Russell Standish wrote:
On Tue, Mar 03, 2015 at 05:06:58PM +1100, Bruce Kellett wrote:
Russell Standish wrote:
On Mon, Mar 02, 2015 at 07:52:57PM -0800, meekerdb wrote:
On 3/2/2015 5:49 PM, Jason Resch wrote:
Maybe that's enough though, to implement a brain and observer,
that they stop interfering in at least one basis (assuming they're
not contradictory, might all bases exist?)
Bases are just coordinate systems for Hilbert space. We choose
them. Of course that doesn't keep Platonists from supposing they
exist, but physicists generally assume coordinate dependent things
measure up to their standard of "exists". If brains and observers
exist they should have some coordinate independent definition.
Or perhaps they define their own coordinates. The person who choses to
measure momentum is simply a different person to the one chosing to
measure position. And the basis is correspondingly defined.
The difference between a position or momentum measurement is not a
different choice of basis. Each observable is an operator in a
separate Hilbert space -- the choice of basis in these spaces
remains problematic.
The basis is defined by the eigenvectors of the chosen measurement
operator.
But we choose the measurement operator in a classical context. The
problem arises when we attempt to construct that classical context from
the uninterpreted quantum formalism. The operators are not defined /ab
initio/. This is why Bohr used the Correspondence Principle -- classical
physics guides us by giving the form that we need to reproduce the
classical limit. Without knowing what we want in advance we do not know
what operator to use, and the eigenvectors are undefined.
Bruce
--
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/d/optout.
