From: helbig@asclothestro.multivax.de   
      
   In article <5d09ce65$0$22341$e4fe514c@news.xs4all.nl>, Jos Bergervoet   
    writes:   
      
   > On 19/06/17 9:52 AM, Lawrence Crowell wrote:   
   > > On Sunday, June 16, 2019 at 10:41:37 AM UTC-5, Michael Cole wrote:   
   > >> In my humble opinion, the \_fatal flaw_/ of many worlds is   
   > >> that it is metaphysics, not science.  That interpretation of QM is   
   > >> untestable. It is fun to think about, but it is a question of philosophy   
   > >> that is outside the province of science.   
   > >   
   > > This is the case for all quantum interpretations. They are auxiliary   
   > > postulates added onto QM. There seems to be no experimental criterion   
   > > to determine which of any is correct.   
   > >   
   > > [[Mod. note -- Exactly.  If there were an experimental way to   
   > > distinguish one interpretation of QM from another, or to refute   
   > > some of them, then we wouldn't still be arguing about interpretations   
   > > 90 years after the birth of QM!   
   > > -- jt]]   
   >   
   > That reasoning is not valid. There also was arguing about whether   
   > gravitational waves existed, until 90 years after the birth of GR.   
   > Still there was an experimental way!   
      
   There is an important distinction here.  First, the controversy over   
   whether gravitational waves exist and, if so, whether they carry energy,   
   and so on, was basically because GR was not fully understood.  At the   
   latest with beads-on-a-stick Gedankenexperiment it was clear that there   
   are gravitational waves in GR; this was more than half a century ago.   
   Second, after this, no-one doubted that gravitational waves could be   
   detected IN PRINCIPLE.  On the other hand, the definition of an   
   INTERPRETATION of quantum mechanics is that there is no way to   
   distinguish between it and another interpretation EVEN IN PRINCIPLE.  Of   
   course, someone might think of one at some point in the future, but then   
   that which can be distinguished experimentally is no longer an   
   interpretation, but a separate theory.   
      
   > For QM you basically have (at least) two fundamentally different   
   > theories being proposed.   
   > QM0: time evolution is always unitary, described by clear equations.   
   > QM1: time evolution is sometimes unitary and described by clear   
   > equations, and sometimes non-unitary with an as of yet unknown   
   > time-evolution equation.   
   >   
   > Within each of the two theories there may be several interpretations,   
   > and within those two groups the interpretations may be experimentally   
   > indistinguishable as you describe, but the two theories remain   
   > different. Calling QM1 an interpretation of QM0 is like calling the   
   > flat Earth theory an interpretation of the round Earth theory. Or   
   > GR without gravitational waves an interpretation of GR.   
      
   I agree here.   
      
   > And of course if there is non-unitary time evolution, then it could   
   > in principle be experimentally detected, and a precise mathematical   
   > time-dependent description could be found for it. It just might take   
   > more than 90 years..   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)