From: scerir (scerir@libero.it)
Date: Fri Nov 15 2002 - 15:33:51 MST
> ### I wonder if you could treat consciousness as the measurement that
> collapses the superposition.
> Rafal
E.P. Wigner's proposal for a solution to the quantum measurement problem
consisted in postponing the state reduction to the very end of the
'von Neumann chain'. A state 'reduction' is brought about only when
the consciousness of an observer is reached.
Wigner thereby elaborated on a suggestion by London and Bauer (1939):
consciousness randomly selects one product state out of the superposition
of product states and it thereby effects a state reduction.
Wigner conceded that we do not have at our disposal a
description of how a state reduction is effected by consciousness.
Nonetheless, he suggested that the dynamics of quantum theory has to
be modified in such a way that events of state reduction by consciousness
are taken into account.
In particular, in the paper `Remarks on the Mind Body
Question' of 1961, Wigner described his proposal as amounting
to`the postulate that the equations of motion of quantum mechanics cease to
be linear, in fact that they are grossly non-linear if conscious beings
enter the picture'.
In this context, Wigner raised the well known paradox (based on
Schroedinger's cat paradox) for which he has become famous, namely
the paradox of Wigner's friend: if one observer A considers another
observer B, 'the friend', who makes an experiment on a quantum system
and if the observer A describes this (isolated!) 'whole' arrangement
(quantum system + observer B)in the terminology of quantum mechanics,
he will end up ascribing a 'superposition' of different states of
consciousness to observer B. But the conscious observer B 'knows' very
well the outcome of the experiment 'he' was performing.
Wigner proposes to avoid this paradox by maintaining that quantum theory
does not apply to consciousness; consequently, there are no superpositions
of different states of consciousness. He assumes that a state reduction
takes
place on the level of the friend's consciousness. This point underlines
that Wigner conceives state reductions as being caused by the consciousness
of the first observer B.
In papers of 1982-1984, E.P. Wigner changed his mind and appreciated the new
approach by D. Zeh ('decoherence'). The philosophical reason for his
change of position is that Wigner considers solipsism to be an implication
of
his earlier views on physical reality and the interpretation of quantum
mechanics. Solipsism is already hinted at in some earlier papers as a
possible consequence of quantum mechanics.
E.P. Wigner also wrote (Nov. 18, 1978)
" ... as far as living organism of any complexity are concerned, the same
initial state hardly can be realized several times. There are no two
identical people and if we repeat the same experiment on the same
individual the initial conditions are no longer the same - the individual
will remember at the second experiment the event of the first one -
his mental outlook will have changed thereby. This means that the
relevant statements of the theory encompassing life will be terribly
different from those of the present natural sciences."
and also ...
"I do not believe there are two entities: body and soul. I believe that life
and consciousness are phenomena which have a varying effect on the
event around us - just as light pressure does. Under many circumstances,
those with which present-day physics is concerned, the phenomenon
of life has an entirely negligible influence. There is then a continuous
transition to phenomena, such as our own activities, in which this
phenomenon has a decisive influence. Probably, the behaviour of
viruses and bacteria could be described with a high accuracy with
present theories. Those of insects could be described with a moderate
approximation, those of mammals and men are decisively influenced
by their minds. For these, present physical theory would give a false
picture even as far as their physical behavior is concerned."
[E. P. Wigner, Philosophical Reflections and Syntheses,
Springer, 1995, page 272.]
see also
http://www.uni-koeln.de/phil-fak/phil/org/dozenten/esfeld/skript/99/SHPMP99.
pdf
> Is the interference the glue that keeps a person conscious?
> Rafal
It depends on which 'interference'! Wigner would say that consciousness
collapses (quantum) interferences.
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