Abstract
The wave-particle duality of light is a well-established concept of modern physics. It postulates that light exhibits both a wave-like face and a particle-like face. But this Janus-faced concept was never consciously applied to the speed of light itself. If light has two faces, it would be naturally to assume, that the speed of light has two faces as well. This assumption which I am calling the »Dual Parametrization of c« shall be outlined.
Helmut Hansen