206 The Poetry of Physics and The Physics of Poetry
scientists including Einstein, Schrödinger, Planck and later, de Broglie,
were unable to accept the operation of chance within the framework of
quantum mechanics. They believed that since quantum theory could not
provide a causal description of the behaviour of individual particles that
it was an incomplete theory. They conceded that quantum mechanics was
a logically consistent scheme, which was able to describe experimental
results accurately. They accepted that the limitations of measurements
imposed by the uncertainty principle made a probabilistic description
necessary. They believed, however, that the uncertainty principle was
only a limitation of our knowledge and that, in actuality, the particle has
both a precise position and velocity and that its behaviour is causally
determined. They could not accept the notion that chance could actually
enter into the behaviour of the physical world.
Einstein, who became the leader of this position, expressed the
concern of his school of thought with his often quoted remark, “I do not
believe in a God that plays dice.” Einstein and the others believed in the
existence of an underlying determinism, which actually guided the
particles. They simply did not accept the idea that the behaviour of
particles could be governed by chance. They wanted to know what was
really happening to the particles. They believed a theory would
eventually emerge in which the hidden causality would appear. They,
therefore, considered quantum theory as incomplete and anticipated the
appearance of a fuller theory, which would eventually replace it. Nothing
has emerged to this day more than 80 years since Schrödinger first
formulated wave mechanics.
In opposition to this point of view were the proponents of the
Copenhagen interpretation who had formulated their ideas in
Copenhagen in the late 1920’s under the leadership of Niels Bohr and
included Heisenberg, Dirac, Born, Pauli and Kramers. They regarded the
new quantum mechanics as a complete theory. They believed that the
uncertainty principle imposed a limitation on our knowledge of the world
and hence, a limitation on the behaviour of the particles themselves.
They made no distinction between reality and our knowledge of reality.
They considered the question asked by Einstein and his followers, “what
is really happening to the particle as meaningless?” What can not be
observed or measured is of no concern to physics since there can never
be verification of a theory of unobservable behaviour. An expression
of the view is found in the writings of Dirac who wrote the following:
“The only object of theoretical physics is to calculate results that can be