Quantum mechanics of the Robertson-Walker geometry

The Wheeler-DeWitt equation for the Robertson-Walker geometry coupled to scalar and Fermi fields is solved. Systematic use of Dirac's method for constrained systems is made and ad-hoc assumptions about the factor ordering problem arising from the classical constraints are avoided. It is thus found that the probability density of finding the universe with a radius R vanishes as the classical singularity at R=O is approached. (author)