"This '
Grandfather Paradox' seems to tell against time travel's possibility.
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.