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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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 ...
OghmaOsiris's user avatar
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39 votes
3 answers
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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 ...
Shokhet's user avatar
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32 votes
6 answers
10k views

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, ...
Rondo's user avatar
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31 votes
4 answers
7k views

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 ...
bitmask's user avatar
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25 votes
3 answers
7k views

Does Doc Brown sabotage himself in Back to the Future 2?

Back in 1955, Doc Emmet Brown is spotted by his past self as he is working on the cable in the park, at which point, the latter asks the unrecognizable white-haired man to "be a pal and hand my ...
Inferry's user avatar
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23 votes
5 answers
5k views

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 ...
Wallnut's user avatar
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23 votes
3 answers
5k views

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 ...
Garrettfromhp's user avatar
22 votes
8 answers
25k views

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 ...
user avatar
20 votes
6 answers
3k views

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 ...
Dave DeLong's user avatar
19 votes
15 answers
30k views

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... ...
Beofett's user avatar
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19 votes
9 answers
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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, ...
iwantmyphd's user avatar
18 votes
4 answers
3k views

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 ...
mau's user avatar
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15 votes
6 answers
2k views

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 ...
Stick's user avatar
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15 votes
12 answers
16k 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 ...
JNat's user avatar
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15 votes
1 answer
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 ...
Eugene Seidel's user avatar
14 votes
3 answers
3k views

At the end of the first Back to the Future movie, how come Marty can witness the original events happening then wake up to visit an alternate family?

At the end of the first Back to the Future movie, Marty comes back ten minutes early, and sees the events from the start of the movie playing out (him running to the DeLorean and going back to 1955). ...
Fuad Ahmed's user avatar
13 votes
2 answers
3k 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,...
AncientSwordRage's user avatar
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13 votes
1 answer
371 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 ...
Allegra's user avatar
  • 211
12 votes
2 answers
6k views

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 ...
John O's user avatar
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11 votes
2 answers
1k 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, ...
VigilanteRin's user avatar
11 votes
1 answer
984 views

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 ...
HorusKol's user avatar
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11 votes
1 answer
1k 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 ...
user23112's user avatar
  • 119
9 votes
2 answers
3k views

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 ...
L. Miguel's user avatar
  • 183
9 votes
2 answers
2k views

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 ...
Trav Lane's user avatar
  • 175
9 votes
2 answers
2k views

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 ...
iwantmyphd's user avatar
9 votes
3 answers
4k views

How do Amy and Rory know who River is in "The Wedding of River Song"?

In the Doctor Who episode "The Wedding of River Song," the entire episode is an alternate version of the season opener, which means the Amy and Rory in the alternate universe haven't been ...
childcat15's user avatar
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9 votes
1 answer
5k views

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 ...
Gomes's user avatar
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8 votes
5 answers
4k views

Trouble of time travel in Harry Potter?

What would happen when Harry and Hermione would meet other Harry and Hermione while using time travel clock? For example scene of execution of hippogriff in Prisoner of Azkaban.
Damian Melniczuk's user avatar
8 votes
2 answers
738 views

Does the Doctor have a black list of times and places?

In one of the latest episodes of Doctor Who (The Angels Take Manhattan) Is this the only such place, or does the Doctor keep a list of places that he can't go?
AncientSwordRage's user avatar
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7 votes
3 answers
2k views

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 ...
MicroMachine's user avatar
  • 1,250
7 votes
1 answer
463 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 ...
Dr Phyz's user avatar
  • 109
7 votes
1 answer
2k views

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 ...
Sparky Marvel's user avatar
7 votes
4 answers
2k views

Will Thomas Granger still be sent back in time?

In the movie Primer, at first, just as in any timeline, what Abe and Aaron experience is always determined by the past. However, as the boxes are developed and the characters start looping back, it ...
S0L1D's user avatar
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7 votes
5 answers
2k views

How did Senator Travers not just survive as a Time Paradox Duplicate

In Decision 3012 (stop reading if you do not want spoilers): Senator Travers uses the time paradox code from Bender's Big Score to go back in time to stop Nixon, and then he disappears when he won ---...
Naftali's user avatar
  • 6,820
7 votes
1 answer
443 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 ...
CBredlow's user avatar
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6 votes
1 answer
1k 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 ...
user19232's user avatar
6 votes
1 answer
268 views

What 90's made-for-tv movie featured a time-traveling policeman who left his wife a note from the past?

I recall watching a made for TV movie in the 90's that takes place in the future about a man who works for a time-travel enforcement agency. At the beginning of the movie he got his wife an old copy ...
Randy's user avatar
  • 69
5 votes
1 answer
300 views

Trying to find a time travel short story

A group of scientists had almost cracked time travel - but then started dying in a series of bizarre accidents. They realised that the universe was protecting itself from the paradox of time travel by ...
Jimblob's user avatar
  • 59
5 votes
1 answer
651 views

Does "Isaac Asimov's Robots in Time" series violate the grandfather paradox?

As anyone who is familiar with the Isaac Asimov's Robots in Time series by William F. Wu is already aware, the Mojave Center Governor does not realize that sending his component parts backwards ...
ritonello's user avatar
4 votes
4 answers
4k views

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 ...
SameOldNick's user avatar
4 votes
1 answer
534 views

Would guys from the Red Dwarf respawn if their future bodies kill themselves?

Would the Red Dwarf guys respawn in case (1) is the group that is to the present (2) is the group that is traveling in the past to visit (1) (1) is in year 8 000 000 for example (2) is in year 8 ...
genesis's user avatar
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4 votes
1 answer
364 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 ...
Freek Wiedijk's user avatar
4 votes
3 answers
908 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,...
Meir Illumination's user avatar
4 votes
0 answers
98 views

What did Stephen R. Donaldson mean by "there is hope in contradiction"?

One of the many recurring sayings in The Chronicles of Thomas Covenant is said in full by one of the characters (a magic lord named Mhoram) as: When you have come to the crux, and have no other ...
Kristian Berry's user avatar
4 votes
0 answers
226 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 ...
rosesunhill's user avatar
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3 votes
3 answers
352 views

How did this [spoiler] interaction occur in Dr Who "Journey to the Centre" episode?

In the episode Journey to the Centre of the TARDIS This character Goes through the rift to warn How can this even possible without destroying the fabric of space time? Or creating a paradox, or ...
JK.'s user avatar
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3 votes
1 answer
1k 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 ...
TimeTravellyParadoxySciFiSmeg's user avatar
3 votes
1 answer
575 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,...
John Sensebe's user avatar
  • 1,692
3 votes
1 answer
206 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 ...
user35971's user avatar
  • 7,192
3 votes
0 answers
294 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 (...
SK19's user avatar
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