Questions tagged [paradox]

A paradox is a seemingly true statement or group of statements that lead to a contradiction or a situation which seems to defy logic or intuition. For the short-lived UK sci-fi series, use the tag [paradox-tv], and for the 2010 film staring Kevin Sorbo and Christopher Judge, use the tag [paradox-movie]

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15
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6answers
2k views

Did Edith Keeler really have to *die*?

In the Star Trek TOS episode 28, "The City on the Edge of Forever", we find that McCoy's drug-fueled tear through the past caused serious and far-reaching effects on the space-time continuum; to wit, ...
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2answers
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Somewhere in Time - Who is this character?

In the time-travel romance movie "Somewhere in Time", a young playwright from 1972 uses an old pocket-watch to mystically travel back to 1912 and meet an actress he has fallen in love with from old ...
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2answers
238 views

Isn't ending of Terminator 2:Judgement day a time paradox?

I have just started watching the Terminator franchise and finished till 2. But its ending had my mind boggling. If Skynet and Terminator, both are created by Cyberdyne, using the microprocessor that ...
4
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1answer
97 views

Story with the continuum hypothesis at the end [duplicate]

When I was in my teens, I think (if so it must have been in the seventies or early eighties), I read a short story about a single person landing in a space ship on a hostile military planet, and then ...
30
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4answers
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What would happen if you portalled the TARDIS inside itself? [closed]

The TARDIS is one of the few fictional objects that could contain themselves. Firstly, because "it's bigger on the inside" but secondly because the TARDIS has some means of sustaining paradoxes (which ...
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11answers
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Why was Marty present in his jump to 2015 in Back to the Future 2?

I was doing some thinking about the paradoxes that arise during Back to the Future 2 when Marty, Doc and Jennifer travel to 2015 to see their future selves and help Marty's kid. It was shown that ...
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0answers
84 views

Does “Star Wars” still exist in “Back to the Future”? [duplicate]

In Back to the Future, when Marty goes back to 1955, he scares his dad by saying he’s “Darth Vader from Vulcan”. Obviously Darth Vader didn’t exist in 1955 as Star Wars didn’t come out for another ...
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1answer
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Shouldn't there be a puddle jumper in Egypt at the end of Moebius in Stargate SG-1?

I've just rewatched Moebius, and made a realisation at the end of the episode regarding the puddle-jumper they use (the one discovered in It's Good to be King: But, I don't remember the puddle-jumper ...
3
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1answer
302 views

In Back to the Future Part II, how does Doc avoid creating a paradox?

In Back to the Future: Part II, Doc Brown discovers that the McFly family is destroyed in the future, and it can all be traced back to Marty, Jr. agreeing to some proposition by Griff and his gang. So,...
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2answers
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Where did 2015 Biff hide the Delorean in 1955 when giving himself the Almanac in BTTF 2?

With the 30th anniversary of the Back to the Future trilogy this year, and several networks showing it, I watched all three for the umpteenth time (and enjoyed every second of them), but wondered ...
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3answers
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Jennifer from BTTF left behind

In BTTF 2 after Marty and Doc come back from the future (to 1985) where Biff has already gone to 1955 and changed 1985, they stop off at what they think is Jennifer's house and leave her on the porch ...
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2answers
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Does Doc Notice His Past/Future Self?

In Back To The Future Part 2, when Doc Brown is riding a bike and ends up coming upon himself (in the past) working on his "weather experiment" to get the old Marty back to 1985, is there any proof ...
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1answer
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What type of paradox kills Weeping Angels?

I'm trying to find ways to defeat Angels beside simply getting them to look at each other. For instance, in the episodes “The Time of Angels” and “Flesh and Stone”, you can't get a large group of ...
22
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8answers
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How did Clara dedicate Emmett's tombstone in Back to the Future 3?

In Back to the Future 3, Doc Brown is only able to save Clara Clayton because of Marty's presence (as they had to scout that area for the plan). Though if Marty had not traveled back in time, Doc ...
3
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0answers
205 views

Is Loki part of a destiny trap?

In Doctor Strange #385 Loki admits that he wanted to make Dr. Strange stronger for the threads to come, e.g. Damnation. However, in Doctor Strange: Damnation #1 it is established that Doctor Strange (...
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5answers
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Could SG1 have used the Time Jumper to steal as many ZPMs as they wanted?

In the events of Moebius, SG1 travels back in time to steal a ZPM from Ra in ancient Egypt. It went something like this: SG1 resolves to steal the ZPM. They travel 3000 years back in time. They ...
9
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2answers
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Wouldn't the paradox machine be useful for the Doctor?

If the Doctor built a paradox machine, he could save anyone and do anything he wanted to do, as the Master did. The paradox machine is powerful enough to let the Toclafane kill their ancestors without ...
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5answers
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Why did future John Connor bother to send the T-101 Terminator back?

In the movie Terminator 2: Judgement Day, future John Connor sends the Terminator back in time to save himself from being killed. But from the perspective of past John Connor (the kid), he sees a ...
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6answers
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How did the T-1000 avoid the bootstrap paradox?

I have watched Terminator 2 several times now, but there is one major problem with it that has been bothering me. The Terminator* was sent back in time to (unsuccessfully) assassinate Sarah Connor, ...
13
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1answer
187 views

SF short story about equation that can answer any question and agents sent back in time to destroy it

I read this short story ages ago in one of the "Year's Best Science Fiction & Fantasy" anthologies— it was about an equation (or series of questions? something like that) written in the 1700s or ...
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0answers
60 views

When does Professor X lose his ability to walk? [duplicate]

At the end of the X-Men first class movie, magneto deflects a bullet causing it to render professor X - who was a boy at the time - to become paralyzed in his legs. However in The last stand when ...
39
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3answers
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Earliest instance of the grandfather paradox

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 ...
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5answers
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If Marty had faded out, would that have destroyed the universe?

In Back To The Future Part 2, Doc Brown says that if young Jennifer (from 1985) were to meet her older self (from 2015), it could create a paradox that would unravel the fabric of the space-time ...
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3answers
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Primer: Will Thomas Granger still be sent back in Time?

In the movie Primer: At first, just as in any timeline, what Abe/Aaron experience is always determined by the past. However, as the boxes are developed and the characters start looping back, it would ...
11
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1answer
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Why did time travelers in Timecop turn into gelatinous blobs of goo-energy if they came into contact with their former selves?

We're told throughout the movie that "the same matter cannot occupy the same space". Yet, even after a few months it's very unlikely that there are many of the same atoms in your body that were there ...
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5answers
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Does Terminator 3 undermine the 'No Fate' concept?

"The future's not set. There's no fate but what we make for ourselves… !" John Connor, quoting John Connor, quoting Kyle Reese, quoting John Connor - Terminator 2: Judgment Day One of the fundamental ...
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1answer
357 views

When Marty travels back to the future, why are not there two of him in 1985? Or they indeed are? [duplicate]

When Marty travels back to 1985 from 1955 at the end of the 1st BTTF movie (and meets his all new present), aren't there two Marties in that moment (the one that has just arrived and the one that was ...
11
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1answer
947 views

Looking for a short story about time travel; characters attempting to fix a boat

I'm looking for a short story that I read once about time travel. One thing that I remember from the story was that the characters were attempting to fix a boat using a time travel device that took ...
2
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1answer
651 views

Why couldn't the Doctor save Adric?

I was regressing to childhood and watching old Doctor Who, and I just got to the episode "Earthshock" and the followup in "Time-flight". Tegan basically asks "why don't we go back in time and save ...
17
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4answers
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Identifying a short story about time travel and paradoxes

I remember having read a short story in which the main character, thanks to a series of happenings also involving time travel, grew up, changed sex, made sex with himself and had a son... who of ...
6
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1answer
254 views

Earliest example of an AI being defeated by a paradox

There is a joke in science fiction about defeating an evil AI with some sort of paradox, but there has to be a reason for this. I'm aware the the I, Robot series had a story where a rival company's ...
4
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0answers
173 views

Where is Everybody? [duplicate]

Someone wrote a short story about the Fermi paradox—well, probably more than one person—but I have a specific story in mind. I can only recall the broad outline. A group of human explorers find a ...
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2answers
535 views

Is there a way to bypass the paradox system with a Time Turner in Harry Potter?

Is it possible to not create a paradox by using a Time Turner to stop someone (e.g Voldemort) from the past? For example, a theory could be that somebody would go back in time by 3 hours, poison ...
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1answer
137 views

Did any universe address the problem of double DNA [closed]

When you mess up time travelling and become your own ancestor, there is a big problem: At some point in time, a child will be born with exactly the same DNA as you. Did any franchise address this ...
3
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1answer
115 views

What will happen when David-A returns after 8 years?

At the end of Flight of the Navigator, David time travels, creating an alternate timeline where he didn't go to Phalon{sic} for 8 years. Lets call the David who disappeared for 8 years, David-A, and ...
14
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10answers
11k views

How could Walter send Peter the letter in the last episode?

THIS QUESTION CONTAINS SPOILERS FOR THOSE WHO HAVE NOT VIEWED THE LAST EPISODE In the last episode of Fringe, Peter finds a tape addressed to him, which was encased in amber. In this tape Walter ...
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2answers
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In the Back to the Future trilogy, does Doc ever piece together the letter about the terrorists?

In the Back to the Future trilogy, Marty writes a letter to Doc to warn him about his impending demise. We learn at the end of the first film that: Nevertheless, at the end of the second film and at ...
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15answers
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How do the timelines from Misfits align?

In episode 6 of the second season, we saw the fulfillment of a number of predictions made earlier in the series. There are a number of spoilers involved in this question. Specifically: However... ...
10
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2answers
912 views

Who came up with the name Melody Pond?

On season 9 episode 4 (Before the Flood) of Doctor Who, The Doctor talks about the bootstrap paradox: So there's this man. He has a time machine. Up and down history he goes, zip zip zip zip zip, ...
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2answers
313 views

What kind of paradox is this? [duplicate]

I was wondering something regarding the Back To The Future movie: Marty McFly is on stage and he's playing Johnny B. Goode. Marvin Berry phones his cousin Chuck Berry (the person who wrote the song). ...
9
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1answer
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Predestination and Bootstrap Paradox?

Can someone please help me understand the difference between Predestination and Bootstrap Paradox by pointing me in the direction of movies that deals with each of them? For instance, Predestination ...
3
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1answer
507 views

Red Dwarf: time and space travel paradoxes in “Tikka to Ride”?

The Red Dwarf episode Tikka to Ride has confused me more than any previous episode: How was it possible for the crew to use the Time Drive to travel back to 1960's Earth, when in the previous episode,...
7
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1answer
366 views

Man goes back in time to observe WW2 and gets stranded in an alternate future

Anyone know the name of this science fiction short story. Man goes back in time to observe Second World War, falls in love, tries to return to future but ends up in a alternate future with no power ...
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1answer
401 views

Doctor Who time paradox Captain Jack [closed]

Jack is the face of Boe and has lived for millions (or billions) of years; The Doctor has called him a fixed point in time and space. In the short of 'time crash' the paradox of meeting himself and ...
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1answer
1k views

Predestination (movie) - predestination or bootstrap paradox? [duplicate]

In the movie Predestination: Is Jane's birth because of a predestination paradox or bootstrap paradox? which one is it?
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2answers
2k views

On the nature of paradoxes in the Whoniverse?

Loosely: How do Paradoxes work in Doctor Who? We see in previous episodes, To allow a paradox to occur. We also have the the weeping angels, that feed off of time loops. They are however supposedly,...
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0answers
108 views

Why can't the Doctor visit a particular point in his timeline to return to Gallifrey (at least temporarily)? [duplicate]

We already know the Doctor never follows the rules of space-time, so why is Gallifrey inaccessible? Shouldn't he be able to, you know, travel to a point in his past when Gallifrey still existed in ...
6
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1answer
976 views

I am trying to find the title to a Time Travel SF short story

I am trying to find the title of a short story published around 2009, in which a boy travels back in time and has to murder his own grandfather in order to erase his own identity and become a member ...
16
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1answer
1k views

Short story: temporal paradox caused by experiment ends world

This might be one of Fredric Brown's short-short stories, but I've tried and could not find a reasonably quick way to look up summaries of all his stories. A group of scientists in a lab decide to ...
9
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2answers
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How do Future Bill & Ted know Rufus' name?

In Bill and Ted's Excellent Adventure, we never see Rufus introduce himself to Bill and Ted. Instead, Future Bill says to Present Bill and Present Ted: "Listen to this dude, Rufus. He knows what he's ...