Resolution of Paradox
Imagine a wormhole in the shape of a horse shoe, shaped like a U but bent round further. A ball travels through space towards one end of the hole and enters it. The ball flies round the horse shoe.
As it goes round it travels in distance and displaces in time; and when it comes out, and flies off through space, it is slightly behind the time when it entered the wormhole.
It flies off and hits itself on the way towards the wormhole - knocking itself off course so that it misses the entrance and never enters the hole.
This is a paradox and the thing is that it is not about having a sex change, going back in time, and sexually assaulting yourself, but about balls and suchlike simple things. Being simple we may do our sums, or so it is claimed.
Said process breaks the Law of Least Action, perhaps the most basic law in physics, it is claimed. We are invited to conclude that all these paradoxes do likewise.