  Einstein, De Broglie and others hoped that the schism between classical and
quantum physics might one day be overcome by a theory taking into account the
essential nonlinearity of elementary physical processes. However, neither their
attempts, nor subsequent ones were able to supply a unifying principle that
could serve as a starting-point for a coherent understanding of both
microphysical and macroscopic phenomena. In the late 1960s the phenomenon of
amplitude quantization, or Macroscopic Quantum Effect (MQE), was discovered in
a class of nonlinear oscillating systems in which two or more subsystems are
coupled to each other by interactions having a specific phase-dependent
character -- so-called argumental interactions. Experimental and theoretical
studies of the MQE, carried out up to the present time, suggest the possibility
of a new conceptual framework for physics, which would provide a bridge between
classical and quantum physics, replacing the Newtonian notion of "force" by a
new conception of physical interaction. The present paper presents a brief
introduction to the MQE and some ideas about its possible significance in the
search for new approaches to the understanding of quantum phenomena.
