Polchinski's paradox

English Etymology Devised by Joseph Polchinski, American physicist. Proper noun A potential paradox serving as a comment on the Novikov self-consistency principle, in which a billiard ball, sent back in time through a wormhole, is launched at such an angle that, upon exiting the wormhole in the past, it collides with its earlier self, knocking it off course and preventing it from entering the wormhole in the first place. en eponyms