  A linear Lorentz connection has always two fundamental derived
characteristics: curvature and torsion. The latter is assumed to vanish in
general relativity. Three gravitational models involving non-vanishing torsion
are examined: teleparallel gravity, Einstein-Cartan, and new general
relativity. Their dependability is critically examined. Although a final answer
can only be given by experience, it is argued that teleparallel gravity
provides the most consistent approach.
