On 1/2/2014 7:37 PM, Jason Resch wrote:




On Thu, Jan 2, 2014 at 8:35 PM, LizR <lizj...@gmail.com 
<mailto:lizj...@gmail.com>> wrote:

    On 3 January 2014 14:31, meekerdb <meeke...@verizon.net
    <mailto:meeke...@verizon.net>> wrote:


        Then I'll start by saying I don't reject MWI, I just have reservations 
about it,
        not so much that it's wrong, but that it doesn't really solve the 
problems it
        claims to - which implies criticism of the position that MWI has solved 
all the
        problems of interpreting QM.  A lot of the above claimed advantages 
knocking
        down straw men built on naive interpretations of Bohr.  Some are just
        assumptions, e.g that physics must be time reversible and linear.

    I thought linearit was probabilities adding up to one, which isn't a radical
    assumption???


I think you might be thinking of unitary vs. non-unitary: http://en.wikipedia.org/wiki/Unitarity_(physics) <http://en.wikipedia.org/wiki/Unitarity_%28physics%29>

    Time reversibility is an observed phenomenon in (almost) all particle 
interactions,
    so surely not an assumption at all?


I agree, things like CPT symmetry, determinism, etc. aren't just assumptions, but underlie every other known physical law that is known.

http://en.wikipedia.org/wiki/CPT_symmetry
The *CPT theorem* says that CPT symmetry holds for all physical phenomena, or more precisely, that any Lorentz invariant <http://en.wikipedia.org/wiki/Lorentz_invariant> local quantum field theory <http://en.wikipedia.org/wiki/Quantum_field_theory> with a Hermitian <http://en.wikipedia.org/wiki/Self-adjoint_operator>Hamiltonian <http://en.wikipedia.org/wiki/Hamiltonian_%28quantum_mechanics%29> must have CPT symmetry.

Collapse of the wave function would be the only phenomenon in quantum mechanics that is non-unitary, non-linear, non-differentiable, and discontinuous. It would also be the only principle in physics that non-local, non-causal, non-deterministic, and violates special relativity.

I can understand that Brent's ambivalence toward MWI, it may not be the final answer, but I think it is a good step in that direction. However, I am surprised that anyone well-versed in the known physics of today, could consider collapse as anything but a wild, unsupported, and almost-certainly-false conjecture.

That's what I mean by attacking a straw man. Fuchs and Peres et al, including Bohr only considered 'collapse of the wave function' as a change in one's information. Bohr said QM is not about reality, it's about what we can say about reality. Only later did people try to invent real collapse theories, e.g. Penrose, and while I don't consider any of them likely I wouldn't say they are almost certainly false.

There is so much well-established physics that must be given up; for apparently no other reason than the ontological prejudice some harbor for the idea that the universe is no bigger than we previously thought.

That's as good a prejudice as every thing must be determined from the beginning.

Brent

--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at http://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/groups/opt_out.

Reply via email to