Similarly, old Biff from 2015 Hill Valley changed his own past enough that he himself would no longer exist. If he had realized this was the case and not left the grace period between making the change and the changes becoming certain, he would have continued to exist, but the moment he passed the point of his changes being certain, he was almost immediately erased from the timeline.
First, it is Canon that, after surviving the bullets in the new version of 1985 at the end of Part 1, Doc decides to go forward in history. It is presumed that he does disappear from the timeline during his trip.
It may be presumed that everything else happens "normally" until he returns — the future that we see in Back to the Future II really happened the first time around. For example, the car accident that we see not happen at the end of Part 3 does.
Perhaps middle-aged-Marty's psychological problems are partly related to the trauma of Doc having disappeared.
Doc reads the newspaper article about Marty Jr in jail and decides he must prevent it. He goes back to 1985 and picks up Jennifer and Marty, then goes forward. This would have caused timeline alteration, including a no-Jennifer-and-Marty universe; but the ripple effect "hasn't happened yet", in accordance with BTTF metaphysics. They necessarily visit the exact same 2015 as the one from which Doc departed. It is only afterwards that things diverge, with the usual weird risks of paradoxes and whatnot, which is why the future of III is unknown in film canon.
The risk is more visible with old-Biff's adventures. He goes back in time and gives the almanac to himself. When he goes forwards, one would think he would arrive in a rich-Biff timeline. He doesn't because, since he left 1955 before the branching point when Marty either does or doesn't successfully take the almanac back, the changes haven't rippled forward as fast as Biff rippled out of the timeline... It may be presumed that he has the heart attack because the rich-Biff died in middle age.
- Old Biff died and faded away because - in the timeline he created - Biff was killed in 1996, per a DVD special feature. Quite probably by Lorraine (or at her request).
But...it wasn't pointless. Doc PLANNED the entire thing. Doc knew that Marty being a hothead about being called "chicken" resulted in a future that was...not really great. He wants Marty to get over this, but can't just say "You're going to be in a car race that Needles eggs you in to, you're going to hit a Rolls Royce and ruin your future." Doing that would cause problems, because as he says multiple times, no one should know too much about their own future. So instead, he comes up with a plan: set into action a chain of events that will cause Marty to mature, and get over his whole problem with being called chicken. So he uses his knowledge of how timelines and time travel works, and figures out this plan, that involves the entirety of BttF 2 AND 3, that eventually gets Marty to mature. His tombstone just HAPPENS to be next to where the DeLorean is buried in 1955? No...he planned it that way. He let it be known that is where he wanted to be buried, so that Marty would see the tombstone in 1955 and plan to come back to the past, and that the events of part 3 would happen and allow Marty to get over his issues and not get in that accident. Another part of the theory is the malfunctioning Time Circuits in part 2. They worked just fine, he simply made it look like they weren't so he'd have an excuse to be sent back to 1885. When he was trying to land the DeLorean in 1955 after Marty burned the book, he says that he has to fly back around due to the wind, but in what we've seen of the DeLorean flying previously, it seems like it is able to do a vertical landing, akin to a harrier jet. So why suddenly does the wind matter? It doesn't. Doc knows that if he stays in the air he will get hit by lightning, and has the time circuits ready to go to 1885, as it is all part of his perfectly thought-out plan.
Doc is a total bad-ass, and one of the greatest Chessmasters ever committed to film, using his own death as part of his plan.
- "Why bother going to the future to change what happened to Marty Jr if the future isn't set in stone and can be changed?"
In a way, this question answers itself. Because the future can change… one may as well "bother" to change the future. It just happens that Doc is cautious enough to not want to change the future "too much", so he doesn't try to prevent the Marty-Jr-in-jail timeline by simply warning young Marty about his future son and waiting thirty years.
Apart from that, this is very clever, though of course like nearly any plan in both film and real life, there seem to be many many ways it could have gone wrong.
- It probably "went wrong" several times. Doc knows how to redo things/warn himself without paradox.
- Considering that there is no Year 0...yeah, it was probably broken then, too. It may have gotten broken when Doc entered "Dec 25 0000."
- Of course there is a year zero, just not everyone calls it that. The number assigned to a year is an arbitrary convenience. It doesn't matter what label your calendar slaps on it, if the time machine knows to go back a certain number of years that's all that matters. Doc programmed his DeLorean with a different calendar than the common modified Gregorian— there are several calendars that use a zero year to mark the birth of Christ.
- Maybe that's how Doc broke it — by setting it to zero.
- Note: this theory presumes that the Telltale games didn't happen.
- Leaving out the instances of people traveling back to where they belong (the various trips back to 1985) and the instances of people trying to fix something (all of the other trips the movies followed), the only time travel in the movies that was intentional were Doc's first trip to 2015 and Old Biff's trip to 1955. Doc probably just figured on thirty years being a nice round number for his trip forward, and Old Biff probably just went back to 1985 because that was the year he turned 18 (and - due to the events of the first movie - the date had a certain significance for him). There's no reason to think that the machine can't travel to other years.
Now, as for when in the Doctor's long and complicated timeline Doc Brown falls, it could be at any point when the Doctor spends a long period of time which the show doesn't account for (e.g. "Season 6B", a 200-year gap between Seasons 6 and 7, which would make him the Second Doctor). We would, though, have to account for the Doctor's incarnations in which he displays annoyance at people addressing him as "Doc", so it's not the First or Sixth Doctor. Or we haven't seen this particular incarnation yet. One theory suggests that it's at the end of a series of regenerations, in which the Doctor is just living out the rest of his years (but not the first set of twelve regenerations, as he's already gone through those and gotten a new set).
- The name of the device supports this - flux is a rate of movement or current (in effect - change) and a capacitor temporarily stores energy. So the Flux Capacitor makes perfect sense for the name of a device that stores temporal changes instead of letting them flow freely.
- This would also explain why Doc and Marty acted as though the new 1985 was the "correct" timeline throughout Part II. It just took a while for the Delayed Ripple Effect to get to Marty's memories.
- It may also explain where Marty's weakness to the word "chicken" came from. Something may have happened exclusively in the new timeline to cause his disposition, explaining why this was absent from the first film.
- To be fair, it was the correct timeline for Doc. Only Marty traveled back in time at that point.
- Perhaps it's the same incident which made Needles his arch-nemesis who was never mentioned in the first film?
- This is actually Fridge Brilliance, rather than Wild Mass Guessing. Otherwise, the "chicken" issue becomes something close to absurdity.
- It also explains why the new 1985 is a good thing rather than the Fridge Horror of your family of 17 years having different personalities and histories—eventually, Marty acclimated to those changes as his new memories caught up.
- Second-movie "1955" Marty is taking part in what appears to him as a Stable Time Loop. The ripple effect went round and round until it found an equilibrium.
- This explains the discrepancy between the ending of the first movie and the beginning of the second. At the end of the first movie, Doc immediately tells Marty and Jennifer that they turn out just fine. At this point, Marty is still his old self, who doesn't have the problem with being called "chicken", doesn't give in to either of Needles' stupid dares, and doesn't get into an accident or get fired. By the time Part II comes around, the ripple effect has already caught up with Marty, rewriting his memories and personality, to the extent that he does all these things, leading Doc to hesitate before answering his question.
- Although it's possible that Mcfly men have a thing for women who look like lea thompson, also Martys great Grandmother looks like Lorraine too
- In Part III, Doc tells Marty a bit about his childhood, which would be pointless if they were the same person. Marty doesn't seem like the type of kid who would be enthralled by Jules Verne anyway. Furthermore, the Doc briefly touches on his family's history in the same movie, and he mentioned in the first film that it took his entire family fortune to build the time machine; therefore, he definitely has a background.
- It is established in film continuity that Doc Brown is very against letting your earlier self become aware that you are their later self! He'd lie to Marty about their being the same person to preserve the universe.
- We see the Jules Verne bits when he's with Clara. He has no reason to lie to her.
- Women talk, man. Clara could accidentally let something slip to Marty. Either that, or Doc replaced his real memories as of being Marty McFly with false memories of a past as Emmett Brown to completely make himself a different person as seen below.
- Doc is visibly younger in 1955 than in 1985 in the first movie. After going to the future, he got a rejuvenation that allowed Christopher Lloyd to play 1985-Doc without heavy age makeup. They also replaced his spleen and colon. In the first film, Christopher Lloyd wore old age makeup as 1985 Doc to make him look older, while the 1955 Doc was Lloyd without makeup, just as with the actors playing George, Lorraine, Biff, and Strickland, since for the majority of the first film, they were playing the 1955 versions of the characters, with the 1985 versions only appearing at the beginning and end of the film. However, for the sequels, Christopher Lloyd was predominately playing the 1985 Doc, with the 1955 Doc only appearing at the end of Part 2 and beginning of Part 3, so rather than have Lloyd wear old age makeup for the majority of the films, the writers wrote in the rejuvenation, in which Lloyd literally ripped off the old age makeup, so he could appear as is. Doc noticeably has more wrinkles before he takes off his disguise than after. Granted, at the end of Part 3 about ten years have passed for Doc, but maybe rejuvenation slows senescence.
- Marty went further into the future to not only get a rejuvenation, but to have his brain genetically enhanced to make himself a genius— a side-effect was that it altered his personality. Before he went back and became Doc, he used his new intelligence to realize the damage he was doing to the timestream, and he had his memory erased or altered just before going back; he then remembered/"invented" the time machine.
- Jossed by the Telltale games.
- In The Sims, Sunset Valley/Pleasantview (the main setting of TS3 was founded by Gunther Goth, who is middle-aged in The Sims 3, the chronologicaly first game in the series. Hill Valley was founded in the year 1850 in BTTF, so that is impossible.
- Sure, THAT'S what's impossible, in a shared universe in which physical time travel is possible via a sports car.
- Does time travel invalidate mathematics somehow?
- Sure, THAT'S what's impossible, in a shared universe in which physical time travel is possible via a sports car.
- But it can't go back before year zero. There's no "BC/BCE" switch. And it can only do four-digit years anyway.
- It can only display four-digit years and zeroes on the dashboard. Doesn't mean it can't actually travel that far.
- Set the display to -4E9. Problem solved.
- Still suffered from the Ontological Paradox.
- Wait, you're saying we are all decendants of Biff?!
- Well, there must be some reason why Humans Are Bastards.
- Alternately, the readout could just turn a different color when in the range of BCE years.
- This means that Marty and Doc are singlehandedly responsible for stopping the advent of hover tech, ubiquitous fax machines, holographic tech, home fusion reactors, flatscreen videophones, scene screens, robotic video waiters, food dehydration/rehydration, and Diana becoming Queen.
- So Marty killed Diana?
- This would ultimately result in paradoxes. The DeLorean would never have had a hover conversion, and Doc would have never saved Clara from certain death using the hoverboard. And we wouldn't see the flying train at the end of Part III. Meaning...
- To be fair, Doc never specified that he'd taken the Time Train to 2015, only that he'd already been to "the future". Could be, he traveled into the future of our timeline well after 2015, by which point hover-conversion will indeed have been invented.
It's just all in another universe. And we don't get hoverboards like they do.
That's not to say that BTTF's future is completely different from ours. Hover tech notwithstanding, perhaps BTTF's future is aware of things like House, Futurama, Harry Potter, the iPhone, and the Internet—all slightly different, of course, and all of which go unmentioned in the film for obvious reasons. (Heck, you could even argue that the likes of Lady Gaga or La Roux had a more lasting impact on the weird fashion sense of the BTTF future than in ours—just go watch the video for "Bulletproof" and compare the singer's look to some of the people in Part II.)
- Confirmed in the comic book. Old Biff mentions having seen Jurassic Park, and Doc sees a Nirvana poster and uses the Internet (The Other Wiki, in fact) during his first visit to 2015.
- Would this then suggest that our reality is the one where the Lybians got lost on their way to the twin pines mall, Doc went back in time but was immediately gunned down by a farmer, and the DeLorean was confiscated by the US government?
However, the arbitrary speed settings were damaged with the time control microchip when the car was struck by lightning in Part II. The replacement transistors and tubes from 1955 didn't have the speed settings that the microchip had, binding the time machine to the 88 mph needed for time travel, leading to the problem in Part III.note
Word of God has it that the car jumped at the end of II because the shock wave from the lightning knocked it into a loop (hence the fiery trails looking like a double six).
- Corollary to the previous WMG: if a BTTF4 ever gets made, this is what it will be about.
- Potentially Jossed by the game - Edna Strickland (the Vice Principal's busybody sister) yells at Biff's daughter Tiff.
- Jossed further in Episode 4 by a reference to Mr. Needleman (probably Needles' grandfather), whose mind map suggests him becoming a hooligan.
- Unless Needles was born out of wedlock and Needleman is his mother's surname.
- The video call information in 2015 gives his full name as Douglas J. Needles, so it’s not a nickname. That being said, another line in the game mentions a Frankie Needles, so maybe he’s Needles’ grandfather instead.
- Jossed further in Episode 4 by a reference to Mr. Needleman (probably Needles' grandfather), whose mind map suggests him becoming a hooligan.
- The refusing to eat sugar could be typical teenager watching his weight, hence why he's drinking Tab in 1985 and asks for Pepsi Free in 1955. And in the late 1800s quality dental care was unheard of, so the gang member's comment is meant to be an aversion of Eternally Pearly-White Teeth.
- Alternately...
His family circa 1985-A can't afford to treat it/their insurance won't cover it, so he has to be extremely careful to avoid sugar (which he does) and get lots of regular exercise (considering how much running/jumping/skateboarding, etc, he keeps up on that too) in order to hold off the need for insulin and lower the chances of complications. In 1985-B, his family is simply better off and could afford better medical care for him to begin with, so he's less concerned about his diet (Hence being totally cool with eating a rabbit full of buckshot).
- But when Marty is seen talking to George the day after he breaks into his house disguised as "Darth Vader from Planet Vulcan", he's seen drinking regular Pepsi, which has sugar in it.
- Maybe Doc found out Marty had diabetes, and keeps insulin around the lab just in case, and there's some in the glove box of the DeLorean.
- And consider how much "walking" he has to do going around 1955 Hill Valley , he probably can handle some sugar.(as long as it's not too much)
- Although when Lorraine accused him of being "square" for objecting to her drinking he took a drink from the liquor, so that could be a very subtle example.
- And bearing in mind that he saw George as a complete wimp in the first timeline - being called "chicken" meant being compared to his father.
- The main theme of the first installment of each trilogy is GENE. The impetus for most of Marty's actions in the first movie is to cause his parents to marry once again, causing him to come into existence from their genes. Likewise, the second movie matches with Metal Gear Solid 2: Sons of Liberty's main theme of MEME. The consequences of information from the future traveling backwards are expanded upon and shown in detail, as Biff uses the Sports Almanac to change his past and eventually 1985. Finally, the third movie fits with Metal Gear Solid 3: Snake Eater's main theme of SCENE, since it puts the main characters in a completely different setting than any of the movies offered, and shows how that affects the other characters' outlooks. It's also like the third game in that it shows familiar character-analogues and recurring series events in a historically earlier context.
- The reason Marty and Doc have time traveled several times without screwing up enough to make any fatal paradoxes is because the sentient parts of time has grown to like them both, and cleans up parts of time to help them out. The fact that the McFly family suddenly becomes awesome, and that Doc eventually found the love of his life, was little gifts from time itself. And the reason they often get into trouble (lightning bolt hitting the DeLorean much? Biff going back in time?) is time wanting to get them into adventures both for its own amusement and them getting amazing memories.
- This is more of a weird idea I had. Concider. "Back to the Future Part III"? The DeLorean was destroyed by the train. "Citizen Brown", the third episode of the Telltale game? The DeLorean A) crashed through a billboard, apparently getting wrecked (pointing your cursor over it at the start of the game has it labeled "Wrecked DeLorean", B) had it's window broken and C) fell from said billboard, and crashed into the ground! Now, maybe it's just me, but I smell something fishy here...
- Which leads to the obvious corollary, or whatever: The fourth installment sees the restoration of the DeLorean. The obvious examples are:
- The Animated Series... although it's questionable if it's ''actually'' canon...
- The first episode of the Telltale game
- And the fourth episode, naturally.
- Which leads to the obvious corollary, or whatever: The fourth installment sees the restoration of the DeLorean. The obvious examples are:
- Jossed by the Telltale game, unless they bought a new pink Mattel hoverboard in the future for some reason.
- As stated in the movie, the Browns didn't come to Hill Valley until 1908, well after Marty and even Doc left the old west.
- And according to the Telltale games, Doc's father was very much against young Emmett's interest in science and wanted him to go into law instead.
This could potentially explain one of Doc's strangest choices...
Marty's drag-racing crash in in the original timeline would've killed the father of Hitomi Shizuki when he was still a boy visiting Issei (first generation Japanese-American) relatives in Hill Valley. Hitomi of course becomes the Unwitting Instigator of Doom for Sayaka's (and the show's) Start of Darkness. But the Ripple Effect created when Marty avoided the crash caused the crash 26 years later that injured Sayaka's love interest's (also a budding musician) wrist, and eventually leads to her contract (and eventual Witchdom...which of course sets off a Domino Effect that destroys the world in one timeline). All their messing around with the space-time continuum had of course put considerable strain on it.
Of course in the previous version where Marty does crash, Marleen becomes a Magical Girl to help her struggling family and deeply depressed father...and eventually a Witch when she's arrested trying to bust out Marty Jr. in Timeline 1a and when Marty gets fired in Timeline 1b. One of the survivors of the crash (Hitomi's would've-been second cousin) became Marty's boss at his office job, initially forgiving and taking pity on him, but nursing a deep grudge that led to Marty's firing.
Before the time machine was invented, Marty was also rather unconfident (he didn't think anyone would like his audition tape), and wouldn't have gotten in that drag race in the first place. But as mentioned above, changing the past the first time around also made him rather more cocky and reckless.
I also wish Doc had never invented that infernal time machine...
- As you might guess after watching this anime, an Incubator implanted the blueprints for the flux capacitor in Doc's head. He thought that with human nature being what he knows, humanity was simply unable to handle the responsibilities of time travel...hence it would prove a great way to harvest souls.
- And then of course Doc doesn't get the hint about the problems of time travel after the DeLorean is destroyed, even disregarding his aforementioned paraphrased quote and his previous resolve to destroy it...he builds a whole new time machine!
A man with the family name of Hill. They stopped calling it Hill's Valley after awhile out of laziness.
- This is explicitly mentioned in Number Two, the first version of the script for the second movie. There's a scene in 2015 where Marty passes by a statue portraying "William Hill, founder of Hill Valley".
- "Red" Thomas was corrupt as Mayor.
- He got on the GoK's bad side, too, which is why the Mayor in 1955 is a bum in 1985.
- A sequel coming out in 2015 is Jossed.
That's why she starts off as Claudia Wells in the first movie and has suddenly transformed to Elisabeth Shue by Part II. (Of course it doesn't explain the fact the same scene has played out twice in the subsequent movies with both actresses.)
- If that's the case, why does Marty recognize her as Jennifer? He clearly has no memories of the new timeline given how shocked he was at seeing his family and house.
Alternatively...
Originally, the second film was going to take Marty to the year 1967. Perhaps his meddling with events of that year causes Jennifer Parker to have the same father but a different mother. Marty goes back to 1985 after these events and the first scene of Part II happens a little later than it did at the end of Part I. Doc returns from the future after finding out that bad things still happen to Marty's kids, and the rest of the film takes place.
- That wouldn't have helped much, as one doesn't need the whole almanac to make a killing; just the highly improbable bets. Old Biff could have set it up so he told Young Biff to mark anything that would yield more than a 100-1 win (e.g. Cubs winning the World Series 2015), and then given that list that he compiled to Young Biff, so he could bet and win.
- Except he also did it in the timeline created at the end of BTTF1, where Marty did not "yet" return to 1955 to stop old Biff, and consequently, Doc never interacted with Marty again until Marty grew up in his proper time.
- Jossed by Bob Gale. During an interview about the game, he said that in the series, the effects of a time jump are never shown before showing the time jump itself. Meaning that LP Doc used a bulletproof vest despite living in a timeline where the events with Marty and Doc in 1885 never happened.
- While he could have avoided being shot entirely once he read Marty's note (by sabotaging the Libyans somehow, for instance, or finding another source of plutonium), it would have created a paradox - if Marty didn't see him get shot, he'd have no reason to write the note (or accidentally travel to 1955, for that matter) in the first place. Doc is too concerned about damaging the fabric of space-time to ignore a paradox of that magnitude - the only way he could survive without risking tearing the universe inside out would be by letting Marty believe the Libyans killed him long enough for Marty to travel back in time. If Marty's note mentioned that he'd been shot in the chest, he knew a bulletproof vest that could handle their ordnance would do it. He may have also managed to contrive a method of swapping their ammunition with blanks (to minimize the risk of bullet fragments from hitting something exposed or some minor change making the Libyans pull off a head shot this time around), in which case the vest was a backup in case they noticed or used different weapons than he expected.
In a new timeline, Marty's music career did not take off and Jennifer left him. He changed his name to Mike Henry and moved to New York, where he had a new wife and kids who do not look exactly like him. There will be an episode that takes place October 21, 2015.
- Except that Strickland acknowledges Doc talks about him like he's a real person.
- Or Doc Brown is his real name.
Alternatively...
- It's not so much that his memories or personality rippled, it's that deep down Marty was always a self assured jerk to the point of arrogance but he grew up afraid to take a chance. After time traveling, not only did he now feel like a bad ass, seeing his new future where he grows up wealthy and happy flips a psychological switch in him, bringing out that aspect of his personality.
- Based on this and the fact Marty stayed in 1955 for a whole week before returning to the very same day he left, it took exactly one week after Marty's return before George, Lorraine and Biff to remember how their lives used to be before Marty messed with their past. Remembering a former life as a white-collar worker who made a living by taking credit for George's work must have compounded 2015 Biff's bitterness. He probably also figured out Doc's Time Machine is the reason his life changed and decided his own attempt to change his past would be a case of "two wrongs make a right", or "left" if nobody corrected him on that specific saying. Upon checking records of his life prior to 1985, Biff figured out when his life became different from what he remembers and it was no mere coincidence that his 2015 self went to the day of the dance that made George and Lorraine a couple.
I may be overthinking things here, but it is in my nature.
This might seem like an obvious statement, because changes in the past should only progress forward linearly, but it has implications for time travelers. Essentially, changes to the timeline do not affect time travelers further back in the past. Objects (such as newspapers, matchbooks or photograps) and people from the future will change as history is altered but (as is seen in the movie) the changes only occur after interference in the past.
First, consider the implications of the 1985A of Part 2. With the Doc of that timeline institutionalized, the Marty of the timeline (supposedly in Switzerland) is unlikely to have taken accidental trip back to 1955 (and he would certainly have no flyer soliciting donations to save a clock tower that no longer exists). Nonetheless, when Marty and Doc go back to 1955, the Part 1 Marty is still there and going through the same events as in the first movie. This might seem like a paradox, but it makes perfect sense if changes to the timeline only go forward: Biff did not change history until November 12, so Marty's arrival on November 5 and all of the events that followed remain part of the past. This also means that, if asked, that Marty would always report that his father is a wimp and that Biff trashed the car; the change to his parents' histories did not change until after his arrival, so he would always remember his original history.
Note that the original Marty's continued existence after Biff's book delivery can be attributed to a Delayed Ripple Effect.
Based upon this hypothesis, Biff could have retroactively prevented Marty's first trip through time if he had given himself the book some time before November 5, 1955. Doing so would have allowed the timeline changes that his actions created to reach November 5, thus erasing Marty's trip from history altogether. Since he chose November 12, though, the changes that he made could not ripple "back" to November 5, preserving Marty's presence in that past.
This also explains why Doc in 1885 does not know of his impending murder by Buford Tannen despite his younger self learning of the event in 1955. When he was accidentally sent to the past, his younger self knew nothing of those events. If changes to the timeline only move forward, the Doc of 1885 would only know of his history as it was before he was sent back in time; he would not be aware of any changes that were made after he left 1955. Possibly, Doc's memories were adjusted once he traveled to some point after 1955.
I admit that this is not a perfect explanation, as it does raise some questions.
That theory being true proves Doc right when he told Marty that going back to 2015 to prevent Old Biff from stealing the Almanac and the Time Machine wouldn't undo the harm he caused by doing so.
One question: If asked before his time travel adventures, the Marty of the post-BTTF1 1985 would probably report that his parents are successful and that Biff runs an auto detailing company; what would happen, then, if a time traveler stowed away in the DeLorean on the night of Marty's first trip through time and then, once in 1955, asked Marty about his parents? Based upon my above hypothesis that the Marty in 1955 is always the same, this would create complications. Still, an argument could be made that stowing away in the DeLorean itself changes history as of 06:00 on November 5, 1955 and thus it could update the Marty of that time. On the other hand, it could create a Time Crash.
Now, keep in mind, "Needle's Story" (the issue that came out before this series and detailed Needles meeting Marty in 1979) ended on Needles in jail, telling Marty that he's coming after him once he gets out. Call me nutty, but I seriously think Needles, once out, is going to stumble across a time machine, most likely the DeLorean, go back to 1979, and go after Marty then. The plot of "Hard Time" most likely is about the repercussions of Needles altering Marty's past.
- I've long had the following theory about the events of the sequels: I think Doc's main goal in bringing Marty to 2015 with him wasn't to rescue his children from disaster but to teach Marty a lesson about the consequences of peer pressure, hoping that it would scare him into avoiding the accident that ruined his future. Consider the following:
- At the end of the third film we learn that the pivotal accident was set to occur later the same day from the point Doc whisked Marty and Jennifer to the future at the beginning of the second film. That's why he was so frantic that they should come with him immediately (and not, say, wait at least a few months to recuperate from their previous adventure): he was trying desperately to get Marty away from the disastrous event, so that at least he'd have some extra time.
- It's heavily implied that Doc knew about the accident the entire time, but chose not to tell Marty. When Marty asks Doc "Do we become assholes or something?" Doc hesitates for a moment then nervously says "No no no no, you and Jennifer turn out fine." This is a a subtle difference with the way the scene was filmed in the first movie (when the creators reportedly had not yet planned for sequels). In the first film, he sounds utterly sincere when he speaks that line. In the reenactment of the scene at the beginning of the second film, he sounds like he's hiding something.
- Why didn't he tell Marty straight out about the accident? He explains it during the scene from the third film where he's arguing with Marty about his decision to duel Buford, and he blurts out about the accident, before stopping himself and commenting, "I can't tell you. It might make things worse." If Marty finds out about it, Doc reasons, he might manage to avoid that particular catastrophe. But his bad habit of submitting to dangerous dares would remain, and with the future thrown into flux, for all Doc knows something worse might happen than the accident—he might even end up dead. Doc decides that his only hope of preventing the accident or anything comparably terrible that Marty might do to himself is to get him to grow out of his bad habit. That's what ultimately ends up happening by the end of the third film, albeit not quite in the way Doc anticipated.
- On the other hand, to save weight and cost, there's no reason not to make the passenger compartment/engine bay tub out of composite materials. It would also make it easier for Doc to electrically isolate the car's electrical system and prevent it interfering with the time machine functions.
The only major difference is that in the Twin Pines timeline, he doesn't relate to his crappy family and has learned not to depend on them more than he has to, while in the Lone Pine timeline, he's confident in himself, but he's also under a lot of pressure to succeed the way his dad did. Since his dad famously refused to back down from a fight, Lone Pine Marty becomes oversensitive to accusations of cowardice because he's trying to live up to George's example.
Obviously, the films are all canon to one another. The some of the recent comic series by IDW fills in some of the gaps in the timeline (such as how Doc and Marty "meet" originally in the 1980s) and even adapts the story of the Telltale game for the storyline "Citizen Brown", which Bob Gale had a hand in for creating and himself considers it as a "Part IV." Now, you're probably thinking, "Where does the animated series fit in? And how?" Well, at the end of the game, Doc and Clara maintain a part-time residence in Hill Valley in 1986. And we know that Doc and Marty still have the DeLorean, and Doc clearly must have the Time Train stashed somewhere whenever he's staying in 1986. And seeing both are intact, and that Doc and his family has a residence in Hill Valley, that could set up the animated series. After the ending to where they jump to whenever, Doc and Marty come back and eventually, Doc and Clara decide to relocate closer to where Doc has the Time Train stashed, and have a bigger plot of land for Jules and Verne to play on and a bigger garage for Doc to perform experiments in. Of course, this allows Doc to be able to update the DeLorean several times and gives it features that could come in handy.
Yeah, there's a lot of holes in the idea, but it does present an intersting scenario.
- Also, this can explain the existence of The Institute of Future Technology in the BTTF ride, as Doc continued with his time travel experiments and inventing items after the events of 1986, leading to the foundation of the Institute.
- Additionally, any inconsistencies or contradictions between the different works could be explained as future time travel slightly altering the past.
- Hill Valley has a memetic effect that makes it very difficult to leave the city, which is why several generations of the same family have remained there for centuries.
- Biff's actions in Part 2 constituted a containment breach, which is why Doc was so adamant about Marty retreiving the Almanac.
- It's never stated but he seems to possess the symptoms of it. He's socially awkward. He is a genius in a particular subject. He is misunderstood by the town. Doc is an undiagnosed Aspie.
This implies the following sub-guesses:
- The first film is a bit of Dramatic Irony for Marty; he's completely unaware that he can just hop in the time machine, hit "Last Time Departed", and go back to his former life (and not the Close-Enough Timeline he creates) without having to take any action to get his parents back together. The problem is that nobody told him this was possible; Future-Doc got shot before he had a chance to explain it (and was never planning to send Marty to the past anyway), and Past-Doc hasn't built the time machine yet and doesn't know it contains that function. It is kind of a moot point, because (1) Marty still has to wait for the lightning storm to even be able to power the DeLorean and is at risk of the Delayed Ripple Effect catching up to him while he's still in the past, (2) he actively refuses to use LTD so he can buy himself time to save Future-Doc from getting shot, and (3) he clearly prefers the Close-Enough Timeline in any event.
- It resolves an inconsistency in what happens when you travel forward in time. The films show different things; in Part I, when Doc sends Einstein one minute forward in time, Einstein never encounters a future version of himself, but when Marty goes forward in time in Part II, we see that there is a Future-Marty. But one would expect, from Einstein's example, that Marty would have gone missing in the future. But LTD can explain it. In Einstein's case, with no LTD, he disappears for the length of his minute-long journey. In Part II, Doc had already travelled to 2015 without Marty and encountered a version of Marty who lived out the next thirty years. Not liking what he saw, he went back to 1985 to collect teenaged Marty and then hit LTD so that he would return to the exact version of 2015 he left — which contains a Future-Marty (and therefore Marty Jr.). It resolves the problem of how you can "extrapolate" what your future self would have done had you not gone forward in time — the only way to do this is to travel with someone else by LTD, and that "someone else" would have already seen it.
- Old Biff uses this function to return to 2015. He maybe doesn't understand what he's doing, but it's vitally important. Without LTD, the Ripple Effect would erase him from existence once he arrives in 2015, because he gets killed in the Bad Future's 1996 and he shouldn't exist in 2015 anymore. But with LTD, he doesn't suffer any of the consequences of his trip to the past — one of which would be no DeLorean. Without the Delayed Ripple Effect (and its inconsistent application), it explains how the DeLorean doesn't fade out and allows Doc and Marty to leave 2015. (This guess, of course, requires us to disregard the Deleted Scene in which Biff fades out once he arrives back in 2015, suggesting the Ripple Effect did catch up with him. Let's just say that scene was deleted for a reason.)
- As for why Doc and Marty do encounter the results of Old Biff's time journey, there are several possibilities:
- The first is a limitation of the LTD protection — it only works on the people who make the journey. Doc and Marty are inattentive and don't notice that LTD is set to 1955 and not 1985, so they use regular time travel and suddenly encounter Old Biff's changes.
- The second is that LTD only works once per timeline. It's possible to "undo the undo" — if you were to LTD and then go back in your original direction, the changes you made would reassert themselves. Perhaps there's a setting that Old Biff unintentionally tripped to cause that to happen.
- The third is that Old Biff figured out how to change the Last Time Departed. He was only concerned about Doc and Marty finding out that the DeLorean had been stolen, so he changed LTD to the original 1985 departure date as it was when he stole it. He sees it like rolling back the odometer to obscure a joyride like in Ferris Bueller's Day Off, but he somehow managed to shift LTD from 1955 to 1985 in the same timeline, which is as he left it — with himself in charge. Doc and Marty hit LTD without noticing anything suspicious — and are in for a nasty surprise when they arrive.
- LTD may also enforce a little San Dimas Time. In the Part II example, Doc and Marty (and Jennifer) leave 1985 in the morningnote , but they return to 1985 in the evening. If they used LTD, they should have arrived in the morning. But it works that LTD takes you not to the exact point you left, but rather a certain amount of time later — the exact amount of time you were gone. And given that they spent most of the day in 2015, they'll have wasted most of the day in 1985. The two trips to 2015 are the only other uses of LTD that we see, and both plausibly run on San Dimas Time — Old Biff got out of 1955 as soon as he could and returned to 2015 soon after he left, and Doc is pretty frantic in 1985 trying to get Marty and Jennifer on the move because if they're too slow, LTD will make him miss his window to intercept Marty Jr. in 2015. If this isn't a requirement of the Timey-Wimey Ball, Doc may have included this feature on purpose to prevent awkward questions of aging.
- Really, there would be no need to go forward in time to fix one specific problem in the future (which could just as easily be undone as soon as they got back) when it would be easier simply to tell Marty and Jennifer what was going to happen in advance.
- It also wouldn't be necessary to knock out Jennifer for answering too many questions, leaving her to be picked up by police and trapped in her future home.
- And then he has an argument with Marty over the almanac, claiming it's a misuse of future knowledge, resulting in him angrily and nonchalantly throwing the book in a trashcan, only to be picked up by Biff. If Marty had kept the almanac, he would certainly be less likely to use it for nefarious purposes than Biff ever would. If the Doc had kept the almanac to destroy it safely and properly later, Biff wouldn't get his hands on it. There would then be no need for the alt-1985 and 1955 segments, and the dangerous attempt to wrest the almanac off young Biff in the middle of a thunderstorm wouldn't have left the Doc trapped in 1885.
Marty is an impressionable Hard Rock loving teenager who sees the documentary, which includes Nigel Tufnel's demonstration of his famous amplifier that goes up to eleven. Marty is suitably impressed; seeking that extra boost for his own music, he looks up someone in Hill Valley who can build equipment for him. And sure enough, Doc is indeed advertising his services in this field (look at the sign outside his garage in 1985). Marty finds Doc, introduces himself, and asks for an amplifier that can go up to eleven like Spın̈al Tap's. Doc sets Marty straight about the problems with his (and Nigel's) thinking, but does so in an informative and entertaining way so that Marty doesn't feel that stupid. The pair take a shine to each other, and Doc invites Marty to help him build a mega-amplifier anyway — which Marty sneaks in to test in the very first scene of the film.
But in the Lone Pine timeline, Doc has had experiences his Twin Pines timeline counterpart has not. He's seen the potential consequences of messing up the timeline (Marty nearly erasing himself from existence) and also the terrorists' threat to his own life, which he's prepared for. This Doc is much less likely to take chances of any sort than the original Doc.
Of course, by the end of Part III, and after the obvious passage of many years, his regrets about ever having made the time machine (as of Part II and most of Part III) are allayed. After all, everything worked out fine and he has a happy life with a wife and kids... so he thought, "What the hell!" once more, and made a locomotive time machine...