Flash Forward Gets Schrödinger’s Cat a Little Wrong
Posted by Karl Withakay on October 29, 2009
Tonight’s episode of Flash Forward, “Scary Monsters and Super Creeps” contained a flawed portrayal of the Schrödinger’s Cat thought experiment (note the 2 separate links) in a conversation where a quantum physicist is trying to pick up a hot woman on a train by telling her he can explain what caused the flash forward. After mentioning that the most basic concept she needed to understand was quantum superpositions, they have some witty flirting and then the conversation proceeds as follows:
Physicist: “Imagine you have a cat, a teeny tiny cat that fits in the palm of your hand. You also have a poisonous sardine. Once we close your palm there are two possible scenarios: either the cat eats the sardine and dies or the cat doesn’t eat the sardine and lives. Quantum physics says until we open your hand to discover the cat’s fate, both eventualities occur at the same time. For us, the cat is both living and deceased.”
Hot Woman “But how can that be?”
Physicist: “That’s the miracle of quantum mechanics. The observer get to decide.”
The problem is that this thought experiment leaves out an important element of the original, a quantum probability. In the original experiment, the cat’s life or death is dependent not on a poisoned sardine, but on the potential decay of a radioactive isotope source. If the source decays and emits a decay particle, a hammer triggered by a Geiger counter breaks a vial of poison, killing the cat; otherwise the cat lives. The key is that the decay or non-decay of the isotope is a quantum probability, whereas the cat eating a poisoned sardine is not.
Schrödinger originated this thought experiment in an attempt to illustrate what he saw as a flaw in the Copenhagen interpretation of quantum mechanics. According to quantum mechanics, the cat is both alive and dead (because the isotope has both decayed and not decayed) until the observer collapses the quantum wave function by observing the state of the cat (which is dependent on the state of the isotope), even though common sense says the cat was obviously either dead or alive before being observed. The experiment also has nothing to do with the observer “deciding” anything. The act of observation collapses the quantum wave function to one state or the other, but no choice of states is involved or possible.
The Flash Forward thought experiment was an not an example of quantum superposition since no quantum state was involved, and it wasn’t Schrödinger’s/Schroedinger’s Cat.
Cordial Deconstruction 
Ba!nesy said
I’ve just begun to be interested in Schrodinger’s Cat theory, and while I cannot be 100% sure of it’s meaning, i’m going to take a stab at why I believe he told this version.
What was an important part that you left out about ‘Flashforward’s’ version of Schrodinger’s Cat, was that the Physicist asked for the womans hand. The Physical touching of her hand was part of his ‘pickup’ routine (as told by many experts at picking up women aswell as many online ‘pickup’ websites etc.) Although there was no radioactive device, no hammer etc, but surely, the point was mad that there are two posible outcomes, Kitty lives, or Kitty Dies.
As far as the observer gets to decide, well like i said i’m just learning about it, but I realy do believe that the kitty in the hand, touching her hand, was the main reason for not saying “imagine a box, with a cat and a…” where there would be no physical interaction between man and woman.
cordialdeconstruction said
Sure, he was looking for an excuse to hold her hand, but without the quantum state, it’s not Schrödinger’s cat. The Schrödinger’s cat thought experiment was devised to show what Schrödinger saw as a flaw in the Copenhagen interpretation of quantum mechanics when applied on a macroscopic level, and he devised a way to make a make a macroscopic effect from a quantum state. His point was that the cat isn’t both alive and dead. Since the state on the cat was dependent on the quantum state of the isotope and according to the Copenhagen interpretation the isotope was both decayed and not decayed until the quantum waveform was collapsed by observation, the cat must be both alive and dead until observed, which Schrödinger considered absurd. He considered this to mean that there was a problem with the Copenhagen interpretation of quantum mechanics since the cat was clearly alive or dead independent of observation.
Without the quantum state, it’s just not a quantum superposition, but only a superposition of non-quantum probabilities, and superposition of non-quantum probabilities is exactly what Schrödinger was pointing out as absurd. With a poisoned sardine, the state of the cat is dependent on a choice by the cat of whether to eat the sardine or not and has nothing to do with quantum mechanics or observation at all.
Amnesia said
Maybe that is why he did not mention that it was Schrödinger’s cat and simply said a cat. But yeah he says “Quantum physics says” that was not very smart, thought neither seemed the girl, so I guess that might have been his reason to not mind being not so very accurate.
I just went back to the episode and he does mention Schrödinger’s cat at first..
Simon: Are you aware of the Double Slit Experiment? ?
Camille: Well, there was that one time in college…
Simon: What about Schrödinger’s cat?
Camille: No, I’m not that kinky.
yeah bad move from the show’s writers..
And the common thing between the 2 experiments is the uncertainty principle, so I’m guessing that is what caused the flash-forwards..
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your wrong said
Ok, you seem to have completely missed the point here. The point of Schrodinger’s cat is precisely about quantum probability, which you have stated, and you seem to have a knowledge of this thought experiment and what it means. The thing that is really getting to me is the fact that the point is still being made in almost exactly the same way, but you are quibbling over the fact that it is not explained fully and mentioned the radioactive isotopes and the Copenhagen interpretation. Surely a 10 minute conversation about this thought experiment would waste time in the programme and really doesn’t matter. The nitty gritty stuff is for scientists, not for people just watching some action on television. Don’t get me wrong I love reading physics as much as any studious person, but it really doesn’t matter in the slightest that he didn’t go into every single little detail regarding the experiment. Stop wasting your time complaining and read more physics, you’re obviously interested in it. Not only that but you’ve wasted my time having to correct your ignorance.
Karl Withakay said
It would appear to be you who has completely missed the point and demonstrated your ignorance on the topic. By substituting a poisoned sardine for the decay of a radioactive isotope, quantum probability has been eliminated from the thought experiment and has been replaced by a regular non-quantum, deterministic event.
Further, when the physicist states that the observer gets to choose whether the cat is alive or dead, that is not quantum physics and the collapse of the quantum waveform, it’s a philosophy of a post modernist subjective reality, dependant on the perception and will of the observer. In quantum mechanics, the observation of the cat in the original thought experiment collapses the quantum waveform and solidifies the current state of the cat; it does not choose which state the cat is in, which is what the physicist in the TV show said.
The writers completely misunderstood the thought experiment, and got it wrong on two key points. They replaced a quantum probability with a deterministic event, and then gave the observer a choice in the end state of the cat rather than the observation only being a choice to create the end state of the cat with no ability to choose what that end state was.
It is acceptable to boil a scientific concept like quantum probability and decoherence down to a form the average TV viewer can understand, but only if it remains relatively accurate in the key points.
I have not wasted my time at all, and if you have wasted you time is not my fault. It would seem that I have either read more physics than you, or I have at least better understood and appreciated the nuances of what I have read. It also seems that you either failed to pay attention while reading my post, or you were unable to understand they key points of my post. If by reading this reply you better understand the key points as to why the writers got the thought experiment wrong, then you have not wasted your time at all either.
And by the way, you’ve spelled your name wrong if your intention was to say “you’re wrong” rather than talk about a wrong that I posses. I normally don’t quibble about simple spelling mistakes, but I would think if someone takes the time to compose a 181 word statement claiming someone is wrong on a matter of quantum physics, that they would take time to make sure they haven’t confused “your” with “you’re”. Such a mistake hardly adds to your credibility.
Your comment has been Cordially Deconstructed.
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man said
I cordially accept your deconstruction of my argument! Reading my argument back now I do accept that I was too hasty in my reply to read it back and realise my errors. I do however want to point out that I do understand the thought experiment and do understand that the events described on the show were completely deterministic rather than down to quantum probability. I just meant that shortening the thought experiment down was the right thing to do in the show, rather than having a longer more detailed discussion – after all he was only trying to bed her! Anyway, I apologise for hastily coming to my conclusion without properly thinking about it. I love FlashForward for the reason that it makes the viewer actually consider more than just the storyline – it has an extra element that allows viewers to get involved with the physics of the events unfolding rather than just overly dramatised rubbish that could be written by a six year old (like lost – the worst program ever to intrude my living room). I can’t believe I spelled “you’re” wrong either haha
man said
Don’t answer then bitch.
Karl Withakay said
What were you hoping for?