Flashforward, Deja Vu and Hollywood's problem with time travel


Tonight I watched the debut of FlashForward, which is based on the novel of the same name by Rob Sawyer, an SF writer from my hometown whom I have known for many years. However, "based on" is the correct phrase because the TV show features Hollywood's standard inability to write a decent time travel story. Oddly, just last week I watched the fairly old movie "Deja Vu" with Denzel Washington, which is also a time travel story.

Hollywood absolutely loves time travel. It's hard to find a Hollywood F/SF TV show that hasn't fallen to the temptation to have a time travel episode. Battlestar Galactica's producer avowed he would never have time travel, and he didn't, but he did have a god who delivered prophecies of the future which is a very close cousin of that. Time travel stories seem easy, and they are fun. They are often used to explore alternate possibilities for characters, which writers and viewers love to see.

But it's very hard to do it consistently. In fact, it's almost never done consistently, except perhaps in shows devoted to time travel (where it gets more thought) and not often even then. Time travel stories must deal with the question of whether a trip to the past (by people or information) changes the future, how it changes it, who it changes it for, and how "fast" it changes it. I have an article in the works on a taxonomy of time travel fiction, but some rough categories from it are:

  • Calvinist: Everything is cast, nothing changes. When you go back into the past it turns out you always did, and it results in the same present you came from.
  • Alternate world: Going into the past creates a new reality, and the old reality vanishes (at varying speeds) or becomes a different, co-existing fork. Sometimes only the TT (time traveler) is aware of this, sometimes not even she is.
  • Be careful not to change the past: If you change it, you might erase yourself. If you break it, you may get a chance to fix it in some limited amount of time.
  • Go ahead and change the past: You won't get erased, but your world might be erased when you return to it.
  • Try to change the past and you can't: Some magic force keeps pushing things back the way they are meant to be. You kill Hitler and somebody else rises to do the same thing.

Inherent in several of these is the idea of a second time dimension, in which there is a "before" the past was changed and an "after" the past was changed. In this second time dimension, it takes time (or rather time-2) for the changes to propagate. This is mainly there to give protagonists a chance to undo changes. We see Marty Mcfly slowly fade away until he gets his parents back together, and then instantly he's OK again.

In a time travel story, it is likely we will see cause follow effect, reversing normal causality. However, many writers take this as an excuse to throw all logic out the window. And almost all Hollywood SF inconsistently mixes up the various modes I describe above in one way or another.

Spoilers below for the first episode of FlashForward, and later for Deja Vu.

Update note: The fine folks at io9 asked FlashForward's producers about the flaw I raise but they are not as bothered by it.

In FlashForward (both book and show) at one moment, everybody in the world blacks out for a short period, and sees a vision of themselves in the future. (6 months ahead in the TV show, 20 years in the book.) The blackout causes major disasters (cars crash, etc.) but the real story is the visions. It becomes clear quickly that the visions are of a specific future. People who were meeting together both see the same meeting, people watch the same TV shows, read the same newspapers.

However, the show diverges from the book in an important and mistaken way. Most people see a vision of some random snippet of life. They are in a meeting, or on the toilet, or asleep and dreaming, or watching a regular TV show. However, the lead characters see scenes that are the direct result of the FlashForward catastrophe. One is an FBI agent who sees himself working on the FlashForward case. His wife has a meeting with somebody she only meets because she treats his son for injuries from the catastrophe.

This makes no sense. If the visions are of a world after the FlashForward, then the magic day, 6 months in the future, would be the most anticipated day in the history of the world. Forget the moon landing, forget Canada-vs-USA for Hockey Gold. Nobody would be doing something mundane. Everybody would be awake, no matter what time it is. Everybody would be either gathering with others, or watching TV, with many trying to act out their now misremembered memory of the vision they had, and others working prevent it.

So we see a world where most people are seeing the future which would have been, a mundane future. But that future is clearly not true, it is at most an image of what might have been had there not been a big world event. Yet a few characters are seeing the world with the big event. It's the same world, but it can't be.

In the novel, people learn quickly that the seen future is not certain. For example, people who saw visions of the future die -- sometimes because of the bleak future they saw. With the first such death it's obvious that the vision is not an assured future, and people can work to change it (or bring it about) as they see fit. The TV show future is neither, it just makes no sense.

A few other quibbles: A thousand planes crash. In reality, planes are all on autopilot, even when landing and taking off. Only a few would crash. Even planes not on autopilot would not hit the ground in 137 seconds in most cases. It is reported that Hong Kong is devastated -- but it would be around 4 in the morning there, so in fact the effect would be quite mild, and most people might not even remember it. 1/3 of the world would be asleep, and thus face minor trouble -- and as such perhaps come to dominance in the injured world. Based on the regular death rate, we would have seen the proof that the viewed future was not set within minutes, not weeks.

But can they get past the big one, and move more to the novel's story where the visions are just a warning? It's hard to see that happening, since the main plot is the FBI agent trying to determine the cause of it all.

Update: The producers, when asked, suggest that a character might be on the toilet because "sometimes you just have to go." While that's true enough, he would not be idly reading and sitting, he would be very annoyed. And having seen the toilet scene and been disappointed by it, he would make sure he didn't have to go. But many other characters are having totally mundane experiences that could easily be avoided. And all the people watching TV are seeing ordinary TV shows, not the "live coverage of the big event" that would be on every channel.

Deja Vu

Deja Vu has a similar problem. In this film, after a terrorist attack, we get a great plot... The spooks have a device that can look back just over 4 days, and they need to use it to solve the crime. This would have made a great story, but they decided to make it two-way and allow first a message, and then a man, to go back in time.

The problem is that some of what they experience is the result of those trips back in time, but some of it is not. In the movie, Denzel goes to the murdered woman's house, and sees bloody swabs and a message on the fridge that, it turns out, were left by him when he went back in time. The problem is that the future created by his trip in time, which has that message and bloody swabs, has no murder and has no terrorist attack. There is no reason for him to be in the house or investigating the crimes at all in that future.

The movie has this problem because it wants to tease you and make you wonder if it's of the Calvinist sort above, or the modified form where you try to change things but they happen anyway. This creates some suspense, "is it all going to happen again, in spite of his time travel?" But as soon as he saves her, it no longer can, since the whole investigation starts because he discovers that she died before the terrorist bomb. Once she doesn't die then, the new future can't be the old one. And yet bizarre coincidences keep coming, to tease the audience, not to make any sense.

Indeed, even the first note sent back has this problem. Denzel's partner's car is found parked at the Ferry. This is because he saw a note sent back in time and went to investigate the ferry, and was killed. He also damaged the terrorist's car, making him need a new one -- but he's already set up an appointment to steal the car from the woman he will murder. And that's the car he uses anyway.

It's sad because the movie started out well, and might have ended well had he been unable to get the Hollywood ending and save the girl and stop the bomb. But it's really sad because the story with the device that spies into the past would have been a great consistent story, one that doesn't violate the laws of physics at all, and one which has been explored in the past in some great SF. (There are a number of privacy concerns with such technology of course, which are brought up in some of that SF.) The movie is well made and has gripping moments, which makes it doubly sad because it could have been great.


As might be expected, this is a topic that has already been
analyzed by others. Here's but one recent example:

Temporal Anomalies in Time Travel Movies:

The author(s) seem to be analyzing time travel movies purely in terms of the mechanics of one particular role playing game called Multiverser. Hence the strange invented jargon. That's... cute, I guess, but it's not very meaningful unless you happen to be playing Multiverser. Which I've never heard of until now.

A better reference might be Paul J Nahin's Time Machines: Time Travel in Physics, Metaphysics and Science Fiction. It's ten years old so doesn't include recent examples, and there's a slight bias towards the Novikov Consistency Principle - the author really, really doesn't like any story which actually involves changing the past. Many worlds doesn't get a look in. Other than that it's really quite good.

Time travel is an interesting topic but my question is whether you think that it could ever be physically possible? I can't imagine any possible way that one could go backwards in time. Forward seems slightly more plausible because the future hasn't already happened and time is already moving in that direction, but it seems like even this in any scenario would have to be more like "sitting out" than "traveling forward". You can cryogenically yourself and hopefully wake up in the future with no time seeming to have elapsed, but you haven't travelled anywhere.
I have to say I thought Deja Vu was a pretty good movie. The problems you pointed out are honestly not ones that I had thought about but now do seem quite clear. However I chose to take a girl on a date to see this movie, and had Denzel not come through in the end and saved the day it would've been less romantic and probably worse for me. Thank you again Hollywood. The explanation for how the machine worked was about as coherent as the flux capacitor but I guess I caught something about folding the fabric of the universe on top of itself. Sounds cool, but made up too. I guess what it all comes down to is just fiction and people's endless wishes to change what has already happened but I for one think that you have to, and always will have to live with the decisions and the mistakes that you've made.

Is probably not possible, and there is strong evidence in that we don't see it. Time travel we can see the results of is almost surely not possible.

Yes, I understand why Hollywood wants Denzel to save the girl and give the standard ending. However, they still could have done that in a consistent way.

Physicists say the same thing that time travel is more likely if you go forward than backwards. however I have an obvious comment on that. Or maybe not so obvious - since I haven't seen it anywhere else). If you go backwards you would have a date and time in mind, because you want to see a specific event. however you don't have that option if you move forward. I said that badly. But what I wanted to illustrate that - you know where you are going if you go backwards, but you have no idea of the conditions when going forwards since it hasn't happened yet.

AND because the same physicists say there are many futures (depending on present actions)HOW would you pick one possible Future from the others? Its possible that because of the Schrodinger Paradox (hope that is right name), that by going to a certain date in the future you would set that past (between when you leave and that future point in time) in stone? - make it the reality? So then that future would now be the only one possible? and no other? Along with how that future came about! MMmm, that might make a good movie story! at least the idea would be a new one. Lol. (It would no longer be a story about stopping someone from changing the future - but from picking a future - simply by looking at it)

You ask whether Time Travel is categorically possible, with emphasis on travelling farther into the future.
It has in fact been proven that someone can travel into the future at a faster rate. This depends on the speed the person is travelling.
For example, in numerous scientific studies, physicists have synchronized atomic clocks and have placed one on a jet and another on the ground (i.e. no relative motion). The result is that the atomic clock on the jet is a few nanoseconds behind the one that remained on the ground. This means that the clock aged more slowly then per usual and thus has reached the present faster.
Of course this is nigh insignificant but at speeds close to the speed of light, it has been theorized that one could travel hundreds of years into the future while only having aged anywhere between a few weeks to a few months.
(An interesting tid-bit in SF, it has been hypothesized that if this technology were possible, you could have a theater full of people watch a half a show with a younger cast, go at a fraction of the speed of light and return 20 years in the future (more or less a day depending on the speed, and watch the 2nd half with a more matured cast. Wouldn't that be exciting)
Anyway, travelling in the future is not difficult as we are doing this already. However, if you go into the future, our current understanding of Physics and Space-Time have no way of bringing you back to your 'natural' time. (Perhaps somewhere delved within Quantum Mechanics, M-theory or something unknown holds the answer.)
Good Luck though


That neatly sums up my experience of Flashforward. I'm really, really hoping it will be written intelligently, but so far it appears to be massively inconsistent.

Did the flashforward happen in the future they see, or not? If the main character is investigating the flashes, that implies it did. But if everyone else is doing something utterly mundane, that implies it didn't. They can't have it both ways.

It's also easy enough for the characters to figure out if the flashforward happened in the future they saw, and if the future is malleable. For instance, thousands of people die on flashfoward day - but if any of the dead were seen alive by others in the flashes, then we know the flashfoward changed the future. For that matter, if your vision involved a big old oak tree in your back garden, it only requires an axe to test if you can change the future. If the main characters aren't smart enough to realize these things, it will be very frustrating to watch.

Also I'm not sure why Big Ben would burst into flame if left unattended for two minutes....

Deja Vu's a complete mess, but you get the occasional movie that handles time travel well, taking one model of how it works in their fictional universe and running with it. The first Terminator movie. Twelve Monkeys, perhaps, although I haven't seen it recently. And, of course, Primer.

"The problem is that some of what they experience is the result of those trips back in time, but some of it is not."

It's a while since I've seen Deja Vu, so I don't know whether the following rationale would make sense of it, but it's possible to have a logically consistent version of time travel where this happens under "Go ahead and change the past" if there has been a previous failed attempt to change the past. I'll take the example of a hero trying to avert an explosion, and explain how it might play out:

It requires that there was a first version of events ("earlier" in time-2), in which the explosion occurred, there was no time-traveller to prevent it and no clues; but events eventually lead to the hero(v1) going back in time to try and avert it, creating version 2 of the timeline...

In which the hero (v1) fails, and the explosion still happens. However, forewarned with his knowledge of the v1 timeline, he leaves a number of clues to himself, and makes a number of changes to make his investigation easier. So in the v2 timeline, events unfold as before, only with the clues and changes left by hero from v1, so it plays out a bit differently for the v2 hero. He still eventually ends up travelling back in time, creating v3 of the timeline...

In which the v2 hero makes the same changes and leaves the same clues, this time because he knows that they happened in the v2 timeline. To v2 of him, it might appear to be a "Calvinistic" chain of events, but this is just an illusion. He, unlike the v1 of himself from the original timeline, is forewarned and better prepared, so has a better chance of averting the explosion, and succeeds!

Since there is no reason for v3 of him to travel back in time, the timeline now becomes stable, with the intervention of v2 coming seemingly out of nowhere - he has erased his original timeline, and is now a time-orphan.

With multiple time-interventions, it would become even more complicated. As long as the hero had reason to go back in time, there's no knowing how many times the loop might repeat itself, producing different versions of the timeline, before it stablised with a version of events that did not involve another attempt to change the past.

There you go, all it takes it a bit of wibbly wobbly, timey wimey, 4-dimensional thinking! :-)

What is important is the history we see in the movie has to have resulted only from the most recent iteration of these trips, and of course the hero has to die or vanish in this, the 2nd last iteration.

The scriptwriters claim their original script was fully consistent but this did not make it to screen.

To do this right, you might actually write it so the character does not die in the 2nd last iteration, but fails, and then tells himself what to do. In such a story, Denzel would be the mastermind, pretending to not be aware of the time machine etc. Good acting.

Otherwise it is hard to explain why he doesn't just phone his office and stop the terrorist. He has the guy's name, planned location, knows to be cautious or he will be spooked. Spook him is fine, catch him later with the time machine. You can catch anybody with that machine now that he knows how to use it.

Maybe you could make this work but it needs a lot of hidden fanwanks.

7 years later but i cannot let that slip, there is a major issue with this thinking.

It goes like this, where is v1 Dough in V3 world? They completely denied it's existence in the latest version of the world.

Basically, you say that we are monitoring v2 from the start of the story, Dough is being guided by V1 of himself that wen't to the past already and failed. The way he failed is also flawed but no need to get into that. The problem is when he is going back a 2nd time, he is going back into a timeline where he existed a 2 place already creating a 3rd version of him in this reality. But when this happen, v1 cease to exist.

Also, this setup actually allowed them to go further than 4 days in the past. What if Dough instead of saving claire in v3 actually went to the FBI speak with the team and leap further in time, i guess they weren't so smart after all. If you're point is that he already experienced 1 travel and might not survive a second, why not having v3 of him leaping instead, which would have without fail convinced everyone that he is coming from a time leap.

I actually enjoyed Deja Vu very much. I love time travel movies, especially when I was a kid watching the Back to the Future Series of films.

The only problem I had with Deja Vu was --What if "Doug" from the future *did* survive being thrown into the water and both he and Claire swam to the shore and then met Doug from the present...

The movie worked in the end because Claire met Doug from the present and she ended up believing Doug from the past. The ferry explosion was prevented and Claire was saved-all from Doug from the past....But would Doug from the present even believe Claire? When they met there was a sense of a "Deja Vu".....

How would it work if Doug from the future survived? That would be so complicated and confusing....

Would Doug from the present live with Doug from the future and they would be like brothers or roomates?
What if Doug from the present was married?
Would Doug from the future have to go back (to the future) to avoid a time paradox???

Seems messy....


I'd be interested to see you revisit this post in light of how the series turned out.

And they did a better job than I expected. In essence -- these are spoilers -- they showed everybody's flashforward as being a view of the post-flashforward universe.

This makes much more sense than having some people's FFs be of a world without an FF, and some people seeing the world with an FF. However, it is hard to reconcile because they showed that the future can indeed be changed, that many of the bad-guys have had multiple FFs and seen multiple futures. Instead the FFs were exact in a way that can't be explained by coincidence and people trying to have the same FF.

It remains a problem that lots of people reported mundane FFs. The main characters had non-mundane ones and we learned what led to those FFs, which is fine. But the rest of the world should have all been seeing scenes of big parties, watching TV coverage of the FF. Large numbers of them should have been of them staring at pre-prepared lists meant to be messages back in time. Nobody should have been asleep.

And with such a determined future, the people who died before they were meant to die don't make much sense.

It seems that some of the FF's (*) did still come true, only with differences in the details. I think that the whole idea of the series was that the FF showed you the universe with the highest probability of actually existing; I would have liked to see, for example, whether someone else was giving the African Speech.

(*) yes, I know. But the style guides' foolish insistence on "plural NEVER has an apostrophe" can lead to confusion in the case of acronyms; "FFs" might well mean something other than "plural of acronym FF".

The problem is a lot of FFs came true not because they were the most probable thing but because they were highly improbable things that somehow were going to happen through a long series of unlikely events. And some came true in spite of the people working to not have them come true. Sure, you can imagine that Olivia is meant to be with Lloyd. But that Janice is going to get shoved at a particular time on a particularly crazy mission and need to go for an ultrasound? Others came true only because of great effort to make them come true (Keiko) but others (car crash into water) are the results of chaotic events.

In other words, it was all destiny, but oddly a destiny that some people can change and others can't.

One point they didn't say but might have been the case -- because Dimiti was holding the QED ring during the vision period, it could have explained his lack of flashforward. Truth is, if he was really slated to die, and didn't, that should have changed a lot of other people's visions too.

They left loose ends. They said the President's FF was of him losing the presidency but we didn't see that at all. Anyway, this will remain unwritten.

I understand the points raised with the paradox of if he changes the events that lead him there to begin with then he would never be there to change the events. Basic time travel paradox.

However, what if the change of events created a different timeline - the timeline where the girl is alive and the boat didn't explode and the original timeline where the boat explodes killing the girl and setting in motion the need for Doug to travel back in time, causing a loop of infinity for that now redundant timeline.


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