How to Avoid Death on a Daily Basis
I was just me.
I looked back to Claire. She already knew what had happened to get us here. I must have succeeded in bringing her back, and she could tell me how.
Which would be a paradox, but what would time travel be without one of those?
It’s the sort of thing sci-fi writers love to put in a story and then never bother to explain. Like just pointing out the possibility of a paradox is enough.
A boy is visited by his older self in a time machine, who teaches him how to build a time machine. He grows up, builds a time machine, goes back and tells his younger self how to build a time machine... so who worked out how to actually build the machine?