grandfather paradox


Also found in: Wikipedia.
Related to grandfather paradox: butterfly effect, Time travel

grandfather paradox

n.
A causality paradox speculated about in theories of time-travel in which traveling back in time would allow one to alter the conditions at the earlier time in such a way as to make current conditions impossible, as by causing the death of one's grandfather, making one's very existence impossible.
References in periodicals archive ?
"This 'Grandfather Paradox' seems to tell against time travel's possibility.
The group of scientists suggests that at least at the quantum level, the "grandfather paradox" of time travel can be resolved.
He looks at Zeno's paradox of the tortoise and Achilles; Olber's paradox of why it gets dark at night; Maxwell's demon and the possibility of a perpetual motion machine; relativistic paradoxes related to aging, distance; the basic temporal paradox or the grandfather paradox; Laplace's demon and the butterfly effect; Schrodinger's cat and other quantum phenomena; and Fermi's paradox and the presence of intelligent life in the universe.
Any theory of time travel has to confront the devastating "grandfather paradox," in which a traveler jumps back in time and kills his grandfather, which prevents his own existence, which then prevents the murder in the first place, and so on.
Devlin's "Some Paradoxes of Time Travel in The Terminator and 12 Monkeys." Devlin, an assistant professor of philosophy at Bridgewater State College, tackles the famous grandfather paradox in time travel: is it possible to travel back in time and kill an ancestor, thus negating your own existence?
Included among the 21 time-travel stories are: Harry Harrison's If, which explores the "grandfather paradox" (could you go back to the past and kill your own grandfather, thus preventing your own birth?); Arthur C.
Some stories, such as Kristine Kathyrn Rusch's "Blood Trail," involve time machines and explore the grandfather paradox (if you travel back in time and kill your grandfather before your father is conceived, you will never be born; but if you were never born, you couldn't have gone back in time ...).
Still; aside from the immense practical difficulties of achieving light speed and constructing stable wormholes, most scientists have traditionally dismissed the notion of time travel because of a problem known as "the grandfather paradox." This refers to the danger that time travelers could annihilate themselves (and thus cancel their trip) by killing their ancestors.
Since universes like Godel's allow some form of time-travel, Earman discusses the grandfather paradox, according to which one could kill one's grandfather by travelling into the past, thereby preventing oneself from coming to life.
The schools are held in secret because of the problems related to time travel - notably what is known as the Grandfather Paradox, where someone might meet their own grandfather and do or say something to alter his life - and their own future.