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75 votes

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

Maybe I am missing a point to your question, but the wrench is a wrench, it either is good for the nut/bolt you use, or it is not. Ie. if the future Doc gave the past Doc the five-eighths wrench the ...
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30 votes

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

Of the options you presented, I'd go with... A) The whole interaction is indeed harmless and will have no effect. In regard to your second option... B) He gave himself the right wrench, but that was ...
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29 votes
Accepted

Wouldn't the paradox machine be useful for the Doctor?

There are several reasons The Doctor would decide against building a Paradox Machine: He doesn't know how The original Paradox Machine was created by The Master. There's no reason to suspect The ...
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27 votes
Accepted

Earliest instance of the grandfather paradox

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 ...
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  • 144k
22 votes

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

I think the case of Old Biff applies here. In BttF Part II Biff from 2015 goes back to 1955 and changes the timeline. He then goes back to the future (roll credits), where he walks off. Offscreen, ...
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17 votes

Did Edith Keeler really have to die?

In the following remember that the entire Federation had disappeared, these people were in a very serious quandary, Captain Kirk even instructed them to wait and each try to correct the time stream in ...
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15 votes

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

It is impossible to give an in-universe answer All talks of time paradoxes are Doc's scientific speculations, which may or may not be true. Nobody had such experiences before, and time travel theory ...
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  • 12.9k
14 votes

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

Alfred Bester, "The Probable Man". First published in Astounding, July 1941. (yes, even before USA entered the WW2). It can be found recently in his collection Redemolished. The description fits ...
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14 votes

Who came up with the name Melody Pond?

There is no easy answer Welcome to the wonderful world of paradoxes. The naive answer is that Amy and Rory chose the name, on behalf of their childhood friend Mels: Doctor: Mels, short for... Mels: ...
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14 votes

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?

From what we see of Marty's post-timeline change family (the one that exists because of Timeline 1's Marty changing how his parents meet), it looks none of the changes prevented Marty and Doc Brown ...
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  • 80.3k
12 votes

Where did 2015 Biff hide the Delorean in 1955 when giving himself the Almanac in BTTF 2?

We can't really say The crucial factor here is to remember that when Biff returned from 1955, he was driving the DeLorean in flying mode, ergo, he knew how to drive a hover-car. Because of this, it'...
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12 votes

How did Clara dedicate Emmett's tombstone in Back to the Future 3?

There is an official answer to this question, involving multiple altered versions of the timeline, in the Back to the Future FAQ by BTTF writer Bob Gale and writer/director Robert Zemeckis. I'll just ...
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  • 50.7k
12 votes

Did Edith Keeler really have to die?

SPOCK: I was recording images at the time McCoy left. A rather barbaric period in your American history. I believe I can approximate just when to jump. Perhaps within a month of the correct time. A ...
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  • 121
11 votes

Why was Marty present in his jump to 2015 in Back to the Future 2?

This was answered in the official BTTF FAQ which was done by the script writers, Bob Gale and Robert Zemeckis: 1.13: When Doc takes Marty and Jennifer out of 1985 and brings them to the future, how ...
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  • 50.7k
11 votes

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?

AncientSwordRage gave a great out-of-universe answer. Here is an in-universe one. Because Marty had already told him the flux capacitor worked, and left a note telling him what to do (in a round-...
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  • 1,156
10 votes
Accepted

Predestination and Bootstrap Paradox?

The two kinds of paradox are extremely closely related, so many times a movie which seems to deal with one actually deals with both. In fact, I've found quite a few places that consider them to be ...
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  • 103k
10 votes

In the Back to the Future trilogy, does Doc ever piece together the letter about the terrorists?

When Marty re-visits the Doc in 1955, he doesn't spend much time there before going to 1885. All versions of 'the Doc' have approximately 30 years to piece together the letter that he had ripped up ...
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9 votes

Where did 2015 Biff hide the Delorean in 1955 when giving himself the Almanac in BTTF 2?

Officially: we don't know. Unofficially - I really doubt he hid it at all. First of all, its Biff - someone who on "The smartest person of Hill Valley competition" would show up only to give a ...
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  • 28.3k
9 votes
Accepted

Jennifer from BTTF left behind

The single changing timeline seems to be the one the writers imagined, and they also imagined that when time traveler A is in one era and time traveler B in earlier era changes history, the world will ...
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  • 50.7k
9 votes

Jennifer from BTTF left behind

There is a single changing timeline I tried to illustrate why I think there must be a single changing timeline. To sum it up, if alternate timelines persist in the BTTF universe, I can't think of ...
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  • 2,339
9 votes

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

This is "Things Undone" by John Barnes. It can be read online here. equation (or series of questions? something like that) written in the 1700s or 1800s Six hundred years ago, in the One ...
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  • 12.4k
9 votes

Wouldn't the paradox machine be useful for the Doctor?

he could save anyone and do anything he wanted to do The Doctor himself has had this exact thought once before: during the Tenth Doctor episode "The Waters of Mars". The deaths of the Bowie Base One ...
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  • 12.4k
8 votes

Did Edith Keeler really have to die?

I think there are three reasons why Edith Keeler had to die. One is the purely practical "real world" script writer's reason. It was suggested that Kirk, et al take Edith back through the Guardian of ...
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  • 151
8 votes

Earliest instance of the grandfather paradox

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, ...
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  • 10.7k
8 votes
Accepted

What type of paradox kills Weeping Angels?

Angels can also be starved to death - they literally waste away, their forms decaying, looking like erosion. The time frame needed to do so in unknown. The way they feed is somewhat unclear - in ...
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  • 12.2k
7 votes
Accepted

Predestination (movie) - predestination or bootstrap paradox?

Both As noted by Michael Edenfield in his answer to a related question, the bootstrap and predestination paradoxes are very closely related. It's not unusual for a work of time travel fiction to ...
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7 votes
Accepted

Did any universe address the problem of double DNA

This is not, in fact, a problem. Your DNA is made up of bits of the DNA of your ancestors, but you might coincidentally share bits of DNA with other people outside of your family. Yes, there might be ...
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  • 1,652
7 votes

Trying to find a time travel short story

Sounds like "The Chronology Protection Case" by Paul Levinson. Summary from Amazon: When NYPD forensic detective Phil D'Amato takes a call from a lady physicist about her missing husband, ...
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  • 8,130
7 votes

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

There was no "snap" If you rewatch the original movie, you'll see that in both cases (up on the clock tower and down at the street post) the cable uplugged. Nothing was broken, it just came ...
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  • 1,076
6 votes

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

Walter is not entirely erased from the timeline. He ceases to exist FROM 2015 because he cannot exist in two places at one time. If you watch the tape that Walter left for Peter it answers all this. ...
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