QUANTUM METAPHYSICS - E-thesis

By assuming that theory corresponds to reality and that the observer is external to the object of
research, physicists have traditionally assumed that a 'complete' theory such as classical or
quantum mechanics should be applicable to microscopic objects as well as to experimental
setups. Physicists have tried many ways of establishing substantive criteria for classicality within
a quantum framework in order to provide a better treatment of classical characteristics. These
include superselection rules, decoherence effects, systems with infinite degrees of freedom and
generalised observables. Most distressingly, none of these appears to be satisfactory; and results
lead to inconsistencies that cannot be resolved in an obvious way. 567 It is confusing that a theory
which is founded on empirical evidence and which as an abstract formalism concentrates on
predicting the results obtainable by measurement, is not able to provide an unambiguous
description of how measurements should be handled within quantum framework. An increasing
number of physicists have begun to suspect that this open problem of measurement may have
far-reaching consequences for the possibility of recognizing an objective reality in physics. 568
According to Instrumentalist thinking, the theory should not be expected to yield direct answers
to questions of what type of world we live in or how the world behaves when measurements are
not taking place. On the other hand, a realistic attempt to understand reality and interpret the
theory might be able, at its best, lead to us reassessing our ideas about the ontological and
epistemological relationship between human beings and the nature in which we exist, which we
manipulate by our actions and describe in our theories. It is no accident that the measurement
problem has become a central question in the debate concerning the interpretation of quantum
mechanics and that the ideas concerning measurement and its significance are widely divergent.
This subject is discussed in greater detail in Section 4.3.6.
4.3. The interpretation of quantum mechanics as a manifestation of change in the
conception of reality
The birth of quantum theory resulted in consternation among several experienced physicists, and
as a consequence, they found it necessary to question many of their earlier beliefs concerning
reality. For example, in the opinion of Sir James Jeans (1877-1946), the universe began to be
more reminiscent of a great thought than a great machine, and Sir Arthur Eddington (1882-1944)
567 Auyang 1995, 82.
568 Mittelstaedt 1998, ix, 103.
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