[simonh]

Many worlds is an interpretation of quantum uncertainly, but what we seem to be talking about here are multiverse theories.

One of these, M-Theory is an extension of string theory and is the only theory known to elegantly unify quantum mechanics with general relativity's gravitational force in a mathematically consistent way. It’s not supported by experimental evidence yet, but I’d hardly characterise it as no different from belief in spirits.

[kldavis4]

Actually, I _am_ referring to 'many worlds' (at least according to the technical explanation in this article: http://blogs.discovermagazine.com/cosmicvariance/2011/05/26/...) and not a multiverse. And yes, there is some hope that there will be some testable empirical evidence at some point, but if in the end it turns out that there are not 'many worlds', then I don't see that big a difference. I'd love it if there were parallel dimensions but it is fantasy at this point.

[akvadrako]

Really your arguments work equally well for any multiverse theory, be it quantum or cosmological or mathematical.