grandfather paradox n.
a paradox concerning the implications of time travel, expressed by the idea that a hypothetical time traveller could potentially go back into the past and (deliberately or inadvertently) kill his or her grandfather, thus preventing the time traveller’s existence and the possibility of having travelled back into the past in the first place; cf. time paradox n.
Suppose for instance in the graduating exercise above, the inventor should decide to shoot his former self, the graduate, he couldn’t do it because if he did the inventor would have been cut off before he began to invent and he would never have gotten around to making the voyage, thus rendering it impossible for him to be there taking a shot at himself, so that as a matter of fact he would be there and could take a shot—help, help, I’m on a vicious circle merry-go-round.]
Flowers First and then Flaws in Amazing Stories July 410/2 (letter)
Why, I might travel in my time machine sixty years into the past, kill my grandfather before the conception of my father, and thus resolve myself into oblivion! ]
Time & the Fourth Dimension in Amazing Stories Jan. 1004/3 (letter)
Suppose I can travel back into time, let me say 200 years; and I visit the homestead of my great great great grand-father, and am able to take part in the life of his time. I am thus enabled to shoot him, while he is still a young man and as yet unmarried. From this it will be noted that I could have prevented my own birth.]
The Question of Time-Traveling in Science Wonder Stories Dec. 610
He is one of the few who have realized that if one travels in time, he would not remain stationary relative to the earth, but would stay in the same spot in space, while the sun (with the earth following) departed, until the machine were shut off. This would remove the killing-of-grandfather paradox.]
Letter in Wonder Stories Oct. 476/3
It seems that the only way to prove that time travel is impossible is to cite a case of killing one’s own grandfather. ]
Letter in Astounding Stories of Super-Science Jan. 422/1
I shall attack the well known grandfather paradox, which is: ‘If you invented a time machine you could go back and kill your grandpa before—before—well before it was possible for you to be born later[.]’
In Defense of Time Travel in Fantasy Scout (#12) Mar. i. 2/1
‘I can't see that anything can ever be done about time—I always think of the “Grandfather Paradox”—remember?’ ‘Yes, I know it by heart…. Time-travel is impossible, because a man could travel back in time, inadvertently kill his grandfather, and thus prevent himself from ever having been born!’
Grandfather Paradox in Fantastic Adventures Apr. 136/1
The Grandfather Paradox is basic to any discussion of time travel… We will call any such interference with the past, especially self-cancelling interference, a Grandfather Paradox.
All the Myriad Ways 111
Considerations like the grandfather paradox have caused many people…to conclude that any solutions to the equations of general relativity that allow such travel into the past must be ruled out.
in S. K. Biswas et al. Cosmic Perspectives xiv. 242
The big mess with the timestream has me all bejabbered, with everyone hollering at me, and this one scrawny little guy keeps howling about the grandfather paradox. I’m stewing over this when I meet gramps, so I kill him. Pull out my Colt .45 and bang!
Project Timespan in Interzone (#116) Feb. 29/1
Frequency [a film] is the flipside of that classic philosophy of physics conundrum, ‘the grandfather paradox’. Instead of speculating what it would mean to go back in time and kill your own grandfather, the film posits what it would mean to go back and save your own father from certain death.
Films: The Quantum Physics of Lost Chances in Magazine of Fantasy & Science Fiction Sept. 83/1
She had a hunch he was simply convincing himself that they couldn’t kill the scientists. Because destroying the scientists from Einstein to Teller would be a modified grandfather paradox. Without those people, there would be no time travel.
Uncertainty in Asimov’s Science Fiction Mar. 31
Research HistoryBen Ostrowsky submitted a 1939 cite from Dale Tarr.
Last modified 2022-03-02 19:46:39
In the compilation of some entries, HDSF has drawn extensively on corresponding entries in OED.