On time travel in "Back to the Future"

**25-TO-30-YEAR-OLD SPOILERS HEREIN**

By now, you’ve probably seen hundreds of things talking about all the stuff Back to the Future Part II got wrong about today: hoverboards (at least commercially available ones); garbage-powered flying cars; the Cubs winning the World Series (this one is still possible, but as things stand at publishing time, it’s not looking good for the Cubbies). What you’ve probably not seen and might not remember, and what has bothered me since I first saw the film years before it was obvious its predictions would be way off, is the fact that it makes some pretty obvious time travel mistakes. 

I count at least two just from memory:

1. When Marty McFly (Michael J. Fox), Doc Brown (Christopher Lloyd), and Jennifer (Elizabeth Shue) travel to 2015 from 1985, they see older versions of Jennifer and Marty, as well as their kids. Well, if they really traveled to the future, they would not see themselves, nor would they have any kids. Because by traveling into the future, they would create a timeline in which, from the point of view of everybody else, they vanished off the face of the Earth in 1985.
2. After old man Biff (Thomas F. Wilson) altered the timeline to make himself rich and powerful, Marty suggests they go back to 2015 and stop him from stealing the time machine. Doc says they can’t because if they traveled into the future from alternate 1985, it would be a different future than the one they visited. So why was old Biff able to return to the same 2015 from which he left after going back to 1955 and giving his younger self the sports almanac?

There are other reasons the second entry is the weakest in the trilogy (the jarring shifts in tone, the half-gimmicky, half-lazy decision for the final act of the picture to overlap with its predecessor), but its blatant sci-fi errors are what stick out the most. My guess is that the filmmakers were so determined to create a more complex and ambitious time travel plot that they overlooked some pretty simple inconsistencies.

Conversely, however, the first and best Back to the Future seems to have the simplest time travel plot of the three. But after some careful watching and analysis, it has the most complex (and certainly the coolest) possibilities, advertently or not.

As viewers may recall, the first movie opens in 1985 with Marty in a less-than-ideal living situation. His father (Crispin Glover) is a pushover still bullied by Biff, and his mother (Lea Thompson) is an alcoholic. His adventure in 1955, however, alters the future so that his parents are rich and successful. But before he finds that out, upon his return to 1985, he witnesses himself escape back in time from the Libyan terrorists.

My theory is that in 1955, the timeline wasn’t altered by Marty’s arrival, but split in two. In one (we’ll call it “Timeline 1”) the McFly family is lower middle class and beset by personal struggles. In the other (“Timeline 2”), they’re much happier and better off.

The Marty of Timeline 1 went back to 1955, and his interference with history led to the creation of Timeline 2. When he witnesses himself going back in time in the mall parking lot, he’s looking at an alternate Marty, for whom Timeline 2 is the regular timeline, and who grew up in wealth and privilege. We don’t know for sure, but it’s possible this Marty’s interference in the past resulted in the creation of Timeline 1. In effect, the two different Martys switched timelines.

In such a scenario, the Marty who grew up in Timeline 2 is in for a sad surprise when he returns to 1985. It kind of sucks for him, but imagine he’s a spoiled, snotty rich kid, and it actually becomes a little satisfying.

Extensive time travel pondering aside (and I haven’t even touched anything from the Western-era Back to the Future Part III), all three films are tons of fun (even the jagged second one, despite my criticisms, is far from a bad movie).

Happy Future Day!

The Ride was pretty great, too. R.I.P.

Update (10:40 PM): And, the Cubs have been officially eliminated from the playoffs. I'm a White Sox fan, so I'm not too upset. But I still want my flying car that runs on garbage!