grandfather paradox

From the paradox proposed by the French author René Barjavel in 1944 in his book Le Voyageur Imprudent, translated as "Future Times Three" into English; in its original form the paradox of one person going back to the past and killing their biological grandfather before the latter fathered the traveller's father, thus preventing the time traveller from ever being conceived in the first place.

grandfather paradox (plural grandfather paradoxes)

1. The paradox of time travel in which inconsistencies emerge through changing the past.