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:

Doc, after tearing up the letter, changed his mind and pieced it back together.

Nevertheless, at the end of the second film and at the beginning of the third film, Marty comes to Doc right after Doc sent the other Marty to the future, causing Doc to faint.

Marty then takes Doc back to his place, and no mention of the letter is made.

In the third film, we see Marty and Doc in 1955 helping Marty go to 1885, and at no point do they talk about the letter, which has by now probably been scattered, swept off the streets by the wind, etc.

Therefore, "Future Doc" (now living in 1885) should be dead by the time Marty arrives in 1885, since interrupting Doc made him unable to change his mind about the letter, and Marty didn't either warn him about the terrorists.

The timeline in which Doc pieced the letter back together, then went to 2015, then went to 1955, then went to 1885 by accident just cannot happen from what I understand.

  • 3
    What's really going to cook your noodle, is whether or not the Doc is already wearing one at approximately 30 minutes into the movie. No exit wounds, no blood.
    – Mazura
    Oct 4, 2015 at 23:18
  • Yeah, that's pretty crazy! I'd say maybe they just shot it once otherwise there would have been continuity problems such as he wouldn't have acted the two takes the same way, but it's true that within the film's context it's pretty nuts to realize this! Thanks! Oct 5, 2015 at 4:32

3 Answers 3


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 and put into his coat pocket.

If 'Future Doc' never put it back together, he'd be dead. The logic must follow that he did, and he always does, in any timeline in which he uses pinball machine parts to make a bomb and is still alive, come 1986.

  • 3
    Yes, I think fabrice d may have missed the fact (noticeable if you watch the scene closely) that he put the torn pieces of letter in his coat pocket rather than throwing on the ground, since the original question says that the letter "has by now probably been scattered, swept off the streets by the wind, etc."
    – Hypnosifl
    Oct 4, 2015 at 22:41

The answer posted by Mazura is spot on. He had to have put the letter back together, or his story would stop in 1985. He also had 30 years of normal linear living to do it in, it's not like he had to have his change of heart that night.

I would like to add a bit of speculation however.

Doc's entire line of reasoning for taking the hard-line against changing his own future was that he feared the consequences of changing anything. He didn't know what would happen with a paradox, whether he'd be erased like Marty or whether he'd break something larger and potentially more world shattering.

What Doc doesn't get until later is, they have already done that. As in your other question, Marty's fathers history doesn't exactly line up with the original timeline anymore, but Marty is doing just fine. The timeline was close enough to work out. The natural conclusion from that is, if Marty could do it, why couldn't Doc? Marty thought this was important enough to change, and if he can get things close enough...

That he still stood in front of a hail of bullets shows just how committed he was to avoid changing anything else. One stray and he still would have been gone.


I know this is an old question, but there's one thing the other answers miss:
Doc didn't scatter the pieces of the letter, he put them back in the pocket of his coat. He knows that a letter like this, if discovered even torn, could alter the future, so he holds onto it to likely burn later.

Also, the 1955 Doc didn't do any time travel, so that letter remains in his pocket until after Marty leaves for 1885. Not to mention that Marty reappears to 1955 Doc just a few minutes after he shreds the letter, so there's not any time for the letter to otherwise be destroyed. Then there's the situation where Doc faints when Marty appears, so Marty likely takes special care of the coat knowing that the letter is in it and that Doc is going to tape it back together.

Marty doesn't mention the letter onscreen, but there's nothing to say he didn't mention it offscreen. But, knowing how stubborn Doc Brown is, Marty likely didn't want to risk pushing the matter. And the most pressing part of this encounter is Marty going back to 1885, not the letter, which he knows gets resolved in it's own due time. The 1955 Doc has plenty on his mind trying to fix a machine he has yet to invent, so the letter is very low on his priority list and a good distraction, instead of finishing destroying the letter while it's still fresh in his mind about the paradox it could create.

  • There was no need or reason for Marty to bring up the letter ever again. From Marty's point of view, not even 20 minutes after Emmet tears up the letter, Marty learns, that the letter will be reassembled without missing a piece. What is there to bring up and discuss? He know his letter will be read and understood in full. Dec 9, 2022 at 10:14

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