Time&Eternity

Time in the Formulation of Scientific Theory 151
quantum theory included Max Planck’s study of black-body radiation in
1900, his discovery of the quantum of action and the derivation of the socalled
Planck’s Constant connected with it, as well as Einstein’s 1905 article
on light quanta. After the wave theory of light had ruled for a century, the
discussion then shifted to photons and light quanta, whereby individual
atomic processes were ascribed a discontinuity that was foreign to classical
physics. 198 It became clear that light, depending upon which measuring
process is used, exhibits two different modes of behavior. It acts like a wave
and like a small, solid object. The two modes of behavior cannot be observed
simultaneously and apply not only to photons, but also to particles
in general. Each object of quantum theory is therefore as much a particle as
it is a wave. Bohr summarized these findings in the complementarity principle,
which had a great impact, and not only on physics. The concept of
complementarity that was new to physics had repercussions on philosophy
as a model for understanding dichotomies. 199
Complementarity thus describes two sides of one and the same object
that contradict each other and never occur simultaneously, but that complete
each other to create a structural connection: “The very nature of the
quantum theory thus forces us to regard the space-time co-ordination and
the claim of causality, the union of which characterises the classical theories,
as complementary but exclusive features of the description, symbolising the
idealisation of observation and definition respectively.” 200
Even if quantum physics has existed as a theory for over sixty years, its
interpretation is still the subject of discussion. Thus, for example, the status
of reality is interpreted in various ways. Positions range from the view that
observations only describe already existing reality to the standpoint that reality
is created only through observation or that only statements regarding
phenomena and their behavior are possible, but not statements about reality
as a whole. The Copenhagen interpretation of quantum theory, which
was developed primarily by Bohr and Heisenberg, is thus not the only one,
but it is certainly the most common. 201
The heartbeat of quantum theory lies in the indeterminacy principle,
which was formulated by Heisenberg. 202 It says that perfect precision in the
measurement of the momentum (= velocity × mass) and position of a particle
is impossible, and this is not because the measurement equipment is defective,
but rather because nature is the way it is. If we know where a particle
is, we cannot simultaneously know what it is doing and vice versa.
Mathematically expressed, this means: The uncertainty of the measurement
of the position of a particle multiplied by the uncertainty of the measurement
of its velocity can never result in a smaller value than h/4πm, where h
is Planck’s Constant, and m is the mass of the particle in question. Thus, the