QUANTUM METAPHYSICS - E-thesis

Bohr stressed the irreversibility of measurement and the individual character of each
measurement situation. Full symmetry would demand that the observer and the observed (the
subject and the object) be interchangeable, with no distinction being drawn between microscopic
and macroscopic variables. 760 As detailed in Section 4.3.6. of this thesis, which dealt with
measurement, the coupling of experimental equipment and the microscopic world could not,
according to Bohr, be portrayed as causal. The attempt to hold onto an objective description from
which the asymmetry caused by the act of measurement could be removed is quite clearly
impossible. If the idea of free experimentation is accepted, we cannot examine the whole world
externally as an deterministic clockwork mechanism in which only events resulting from the
initial conditions are possible.
If it is assumed that an all-embracing model or theory which imprisons both human activity and
human will could somehow be constructed, that we could describe the future course of
development of the whole of the world as if we were outside it, such a model could hardly be
presumed to be reversible in nature. 761 We should obviously need to know beforehand, while
writing the theory, what kind of world will develop as a result of the actions we take. Even
though development can to some extent be predictable and in broad terms we are perhaps forced
to make specific choices if we wish to preserve the conditions we need to continue our existence,
any attempt to adhere to reversible objective laws and to remove the asymmetry caused by
measurement from our theory is clearly impossible. The world is changed as a consequence of
the actions we take.
In spite of the changes observed in the world, belief in the fundamental unchanging character of
reality has been a central point of departure in the portrayal of nature since Eleatic times. We
have been able to improve our understanding of reality and the movements and change observed
in the world with the help of some basic invariances. As Eino Kaila pointed out in his analysis,
Galilei surpassed Aristotle in his understanding of the significance of dynamic invariance: in
addition to individual substances or properties, specific major relationships can remain
unchanged as change takes place. 762 When developing theories, it is typical to find new
conformity to laws, according to which different phenomena can be returned to the same
straightforward causes. In the description of nature by classical physics, an attempt is essentially
760 Pais 1988, 243-245.
761 For example in the many-world theory the branching of reality increases with time.
285