For a long time, Back to the Future, Part II was my favorite movie of the trilogy. It was only with time and multiple viewings that I realized how bad it is, and how good the first one was--even Part III was more internally consistent. Here's why:

[NOTE: I'm assuming everyone in here has seen the movie. If you haven't, and wish to, read no further.]

When the Biff of 2015 steals the time machine, not only does he figure out how to use it with apparent ease, but he comes back to 2015 without a hitch (well, until he presumably dies after getting out). Yet, when Marty and the Doc go back to the "altered" 1985, and Marty suggests going back to 2015 to stop Biff from getting the book, Doc tells him that they can only go forward to the future of the alternate 1985. If so, Biff should have been *equally* unable to return to Marty and Doc's "good" 2015; indeed, they would have never gotten the time machine back at all.

Just some before-work nitpicking.

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"Call me old-fashioned, but I think fire is magic. And it scares me a lot."

--The State

As fun as they are, the Back to the Future movies only work by repeated application of the Mystery Science Theatre 3000 mantra.

"If you're wondering how he eats and breathes and other science facts
(Lalala)
Then repeat to yourself 'It's just a show, I should really just relax'"

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Carl Matherly

Offical Battlestar Galactica Apologist

Named Time Magazine's 2006 "Person of the Year"

It is easy to work that particular time machine - I mean the controls are all labled and everything. The only tricky part might be getting up to 88, but even someone like Biff could figure out "go faster until it works".

The timeline in the Back to the Future movies takes time to adjust to changes. Marty doesn't immediately disappear when he takes his dad's place in meeting his mom in part I - it takes most of the movie for that to happen.
Presumably the changes Biff put in place in 1955 took time to "filter" down through the timeline to 2015, allowing Marty and Doc to go back to 1985 before everything changed completely.
Hey, it's time travel. Nobody knows how it would really work.

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"You miss 100% of the shots you don't take" - Wayne Gretzky

Hey, it's time travel. Nobody knows how it would really work.


Oh! Oooh! I do I do I do!!! :waves hand excitedly:


...it wouldn't. But that's boring, and nobody would want to see a time-travel movie about how they can't really time travel.

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I'm like one of those idiot savants...well, except for the savant part.
"In order to increase awareness of the homeless, security have been given binoculars."

Doc: "If my theory's correct, when this baby hits 88 miles per hour, you're going to see some serious s@!#."
The radio-controlled DeLorean accelerates straight towards the Doc and Marty, with Einstein visible in the windshield.
Marty starts to edge away. Doc looks at him and he steps back.
The car is getting closer and going faster. The flux capacitor lights up behind Einstein.
Marty again steps away from the Doc. The Doc grabs his arm and pulls him back.
Doc: "Wait for it!"
Suddenly the DeLorean smashes into Doc and Marty, throwing them up into the air and hurling them to the pavement of the Twin Pines parking lot. The DeLorean continues on to crash over the concrete barrier and then flip over. It's fuel tank explodes, rupturing the nuclear plant and showering the area with fall out.
As Doc Brown lies dying from his injuries and radiation exposure, he looks over at Marty's twisted form.
Doc: "Well. I guess time travel isn't possible after all."

The End

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"You miss 100% of the shots you don't take" - Wayne Gretzky

@ Jason, Hahahaha, I LOVE it! ...Though I have no gripes with the original, I think this way is just a good.

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I'm like one of those idiot savants...well, except for the savant part.
"In order to increase awareness of the homeless, security have been given binoculars."

I think you're looking too hard for nits; there are many other much more fundamental problems--if you even get past the idea of time travel itself.

Just start with the whole 88mph thing; in south California, the Earth's rotation alone means the Delorean would be going 800mph all the time--to say nothing of Earth's movement around the sun, the sun's movement in the galaxy, the galaxy's movement, etc. Which brings us to fundamental problem #2: if you went back in time, Earth would be in a totally different place, yet the Delorean somehow winds up in the same geographical location.

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Do try not to take me too seriously.

Never mind the fact that Marty and Jennifer instantly travel 30 years into the future, but are still apparently somehow living their lives, so that Marty can meet his future son and Jennifer can meet her future self. How does that work? i.e. In the initial DeLorean test, Einstein didn't jump 1 minute into his future and meet his future self... but then Doc didn't send him back, either.

If the future Marty/Jennifer are the same Marty/Jennifer that had already experienced the subsequent events of the alternate '85 and trip back to 1885 (well, Marty, anyway, since Jennifer was out cold for all of that), then wouldn't at least Jennifer expect to meet her younger self on that day, or Marty Sr. know not to fall into Needles' ill-defined corporate scam (assuming Jennifer passed on what few details she learnd of it to Marty)? That, in and of itself, would seem to make the timeline inviolable, by virtue of the fact that any time-travel events were already, and always will be, part of the timeline. This would then invalidate the central premise of the series: altering the past to one's detriment (Marty) or benefit (Biff).

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Bearer of the highly coveted "I found Venus in nine Apollo photos" sweatsocks.

DataCable^2008 A+

It may just be gravity, so that even when timetraveling the car can't go up the well.

As for the speed needed, perhaps it is important that the speed is somehow relative to the earth... Maybe there is a sort of timelike counterpart to escape velocity, so that there is a minimum rate for effective timetravel(or else you just drop back to the same time), and that when the fluxcap kick in it somehow switches the car's spatial velocity relative to the earth over to time velocity along the propper dimension(s)...

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Game over, you lose, we hope you enjoyed playing the exciting game of Thermodynamics...

Re DataCable:
<<Never mind the fact that Marty and Jennifer instantly travel 30 years into the future, but are still apparently somehow living their lives, so that Marty can meet his future son and Jennifer can meet her future self. How does that work? i>>

Thats bugged me, too.

Re Jason:
That movie is just waiting to be made...

<<The timeline in the Back to the Future movies takes time to adjust to changes. Marty doesn't immediately disappear when he takes his dad's place in meeting his mom in part I - it takes most of the movie for that to happen.>>

That's an idea...it's sort of reminiscent of an old Robert Silverberg story, set in a world where time travel is so easy that people can--and do--travel back constantly to alter the present to their own benefit. The main character is being persecuted by someone who keeps changing his past, and hence his present--his only trump card is that when the universe "switches" he can remember the old one for just a minute or two.

Thanks all for the replies. For the record, I still love the movies (though Part III hasn't grown on me yet); I guess time travel being my favorite SF "sub-genre" makes me pickier than I otherwise would be.

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"Call me old-fashioned, but I think fire is magic. And it scares me a lot."

--The State

Ah, then you're probably familiar with "A Sound of Thunder"...a prime example of how you take something so elegant and beautiful on paper, and turn it into...well, typical Hollywood fare, not fit for 3am sci-fi channel slots (though, that's where it landed anyway).

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I'm like one of those idiot savants...well, except for the savant part.
"In order to increase awareness of the homeless, security have been given binoculars."

I am reminded of Arthur C. Clarke's use of "Bradbury's Defense" in "Imperial Earth":

"One dreadful boy ran up to me and said:
'That book of yours, The Martian Chronicles?'
"Yes," I said.
"On page 92, where you have the moons of Mars rising in the east?"
"Yeah," I said.
"Nah," he said.
So I hit him.

The Ray Bradbury Theatre did a much better job, naturally.

There's also the Clancy defense (which he used on Alt.Fan.Tom-Clancy):

"guys, it's *fiction*." (I think the question was something about how Red Rabbit had two real-world events happening the same year when they happened a few years apart).

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Todd (Bowie, MD, US, North America, Earth, Sol System, Vega region, Local Bubble, Orion arm, Milky Way Galaxy, Local Group, Virgo A Cluster, Virgo supercluster, the universe in which spock is clean shaven)

Quidquid latine dictum sit, altum sonatur.

personal page: http://blog.astrosketches.info

I strongly believe that well-thought-out fiction is better fiction than poorly-thought-out fiction. Generally, the more fantastic it is, the more thinking-out it needs.

However, stories about time travellers changing the past cannot make narrative sense*. No matter how hard you try, there will always be a hole somewhere in the plot**. So the art is to cover that hole as well as you can.

Romanus, the fact that you were able to enjoy the film repeatedly before noticing the hole suggests it was hidden well. I must admit I spotted it immediately, but I have read a lot of time travel stories! Certainly the plot holes in BTTF are a lot less distracting than in most time travel films; that, and the fact that the action is done so well, are good reasons to love 'em!

*Stories about time travellers who cannot change history can make narrative sense.

**Offhand I cannot actually remember spotting the holes in the other two films but I'm sure they're there.

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Nothing beautiful was ever made from gravel.

"*Stories about time travellers who cannot change history can make narrative sense."

"By his Bootstraps" by Heinlein--fits together like a jigsaw puzzle!

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Todd (Bowie, MD, US, North America, Earth, Sol System, Vega region, Local Bubble, Orion arm, Milky Way Galaxy, Local Group, Virgo A Cluster, Virgo supercluster, the universe in which spock is clean shaven)

Quidquid latine dictum sit, altum sonatur.

personal page: http://blog.astrosketches.info

Actually that sounds like a fantastic setup for a modern day Waiting for Gadot. Two characters are inventors trying to invent time travel, and they never succeed. Even if some might find it boring, at least it hasn't already been done to death.

Primer. I don't know of any time travel related plot holes, though it's hard to say whether it counts as changing the past if you're only repeating the same day.

I have seen that. Can't say I enjoyed it. I found it very hard to follow, but if it was saying what I think it was saying, it was a pretty standard time travel story presented in an obscure manner.

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Nothing beautiful was ever made from gravel.

In Back to the Future III, the railroad tracks leading to the gorge don't shift or sink at all in a hundred years and aren't moved at all to accommodate the building of a connecting bridge. It wouldn't have taken much of a change to wreck the train.

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Life is like a box of chocolates. All of your choices are bad for you.

That pretty much sums up the whole thing.

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
"The Mayan symbol for "book" looks a lot like a triple hamburger, but I've never seen them claiming it as proof the Mayans had Big Macs." - KaiYeves
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Not really.

We don't know if time travel is possible or not.

If it is possible, then the way it works will make sense.

Any time travel scenario that doesn't make sense is therefore invalid.

In fiction it only has to appear to make sense if you don't scrutinise it too closely.

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Nothing beautiful was ever made from gravel.

Well, it makes sense if you've ever studied Temporal Ballistics. You need to factor in Brown's Constant to compute the appropriate McFly Transformation when converting Delta V into Delta T (for time). The 88MPH is necessary for establishing a field demarcation in order to establish the motive frame of reference against which the neutron flux is measured (the neutrons being sourced from the plutonium or the Mr. Fusion).

Do I get a cookie now?

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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau

I would think that a time travel story need not have plot holes as long as the rules for time travel in the story universe are presented up front and the rules are carefully followed. Aside from "history can't be changed," "many worlds" time travel (typically, going back in time creates a new "branch" for events to occur) and "privileged" time travel (where there is one timeline, but some mechanism that keeps the traveler from being affected by changes) are pretty common. I think these have been handled well in written fiction a number of times, but usually not that well on TV or in the movies. The problem with BTTF is that they went with "privileged travel" but the privilege was vague and not always followed.

Still, I liked BTTF I and II. In BTTF II, I especially liked the "future": They had a future with some fun bits (the flying cars and Mr. Fusion), yet it wasn't a dystopia or utopia. You don't see that often in movies.

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Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

Every single time-travel story I've seen Hollywood do adheres to the simple rule that you can't change the past -- that causality is maintained through a sort of reverse causality.

Except for that one time they don't.

I'd be happy to see just ONE movie where they stuck to one idea about time (as Heinlein did in that wonderful short story) and resist the urge to stray from it.

Of course, as a friend of mine points out, it is never the "time line" that is preserved. It is _history_ that is preserved. You can muck about all you like, just as long as you don't accidentally kill anyone with a name that appears in books.

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"You keep using that word. I do not think it means what you think it means."

In the first Terminator movie, causality was maintained. Indeed, the good and evil time travellers were in part responsible for the history that one was seeking to change.

Of course all that changed in the second film.

There was also an episode of Murder Most Horrid, starring Dawn French, in which she built a time machine to go into the recent past. Events unfolded exactly as she had seen them unfold before, but this time around they made sense!

This presupposes that your presence in the past is "new material" - that "originally" there was no time traveller mucking about. I believe this is the central fallacy of most objections to time travel.

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Nothing beautiful was ever made from gravel.

Watch "12 Monkeys". The future scientists know the past can't be changed, so time traveler is sent back not to change the past, but to get more information about how a disaster happened, which the future's scientists might be able to use to fix the problem. While he's there, it feels like the present to him (as whatever time you're in would always be), and he's so used to thinking of the future as undefined from the perspective of the present, that he's tempted to try to change history anyway...

Harry Potter and the Prisoner of Azkaban uses time travel in a logical consistant way (Well, beyond the "A wizard did it" factor). In the time loop at the end, nothing is changed, we just see events from a diffrent perspective. (It helps that Time Travel wasn't a central theme and so was just used as a (well set up) Deus ex Machina).

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Carl Matherly

Offical Battlestar Galactica Apologist

Named Time Magazine's 2006 "Person of the Year"

Watch it again...in the end it looks to me like the leader who started the project is doing just that. She even calls herself an "insurance policy" IIRC. Which means Bruce Willis' character was put through all that for no reason at all.

Either way, it's one of my all time favorite movies.

Huh. When my wife and I watched it, we came to the same conclusion Delvo did. That the "insurance" was getting a sample of the original strain or some other data to be used in the future. After all, the viles are already opened (at security). The virus is already 'loose' and the plauge is inevitable.

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Carl Matherly

Offical Battlestar Galactica Apologist

Named Time Magazine's 2006 "Person of the Year"