How many alternate timelines exists in the Back to the Future universe?

[Gyrate]

There are lots of helpful(-ish) diagrams on the subject available.

[oft_wears_hats]

@BeepKillBeep

I was talking about this in a recent Terminator thread.

I have often imagined it is something like this:

1 - Skynet is built and becomes self-aware. Judgement Day happens.
2 - Humanity (without John Connor) fight back and win.
3 - Skynet as a last ditch effort sends a terminator back in time to change things but not to kill Sarah Connor.
4 - Kyle Reese is sent back in time to prevent the change.

2…4 happens N times and that it is possible that although Skynet isn’t winning post-Judgement Day, perhaps things are improving for Skynet. It might be getting closer to winning.

5 - At N+1, Kyle Reese sires John Connor just as a matter of coincidence.
6 - The post-Judgement Day war is a disaster for Skynet this time around. It realizes that it absolutely must ensure no John Connor.
7 - The events of “The Terminator” and subsequent movies happen.

At the risk of continuing the hijack, I like that idea. It tracks well with the thesis of the third movie (which was one of the only good ideas from it). That both humanity and SkyNet are fighting to change their fates but neither can. The universe has paradox-absorbing crumple zones built into it. Humanity is destined to suffer Judgment Day, and SkyNet is destined to be defeated in the end. Both sides can fight to change things, but neither will ever be able to avoid it entirely.

I recall that some of the special features in the BTTF DVD set released in 2002 or so mentioned the idea of the universe automatically preventing paradoxes.

[cochrane]

@Hail_Ants

Ever since I first saw BTTF Part 2 some 25 years ago I’ve wondered about this. Old Biff clearly seems to be in some kind of distress when he gets back to 2015. I just saw it the other day on TV and although they try to make it look like he merely hit himself in the chest pulling his stuck cane out of the car, there still seemed to be more to it. I guess maybe they had the option of showing him disappear in a flashback in III or something, but decided against it…

Yeah, they showed it to test audiences, who were confused by it. It’s one of the deleted scenes on the DVD.

[Munch]

@Sterling_Archer

The really confusing one, to me, is the Terminator-verse. So Reese goes back in time and sires John Conner.

The Conner surname is in the Roseanne timeline. The Connor surname is in the Terminator one.

[borschevsky]

@cochrane

According to the commentary on the DVD for Part 2, old Biff didn’t return to the 2015 he left. He went to the alternate 2015 he created when he gave his younger self the sports almanac in 1955. In that timeline, Biff was shot by Lorraine (in the year 1987, I believe), whom he had married. Since Biff died in that timeline, he faded out of existence as soon as he returned to 2015.

So is this saying that while Marty & Doc are in 2015, it changes around them to the new timeline? They use the Delorean after Biff brings it back, so if old Biff is in alternate 2015, then so are they.

[Hail_Ants]

@borschevsky

So is this saying that while Marty & Doc are in 2015, it changes around them to the new timeline? They use the Delorean after Biff brings it back, so if old Biff is in alternate 2015, then so are they.

This is where it starts to get complicated, because yeah it would.

After Old Biff comes back to 2015 it would mean that everything would have been different. Marty’s mom would have married Biff, and his dad would have been long since dead having been murdered by (young) Biff. If they had gone back to Marty & Jennifer’s futuristic house before leaving 2015 then everything would have been different. It would have been the same timeline as when they travel back to the violent 1985 from there. Doc says as much when Marty suggests going from the violent 1985 back to 2015 to try and fix things. Doc says they’ll have to go back to before things changed, before the almanac gets left in 1955. Being that Doc and Marty were the original 1985-versions it’s plausible that they would have been immune to any ripple effects Old Biff caused. Or something.

Michael J. Fox once addressed this on Letterman. He said fanboys would sometimes try and ask him these convoluted time travel questions. He would just smile and say, “I don’t know, I’m an actor, they pay me and I just move around and say stuff…”

[Enderw24]

We could also argue that 99% of the entire film franchise takes place in alternate universe 1A, after Einstein’s successful 1 minute leap forward.

Universe 1B ends the movie with a confused van full of Libyean terrorists rescuing a dog from a blood splattered DeLorean.

[Quimby]

If you really want to Nitpick Young Marty and Jennifer meeting Old Marty and Jennifer could be a problem. Going by the rules established when Einstein jumped one minute into the future, Doc and Marty should have emerged into a Future where the three of them disappeared 20 years earlier.

But then again, maybe it would take time for that change to ripple forward and would have only been an issue if they had stayed in 2015 for too long. The movie also establishes that as well…hmmm now I’m not so sure if this is a nitpick or not.

[Cartooniverse]

@Munch

The Conner surname is in the Roseanne timeline. The Connor surname is in the Terminator one.

I knew Roseanne Barr and John Goodman figured in this somehow !!!

[Stranger_On_A_Train]

All timelines exist simultaneously in a superposition of relative states. The focus follows the particular timeline states that Marty Prime experiences (except for the few curious scenes where the focus follows Jennifer, and the one where Doc proclaims his love to and truth about to Clara) but nother Martys are neither killed nor disappear. Despite Marty seeming to start to disappear during the Enchantment Under The Sea Dance, he’s really just not compatiable with that particular state and will decohere into a more probable state.

Of course, this also means that Lorainne still gets raped by Biff and turns into an alcoholic and/or is forcibly married to Casino Magnate Biff, Doc is still murdered by ‘Mad Dog’ Tannen, and Marty crashes his truck. So, really, not any better of a future than the disappearance of supposed alternate characters. Now, think about what that means for your own life.

Hugh Everett was kind of a dick, but the only other rational altenrative is that it is all predetermined by nonlocal hidden variables, and almost nobody is happy with that.

Stranger