The grandfather paradox is a proposed paradox of time travel first described (in this exact form) by the science fiction writer René Barjavel in his 1943 book Le Voyageur Imprudent (Future Times Three). The paradox is described as following: the time traveller went back in time to the time when his or her grandfather had not married yet. At that time, the time traveller kills his or her grandfather, and therefore, the time traveller is never born when he or she was meant to be.
Despite the name, the grandfather paradox does not exclusively regard the impossibility of one's own birth. Rather, it regards any action that makes impossible the ability to travel back in time in the first place. The paradox's namesake example is merely the most commonly thought of when one considers the whole range of possible actions. Another example would be using scientific knowledge to invent a time machine, then going back in time and (whether through murder or otherwise) impeding a scientist's work that would eventually lead to the very information that you used to invent the time machine. An equivalent paradox is known (in philosophy) as autoinfanticide, going back in time and killing oneself as a baby.
The grandfather paradox has been used to argue that backwards time travel must be impossible. However, a number of hypotheses have been postulated to avoid the paradox, such as the idea that the past is unchangeable, so the grandfather must have already survived the attempted killing (as stated earlier); or the time traveller creates - or joins - an alternate time line in which the traveller was never born.
Other articles related to "grandfather paradox, grandfather":
... Consideration of the grandfather paradox has led some to the idea that time travel is by its very nature paradoxical and therefore logically impossible, on the same order as round squares ...
... The best examples of this are the grandfather paradox and the idea of autoinfanticide ... The grandfather paradox is a hypothetical situation in which a time traveler goes back in time and attempts to kill his grandfather at a time before his ... case the time traveler never would have gone back in time to kill his grandfather ...
... use of the restricted action resolution of the Grandfather paradox ... For example, you couldn't go back in time and kill your Grandfather because then you wouldn't be born ...
Famous quotes containing the words paradox and/or grandfather:
“A good aphorism is too hard for the teeth of time and is not eaten up by all the centuries, even though it serves as food for every age: hence it is the greatest paradox in literature, the imperishable in the midst of change, the nourishment whichlike saltis always prized, but which never loses its savor as salt does.”
—Friedrich Nietzsche (18441900)
“Then, bringing me the joy we feel when wee see a work by our favorite painter which differs from any other that we know, or if we are led before a painting of which we have until then only seen a pencil sketch, if a musical piece heard only on the piano appears before us clothed in the colors of the orchestra, my grandfather called me the [hawthorn] hedge at Tansonville, saying, You who are so fond of hawthorns, look at this pink thorn, isnt it lovely?”
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