Monday, April 5, 2010


Don't judge me.

Okay, I don't feel like writing much about the plot (pretty thin, with not very sympathetic characters) or the comedy (actually, a lot of it was pretty funny). But I do want to talk about the philosophy of time travel in this flick.

I know the point isn't to obsess over the rules of time travel, just let it go and enjoy the movie. I can't help it, I'm a physicist with a fondness for time travel movies. After all, I once reviewed a movie (scroll down to TIMECRIMES) by providing a Feynman diagram. In fact, I've been thinking for some time of doing a project of Feynman diagrams of famous time travel movies. I also ranted about how poor time travel logic ruined the suspense in TERMINATOR SALVATION, completely ignoring all the other elements that ruined it. Okay, I'm a time travel logic geek (saddest day of my life was figuring out BACK TO THE FUTURE was not really a time travel movie). So, completely ignoring the use of a hot tub as a time machine (silly, but no more ridiculous than a phone booth or a DeLorean), what's the logic when our heroes go back in time? Warning, there will be spoilers:

4 guys (3 old friends and one nephew) go back in time 24 years. To themselves, the 3 old guys look like their 40-something selves. But to other people (and in the mirror) they look like young versions of themselves (they feel young, too). This leads to the first problem--shouldn't the young guy not exist, or be a ghost only they can see, or something? They actually mention this once, then ignore it. But the logical inconsistencies start there. In the meantime, he flickers in and out of existence, a sign that something they do or do not do there will result in or prevent him being born.

Although the characters express the "Butterfly Effect" ethos--don't change anything or the future will be destroyed--they don't really stick to it much. However, there's a sort of force that makes plot-relevant events happen no matter what--John Cusack's character gets stabbed in the eye, Rob Corddry gets the crap beaten out of him, and it seems there's nothing they can do to stop it. However, other major things can and do change.

Then in the end, when Chevy Chase finally fixes the hot tub time machine, 3 of the characters go back and one stays behind. That--along with everything else they changed, drastically changes the future. That's fine, and it's fine that characters from the 80's remember them when they meet again in the 00's and recognize they've come back in time, although it would be a jarring change for them. The only thing that bugged me there is the characters who don't age in twenty years.

Again, I know I shouldn't care about any of this. I know it's a lazily scripted, silly little piece of fluff. But I can't help but notice the time travel logic is lazy, silly, and ultimately doesn't work, too.

Running Time: 100 minutes
My Total Minutes: 179,997


tim m said...

Unfortunately, there's a lot of bad science in movies. A friend from college became the science advisor for one of the Star Trek series (he has a PhD in applied physics) in part because he was recruited by a mutual acquaintance, who was a writer for the show.
Why do you say Back To The Future isn't a time travel movie?

puppymeat said...

This is exactly why you shouldn't overanalyze, because this ruins one of my favorite movies. But here goes:

BACK TO THE FUTURE is not space-time diagrammable.

When Marty McFly travels back to 1984, he causes the universe to "branch off" and everything after that point is different from what his universe originally was. Another way to say that is he didn't travel back in time (in his universe), he traveled to an alternate universe that happened to have the quality that it shared an exact timeline with his universe up until the point he entered it. This leads to a major logical inconsistency:

1. Why would anything that happened in the future of the second universe affect what happened in the first? I.e., if he's not born in the second universe, how does that make him not born in the first? You can diagram it as two universe, or even one universe with two (or more, counting the sequels) branches. But you have to draw an extraneous dashed line for action across universes to threaten his birth in the first universe.

Bottom line, it's not Feynman diagrammable, ergo it's not logically consistent time travel.

Now 12 MONKEYS, there's a time travel movie.

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