Specifically, [these recent books that deal with parallel
universes] argue that if some scientific theory X has
enough experimental support for us to take it seriously,
then we must take seriously also all its predictions Y,
even if these predictions are themselves untestable
(involving parallel universes, for example).
As a warm-up example, let’s consider Einstein’s theory of
General Relativity. It’s widely considered a scientific
theory worthy of taking seriously, because it has made
countless correct predictions—from the gravitational
bending of light to the time dilation measured by our GPS
phones. This means that we must also take seriously its
prediction for what happens inside black holes, even
though this is something we can never observe and report
on in Scientific American. If someone doesn’t like these
black hole predictions, they can’t simply opt out of them
and dismiss them as unscientific: instead, they need to
come up with a different mathematical theory that matches
every single successful prediction that general relativity
has made—yet doesn’t give the disagreeable black hole
predictions.
-- Max Tegmark, Scientific American guest blog,
2014-02-04
I would think the first objection to that line of reasoning would be that we know General Relativity is an incomplete theory of reality and expect to find something that supersedes it and gives better answers regarding black holes.
Better answers, yes, but I’d expect the new answers to be at least quite like the GR answers. I mean, probably no singularities in the real theory, but lots of time-warping and space-whirling, surely. He only says ‘take seriously’, not ‘swallow whole including the self-contradictory bits’.
Well… Einstein didn’t need a complete theory of quantum electrodynamics to predict the coefficients of spontaneous emission from thermodynamical arguments; I don’t think Bekenstein and Hawking need a complete theory of quantum gravity to make predictions other than those of classical GR either.
-- Max Tegmark, Scientific American guest blog, 2014-02-04
I would think the first objection to that line of reasoning would be that we know General Relativity is an incomplete theory of reality and expect to find something that supersedes it and gives better answers regarding black holes.
Better answers, yes, but I’d expect the new answers to be at least quite like the GR answers. I mean, probably no singularities in the real theory, but lots of time-warping and space-whirling, surely. He only says ‘take seriously’, not ‘swallow whole including the self-contradictory bits’.
Well… Einstein didn’t need a complete theory of quantum electrodynamics to predict the coefficients of spontaneous emission from thermodynamical arguments; I don’t think Bekenstein and Hawking need a complete theory of quantum gravity to make predictions other than those of classical GR either.