X-Message-Number: 9280
From: Ettinger <>
Date: Fri, 13 Mar 1998 21:35:44 EST
Subject: More FTL & quanta

Adding to my earlier post about non-locality and ftl signals:

As I understand it, the Aspect experiment consisted of sending two newly
created photons in different directions. Their (potential?) spins must be
opposite, to conserve total spin. When they are widely separated, their spins
are quickly measured, one after the other, and are indeed opposite.

In the Copenhagen interpretation, neither photon could "have" a spin prior to
measurement. Either photon, when observed, might have spin up or
down--impossible to tell in advance. But in any case the second photon, when
observed in its turn, will be found to have spin opposite to that observed for
the first. This seems to suggest either that (a) a signal was sent from the
first to the second, or (b) each "really" did have a definite (although
unknown) spin before the observations. But (a) is supposedly ruled out by
relativity--no signal faster than light--and (b) is ruled out by requirement
of collapse of the wave function--an observation must be made before the spin
acquires a definite value.

Many-worlds supposedly offers another alternative. Deutsch and others believe
many-worlds is  philosophically superior to other schemes, and also is
beginning to accumulate experimental evidence from quantum computation; and
reluctance to accept it is the result of unflattering psychological
conditions. 

Minority positions include that of the late David Bohm, who postulated
something akin to the old "pilot wave" idea, and Bart Kosko, who says quantum
theory has got to go because it is linear, and reality is not linear. 

Other interpretations of many-worlds include that of Barrow (a few years back,
at any rate) who thought it implied that all LOGICALLY POSSIBLE events would
occur in the multiverse. He specifically included a universe in which you
(your counterpart) would never die. If he is right, and if a counterpart is
"really" you, then you are ALREADY immortal, so quit worrying.

And of course the late Gary Feinberg and others denied that special relativity
rules out ftl signals--only ftl by "tardyons" or particles of ordinary matter;
"tachyons" can have any velocities GREATER THAN that of light as well as other
peculiar properties. A small problem is that so far no one has observed
tachyons.

Problems in textbooks of quantum theory involve isolated systems. Yet a
supposedly fundamental tenet of some interpretations of quantum theory is that
there are no isolated systems, and there is just one wave function for the
whole universe. 

Wave functions "collapse" whenever an "observation" or "measurement" is made,
yet all material objects are supposedly connected at all times, at minimum by
gravitation, since everything material affects and is affected by the geometry
of spacetime. Since (say) changes in position of all particles (and fields
etc) are conveyed, at least at light speed, to all others, why are not all
wave functions in a constant state of collapse?

About practicality: If I could be convinced that many-worlds is real, and that
survival of a counterpart would represent my survival, my behavior would
change. Unlikely. 

Have I made mistakes in interpreting the interpreters?

Anyone who is not thoroughly confused just doesn't understand the situation.

Robert Ettinger

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