I was just discussing Back to the Future with a friend of mine (I've never seen it), and he described the grandfather paradox to me. I told him the term for it, and he told me that BttF invented it. I told him that he was wrong, and he asked me where it came from.

Wikipedia's earliest mention is from 19311, but it's clear that it was known even before the 30's:

The grandfather paradox was described as early as 1931, and even then it was described as "the age-old argument of preventing your birth by killing your grandparents".

What is the earliest mention of the grandfather paradox in science fiction/fantasy?

To quote the University of Oregon's (?) definition:

[...] the famous grandfather paradox. Imagine you build a time machine. It is possible for you to travel back in time, meet your grandfather before he produces any children (i.e. your father/mother) and kill him. Thus, you would not have been born and the time machine would not have been built, a paradox.

To be clear, I am not seeking a description of the paradox that is strictly limited to grandfathers; I am interested in the broader definition of the paradox, where a traveler to the past changes the past in such a way that s/he never would have/could have traveled to the past.

1 Nahin, Paul J. (1999). Time Machines: Time Travel in Physics, Metaphysics, and Science Fiction (2nd ed.).

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    Not completely clear what you're looking for. For one thing, the first mention of the grandfather paradox may well have taken place in a non-fictional context, i.e., in reviews or discussions of time-travel stories, such as in the letter columns of the old magazines. I assume that you want the first grandfather paradox in a fiction story, is that right? Well, what about those stories where a character sets out to kill his grandfather but fails for one reason or another, e.g. kills the wrong man? Or do you insist and the grandfather-killer disappearing?
    – user14111
    Commented Jul 4, 2017 at 23:16
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    Great Scott! You have NEVER seen Back to the Future? This is heavy!
    – xDaizu
    Commented Jul 5, 2017 at 7:40
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    Have none of you read H.G.Wells' The Time Machine (1895)? The protagonist is constantly trying to go back and fix the events that led to his fiance's death but his fiance's death is what caused him to build his time machine in the first place. The author also published the Chronic Argonauts in 1888 and talked about time travel extensively.
    – Rick Ryker
    Commented Jul 5, 2017 at 17:14
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    I read the abridged version years ago, @RickRyker. I don't remember that part of the story (I thought he was just travelling back and forth through time "For science!"), but maybe it's time to revisit it.
    – Shokhet
    Commented Jul 5, 2017 at 17:57
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    @Shokhet - I think I recall that storyline is from a more modern adaption. I don't think the original had it, I think that time-traveling was purely for science, but if it's in an adaption it would be easy to confuse for the original.
    – Megha
    Commented Jul 5, 2017 at 20:00

3 Answers 3


1929: "Paradox", a novelette by Charles Cloukey, mentioned on p. 286 of Paul J. Nahin's book Time Machines: Time Travel in Physics, Metaphysics, and Science Fiction, Second Edition; originally published in Amazing Stories Quarterly, Summer 1929, available at the Internet Archive; reprinted in Amazing Stories, September 1968, also available at the Internet Archive.

In the following excerpt a character discusses various paradoxical aspects of time travel, including the grandfather paradox:

"Gentlemen, I am going to omit details. It is becoming late and there is another part of this story I want to tell. Suffice it to say that I was transported into the past farther than I had come into the future! I placed the manuscript in the doctor's mail box. But before I did this I had to walk a mile, for I had arrived that far away from his house. While I was walking, my mind cleared. Because this manuscript had been found by the doctor, I reasoned, I had been able to go to 2930. But also, only because I had gone to 2930 had the manuscript come into being. Which was the cause and which was the effect? That is a paradox I cannot explain. A thousand years from now it will be understandable and common to the people of the world.

"I started reasoning along another line. Suppose I should have traveled into the past to the time when my grandfather had been a little boy. If I were so inclined, I could kill my grandfather before he had had a chance to meet my grandmother, thereby depriving myself of the privilege of being born! But the fact that I was present to kill my unfortunate grandfather would show that I had been born. Therefore, I could not have killed my grandfather. It was hopeless.

"The most intelligent man in the world in 1428 could have proven to his entire satisfaction that such a thing as radio was scientifically and logically impossible; yet we have radio to-day. I actually convinced myself that time-traveling was logically and scientifically nothing but the utterest nonsensical paradox; yet I delivered the manuscript as per Bonn’s instructions.

"Then, still following instructions, I returned to the exact point at which I had arrived from the year 2930. As I returned I wondered what would have happened if I had thrown the manuscript into the river, instead of putting it in the mail box. Hawkinson, next morning, would never have found it, and therefore could never have sent me into the future. But unless he had found it and sent me into the future, I could never have had the manuscript to throw into the river. However, I seemed to think that throwing the manuscript into the river would be deliberately cheating fate. So I had delivered it.

"Later, when my life was at stake, I deliberately did cheat fate. That's why I’m here now. My death was scheduled for yesterday. I’ll explain that later on.

"I stood near the river, ready to follow Bonn's final instructions. I was to press a button in the belt that helped to support the complex improved time-machine on my back. I was ready to return to Bonn and tell him that the experiment was a success, that his invention had functioned as well in sending me back through the fourth dimension as the other had in sending me into the future. I was ready to return to Dwar Bonn. But suddenly I hesitated. Why should I go back into the future? Nothing compelled me to comply with Bonn's request. I had not even promised him to return. He had taken it for granted that I would. If it had not been for that aversion I then had for the thought of cheating fate, I think that then and there, I would have taken off the portable machine and thrown it into the river.

"Another thought occurred to me. The night before Hawkinson had called me on the phone I had been sleeping peacefully in my Lansdowne apartment. Undoubtedly I was sleeping there peacefully that very second, for I had traveled back through time to that same night. Then, if I should throw the machine into the river, there was nothing in the world to stop me from going over to Lansdowne and waking myself up. The idea fascinated me. It occurred to me that I would have a hard time convincing myself that I was I. Suddenly I started again. It was a scientific impossibility for a man to be in two places at the same time. But I was.

"Another paradox. I then determined that I should return to 2930 and have Dwar Bonn explain things to me. So I pressed the button in my belt. The 7.6 grams of 'solid electricity' in the generator of the outfit on my back was changed from matter into energy, producing a powerful current, which was transformed into what Bonn always called the NN-4 wave by the apparatus on my back, and I rose through the fourth dimension once more. I found Bonn smiling as I suddenly appeared in the laboratory, hardly a foot from the point from which I had started.

" 'It is a success,' he said. 'You've been gone thirteen seconds!'

"A short while later I requested him to explain to me the seeming paradoxes connected with time-traveling. And he did! He explained them fully. He explained them logically and painstakingly. He explained them as simply as he could, but the cold fact remained that my brain was a thousand years behind his. (I defy any scientist of to-day to write an explanation of the talking movies that would be understandable to a man living in the tenth century.) Bonn finally decided to stop trying. He told me that if I decided to remain in that era of time, he would arrange for me to be hypnotically educated by machines built for that purpose, though my brain would probably not be capable even then of comprehending the abstruse science behind that seeming paradox. For a long time I puzzled over myself and the hypothetical murder of my innocent grandfather, but it remained, and remains yet, an endless circle to me.

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    Thank you. This is the first answer (of three, thus far) that has both the grandfather paradox, as well as a date earlier than 1931. Thank you very much, and +1 :D
    – Shokhet
    Commented Jul 5, 2017 at 1:34
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    Note that the example of killing one's grandfather may have been inspired by a letter which appeared in the January 1928 issue of Amazing Stories, see p. 1004 on archive.org here. Discussing the paradoxes of being able to interact with the past, the letter-writer (one Thomas H. Cassidy) writes "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!"
    – Hypnosifl
    Commented Apr 21, 2023 at 21:54
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    Also, since the OP was interested in any discussion of similar paradoxes even without grandfathers, this letter from T. J. D. in the July 1927 issue of Amazing Stories also discusses the problem of an inventor going back to see their own school graduation, saying that if "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".
    – Hypnosifl
    Commented Apr 21, 2023 at 21:55

René Barjavel novel Le Voyageur imprudent (Future Times Three) written in 1944. Is not as old as beichst example but I think it captures the spirit of Granfather Paradox better.

Pierre Saint-Menoux, a time-traveler, tries to assassinate Napoleon Bonaparte before his rise to power but a soldier jumps to take the bullet. This soldier is the time-traveler ancestor so he is wiped out from existence, yet for him there is no real ending: he is constantly oscillating between existing and non-existing.

There is an appendix explaining the paradox.

PS: After a wikipedia search I found an earlier example: Ancestral Voices by Nathaniel Schachner, published in 1933 in Astounding Stories. I found it can be downloaded here (i'm pretty sure there is no longer a copyright)

Time traveler Emmet Pennypacker kills one ancient Hun and without realizing who will disappear from the racist world of 1935.

However in this story the descendants of the hun, including the time traveler, just vanish without an explanation of who then did the first time travel if Emmet Pennypacker vanished (IMO it doesn't really develop the Grandfather paradox theme like the other story).

  • @user14111 yep, found it but I have not heard of that story until this search
    – Ram
    Commented Jul 4, 2017 at 23:31
  • @user14111 I don't agree because after reading a bit of Ancestral Voices I didn't find the descendants just vanishing a nice tie up, without a good explanation of who then travels in time to erase the hun. I found the first story a more prototypical and satisfying example.
    – Ram
    Commented Jul 4, 2017 at 23:37

I don't know if this would match what you are seeking. But in Wikipedia under the section for backward time travel there is the following description which seems like it might. Namely that by traveling to the past the protagonist has changed the future to an extent to create an alternate history/reality. At the least it sets a year to beat of 1881 :-)

Wikipedia Backward Time Travel

"Edward Everett Hale's "Hands Off" (1881) tells the story of an unnamed being, possibly the soul of a person who has recently died, who interferes with ancient Egyptian history by preventing Joseph's enslavement. This may have been the first story to feature an alternate history created as a result of time travel."

  • Maybe a link to the original source could be more valuable than quoting wikipedia (wich is second hand)
    – Edelk
    Commented Jul 4, 2017 at 21:23
  • Good suggestion. I found the following also out on Wikipedia. en.wikipedia.org/wiki/Edward_Everett_Hale "In 1881, Hale published the story "Hands Off" in Harper's New Monthly Magazine. In the tale, a narrator goes through time to alter events in the past, thereby creating an alternate timeline. Paul J. Nahin writes that this story makes Hale a pioneer in emerging science fiction, time travel, and stories about changing the past."
    – beichst
    Commented Jul 4, 2017 at 21:28
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    I don't understand how this qualifies as an example of the grandfather paradox. Commented Jul 4, 2017 at 21:31
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    I don't think this counts, beichst, sorry. I think the most important defining characteristic of a grandfather paradox scenario is that the change created in the past should nullify the future action that caused the change in the past. I've never read "Hands Off," but from your description I'm not seeing that part of the paradox. I will see if I can edit the question to make that point clearer. cc @ApproachingDarknessFish
    – Shokhet
    Commented Jul 4, 2017 at 21:43
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    "Hands Off" was mentioned in this old answer and is available for free at the Internet Archive. The protagonist thinks he changed the history of the world, but it's really just a simulation that he's tampering with. Anyway, no "grandfather paradox".
    – user14111
    Commented Jul 4, 2017 at 23:22

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