Marty McFly and his girlfriend Jennifer Parker traveled to 2015 in Back to the Future Part II, but their existence in two separate timelines has become a img of confusion among viewers. Michael J. Fox reprised his role as Marty for the Back to the Future sequel, with actress Elisabeth Shue taking over the part of Jennifer. Picking up from the events of the 1985 original movie, Marty and Jennifer agreed to travel to the future with Doc Brown (Christopher Lloyd) to help the couple’s future children. Jumping to 2015 from 1985 had dire consequences, but it also unearthed a long-term debate within the franchise canon.
Time travel is never an easy concept to pinpoint in storytelling, and the same can be said with the Back to the Future franchise’s focus on jumping through time and space. On the surface, the series followed a young man tasked with repairing moments in the past and future to stabilize the present-day timeline in 1985. Diving deeper, Marty and Doc’s time-traveling journey introduced eight different timelines with the threat of paradoxes. Understandably, some details regarding the altered timelines were questionable from a logistical standpoint, but the intricate story was enough to make up for the supposed continuity issues.
One debate that still has a history of popping up stemmed from Marty and Jennifer’s trip to 2015. The first act in Back to the Future Part II focused on preventing Marty Jr. from partaking in a robbery that would destroy the McFly family’s fortune. During the mission, the older version of Marty and Jennifer came into play, in addition to the presence of the pair’s two children. However, viewers questioned how Marty and Jennifer could exist in 2015 if they left the year 1985. By leaving the universe, the pair shouldn’t have been present in 2015, nor would their two kids. While some have labeled the Back to the Future story direction a plot hole, others have argued how Marty and Jennifer could exist in 2015.
Those convinced that Marty and Jennifer’s simultaneous existence was a plot hole have primarily used the evidence surrounding their departure from the universe. Based on the alleged time travel rules, the pair would have ceased existing once they left the year 1985. This was proven when Einstein was sent one minute into the future in the original film. For his short time travel journey, the dog didn’t exist in 1985 until he returned. Following that track, Marty and Jennifer wouldn’t have existed in 2015 until they returned to the year 1985.
On the other hand, some viewers have suggested that there were always lag times connected to events in time travel. Marty and members of his family didn’t begin fading when he traveled to 1955 until several hours had passed. If Marty and his girlfriend remained in the 2015 timeline for longer in Back to the Future Part II, it’s possible the older versions of themselves would have started fading from existence based on the paradox being formed. There was also evidence suggesting that the future wouldn’t have been changed until Marty and Jennifer returned to 1985. The pair always had plans to return to the present, and since the future’s outcome depended on the events of the time they left, there was no reason to prevent their existence in 2015. The popular franchise may never clarify the franchise’s rules for time travel, but it’s still important to look at different sides of the debate regarding plot holes.