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

Comment to a paper [arXiv:1103.4937] of M. Villata on antigravity