  We present a necessary condition on the solar oscillation amplitude for CP
violation to be detectable through neutrinoless double beta (0\nu\beta\beta)
decay. It depends only on the fractional uncertainty in the \nu_e-\nu_e element
of the neutrino mass matrix. We demonstrate that even under very optimistic
assumptions about the sensitivity of future experiments to the absolute
neutrino mass scale, and on the precision with which nuclear matrix elements
that contribute to 0\nu\beta\beta decay are calculable, it will be impossible
to detect neutrino CP violation arising from Majorana phases.
