A theory revolving around the reason Doc Brown time-traveled with Marty McFly to 2015 in Back to the Future Part II recontextualizes the doctor's actions in the film, and it makes a lot of sense when you stop and think about it. Doc and Marty's time-traveling adventures always put the pairing in precarious situations with life and family-altering implications within the universe.

The second Back to the Future film, whose future is now 10 years our real-world past, features the iconic duo of Doc and Marty traveling to 2015. Ever since the release of the sequel in 1989, it has been believed Doc Brown took Marty McFly to the future to prevent a specific incident from occurring. With that being said, a new fan theory suggests there might've been a very different motivation behind it.

Doc Was Trying To Save Marty, Not Marty's Kids, In 2015

While Doc Brown Told Marty He Was Trying To Save His Future Family, He was Actually Trying To Help Marty Himself

Back to the Future Part II begins with Doc Brown roping Marty McFly and his then-girlfriend, Jennifer Parker, into another time travel adventure. This time, the crew doesn't travel back to the future, but further into the future instead, 30 years exactly from 1985 to 2015. Doc Brown's reasoning for pulling Marty into this escapade is simple: to save his future family from falling apart.

Doc Brown pinpoints a central event as the genesis for all of McFly's troubles in the future timeline. Doc states that everything bad that happened to Marty's family was because of this single event, causing a chain reaction that spiraled out of control, which is why they need to prevent it from ever happening. The event in question? When Marty Mcfly's son, Griff Tannen, the grandson of Biff Tannen.

Doc's True Mission Explains Why He Couldn't Tell Marty About The Rolls-Royce Accident

Marty McFly's Robbery Was Not The True Inception Of The McFly Family's Downfall

Doc Brown might have told Marty everything began to fall apart for the McFly clan because of Marty Jr.'s foray into crime, but in actuality, their outlook on life was already subpar in 2015. The reason for this stems from Marty's drag race with Needles in 1985, spurred by Marty being called "chicken." The race ends poorly for McFly, crashing into a Rolls-Royce.

Doc Brown recognizes Marty's obsession with retaliating when called "chicken" as his biggest weakness, prompting him to intervene.

Marty McFly grew resentful after this event. During the crash, Marty's right arm was broken, leaving him unable to play his beloved music anymore. Because of this, Marty started to feel sorry for himself, a sentiment that would follow him 30 years into the future in 2015, when he was married with children. Doc Brown recognizes Marty's obsession with retaliating when called "chicken" as his biggest weakness, prompting him to intervene.

A highly perceptive Reddit theorizes Doc Brown is playing the role of one of the ghosts from Charles Dickens's A Christmas Carol because two film adaptations of the story were released in 1984, the year before Back to the Future's main timeline is set. Their fan theory argues that Doc represented the Ghost of Christmas Future in that he was trying to get Mart to change his ways without being forthright about his future. Because of this hypothesis, Doc Brown couldn't tell Marty about the incident with the Rolls-Royce, leaving Marty to learn the lesson for himself later and change.

Doc Did For Marty In Part 2 What Marty Did For George In Back To The Future

Doc Brown Takes On The Role Marty McFly Did In The First Back To The Future, Helping Someone Make A Lasting Life Change

Suppose the theory about Doc Brown implanting the mindset in Marty McFly is to be believed. In that case, it serves a highly similar purpose to what Marty McFly does to his father in the original Back to the Future. Marty's dad, George McFly, wasn't exactly the toughest guy in school when Marty met him in 1955. Because of this, and Marty's future mom Lorraine unwittingly falling for her son, he has to scheme to get his parents together so Marty McFly won't be erased from existence.

Marty McFly succeeds with his plan, which features George standing up to Biff, his school bully, and finally landing the girl of his dreams. Doc Brown's actions in Back to the Future Part II serve a similar purpose. Unbeknownst to Marty, Doc insinuates the idea in his head that the source of all McFly's troubles comes from Marty's aversion to being called "chicken," leading to the eventual downfall of his family. Marty might not have known it then, but Doc Brown led him to alter his methods, which saved the McFly family from a world of hurt in the Back to the Future Part II.