Jim Kakalios of the University of Minnesota has achieved internet demi-fame — he has a YouTube video with over a million and a half views. It’s on the science of Watchmen, the movie based on Alan Moore’s graphic novel. Jim got that sweet gig because he wrote a great book called The Science of Superheroes — what better credentials could you ask for?
More recently Jim has written another book, The Amazing Story of Quantum Mechanics. But even without superheroes in the title, everything Jim thinks about ends up being relevant to movies before too long. The new movie Source Code features a twist at the end that involves — you guessed it — quantum mechanics. Jim has applied his physicist super-powers to unraveling what it all means, and was kind enough to share his thoughts with us in this guest post.
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There is an interesting discussion taking place on the internets concerning the ending of the newly released film SOURCE CODE, that suggests that the film concludes with a paradox. I believe that any such paradox can be resolved â with Physics!
This entire post is one big honkinâ SPOILER, so if you want to read about the final twist ending of a film without having seen said film â by all means, read on, MacDuff!
In SOURCE CODE, Jake Gyllenhaal plays US helicopter pilot Colter Stevens, whose consciousness is inserted into another manâs body (Sean Fentress, a school teacher in Chicago) through a procedure that requires a miracle exception from the laws of nature (involving quantum mechanics and âparabolic calculusâ â by the way, there is no such thing as parabolic calculus). Thanks to some technobabble (or as Q-Bert on Futurama would describe it â weapons grade bolognium) Colterâs mind can only enter Seanâs body in the last eight minutes of Seanâs life. As Sean is sitting on a city bound Chicago commuter train, on which a bomb will explode at 7:58 AM, killing everyone aboard, the goal is for Colter to ascertain who planted the bomb. He cannot stop it from exploding, he is told, because that has already happened. He cannot affect the past, but he can bring information obtained in the past back to his present time. Learning the identity of the bomber would enable the authorities to prevent the detonation of a threatened second âdirty atomicâ bomb is downtown Chicago.
While the above can be discerned from the movie trailer, what I am going to discuss next involves the actual ending of the film, and if you do not want this ending spoiled, you should stop reading now.
Colter learns that the reason his last memory is being attacked in his helicopter in Afghanistan is that he in fact died in the crash. His mangled body is kept artificially alive, and his brain can be activated, and sent to inhabit the body of Sean Fentress (who happens to be a neurological match). At the end of the film, after multiple failed attempts, Colter manages to identify the bomber. Providing this information to Col. Goodwin (a military officer played by Vera Farmiga) and Prof. Rutlidge (the great Jeffrey Wright), the scientist who designed the Source Code project, the terrorist is caught before he can set off the second bomb, but after, of course, the first bomb on the Chicago train explodes.
It is left somewhat vague as to whether Colter is going to parallel realities, a la the Many Worldâs interpretation of Quantum Mechanics, or whether he is engaging in a quantum/ neurological simulation. If the former (which seems to be borne out by the ending) then this would tie into notions of time travel being explored in the context of quantum gravity. That is, if one could time travel into the past, you need not fear any Grandfather paradox (what if you killed your ancestor â preventing your birth, but then you would not be able to travel back in time to ice Grandpa). Some physicists argue that time travel is only possible via parallel realities. You do not go back in time in your own reality, but to an alternate Earthâs past. You can thus kill as many grandparents as you have bullets, remaining safe in your own timeline. In any event it is assumed that the bomber is the same person every time Colter enters the Source Code.
While everyone is celebrating the capture of the bomber, the first successful trial of the Source Code project, Colter convinces Goodwin to send him back one last time, to try to save the passengers on the train. At the end of the eight minutes, he convinces Goodwin to terminate his life support, allowing him to die in actuality, as the world and his father believe happened months ago in Afghanistan. Needless to say, he manages to stop the first bomb from exploding on the train, hands the bomber to the authorities, and kisses his love interest just as the eight minute mark is reached. We see Goodwin make good on her promise and end his life support at that moment, at which point she is arrested my the military police for acting against Rutlidgeâs instructions.
On the train however, Sean/Colter is still alive after the kiss. The film implies that he goes on to live happily ever after in Seanâs body, with Colterâs mind, while Colterâs deformed body remains at the Nellis laboratory on life support. As the bomb never went off on the Chicago train â there was no reason to activate Coulter and send him into the Source Code, and the project awaits its first true trial by fire. Thus it is indicated that we are witnessing two alternate realities â one where Goodwin is arrested after pulling the plug on Colter following the successful application of the Source Code, and the other where Sean/Colter is still alive, where the Source Code project has not been activated.
Among the many discussions Iâve noted on the web about the ending of this film, I wish to address two particular issues that are being debated by the Hive Mind. In the filmâs final reality, where the bomb does not explode on the train â does Colterâs consciousness reside in two places at once? And, what happens to Sean Fentrissâ consciousness in this final reality?
Reasonable people may reach different conclusions concerning these two points. As I am a physics professor â I will tell you the RIGHT answers!
(1) In the final reality â Colter is NOT consciousness in two places at once. He is awake and aware in Sean’s body and at the same time his damaged body is in the Nellis lab â IN A NON-CONSCIOUS STATE. He is not awake and aware in the lab at Nellis, he can not initiate motion or form an independent coherent thought. He is in essence brain dead, kept artificially alive until there is a time and need for him to be activated (if there is a terrorist attack).
Even if he is activated â this would NOT influence or affect Colter in Sean’s body, as it would take place in Sean/Colter’s FUTURE. Remember he was sent back to Chicago at 7:50 AM â the bomb exploded at 7:58. Time progresses forward for both Sean/Colter and Nellis/Colter at the same rate. This was why Goodwin and Rutlidge were upset about how many trials it was taking â for each trial burned up a minimum of eight minutes, and brought the second explosion closer to happening.
What you are doing and thinking now is not affected by what you will be doing and thinking several hours from now. Do you know what you will be thinking about several hours from now (ok â for the guys this is an easy one). Nellis/Colter may not be activated for weeks/months/years later. But even if he is â Sean/Coulter can live his life, unaffected by what is happening in his future. There is no paradox, for Colter in Sean’s body is only awake and conscious at one point in time. Colter is NOT like Schrodingerâs cat, in two different conscious states simultaneously, as they are separated in time.
(2) What happened to Sean’s consciousness? Here there is a potential problem. Basically I believe Sean is dead. When Colter’s mind jumps into his body, it over-writes Sean’s consciousness. Rutlidge probably knows this, and ignores the ethical issues. Sean will be dead when the bomb explodes after all, and Rutlidge believes that cannot be changed. By sending Colter into Sean’s body, he robs Sean of the last eight minutes of his life. As Sean is unaware that a bomb will explode, killing him and everyone on board, he would not do anything extraordinary in those eight minutes. Rutlidge probably believes that it is acceptable to sacrifice the last eight minutes of one man’s life in order to save millions of lives if they can prevent the second bomb blast in downtown Chicago. Every time Coulter enters the Source Code at 7:50 AM, he essentially kills Sean. Sean will die in every reality where Colter does not enter the code, and he will also die in all N â 1 realities where he does â so this is an ethical problem of order 1/N where N goes to infinity.
Alternatively, Sean may be alive in Colter’s damaged body â but there was no suggestion that something like that was happening. Here I’m taking the Quantum Leap analogy too literally. (There is a wonderful tip of the hat to Quantum Leap â listen carefully to Coulterâs Dad).
Sorry this is so long. Never ask a professor a simple question â you always get a lecture in reply!
Great article, thanks! I’m happy that your wrap-up mirrors my own conversations after seeing the film last night.
I totally missed the Quantum Leap reference though. Can’t wait to get this on Blu-Ray and have another watch.
Oh, and FTR that was a perfectly acceptable length. Like a good dress: long enough to cover the subject but short enough to keep it interesting.
You say, “Colter is NOT like Schrodingerâs cat, in two different conscious states simultaneously, as they are separated in time.”
But, as everyone knows đ different times are just special cases of different universes. Other than that, I agree with every word you say đ
by the way, there is no such thing as parabolic calculus
Which is why we can’t project consciousness back in time!
My interpretation was slightly different. It was my understanding that Rutledge and Goodwin viewed what they were doing as a computer simulation only. In other words, they used the 8 minutes of memories that they could recover from the recently dead train victims to construct a computer simulation in which Colter could reenact said 8 minutes over and over again. Thus there is no ethical dilemma of taking over Fentress’ mind because to them it wasn’t him, just his memories powering the simulation.
What Colter figures out while inside (unbeknown to us as the audience), is that it is more than just a computer simulation, it is an alternate reality. The hints we get that it might be more than a computer simulation are subtle. He can interact with things that no one on the train should have a memory of, for example. One of the big things that gave it away for me was that Christina didn’t say the exact same thing every time he woke up. This would not have occurred if it was purely a memory. Once he figures this out, he want to save the people on the train. When his body dies in the original world, his consciousness no longer needs to return to his body and he can remain in the alternate world in Sean’s body.
To live happily ever after no doubt.
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If as you say “He is not awake and aware in the lab at Nellis, he can not initiate motion or form an independent coherent thought”, then why does the unconscious brain dead body mouth words and exhibit rapid eye movement while Coulter is inside Sean’s body?
I think Rutledge knows what’s actually going on, but presents it as a computer simulation being run with Colter’s brain as the computer to sidestep any ethical issues. This is why he does not want to give Colter the opportunity to save the train.
The other ethical issue here is the violation of the female character. Coulter uploads into Sean’s body…gets infatuated with a lady and then uses her actual feelings for Sean to ingratiate himself with her. Who’s to say that one week later, when she realizes that this Coulter character is radically different from Sean that she likes him at all? Unless we’re willing to grant that they both fell in love with each other (in both directions) during those eight minutes…while she thought he was the person she’d known for a long time…then, it seems like a pretty gross violation.
My only question is then if Colter is used again in the Source Code for this new reality, and decides to stay in _that_ body, will he now have multiple incarnations of his consciousness wandering around?
I agree with the idea that they switch consciousness. Which actually means that Goodwin kills Sean at the end of the movie in the original universe.
Also the 8 minute window is crap, since he clearly lives longer in the universe(s) when he gets off the train. They should have figured it out then that he wasn’t returning to the home universe until he was killed.
Same question as Allison – when Colter’s awoken for the Source Code, will he be yanked out of Sean’s body, or will he have a separate incarnation of his consciousness?
I also think it’s ethically murky for him to use Sean’s body to start dating Christina. She had a crush on Sean, not Colter…she was waiting for Sean to ask her out, not Colter…so when he stops being the Sean she had a crush on and starts being Colter, what then?
^ Quantum RAPE! đ
Great exploration of the movie, btw…but I’m with AJ, that was bugging me the whole time I was reading the OP.
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Not yet.
“…his helicopter in Afghanistan is that he in fact died in the crash. His mangled body is kept artificially alive, and his brain can be activated…”
Well, then, he “IN FACT” isn’t dead.
Fatal end to a preposterous storyline, plot and premise right there.
This junk has more to do with spiritual thinking than anything remotely resembling quantum mechanics…or good science fiction for that matter. Can you say “gimmick”?
The first part of the movie is just standard sf: captured memories, computer simulation, a separate consciousness interacting with both of those. No need for the qm or “parabolic calculus” unexplainium. The fact that the writer and director felt the need for the unexplainium underscores the fact that they don’t really get hard sf (and please, no one imply that the director inherited his knowledge of sf genetically from his dad, as one reviewer has….).
I disagree with AJ that we know we’re in an alternate reality when Sean/Colter starts to see changes. A different interpretation is that Colter is just exploring parts of Sean’s memories that Sean hadn’t: seeing things that Sean hadn’t noticed and interacting with some of them in the simulation in plausible ways. This is consistent with the idea that Colter’s mission didn’t have to succeed, it just wouldn’t have made a very good premise for a movie in that case.
For me, the movie would have been more of an artistic success if it had ended at what seemed the natural and perfect ending point, the big “freeze”. After that point, one either has to invoke alternate reality, many worlds type unexplainium, which isn’t very good sf, or good writing, no matter how one tries to clean it up OR just imagine that though Colter’s body and brain are now dead, there’s no real reason why the simulation can’t keep running…… (this idea has been explored in almost countless sf venues, and very well done in the two wonderful “Moriarty” episodes of ST:TNG). With this interpretation, there’ are no real ethical dilemmas, other than the huge one of the asshole Rutledge, who, since he is an asshole, doesn’t care. This is why I found the Quantum Leap nod so perfect, as it highlighted the sure HORROR that Sam Beckett was subjected to and pointed out how very similar that was to what is being done to Colter.
To explore that in another context, one can read Orson Scott Card’s short story ” A Thousand Deaths” (probably out of print, so you most likely won’t be putting any money in OSC’s pocket by doing so).
“After that point, one either has to invoke alternate reality, many worlds type unexplainium, which isnât very good sf . . .”
That’s because many-worlds isn’t fiction, right? đ
@ Karl I’m very happy to leave the discussion of whether many-worlds is fiction to the “experts” to mumble about! Personally, I’d rather hear/read characters mumble plausible technobabble than qm/consciousness woo.
There’s a Roger Corman movie from 1957, The Undead, which deals with past-life regression which leads to changes in the present. And then there was the TV soaper Dark Shadows…
The whole time I was watching the movie, I kept thinking how cool it would be if they used my app to trigger the branching of the other universes: http://cheapuniverses.com/universesplitter
(It’s an app which uses an actual quantum event to split the universe at your whim. Really.)
The whole time I was watching the movie, I kept thinking how cool it would be if they used my app to trigger the branching of the other universes: http://cheapuniverses.com/universesplitter
(It’s an app which uses an actual quantum event to split the universe at your whim. Really.)
Sorry about the double post!
An interesting post. The only neglected point, I would offer, is the rather liberal treatment of the human brain as being read-writable RAM. This may work for computer programs, but the biological roots of consciousness are not equivalent to that model. The movie failed horribly on that point.
I agree with AJ, I thought that when Coulter went out of the bounds of the computer simulation i.e. outside the parameters of the programming of the simulation, he crashed the system. Hence, the reason why they tried many repetitions of the card sequence to regain communication with him. Also, there was a time when the simulation broke down, and Coulter began seeing the “code” of entities in the simulation. This reminded me the ending of the Matrix when the code was intelligible to Neo. Coulter came back to life by “coding” his environment by saving himself in the cold capsule. Coulter, when activated during those 8 minutes was able to transfer his consciousness into the code of the “simulation.” He wrote himself into the simulation. With the help of Sean’s memories. (He has to use the memories of Sean, because Coulter’s memories are wiped clean, i.e. he is deactivated after each mission). Therefore, his consciousness was able to continue to exist in the computer servers of the simulation. Basically, as an intelligent program, AI (but not artificial). Since, his consciousness is now coded, he does not need his body anymore.
Being part of the code and being aware, he can also communicate with Goodwin via email or text.
I may have misunderstood the ending, but I thought that Goodwin was not arrested but disciplined. The communication she received from Coulter was to let her know that he was “alive” in the simulation and had prevented another and different terrorist attack. She began to go and tell Rutledge of this email, but thought better of it. She did not tell, because he would have tried to continue to use Coulter for the project. even though Coulter’s body and brain were dead, killed/deactivated by Goodwin.
I also agree with Viggen, but hey the movie is for fun. It works because we have to use some imagination.