understand things like Linde's Bubble Theory could still be applicable). I am not somehow mistaken in asserting this, am I? As an addendum, I have taken the position of instrumentalism in QM until someway of distinguishing between the interpretations is discovered and until a complete theory of quantum gravity is attained. Is this a respectable position, or am I misguided in thinking this? I appreciate whatever help you can give me.