Not at the levels of scrutiny that a cosmologist would want. Especially not one named after time itself. (Thanks for the compliment, BTW. Even if it was likely also a bit of a nerd joke at my expense.)
Still, the example Chronos gives isn’t a problem, because that’s consistent between movies. Objects always seem to change faster than do the minds of the time travelers. We don’t need to establish a reason for this for consistency to hold. The BttF “universe” obviously doesn’t work on the same rules as our own.
Not a problem. He has already greased the palm of the local constabulary. I suspect the fee is the same whether the cable runs east-west or north-south.
The whole thing sets up a predestination paradox. Think about it, why would Doc Brown and Marty McFly be friends at all? A ~60 year old anti-social nutjob and a 16 year old high school student? They didn’t seem to have any social connections(he’s my uncle, he was a mentor to my father, he was a teacher, etc.) aside from the fact that Doc Brown had a cool amplifier room that Marty liked to jam in, what was the basis of their friendship? How did the meet? Why?
It’s clear, on retrospect, that Doc Brown, knowing how important Marty would be to his life, groomed a young Marty McFly and cultivated his friendship. He may even have built the amplifier room specifically to appeal to Marty because he knew of his musical aspirations. It was only in that one scene and doesn’t fit in with any of Doc Brown’s other known hobbies/interests/scientific lines of inquiry.
How about this: when they arrive in 2015, shouldn’t they arrive in a version of 2015 where they disappeared without a trace back in 1985? If not, does old, Loser Marty remember this adventure?
Yeah, but he’s a loser. A slacker.
It is not until the “gunfight” with Biff, Mad Dog Tannon, that he learns how not to be a testosterone poisoned loser.
He will have remembered. But because young Marty never witnessed older Marty and his family, there’s no inconsistency there. Older Marty has no awareness of his impending loserdom. Right up to the end young Marty still thinks he’s going to be a successful rock star.
He had about 30 years to come up with an adequate defense–I suspect the vest has some extra reinforcement, probably strike plates.
The timing was precise, but their schedule wasn’t. They knew to the minute, not the second, when the lightning would strike. The whole thing was a gamble. If the car had started immediately, Marty would have hit the cable too soon. Instead, it delayed him just enough to make the timing work out.
Doc is a scientist–and a mad scientist, at that–not an engineer. There are several things he could have done to widen the contact window. For example, he could have extended the hook farther forward of the car and rigged it to a long coil of cable, so that it would catch early and pull off the car, remaining attached by the unspooling wire.
Your particular solution presents some technical difficulties. That long a stretch of the heavy cable would be difficult to support over the middle of the road, not to mention a lot more difficult to hang in the limited time Doc had. There’s also the added risk of it sagging and letting the lightning ground out, or the DeLorean simply pulling it down due to some small swerve or pothole. It might even have been that that was the longest cable he could scrounge up. These things could be overcome, but again, Doc isn’t an engineer, and they were working under a deadline.
If they had missed their window at the clock tower, Doc would probably have come up with something like that eventually. In the meantime, they had a known location and a very small time window when they knew there would be a usable strike. Doc probably also had an unstated goal of getting Marty out of history as soon as possible, before he caused any further disruptions. Also, it’s part of Doc’s mad sciencing style: he gets a very specific inspiration and obsesses on carrying it out. His Mark I is the finished product.
My best guess is that whoever it was thought there was a period when another instance of the DeLorean had been sitting around since 1885–the instance that Marty took back. The idea behind that would be that between the time Marty damaged the fuel line and the time they came up with another way to get the car up to 88, there was a future in which that instance of the DeLorean never traveled forward again, so there would be the remnants of a 140 year old DeLorean in a cave somewhere.
If this is what they were claiming, it’s an indication that they haven’t thought through how time travel works in the setting well enough. More than that, there was never even a time in the movie when all four of those you list were in their places. I’m not disputing your reasoning; there will be a point at which all four instances will have been there during that period. However, the characters (and vicariously, the audience) never experience that point. The changewave that causes the DeLorean to have been in the mine can’t start propagating until Doc gets blasted back to 1885 and leaves it there, so in the timeline we see in the movie during the critical period, there is no car in the mine. By the time the changewave establishes the timeline in which the car is hidden there, Old Biff and Future Doc have both left the time period with their instances of the DeLorean.
So, by the time 1955-Doc and Marty find the car in the mine, there has been a time when there were four instances of the DeLorean around, but that time was never shown in the movies.
And this is reason to assume Doc somehow knew about Marty before any modifications in history even occurred? I think you need to take a Razor to that assumption. How about this: Doc, being inclined to seclude himself in his lab and work on stuff, decided to pay a kid from the neighborhood to run errands for him. He needed an Igor. He happened to pick Marty, and they found that they got along well. It could have happened any number of ways. Maybe Marty tried to make a little money mowing lawns at some point, and Doc was one of his customers. Or he saw Doc struggling to carry a bunch of groceries/supplies/gadgets inside, and being a basically good-natured kid, stopped to help, leading Doc to think that having an extra pair of hands around occasionally could be useful. Maybe it was as random as Marty stopping to play with Einstein when Doc was out for a walk. None of it requires predestination, just a working relationship that turned into a friendship due to complementary personalities.
Only if they don’t come back. Since they did, they don’t.
As GuanoLad said, 2015-Marty eventually will have always remembered his adventures in time. At the time we see him, he remembers his first trip to 1955 and the original timeline he lived in before the trip. He doesn’t remember 1985-Marty visiting 2015, or any of the other travels that resulted, because the changewave that establishes those memories (and an otherwise altered life for him) won’t be triggered until 1985-Marty returns to 1985 for the third time.
You’re right, they should have arrived in a 2015 with no old Marty (or Jennifer) at all.
The assumption is that they will eventually travel back to 1985, but the BTTF movies never worked that way. If things are the way they are because of eventual time travel, then Marty’s parents would have never been losers in the first place.
This thread is starting to hurt my head. If time travel is at all possible it will not exist the way BTTF portrays it, there are far too many paradoxes. Even so, it does raise some fun points to consider.
This may be listed above and I just missed it because, thanks to this thread, I’m starting to see these movies in a different light.
Marty 1- the Marty we’re introduced to at the beginning of the first movie was raised by world weary George and Lorraine. He befriended the Doc for whatever reason, but I suspect at the heart of the relationship is that Doc was a better role model than George. This Marty has ambitions but lacks the courage to see them through. Doc 1 accidentally sent Marty back in time.
Marty 2 - the Marty raised by confident George and Lorraine. We don’t meet this Marty in the first movie, but he’s the only Marty that the Doc in Parts 2 and 3 has ever known. This Doc had to have sought Marty 2 out and sent him back in time knowing that he was predestined to have to go. Doc 2 deliberately sent Marty back in time though we never saw that specific event happen. The relationship between Marty 2 and Doc 2 would have to be different too, probably more mentor than role model. It would be fun to see how Marty 1 and Doc 1 would have reacted together in 1885 vs the version saw with Marty 2 and Doc 2.
At some point in Part 2 the change wave had to hit Marty and change him from Marty 1 to Marty 2. We know it wasn’t in Part 1 because he recognizes that his parents and house changed. Given the rules of the movie the change wave will eventually make Marty think he was always raised in the second house with confident parents. I wonder if this is why Marty in parts 2 and 3 always reacts to people accusing him of being chicken which was never featured in the first movie. It’s a different Marty.
So that raises a new question - Marty 2 had to go back in time to have almost the same adventure Marty 1 had - but he would have had very different motivations for doing so. Marty 1 changed his future, but Marty 2 has to preserve his future. We never saw Marty 2’s adventure, but if you were to talk to Marty in 1885 about his trip to 1955 it would be different to what we saw.
That’s not my interpretation. I don’t think a Marty exists who was raised by the “improved” George and Lorraine. When Marty went back to 1955 and changed the events, he created a new timeline. IOW there is no Marty1 and Marty2; just one Marty because he is the one traveling from one timeline to another. That’s why his memories never change.
Doc1985 does not go to 1955, so when Marty changes the timeline in '55, Doc1985’s memories do change. He remembers meeting Marty in '55 and getting the note that warns him about the Libyans. So from the end of BTTF1 you could call him Doc2-1985. (We never see Doc1 - the one who didn’t know Marty until the 1980s - in 1955, so he’s always Doc2-1955. And of course Doc2-1985 is the one who goes back with Marty1 to 1885.)
Even the old, sad Marty we see in 2015 is Marty Prime. But you could say that once young Marty avoids the car accident, this old Marty changes to Marty 2. That’s the only version of Marty that changes, though, because Old Marty didn’t create the new timeline, young Marty did.
I see your point in that his personality didn’t change all that much so it seems like we’re always seeing the same Marty.
But think about Biff 2 in 2015 - he’s the Biff that was created in Part 1 and that we see washing George’s car at the end of Part 1. He’s the Biff who Marty bumps into in 2015, steals the Almanac, and takes back to Biff Prime in 1955. That encounter created Biff 3 who created alternate 1985 and then died sometime before 2015. When Biff 2 came back to 2015 to drop off the DeLorean he only briefly existed before vanishing. Time didn’t go around Biff 2, it caught up to him.
Likewise time can’t go around Marty forever, at some point time has to catch up to him and change him. If you ask Marty about his childhood at different points in the movies I think you’d get different answers.
Skammer is close, I’d say. We never meet your Marty-2, but we see him briefly, as Marty-Prime watches him fleeing in the DeLorean until it exits the timestream. Somewhere in my massive posts above (I think in answer to the memory challenge from Chronos), I went into detail why, but here’s the short version: the changewave that would have produced Marty-2 passed through 1985 while Marty-Prime was undergoing displacement. He was isolated from the timestream, so he didn’t change with it. (Indeed, part of my hypothesis includes a time vehicle being unable to reenter the time stream at a point when it is in flux, but never mind that, never mind that.)
So, when Marty-Prime returns to 1985, he takes the place of Marty-2, but he does not and will never remember the events of Marty-2’s life up to the point of his initial displacement. Everyone else around him remembers Marty-2, though. From the comments by the McFly family and the fact that he’s still involved with Jennifer, I suspect Marty-2 wasn’t really all that different from Marty-Prime in personality. Given that, and the fact that the McFly family lives in the same house in both timelines, Doc-2 probably didn’t have to go to any special effort to establish contact with Marty-2, although he did have to conceal his foreknowledge of the events that were to occur on the morning of the test.
Oh, and Marty-Prime was trying to preserve his future as well. He just made a hash of it. Marty-2’s adventure probably would have looked pretty much the same, except that he would have taken some actions deliberately that Marty-Prime stumbled into.
There are 3 Martys in 1985: Marty-1, whose adventures we follow through the films; Marty-2, who disappears in the Delorean at the end of BTTF-1, and Marty-3, who we never meet – he’s the Marty who grew up in Biff-world in BTTF-2 (Biff mentions that he’s supposed to be away at boarding school).
Biff-world, Doc tells us, is a separate time-line created when 1955 Biff is given the Sports Almanac. The reason they can’t go into the future to stop old Biff from doing this is that the 2015 they would return to exists in a separate time-line from the one they originally visited.
Doc is describing multiverse theory, and thus there are four 1985s we are shown, three of which split from one another due to the events on that fateful day in 1955, and the fourth, apparently, from events that take place in 1885 in BTTF-3 (there is a 5th 1985 implied, of course: the one in which George and Lorraine never kiss, and Marty doesn’t exist). The first movie opens in 1985-1 and ends in 1985-2. Biff-world exists in 1985-3.
Each of these 1985s (along with infinite variations) is presumably populated with its own population of Martys, Docs, Jennifers, Biffs, etc… What Marty and Doc are really doing is universe-hopping. They are not really changing history, they are visiting universes in which their actions are part of the sequence of events in that universe. Note that, by leaving Jennifer-2 in 1985-3, that universe has two Jennifers and 1985-2 has none. The fact that Jennifer exists at the end of BTTF-3 tells us that Marty has returned from 1885 to 1985-4, not 1985-2 or -1.
We leave 1985-1 when Marty first goes back in time, and we never return. In that universe, Doc-1 is killed by terrorists and Marty McFly suddenly disappears with no explanation that same night, never to return. That Marty, Marty-1, returns to 1985-2 and replaces his doppelganger, Marty-2, who disappears in the Delorean but never returns (else we would have a universe with 2 Martys – sequel anyone?).
Unless Marty-2 manages to return from 1955 without interacting with his parents and thus replaces Marty-1 in 1985-1, a world in which his dynamic SF-author father is now a cubicle drone and his mother is a bored, tired housewife who disapproves of his girlfriend.
Of course several commentators (none here) have remarked that George must have been a bit bothered by the fact that his youngest child grew up looking exactly like Calvin Klein, the kid from High School who his future wife had such a crush on.
But then perhaps at some point he was looking through old McFly family photo albums and noticed that Marty also looked exactly like George’s great-grandfather Seamus. But then he would’ve noticed that his wife Lorraine looked exactly like his own great-grandmother Maggie.
At that point I imagine he just stopped looking at his family tree and just started drinking.
BttF cannot possibly be a multi-universe hopping story. If it were, the entire events of the first movie wouldn’t have happened. He wouldn’t have started to fade away and his family disappear if he had simply created a new universe, separate from the one he originally came from.
The changewave thing seems to make a certain amount of sense to me, but it contradicts a lot of what we know happened. When Marty goes back to 1955 the first time and sets things in motion that will keep his parents from ever getting together, he starts to fade away because he won’t have existed anymore. That is, the change-wave is slowly propagating through the photo and his physical body.
However, it instananeously propagates the moment his parents kiss and get back on the right track. That’s a contradiction. Shouldn’t it have taken time for him to get healthy again, and his family to reappear in the photo, as slowly as it took the first time to affect him and the photo?
I can buy the bit of logic that says Marty-1 doesn’t fade away even though there is really a new Marty-2 raised by parents who are in personality quite different because he was in 1955 when the changewave propogated through 1985. But then why wouldn’t this very same logic keep him from fading away slowly? He changed history in 1955, his parents never meet and never kiss, and he is never born. But he’s outside of 1985 when this changewave goes through, and he never gets affected while also never having traveled into the past.
I agree. There is no need to invoke a multiverse, and indeed, it contradicts observed facts. The only point at all in its favor is Doc’s explanation about 1985a, and that could have simply been a simplification for Marty’s benefit. Note that Doc says the timeline skewed into the new version, not that they had jumped into a new timeline. (It’s also possible that he simply hadn’t figured out exactly how it all worked at that point, but he knew enough to get on with.)
Maybe I should make a page I can link in every BttF thread.
I refer to my explanation for the way time travel works in the BttFverse as Temporal Hysteresis. (Hysteresis, by the way, refers to the state of a system being dependent not just on current conditions, but past conditions.) Here’s the quick version:
The timeline is resistant to change. The effects of a new change to history propagate slowly forward along the timeline, but the effects of changes that revert key events back to their original state propagate very quickly.
The propagation speed of a changewave is affected by a number of factors. The “breadth” of the wave–i.e. how extensively the change affects things–is a major one. For example, the changewave caused by Doc arranging for a piece of paper to sit in a box for 70 years was much narrower than one that erased three children from existence, and consequently propagated much faster.
The propagation speed of a changewave is not constant. It slows as it triggers secondary changewaves. This is why it took less time for the changewave from Marty’s interference to catch up to Dave than it did to progress from Dave’s birth to Marty’s–unmaking Marty’s siblings triggered major secondary changewaves, slowing the primary one. Even very narrow changewaves will gradually slow, as they inevitably initiate some secondary changewaves, however minor. (I speculate that the rate asymptotically approaches realtime, but establishing that would require far more data than we have.)
Changewaves propagate independently. The reversion wave triggered by the kiss propagated much faster than the novel changewave caused by George’s change in attitude. This is why Marty’s memory of his original life was restored along with his existence.
A time traveler is insulated from the effects of a changewave while undergoing temporal displacement.
Temporal displacement appears effectively instantaneous from the perspective of the time traveler, but this is an artifact of their disassociation from the timestream. Changewaves continue to propagate through the timestream while the traveler is in transit. Indeed, it is possible that the time vehicle cannot reenter a point in the timestream that is in flux due to a changewave, effectively leaving the traveler in a holding pattern until the changes at the target coordinates are complete. The changewave was already through 1985 when Marty reentered the timestream–it changed while he was outside of time, so he wasn’t affected. Note that we saw a very noticeable effect of the change already in place when he approached the mall.
[li]Years & years ago Michael J. Fox was on Letterman and he mentioned that fanboys would often come up and ask him crazy, complicated time-travel theory questions like these. He said he’d very politely just shrug and say, “I don’t know, they just pay me to walk around and say lines…”[/list][/li][/QUOTE]
