  In a recent paper of M. Villata [arXiv:1103.4937], it is claimed that
"antigravity appears as a prediction of general relativity when CPT is
applied." However, the present paper argues that Villata puts the cart before
the horse qua methodology, and that the resulting theory cannot be reconciled
with the ontological presuppositions of general relativity. The conclusion is
that Villata's suggestion for the physics that might underlie a gravitational
repulsion of matter and antimatter is not acceptable in its current state of
development.
