  A Lorentz invariant model for gravity-induced quantum state reduction is
presented, which is mainly developed from Penrose's argument that the time
translation operator in a superposition of macroscopic states is ill-defined.
The problem to define a Lorentz invariant stochastic dynamics for the
wave-function is solved by assuming that the stochastic time flow is running
orthogonal to the deterministic, unitary time evolution inside the
four-dimensional space-time, which makes the direction of causality independent
from the chosen reference frame. This new view allows to accept Bell's position
on the implication of quantum non-locality on relativity, without having to
give up the Lorentz invariance of the specified dynamics. It is shown that it
is possible to formulate on the basis of this new view a meaningful physical
model. The model is also checked for possible higher order effects, which
provide new starting points for experimental research.
