  We consider the quantization of a Friedmann-Robertson-Walker universe. We
derive a reduced square root Hamiltonian by choosing the scale factor as time
variable and quantize the theory using the Dirac method. From the resulting
spinor equation we show that there is no semiclassical wave packet that avoids
the Big Bang singularity. Our work raises the question concerning the
relationship between the choice of time and singularity avoidance.
