New Mind
In 1961, the Nobel Prize-winning physicist Eugene Wigner conceptualized a thought experiment revealing a little-known paradox of quantum mechanics. Wigner’s thought experiment demonstrated a strange quirk of the universe. It allows for two observers to experience two different realities from the same event.
It’s based on a quantum measurement of a physical system. In our example, we’ll use the polarization of a single photon. Polarization is a property of photons that when measured, can be described linearly as being either horizontal or vertical. However, in quantum mechanics, until that measurement is made, the photon exists in both polarization states at the same time. This is known as a superposition.
The collapse of a superposition into a known state is a fundamental quantum principle illustrated famously by the double slit experiment. In the double slit experiment, an electron beam is projected through two slits, creating a wavelike interference pattern over time. Once a measurement device is placed in front of one of the slits, probing the electron, the interaction of the measurement device with the electron causes the wave to collapse into a defined electron path.
In Wigner’s thought experiment, he envisions a friend working in a separate lab from his own. His friend is tasked with measuring the polarization state of a single photon and recording the result. To an observer outside of the lab, the friend’s measurement is a unitary interaction that leaves the photon and friends record in an entangled state. The recorded state and the polarization state of the photon are in effect the same information.
Wigner himself can observe the experiment, though he is provided no information about his friend’s measurement or the recorded outcome. Without this information, and with no means of interacting with the photon, quantum mechanics forces him to assume that the photon’s polarization is in a superposition of all possible states.
When Wigner finally asks his friend to read him the recorded measurement, from his perspective the superposition state of the photon now collapses into a single polarization state. Wigner and his friend’s record now both share the same polarization state information as that of his friend’s measurement.
This creates a curious implication. During the period of time when Wigner is forced to view the photon as being in a superposition, his friend views the same photon as having a defined state. But since both points of view must be regarded as equally valid, this is where an apparent paradox comes into play. When now exactly did the collapse of the photon’s superposition occur? Was it when the friend had finished his measurement, or when the information of its result entered Wigner’s consciousness?
This paradox potentially creates a rift in the foundation of science itself, calling into question the nature of measurement. Can objective facts even exist? Scientists carry out experiments to establish objective facts, but if they experience different realities how can they agree on what these facts might be?
Wigner’s thought experiment was put to the test by a team of physicists at Heriot-Watt University in Edinburgh with the results being published in February 2019. The experiment tested for the validity of observer-independence at the quantum level, similarly using photon polarization. Using an extended variant of Wigner’s friend scenario, the results of that experiment lends considerable strength to Wigner’s thought experiment and interpretations of quantum theory that are observer-dependent.
This view of reality questions if observers have the freedom to make whatever observations they want. It also brings locality into question. Locality limits an object to only be directly influenced by its immediate surrounding. It prevents interactions at a distance.
Several counter-arguments have been proposed against the paradox created by Wigner’s experiment. The most obvious counterpoints are those of flaws in assumptions made within the experiment itself. Some have proposed that a privileged position as an ultimate observer, encompassing the entire experiment would be able to reconcile the paradox by viewing the experiment from a larger world view. Others have suggested that conscious observation without interaction do not count as observation, therefore no paradox is created. Some interpretations have even speculated that the observation is personalized due to the information available to the observer and that there is no paradox created, just missing information.
To date, no framework of quantum mechanics offers a full explanation for the implications of Wigner’s thought experiments. And with experimental evidence edging closer to undermining the idea of observer-independent objective reality, the fundamental assumptions of science itself may be in danger.
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The Wigner's Friend paradox proves that the Copenhagen Interpretation is wrong and the Many Worlds Interpretation and its derivatives are the only way to go. Period. Come on people, we would never have gotten past the dark ages without rejecting unscientific notions in physics. Quantum mind new age nonsense is no different. We must keep the cranks out of physics if we want to see real progress.
So it basically says that events don’t happen until you become aware of them and even after they become fact what you witnessed may be different from what others witnessed and you both can be right.
Could have also used a USB drive as an example of superposition.
What if Wigner lies? Will the photon reach a different polarization state for his friend?
How many angels can dance on the head of a pin? Humans just hat to say, I don’t know.
If I understand correctly, when I see my girfriend in my bed with the neighbour, I must not automatically trust my observation. My girlfriend saying the neighbour is in fact not there might be true!??? I think I shall apologize to her since I observed them in a superposed position, which makes him not being there a real possibility.
2:14 when wigner ask his friend, but his friend lies … what happens then? 😮
gosh double commercial are fucking insanely annoying yourube is getting more and more disgusting !
Daca observatorul INTENTIONEAZA SA DEA O TRAIECTORIE fotonului se va observa ca respectivul foton ar urma ENERGIA INTENTIE A OBSERVATORULUI. Ne intoarcem la axioma spiritualista care spune ca ENERGIA ESTE MISCARE CAREIA DACA-I DAM UN VECTOR ,aceasta va urma ENERGIA INTENTIE
"The most obvious counterpoints are those of flaws in assumptions made within the experiment itself"
that is the end of the godamn story ffs.
the thought experiment is flawed. it invalidates itself.
There's a clear answer to this in Logic and Epistemology: Observations (and their formulation) are contingencies about an object of the world. The observations can all be true yet contradict each other because they are contingent on a context of observation. The TRUTH lies WITHIN the object-in-itself (i.e. truth is ontological), but it cannot be fully known strictly empirically (through observation). A true statement is therefore merely the shadow of the truth that lies within the object itself, and as such it is not invalid (given it is true), and it may lead the observer to deduce the rational truth about the object. Theorems that describe formally the intrinsic nature (the truth) of an object can only be formulated by reason and induction — observations (and often multiple, seemingly contradictory observations) are only the preamble that precede the work of Reason, and come in its wake to validate its logical propositions. It's useful to revisit Kant and Leibniz; but also to enquire about the history of Logic as a domain of reason.
Well that was a nice video – let's go to the comment section to meet some Youtube scientists
I would be careful to not jump directly to the conclusion that reality is subjective when there is still the possibility that it is merely relative.
Perhaps reality lies in the communication of perception. Thus positive statements and world view very much impact world reality
“when wigner is forced to view the photon to be in superposition” – he can view it only as H or V. Viewing in superposition is impossible as was said at the beginning you can measure only V or H. It doesnt make sense. Nobody can force him to do something that is impossible. So the act of forcing doesnt occur and the “when” refers to a time which doesn’t exist. The argument is a complete nonsense and falls apart.
what does it mean to measure something?
“measure a polarization state of a single photon” – is a photon given in advance and he has to measure it? or can he measure the polarization of any photon? Because the latter case is trivial. My lamp is producing so many photons that I can be sure some of them will be H polarized. So I don’t use any apparatus at all and just write down an “H” as a result onto a paper. I measured the polarization of one of those H polarized photons from my lamp.
its not true that polarization can be described either horizontal or vertical. it can be described as tilted 45 degrees as well. it can be described as circular clockwise or circular anticlickwise. so the premises of the argument of this video are false therefore the conclusion is invalid.
what does it mean “two realities from the same event” when we talk about quantum mechanics? all i know about quantum mechanics is it seems to be a completely bizarre nonsense which nobody understands and ordinary experience cannot be trusted in it at all. how do we know there is a reality in QM at all? How do we know QM realities can be compared at all? How do we know we can talk about events in QM at all? How do we know we can rationally think and logically reason about QM at all?
i cant imagine how i can measure a polarization of a single photon. never done that. my eye cant even detect a single photon. i know how to measure a bolt diameter with a caliper. thus i cannot imagine what properties this measurement has, like precision, repeatability, if it can be combined with measurement of other photons, if it can be done at arbitrary time or we have to wait for an emission of the photon, etc. since the quantum mechanics is so bizarre and nonsensical, i don’t know if i can use common sense when thinking about it, if i can use logic, if i can ise mathematics or not, if its prrmitted to be internally inconsistent, self-contradictory or not. its a complete black box for me thus i cannot think about it at all and cannot follow the thinking presented in this video cannot see whether it even makes sense is valid or not, true or false. i cant even imagine a photon. i dont know what size it has, how its emitted or absorbed, if its creation and absorption are instantaneous or have some duration, if the photon travels in a particular direction or spreads in a cone like pattern, if its spherical or elliptical, what happens if it hits partially reflective surface. I don’t even know if photons exist! ALL I KNOW IS THAT SOME PEOPLE CLAIM FOTONS EXIST.
What if the friend lies?
This just proves scientists are trying to break away from reality.
I don't think any random person on a good day can tell what way light is being polarized without it being measured… So that flaw (which was mentioned in the video) is the one that needs to be addressed meaning both participants need to measure the photon at the same time. If both measurements are consistently different when using the same tools to measure polarity of the photon then we can argue objective reality might not exist at least on some quantum levels.
They might be giants said science was real though
Or it is just a lie…
there is no consciousness involved in QM, why bring this up, you will only bring more misunderstand of QM for laymans, the measure of a state is what change the state, not look at it or think about it.
Don't mind me, i'mJust collapsing a few superpositions.
It's awesome seeing so many people thinking what I'm thinking that Paradox thrown around too much without necessarily there being one… also, if someone is doing an experiment and the interaction causes the to waveform collapse and I don't know about it, that doesn't mean it didn't collapse
Just because I have not yet been told the fact doesn't mean that there is an "alternative fact" in my mind, only ignorance. The superposition breaks down when the particle is observed. Not later, when the result is being told to someone else.
Weak video, on CPUs was great, this… if you do not understand there are no observation without interaction, is flow in your perception. You can't observe particle and not interact with it, for macro things they emit particles, so you can catch them and make deduction, but for eg photons, you must interact to observe. And all things suggests that particle are not local, or move back in time. IMHO not local is more consistent.
You may than ask, why I watch this video? Because then observation is interaction, and all experiments are observation and not take in account collapsing quantum state, how many "well known" things are only true then observed, but may not then are not observed -> not interact? Because as double slip experiment, if we try make sure what happen, we destroy result, no local particle interact without collapsing (wave interference), so maybe many more thing are with it, but because constant observation we missed it in experiments?
Voting for the solution where the "conscious" part is the flaw. Superpositions do require a consciousness to collapse but an observation is merely the interaction of two systems, as far as I understand it and as suggested by one of my favourite videos on this topic https://www.youtube.com/watch?v=8DGgvE6hLAU
Also, amazing video New Mind, deserves way more views … and as usual with this topic, went "slightly" over my head 🙂
some late thoughts. good work. qm is not a complete theory, yet. in qm, observation is not 'seeing with a human eyeball'. in qm, observation is a recording of an event, where the recording method must be Wholly Passive, and does Not introduce any extra energy/photons (for 'seeing'), into the experiment. imo, this thought experiment posits a simultaneity of events, that does not exist. btw, there are occasional, distracting mispronunciations in yer videos. at :19, it's not 'noble', it's No-BELL. also, not sub-SEE-quently, as pronounced in yer stealth video. cheers googletranslate
There's not a paradox here, as stated early in the video his friends info, and the state of the photon are the same info. So when Wigner still sees the photon as in a superposition his friends observation is ALSO A SUPERSPOSITION. and that superposition doesn't collapse until Wigner "observes" if by asking what the photon is.
….yet notable luminaries such as Neil deGrasse Tyson, Brian Greene, Michio Kaku, Jim Al-Khalili and others will state emphatically that Quantum Mechanics is the most accurate and powerfully predictive tool known to man….
I've watched most of your videos and this one is much worse than the others. Either you did a bad job describing the paradox or the paradox itself if dumb. Nevertheless keep up the good works as with other videos.
yes.
So, here's an interesting if somewhat pointless question:
Can you disprove science?
And I don't mean stuff like gravity, thermodynamics, relativity, and so on.
Those are the PRODUCTS of science; what we discovered while using the tool of science.
No, can you disprove science itself? The basic principles behind it, and if so, how?
Because ironically, one of the arguments given against God, religions and similar notions (see, magic, fairies, invisible unicorns, etc) is that in most cases you can neither prove, nor disprove that such things exist, not even in a hypothetical context.
So, can you disprove science? And if not in practice, what about hypothetically?
What would disprove the validity of science?
(And yes, unfortunately the nature of this question amounts to 'can you use science to prove science whether science is valid.' But that's a reasonable enough question given what science is meant to be…)
The biggest irony of this particular thought experiment, is it relies on a set of scientific theorems to be valid to even meaningfully ask the question, yet the outcome calls into question the validity of the scientific method itself, and thus also everything that derives from it, including the laws, postulates, and theorems the thought experiment depends on to hold any meaning.
In some ways this makes the thought experiment a very bizarre variant of the grandfather paradox.
If you show it to be true, it destroys itself, which then causes it to come back into existence, and so on and so on…
Truly bizarre…
i think objective facts exist independent of us. we only measure – observe – them. nothing too difficult in it. any uncertainty we have is only in how accurate we are in measuring things
I am guessing there are incorrect facts mentioned about the quantum experiment explained during 2.00 till 2.20.
Oh c'mon, we should abolish this concept of our consciousness having anything to do the QM, simple fact is, that for some reason is either being misunderstood or intentionally manipulated, is that what we call 'observation' is actually causing a particle to interact with a particle. Which what causes the wave function to collapse, nothing more, nothing less. You have no influence over reality in this regard.
Finally! Someone who explains the double slit experiment as it is, without the new age "create your own reality" crap.
Nicely done but it highlights the inability to progress when materialism is ASSUMED and theories about how to fix it are bound by its reliance on assumptions and the math
Clueless about so much.. some in the field WILL admit this is a fact, most try to focus on the good not how the model has been failing to answer so much for so long, how long since it actually went anywhere and was updated to be more elegant and LESS COMPLEX ? maybe never it just gets more and more complicated ? everyone is focused on trying to find those tiny details that MUST be there because.. just must ? this is counter productive AF ! despite how great and close and useful and time tested and seemingly right it is, you have to TRY to break out of the belief in the fundamental nature of reality you build your model on. Assumptions that were valid need to be evaluated without a vested interest. I don't expect that until there is no choice and the better model is accepted, then it will be a quiet oops and OK LETS GO FORWARD. To abandon the particle model now would be career suicide for most who literally need it to be accepted ! to validate their existence and right to a paycheck and research grants, so on and so on. There is the opposite to incentive for entrenched materialists but the nails are covering the coffin.
https://www.youtube.com/watch?v=-kNtJ08a-ss MBT is actually so easy and obvious.. initially it is super confusing to most, or rejected because of beliefs or snap judgement as people tend to make. Open minded thorough investigation is all that is required. Its nothing more than a new viewpoint that lets the standard model of particle physics be a part but not THE whole, since IT DOES NOT WORK as the fundamental answer. MBT just works, and even if 0 care for logic and modelling things to understand functionality etc.. Tom is the most useful person no matter what isn't right in your life. Find the right video, ask on a recent video if you have to.. give him a chance he will make your life AMAZING and things that were so hard can become non factors or even positives in your life so easily ! ever heard someone overstating the power of the mind ? wrong ! learn MBT you will see they actually understated it. Happy evolving everyone 🙂 fingers crossed for anyone who dips their foot in by listening to a few minutes of intro. Tom who ? Tom the physicist who found out reality wasn't what he was taught and took it upon himself to spend almost his entire life researching meticulously. One Q&A member once asked was there anything his father taught him that was really significant and he clearly did. SON IF YOU'RE GOING TO DO SOMETHING NO POINT UNLESS YOU DO IT RIGHT. He committed 100% and clearly was very careful that the data was beyond enough to make conclusions and progress. How we interpret data, what information actually is, so much is.. too much for me to tell 🙂 enjoy !