On Fri, Jan 3, 2014 at 1:46 AM, meekerdb <[email protected]> wrote:
> On 1/2/2014 10:38 PM, Jason Resch wrote: > > > > > On Fri, Jan 3, 2014 at 12:20 AM, meekerdb <[email protected]> wrote: > >> On 1/2/2014 7:37 PM, Jason Resch wrote: >> >> >> >> >> On Thu, Jan 2, 2014 at 8:35 PM, LizR <[email protected]> wrote: >> >>> On 3 January 2014 14:31, meekerdb <[email protected]> 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) >> >> >> >>> 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. >> > > I agree Bohr was closer to Fuchs and Peres, but Heisenberg, von Neumann, > Wigner, etc. all believed in collapse, and CI is still taught as the > orthodox interpretation in most places. It's not exactly a straw man. > > To say the theory is only about our information seems like a kind of > cop-out to me. We don't see other theories in science described as only > speaking about the information that we can gain not about anything that > real external to us. Why can't QM be a realist theory like everything else > in science? > > > I sort of see the opposite trend. More and more physicists are looking > for an information based fundamental theory. > > But where is the information coming from? If no where or nothing, this is just a form of idealism. > > > >> 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. >> >> > Let's say someone proposed a new theory to explain why when something > falls into a black hole we can no longer see it, but it ignored that other > theories already explain why we can't see things that fall into a black > hole. > > > Or how about a theory that it's both destroyed at the event horizon and > also falls through to the singularity? > > That's fine. > > Moreover, imagine that this theory, if true, would require faster than > light influences, as well as violations in the second law of thermodynamics > and conservation of mass energy. Would you say this theory was only > "unlikely"? > > > Are you claiming that Penrose's idea does all those things? > > No, it is only an example of the kind of thing collapse represents. An extraneous theory, having no motivation and which contradicts core ideas and principals across physics. > > > >> >> 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. >> >> > Now who is fighting straw men? (You always pretend this this is the > primary, or only motivation for Everett) > > > I don't know about you, but Bruno has said he considers fundamental > randomness to be completely unacceptable. > So that makes collapse 1 of about 10 other serious problems with it. > What do you think about the idea that the whole course of the universe > was set at that (near) singularity at the beginning of the universe? > What do you mean by universe? Clearly we don't remain (or aren't in) just a single possible ((future) history). Jason I realize it was probably not Everett's motivation - he was more interested > in the Heisenberg cut problem. > > 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 [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
