Sunday, 21 October 2012

Symmetry and Creation?

First of all, thank you for providing this service.  I've been reading JCPs books for 25 years, and it's great to see the rationality of faith clearly explained.  Could you please help me with some questions I haven't been able to unravel for myself?
     It's often said that symmetry explains regularity of process.  ie if a specific particle-particle interaction is given by a specific group operator, that explains why each particle pair always interact in the same way.  Ie. a reason for the lawfulness of natural process.  My question is simply this: is it logically necessary that symmetry should apply in this way, or could the universe have worked in any old way?  ie. did God have a choice in the matter?
     Now to Victor Stenger's argument.  He starts with Noether's theorem, to show that conservation of energy, momentum and angular momentum follow necessarily from temporal, spatial and angular invariance, respectively.  Later he shows how the fundamental-force laws follow from the imposition of gauge invariance.  He generalises gauge invariance to what he calls "point-of-view invariance", and argues that quantum mechanics -- including the uncertainty principle -- follows from point-of-view invariance.  He missed out steps in his explanation of this, and I didn't understand it anyway.  I think he's saying that given the uncertainty principle there's bound to be a quantum vacuum, ie. there can be no "nothing" as such.  Does that follow?  And then from the vacuum springs the univ. as a quantum fluctuation.  The v. early universe was smaller than the Planck length, a regime in which space and time are not defined, he says.  Hardly surprising then, he continues, that temporal, spatial displacement and rotational invariance apply in the universe today, along with the abstract symmetries which generate particle-particle interactions.  Is this justified?  But if space and time are not defined for the v. early universe, how could the uncertainty principle apply anyway?  But you can see his punchline.  He's saying that the universe as we find it is logically necessary, thereby removing the need to infer to a Creator-God.  Your advice would be much appreciated....
     Hawking used to say that there was only one possible universe, ie. only one self-consistent and without infinities.  Is it logically or physically necessary that the universe must follow the one fundamental theory that's finite and self-contained, or could the universe have been any old way?
     Now Hawking says there is a multiverse of 10 to the power 500 universes, answering the fine-tuning question.  I'd be interested in your opinion.  Am I right in thinking that Hawking's multiverse theory takes as given anthropically necessary features like quantum mechanics, gravity and regularity of process itself?
Response: Well “point of view invariance” implies that here are observers embedded in the universe who have points of view. So it’s not surprising that you can, with some handwaving, infer from this that the universe must exist and be such that there can be observers.  But it doesn’t answer the problem of what/who “breathes fire into the equations” at all.

PS for a systematic debunking of Stenger, who is basically a scientific fraud in his writings on God, see this excellent, though rather technical paper by Luke Barnes. I've blogged about this here and here.

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