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A theory is scientific if it bets its life on at least one prediction that it makes about the outcome of a doable experiment
If a theory is part of science then there's a possibility it'll get shot down by an empirical observation---by some measurement----the theory makes predictions of so far unknown results that are that clear and unequivocal.
Smolin has come out with a Multiverse theory which can be shot down if anyone finds a neutron star of 1.6 solar mass or heavier.
Smolin Multiverse is not really part of LQG it just uses LQG-brand plumbing.
It happens to use LQG-brand fittings to connect the end of a black hole to the beginning of a universe.
But quantum gravity in general or LQG in particular does not need Smolin Multi to resolve some crisis. As far as QG goes it is fine if Smolin Multi gets shot down! We still have the good plumbing. And probably some other reason will turn up telling why 1/137 is 1/137 (which is for particle physicists to worry about anyway)
Smolin Multi is a falsifiable theory that offers a way to explain parameters in the standard model (particles) and the standard model(cosmology).
It should explain why 1/137 and why
planck/proton mass is 13E18
and why cosmo.constant is E-123
(Smolin says "the dimensionless parameters of the standard models of physics and cosmology", these are examples). And if Multi fails and dies on the launchpad, well there will be other explanations of those parameters.
Smolin Multi says that sets of basic constants become very common if they promote the formation of black holes. this is testable.
Maybe there is one of our standard model parameters which is not adjusted to promote holes. OK find it.
So according to Multi if there actually is an ensemble of universes then those with hole-promoting ("holific"?) parameters are very common---the overwhelmingly most common are universes presumably like ours, in that they promote holes. The inference is that our parameters are not especially rare!
Conscious life is accidental to the theory. I suppose it could play a role in some variant theory but it doesnt----Multi is simple and doesn't need to consider that angle. In Multi what drives evolution is holes and only holes.
The conclusion is that what we've got is apt to be very common.
there are other Multiverse stories floating around in which our type of universe is very rare. there is an ensemble of a huge number of universes which are unfriendly to life or otherwise inconvenient. these are not predictive AFAIK because the premise cannot be shot down by some future empirical observation. those stories do not predict anything (we live in a rare exceptional case and are excused from explaining why it is like this) so they are cop-outs.
At least one such non-scientific Multiverse story seems to have been invented in response to the string theory Kachru crisis of too many vacuums.
But this doesn't matter. the main thing is we now have a Multiverse theory which (whether its wrong or right) predicts something definite for checking where we don't yet know the outcome.
http://arxiv.org/hep-th/0407213 [Broken]
Smolin
Scientific alternatives to the anthropic principle
If a theory is part of science then there's a possibility it'll get shot down by an empirical observation---by some measurement----the theory makes predictions of so far unknown results that are that clear and unequivocal.
Smolin has come out with a Multiverse theory which can be shot down if anyone finds a neutron star of 1.6 solar mass or heavier.
Smolin Multiverse is not really part of LQG it just uses LQG-brand plumbing.
It happens to use LQG-brand fittings to connect the end of a black hole to the beginning of a universe.
But quantum gravity in general or LQG in particular does not need Smolin Multi to resolve some crisis. As far as QG goes it is fine if Smolin Multi gets shot down! We still have the good plumbing. And probably some other reason will turn up telling why 1/137 is 1/137 (which is for particle physicists to worry about anyway)
Smolin Multi is a falsifiable theory that offers a way to explain parameters in the standard model (particles) and the standard model(cosmology).
It should explain why 1/137 and why
planck/proton mass is 13E18
and why cosmo.constant is E-123
(Smolin says "the dimensionless parameters of the standard models of physics and cosmology", these are examples). And if Multi fails and dies on the launchpad, well there will be other explanations of those parameters.
Smolin Multi says that sets of basic constants become very common if they promote the formation of black holes. this is testable.
Maybe there is one of our standard model parameters which is not adjusted to promote holes. OK find it.
So according to Multi if there actually is an ensemble of universes then those with hole-promoting ("holific"?) parameters are very common---the overwhelmingly most common are universes presumably like ours, in that they promote holes. The inference is that our parameters are not especially rare!
Conscious life is accidental to the theory. I suppose it could play a role in some variant theory but it doesnt----Multi is simple and doesn't need to consider that angle. In Multi what drives evolution is holes and only holes.
The conclusion is that what we've got is apt to be very common.
there are other Multiverse stories floating around in which our type of universe is very rare. there is an ensemble of a huge number of universes which are unfriendly to life or otherwise inconvenient. these are not predictive AFAIK because the premise cannot be shot down by some future empirical observation. those stories do not predict anything (we live in a rare exceptional case and are excused from explaining why it is like this) so they are cop-outs.
At least one such non-scientific Multiverse story seems to have been invented in response to the string theory Kachru crisis of too many vacuums.
But this doesn't matter. the main thing is we now have a Multiverse theory which (whether its wrong or right) predicts something definite for checking where we don't yet know the outcome.
http://arxiv.org/hep-th/0407213 [Broken]
Smolin
Scientific alternatives to the anthropic principle
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