Polochinski’s Paradox

Definitions

Billiard Ball -  A small hard ball made from phenolic resin or polyester resin, used in cue spices such as Billiards, Pool, Ect.

Transversable wormhole - Think of it as a portal. As long as a particle can enter through one side of the wormhole and can exit through the other side it can be classifieds as a transversable wormhole 

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At 12:30 a billiard ball is sent into a transversable wormhole that is set 30 minutes into the past. In this case the ball is sent into the wormhole at just the right speed and angle that if the ball were to continue it would collide with its earlier self, thereby knocking it off course and preventing the billiard ball from ever entering the wormhole in the first place

The contradiction lies not within the laws of physics but in the semantics of the proposal: the ball was not hit at 12:30 and was hit at 12:30. Our mind allows us to consider the two 12:30s as separate states in a narrative but space and time doesn't. Even a graph has its own difficulties- it can show the ball both being hit and being not hit but it cannot simultaneously show the collision and non collision.