  In this paper we discuss a causal network approach to describing relativistic
quantum mechanics. Each vertex on the causal net represents a possible point
event or particle observation. By constructing the simplest causal net based on
Reichenbach-like conjunctive forks in proper time we can exactly derive the 1+1
dimension Dirac equation for a relativistic fermion and correctly model quantum
mechanical statistics. Symmetries of the net provide various quantum mechanical
effects such as quantum uncertainty and wavefunction, phase, spin, negative
energy states and the effect of a potential. The causal net can be embedded in
3+1 dimensions and is consistent with the conventional Dirac equation. In the
low velocity limit the causal net approximates to the Schrodinger equation and
Pauli equation for an electromagnetic field. Extending to different momentum
states the net is compatible with the Feynman path integral approach to quantum
mechanics that allows calculation of well known quantum phenomena such as
diffraction.
