We make a direct connection between the construction of three-dimensio
nal topological state sums from tensor categories and three-dimensiona
l quantum gravity by noting that the discrete version of the Wheeter-D
eWitt equation is exactly the pentagon for the associator of the tenso
r category-the Biedenharn-Elliott identity. A crucial role is played b
y an asymptotic formula relating 6j-symbols to rotation matrices given
by Edmonds.