I think this is mostly a science/pseudoscience demarcation issue. For now I consider such notions pseudoscience, but in a very precise way and should not be taken to mean I am lumping MWI with astrology, eugenics, cold fusion, psychoanalysis and alchemy. MWI is of course grounded in science, but is extremely speculative. There's nothing wrong with this, but I hesitate to label it science.
I stressed for now above to indicate that it may be possible in the future to refine, validate or falsify MWI and similar theories, but the fact that it's not falsifiable is why I consider it a fine demarcation issue, a la Popper.
I stressed for now above to indicate that it may be possible in the future to refine, validate or falsify MWI and similar theories, but the fact that it's not falsifiable is why I consider it a fine demarcation issue, a la Popper.