First, it’s important to keep in mind that if MWI is “untestable” relative to non-MWI, then non-MWI is also “untestable” relative to MWI. To use this as an argument against MWI,
I think it’s being used as an argument against beliefs paying rent.
MWI is testable insofar as QM itself is testable.
Since there is more than one interpretation of QM, empirically testing QM does not prove any one interpretation over the others.
Whatever extra arguments are used to support a particular interpretation over the others are not going to be, and have not been, empirical.
But, importantly, collapse interpretations generally are empirically distinguishable from non-collapse interpretations.
No they are not, because of the meaning of the word “interpretation” but collapse theories, such as GRW, might be.
I think it’s being used as an argument against beliefs paying rent.
Since there is more than one interpretation of QM, empirically testing QM does not prove any one interpretation over the others. Whatever extra arguments are used to support a particular interpretation over the others are not going to be, and have not been, empirical.
No they are not, because of the meaning of the word “interpretation” but collapse theories, such as GRW, might be.