  The description of space-time in a quantum theoretical framework must be
considered as a fundamental problem in physics. Most attempts start with an
already given classical space-time - then the quantization is done. In contrast
to this the central assumption in this paper is not to start with space-time,
but to derive it from some more abstract presuppositions like this is done in
von Weizsaecker's "quantum theory of ur-alternatives". Mathematically the
transition from a manifold with spin structure to a manifold with four real
space-time coordinates has to be considered. The suggestion is made that this
transition can be well described by using a tetradial formalism which appears
to be the most natural connection between ur-spinors and real four-vectors.
