1. How do you know that "real universes are not cheap"? Are you an expert on the universe-making process? 2. The "universes" that appear in MWI are simply part

1. How do you know that "real universes are not cheap"? Are you an expert on the universe-making process? 2. The "universes" that appear in MWI are simply parts into which the universal wavefunction gets decomposed. Getting rid of them would require some sort of wavefunction-pruning process. You might equally say "Destroying universes is not cheap", a statement for which I think I have every bit as much evidence as you have for yours. (Of course non-MW interpretations of QM do have a wavefunction-pruning process. They don't generally have much to say about how it happens, and they tend to require ridiculous things like building the notion of "observer" into the fundamental equations of physics. Or, as in the case of Bohmian QM, they include all the same mechanics as MWI plus a bit extra and then claim to be more parsimonious simply because they attach the label "real" to a different subset of what the theory talks about.)