From: aa387@cleveland.Freenet.Edu (Jim Kutz)
Newsgroups: sci.skeptic
Subject: Can quantum terminology be flakeproofed?
Date: 11 Oct 92 15:03:12 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: slc12.ins.cwru.edu


One  reads all  kinds of  horse manure  these days  from magazine
writers  about how  a quantum  event doesn't  really exist  until
observed by  a *conscious* entity.  They invariably cite  quantum
physics as an 'authority' on this. Then they go off on some flaky
'mind over  matter' tangent about  how supposedly one  can choose
which  reality  to  recognize,or  even  just  shut  your eyes and
'refuse  delivery'  on  whichever  aspects  of  reality you don't
happen  to like,  supposedly forcing  reality to  conform to your
expectations.
 
Yet  none  of  the  quantum  physics  experiments I've read about
require a *sentient* observer.  Apparently the observation can be
'captured' equally well by any sort of recording instrument, such
as a photographic plate or event counter.
 
I'm  thinking  in  particular  about  the  classic  particle-wave
experiment where a beam of photons  is split into two beams using
a half-silvered mirror, and the two  beams are then recombined on
a screen  to create  an interference  pattern, thus demonstrating
the 'wavelike'  nature  of photons (or other kinds of particles).
The  interference pattern  disappears whenever  observers try  to
determine which of  the two paths a given  photon took. The catch
is that  the interference pattern *also*  disappears whenever the
observers set up instruments which *could* make that observation,
even when nobody  is actually at the eyepiece  observing. As soon
as the  'split' photons are  rendered distinguishable by  the way
the apparatus is set up, the wave function 'collapses'.
 
Secondly, I've  yet to read  about *any* experiment  in which the
mindset  of  the  researchers  had  any  effect whatsoever on the
outcome of the experiment. In  every case the researchers had the
option  to observe  or not  to observe,  but they  still couldn't
make a  random quantum event come  out a certain way  by means of
'filtered' observation. Nor were observers able to 'sneak a peek'
and then alter the outcome by observing or not observing. The act
of  'sneaking a  peek' always  randomnized the  outcome. Even the
*intent* to  observe has no  effect on quantum  events, which are
affected only by the *possibility* of an observation - regardless
of whether or not an observation actually occurred.
 
I'm trying  to keep this general,  but I'm thinking again  of the
'split beam'  of photons forming an  interference pattern. If the
two beams go through twin maser cavities, that doesn't change the
interference pattern. OK. But if the maser cavities are gimmicked
with some kind of sensor beams (or anything else that could carry
away   information  about   which  path   a  photon   took),  the
interference pattern disappears.
 
What  bothers me  about this  is that  the same  phenomenon would
probably happen in nature if a  stream of photons were were split
up  and  recombined  by  some  natural  occurrence  (  such  as a
naturally   occurring  geometry,   analogous  to   a  double-slit
experiment,  with some  oddity capable  of rendering  the photons
distinguishable ).
 
Obviously,  when a  photon is  traveling along,  minding its own
business, and it encounters  some shiny transparent surface where
it has a choice of paths, the photon doesn't get paranoid and say
to itself:
 
    "Hmmm,  now  is  this  geometry  a  'setup'  by  some  sneaky
    physicist  trying to  *observe*? Or  is this  a natural event
    whose  outcome  will  never  be  observed  by  anyone looking
    closely enough to catch a photon in the act of being *both* a
    wave and a particle at the same instant. Hmm, I'd better stay
    away from that patch of  lichens, because they *could* record
    an interference pattern which  just *might* become fossilized
    and be dug up 50,000 when  those apes over there descend from
    the trees and  evolve into physicists. A photon  can never be
    too careful."
 
I favor  the  notion  that  the  photon  could  care less whether
primitive humans  are doing a fertility  dance or performing some
other ritual called 'observation'.
 
Of course the 'orthodox' quantum mechanical answer to that puzzle
is that the  photon doesn't *have* to make  a decision until it's
'observed'.  The  'official'  quantum  mechanical example usually
given   to   make   quantum   events   more  'understandable'  is
Schroedinger's  'half-alive'  cat.  If   quantum  states  can  be
indeterminate, then  why not a  cat? In this  thought experiment,
the cat is placed in a box with an automated machine. The machine
detects a quantum event which  has two equally probable outcomes.
If the  event comes out  one way, the  machine releases a  lethal
substance and kills  the cat. If the quantum  event comes out the
other way, the machine does nothing. Supposedly the quantum event
remains  indeterminate (and  so does  the condition  of the  cat)
until   the  box   is  opened,   'collapsing'  the  indeterminate
probability waves into  a dead cat or a live  cat. (Of course the
wave  function  collapses  early  if  Schroedinger  hears the cat
scratching  around  in  the  box  before  it's  opened.  Even  if
Schroedinger  doesn't hear  the vibration,  the mere  fact of the
smallest interaction  with the outside  world would be  enough to
collapse the wave function.
 
Well  then what  determines when  the outcome  of a quantum event
*could*  be  observed,  for   purposes  of  collapsing  the  wave
function?  That's  already  been  answered,  by  experiments that
attempt  to 'sneak  up' on  a  split  beam of  photons. The  wave
behavior collapses whenever the two  halves of the split beam are
coupled (  in any fashion  ) to any  chain of events  which would
have a different outcome depending on which path the photon took.
 
So why not just *say* that, and leave the 'observer' out of it?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Note that the term "coupled  in any fashion" would include 'idler
beams'  and other  sneaky  methods  of siphoning  off information
about the split beams of photons.
 
Admittedly,  these effects  hinder  any  attempt to  observe. But
what's actually changing the outcome  is not the observer per se,
but  rather  the  set  of   interactions  which  the  split  beam
encounters.
 
Admittedly there's something *very* strange going on when a split
beam of  photons is further  divided into two  'signal beams' and
two 'idler beams' by 'frequency divider' crystals. What's strange
is  that messing  with the  'idler' beams  can affect the 'signal
beams  and mess  up their  interference pattern,  even though the
two sets of beams had already parted company.
 
OK,  so  that's  weird.  But  it's  not  necessarily  a  'quantum
conspiracy' aimed at frustrating observers  per se. Maybe it just
*happens* that observers are the  ones getting frustrated by that
particular quirk of nature -  and attempting to state natural law
relative to their own viewpoint as observers.
 
The supposition  that "a wave  function collapses only  when it's
observed" is not subject to experimental test. That's like saying
"If  a tree  falls in  the forest  and there's  no-one around  to
record the event, does it make  a noise?" Well if "there's no-one
around  to  record  it",  then  it  can  never  be observed under
scientific conditions, and hence can  never be a scientific fact.
Ditto for  quantum wave functions  that supposedly only  collapse
when 'observed'. Most probably those waves would collapse anyway,
if they encountered a similar  situation *not* placed there by an
'observer'.
 
I think  this point  needs to  be cleared  up, because flakes are
having a field day with  the mistaken notion that quantum reality
'deliberately'  acts  in  such  a  way  as  to foil the objective
observer. This  of course then becomes  the flake explanation for
why paranormal  events never happen  around scientists -  because
reality supposedly becomes 'evasive'  when looked at too closely.
Therefore  a  lot  of  flakes  believe  that  the  key  to making
paranormal events happen is to *not*  try and pin them down. This
in turn invites charlatans to take advantage of flakes, raking in
enough money to file harassment suits in defense of irrationality.
 
Therefore I  think that closing  this loophole with  more precise
language  would help  restore confidence  in 'objective' reality,
and  avoid  feeding  into  galloping  irrationality.  After  all,
quantum reality *is* objective to the  extent that all of the key
phenomena are reproduceable and consistent.  A guy with a pyramid
on his  head sees exactly the  same thing as a  physicist when he
looks into an interferometer.
 
 
          - Jim Kutz (aa387@cleveland.freenet.edu)
 
--
 
A Fair Witness is one who, if asked:
"Is that house over there white?",
answers: "Well it's white on this side."