  We suggest that the difference between time and space is due to spontaneous
symmetry breaking. In a theory with spinors the signature of the metric is
related to the signature of the Lorentz-group. We discuss a higher symmetry
that contains pseudo-orthogonal groups with arbitrary signature as subgroups.
The fundamental asymmetry between time and space arises then as a property of
the ground state rather than being put into the formulation of the theory a
priori. We show how the complex structure of quantum field theory as well as
gravitational field equations arise from spinor gravity - a fundamental spinor
theory without a metric.
