  Based on a unified quantum field theory of spinors assumed to describe all
matter fields and their interactions we construct the space time structure of
general relativity according to a general connection within the corresponding
spinor space. The tetrad field and the corresponding metric field are composed
from a space time dependent basis of spinors within the internal space of the
fundamental matter field. Similar to twistor theory the Minkowski signature of
the space time metric is related to this spinor nature of elementary matter, if
we assume the spinor space to be endowed with a symplectic structure. The
equivalence principle and the property of background independence arise from
the fact that all elementary fields are composed from the fundamental spinor
field. This means that the structure of space time according to general
relativity seems to be a consequence of a fundamental theory of matter fields
and not a presupposition as in the usual setting of relativistic quantum field
theories.
