  We show that the generators of pseudospin symmetry are the non - relativistic
limit of the generators of an SU(2) symmetry which leaves invariant the Dirac
Hamiltonian with scalar and vector potentials equal in magnitude but opposite
in sign, $V_V = - V_S$. Furthermore, within this framework, we demonstrate that
this symmetry may be approximately conserved for realistic scalar and vector
potentials.
