This is the final post in my Back to the Multiverse series, where I apply the mutliverse theory to the Back to the Future trilogy. In my first and second posts, I used examples from the first two films to describe why the travels of Marty did not make sense when applying traditional time travel rules, but became more logical when you apply the principles of the multiverse theory. I will now conclude my series by breaking down the third and final film.
The film begins in 1955, with Marty McFly stranded in the past with the knowledge that Dr. Emmett "Doc" Brown is trapped in the year 1885. Marty and Doc's 1955 selves use the information in Doc’s 1885 letter to locate and repair the DeLorean. Admittedly the existence of this letter and the information it contains does appear that time travel is involved. Nevertheless, we cannot ignore the fact that there are to many inconsistencies throughout the films to believe that this one example makes the time travel theory plausible. In reality the Doc who wrote the letter was from an alternate universe where he was accidentally transported to another timeline and the DeLorean was rendered incapable of further travel. While this may require a leap of faith, be patient, a better explanation is coming.
While retrieving the car, Marty spots a tombstone with Doc's name, dated six days after the letter, and erected by his "beloved Clara". According to the Tombstone, Doc was killed by Biff Tannen's ancestor, Buford "Mad Dog" Tannen. Ignoring the fact that the Tannens have been terrorizing the McFlys and Browns for generations for no apparent reason, Marty decides to go back to 1885 to save Doc. Doc repairs the time machine, replacing the transistors for vacuum tubes, and Marty jumps again to another alternate reality, but farther in the past then he has ever gone before.
But what happened to the Doc he left behind? 1985 Doc never once mentioned that he ever knew that there is gravestone bearing his name in a cemetery in Hill Valley. Consider the psychological impact of knowing that you are buried not far away from where you are living right now. Perhaps this Doc would be terrified enough by his impending death in the past that he may decide never to build the time machine. I cannot confirm this fact, since the time travel premise the films try to present would make you believe that Doc still went ahead and built the DeLorean.
Yet if we remember what happened at the end of the first film, where Doc apparently read Marty's letter explaining to him that he would be shot in 1985, we could now have an explanation of why Doc decided to read the letter after all since he was already petrified by the idea of impending death. This may also explain why he took part in that therapy in the future that added a 30 to 40 years to his life. Again this idea seems to support the time travel theory over the multiverse, but the films provides a number of contradictions that will in the end make you favor the multiverse theory over time travel.
Marty arrives on September 2, 1885, in the middle of a United States Cavalry pursuit of Native Americans. While evading the pursuit, the DeLorean's fuel line is torn, forcing Marty to hide the car in a cave and walk to Hill Valley. En route, Marty meets his Irish great-great-grandparents, Seamus and Maggie McFly. Again we see Marty beginning to make small, but still noticeable, changes to history. For example, he calls himself Clint Eastwood, after the American actor of the same name. Even this simple deception will have major changes to history. Consider how different the real Clint Eastwood's career may have been if there was another historical Clint Eastwood who was also cowboy. The legend of this other Clint Eastwood perhaps may ruin his chances of becoming a famous Western actor. Let us also not forget the butterfly effect. The changes Marty is making is likely to ruin any chance of himself, his family, Doc and many other characters from the last two films from ever being born. Yet Marty continues to exist and his memories of the real Clint Eastwood do not change.
Back to the film: in Hill Valley, Marty runs afoul of Buford and his gang. Buford tries to hang Marty, but Doc saves him by using his steampunky sniper rifle to shoot the rope. Doc agrees to leave 1885, but with the DeLorean out of gasoline, there is no way to accelerate the car to 88 mph. Doc devises a scheme to use a locomotive to push the DeLorean up to speed. As Doc and Marty explore the rail spur they intend to use, they spot an out-of-control horse-drawn wagon. Doc saves the passenger, Clara Clayton. The two fall in love, finding many common interests, especially the works of Jules Verne.
Let us stop here for a second. We learn from Doc and Marty that Clara was supposed to die when her wagon fell into the ravine, hence why both Doc and Marty remember the ravine being called "Clayton Ravine" from their reality. Yet in another timeline Doc saves Clara, without the help from Marty, since the Doc whose tombstone Marty found in 1955 mentioned a Clara. How do we reconcile these conflicting realities (one where Clara dies, one where Clara is saved by Doc and one where Clara is saved by both Doc and Marty) and the unchanging memories of Doc and Marty. Only the multiverse theory makes sense. The Marty and Doc we see on screen both originated from a timeline where Clara died by falling into the ravine. The 1955 that Marty just arrived from and an alternate Doc was buried in was timeline where the ravine was known as "Shonash Ravine". The timeline they inhabit now is likely to be called...well we will get to that.
Back to the film: Buford tries killing Doc at a town festival, but Marty intervenes. Buford then goads Marty into a showdown in two days' time. Consulting the photograph of Doc's tombstone, they note that Doc's name has disappeared, but the tombstone is otherwise unchanged. Doc tells Marty that the tombstone represents the events of the future, and warns Marty that he, not Doc, might be killed by Buford. Doc is mistaken, however, because this is another example of the self-correction attribute of the multiverse and is more evidence that it may be done by an intelligent force that is waiting to see what the existence of foreign people and objects will do before the reality begins to right itself.
The night before their departure, Doc tells Clara that he is from the future, but Clara believes it is an excuse to end their relationship and spurns him. Doc returns to the town saloon to get drunk, but Marty rides to the saloon and convinces Doc to leave with him. However, Doc drinks a single shot of whiskey and passes out. Buford arrives and calls Marty, who realizes his reputation is unimportant and refuses to fight.
Doc revives after being force-fed the bartender's special "Wake-Up Juice" and tries fleeing with Marty, but Buford's gang captures Doc, forcing Marty to fight. Marty uses a firebox door from a stove as a bullet-proof vest (an idea he got from watching a Clint Eastwood film), and then hits Buford in the face with it. During the fistfight that follows, Buford destroys the tombstone and is arrested causing the picture to lose the image of the tombstone once and for all. Marty and Doc depart to hijack the locomotive. Buford is arrested, which is something that Doc and Marty's research in 1955 never mentioned. History is again changed, yet Marty nor Doc express any of those changes, another point for the multiverse theory.
Clara is leaving on the train when she overhears a salesman discussing a man he met in the saloon, despondent about his lost love. Realizing the man is Doc and that he loves her, Clara triggers the emergency brake and runs back to town. She discovers Doc's model of the time machine and rides after him. Clara boards the speeding locomotive while Doc is climbing towards the DeLorean. Doc encourages Clara to join him, intending to bring her to 1985. As she climbs to Doc, the overheated locomotive boiler explodes. Clara falls and is left hanging by her dress. Marty passes the hoverboard to Doc, who uses it to save Clara. They coast away from the train as the DeLorean disappears through time, while the locomotive roars over the edge of the incomplete bridge and is demolished.
Marty arrives on October 27, 1985. He leaves the powerless DeLorean to be destroyed, on Doc's instructions, when a freight train strikes it. Marty returns home, discovering that everything has returned to the improved timeline (I mean who really wants a spineless father and an alcoholic mother when you can have new and improved parents). In reality, Marty simply arrived to the closest analog to the sum of his actions in the multiverse. We see from the film that Clara/Shonash Ravine is now named Eastwood Ravine. Marty is just as surprised as anyone would be when they realize that a place that has been named one thing their entire lives is suddenly renamed overnight. Who was this "Eastwood" that the Ravine was named after? Was it a Marty from another timeline who was spent some time in this reality's 1885? Did he succeed in jumping to another reality, or did he fail and die? We will probably never know, though Marty may one day look the historical Clint Eastwood up and be very surprised by what he finds and how the rest of his timeline reacted to his exploits.
Marty then finds Jennifer sleeping on her front porch. Later, he uses the lessons he learned in 1885 to avoid being goaded into a street race with Needles, avoiding a potential automobile accident. Jennifer opens the fax message she kept from 2015 and finds that the message regarding Marty being fired has been erased, thus the multiverse takes care of that last loose end being the good deus ex machina that it is (though perhaps it is just a bored alien space bat sitting in a cubicle going through the days "Human Correction Protocols").
Marty takes Jennifer to the time machine wreckage. As they survey the remains a WTF moment occurs when a steampunky locomotive equipped with a flux capacitor appears, manned by Doc, Clara, and their children, Jules and Verne. Doc gives Marty a photo of the two of them by the clockworks at the 1885 festival. Jennifer inquires about the fax, and Doc tells them it means that the future has not been written yet. After the Browns bid farewell to their friends, Doc’s train converts into a hovertrain and roars off into an unknown timeline.
How do we explain this? Honestly? Are we to believe that Doc was able to create another time machine by himself when the Doc who wrote the letter needed the assistance of his 1955 counterpart to repair the DeLorean? How was this Doc able to do what other Docs could not? This is probably one of the least plausible things to happen in what is already an implausible film series. In my humble opinion, the only way Doc could have created this new device, was with the help of others.
He probably convinced the United States government, wealthy industrialists and/or 19th century scientists to help him in this endeavor. It probably would have been very easy for Doc to prove to them that he really was from the future. All he had to do was show them the hover board. So they probably helped Doc, but not for free. Doc likely gave them knowledge of future technology in exchange for their assistance. The 1885 reality this Doc left behind is likely much more advanced than our own. Consider the implications of what Doc could give them. Ignore time/multiverse travel for a second, and think about flight, computers and nuclear power. What did Doc do to this reality?!?! And what will they do once they make their own multiverse machines? I am afraid of whatever intelligent being(s) who regulate the multiverse would do when multiverse exploration increases a hundred fold.
I hope you all enjoyed my Back to the Multiverse series. Do not mistake my sometimes sarcastic commentary on the film for someone who does not enjoy the Back to the Future trilogy. I have always been a huge fan and I hope you liked reading my fan theory as much as I liked writing it.