# Bell’s Theorem: The Quantum Venn Diagram Paradox

Henry:  If you have polarized sunglasses,
you have a quantum measurement device. Grant: Each of these pieces of glass is what’s
called a “polarizing filter”, which means when a photon of light reaches the glass,
it either passes through, or it doesn’t. And whether or not it passes through is effectively
a measurement of whether that photon is polarized in a given direction. Henry:  Try this: Find yourself several sets
of polarized sunglasses. Look through one set of sunglasses at some
light source, like a lamp, then hold a second polarizing filter, between you and the light. As you rotate that second filter, the lamp
will look lighter and darker. It should look darkest when the second filter
is oriented 90 degrees off from the first. What you’re observing is that the photons
with polarization that allows them to pass through a filter along one axis have a much
lower probability of passing through a second filter along a perpendicular axis – in principle
0%. Grant: Here’s where things get quantum-ly
bizarre. All these filters do is remove light – they
“filter” it out. But if you take a third filter, orient it
45 degrees off from the first filter, and put it between the two, the lamp will actually
look brighter. This is not the middle filter generating more
light – somehow introducing another filter actually lets more light through. With perfect filters, if you keep adding
more and more in between at in-between angles, this trend continues – more light! Henry:  This feels super weird. But it’s not just weird that more light
comes through; when you dig in quantitatively to exactly how much more comes through, the
numbers don’t just seem too high, they seem impossibly high. And when we tug at this thread, it leads to
an experiment a little more sophisticated than this sunglasses demo that forces us to
question some very basic assumptions we have about the way the universe works – like,
that the results of experiments describe properties of the thing you’re experimenting on, and
that cause and effect don’t travel faster than the speed of light. Grant:  Where we’re headed is Bell’s theorem:
one of the most thought-provoking discoveries in modern physics. To appreciate it, it’s worth understanding
a little of the math used to represent quantum states, like the polarization of a photon. We actually made a second video showing
more of the details for how this works, which you can find on 3blue1brown, but for now let’s
just hit the main points. First, photons are waves in a thing called
the electromagnetic field, and polarization just means the direction in which that wave
is wiggling. Grant: Polarizing filters absorb this wiggling
energy in one direction, so the wave coming out the other side is wiggling purely in the
direction perpendicular to the one where energy absorption is happening. But unlike a water or sound wave, photons
are quantum objects, and as such they either pass through a polarizer completely, or not
at all, and this is apparently probabilistic, like how we don’t know whether or not Schrodinger’s
Cat will be alive or dead until we look in the box. Henry: For anyone uncomfortable with the nondeterminism
of quantum mechanics, it’s tempting to imagine that a probabilistic event like this might
have some deeper cause that we just don’t know yet. That there is some “hidden variable”
describing the photon’s state that would tell us with certainty whether it should pass
through a given filter or not, and maybe that variable is just too subtle for us to probe
without deeper theories and better measuring devices. Or maybe it’s somehow fundamentally unknowable,
but still there. Henry:  The possibility of such a hidden
variable seems beyond the scope of experiment. I mean, what measurements could possibly
probe at a deeper explanation that might or might not exist? And yet, we can do just that. Grant:…With sunglasses and polarization
of light. Grant: Let’s lay down some numbers here. When light passes through a polarizing filter
oriented vertically, then comes to another polarizing filter oriented the same way, experiments
show that it’s essentially guaranteed to make it through the second filter. If that second filter is tilted 90 degrees
from the first, then each photon has a 0% chance of passing through. And at 45 degrees, there’s a 50/50 chance. Henry: What’s more, these probabilities
seem to only depend on the angle between the two filters in question, and nothing else
that happened to the photon before, including potentially having passed through a different
filter. Grant: But the real numerical weirdness happens
with filters oriented less than 45° apart. For example, at 22.5 degrees, any photon which
passes through the first filter has an 85% chance of passing through the second filter. To see where all these numbers come from,
by the way, check out the second video. Henry: What’s strange about that last number
is that you might expect it to be more like halfway between 50% and 100% since 22.5°
is halfway between 0° and 45° – but it’s significantly higher. Henry: To see concretely how strange this
is, let’s look at a particular arrangement of our three filters:  A, oriented vertically,
B, oriented 22.5 degrees from vertical, and C, oriented 45 degrees from vertical. We’re going to compare just how many photons
get blocked when B isn’t there with how many get blocked when B is there. When B is not there, half of those passing
through A get blocked at C.  That is, filter C makes the lamp look half as bright as it
would with just filter A. Henry: But once you insert B, like we said,
85% of those passing through A pass through B, which means 15% are blocked at B.  And
15% of those that pass through B are blocked at C. But how on earth does blocking 15% twice
add up to the 50% blocked if B isn’t there? Well, it doesn’t, which is why the lamp
looks brighter when you insert filter B, but it really makes you wonder how the universe
is deciding which photons to let through and which ones to block. Grant: In fact, these numbers suggest that
it’s impossible for there to be some hidden variable determining each photon’s state
with respect to each filter. That is, if each one has some definite answers
to the three questions “Would it pass through A”, “Would it pass through B” and “Would
it pass through C”, even before those measurements are made. Grant: We’ll do a proof by contradiction,
where we imagine 100 photons who do have some hidden variable which, through whatever crazy
underlying mechanism you might imagine, determines their answers to these questions. And let’s say all of these will definitely
pass through A, which I’ll show by putting all 100 inside this circle representing photons
that pass through A. Grant: To produce the results we see in experiments,
about 85 of these photons would have to have a hidden variable determining that they pass
through B, so let’s put 85 of these guys in the intersection of A and B, leaving 15
in this crescent moon section representing photons that pass A but not B. Similarly,
among those 85 that would pass through B, about 15% would get blocked by C, which is
represented in this little section inside the A and B circles, but outside the C circle. So the actual number whose hidden variable
has them passing through both A and B but not C is certainly no more than 15. Grant: But think of what Henry was just saying,
what was weird was that when you remove filter B, never asking the photons what they think
about 22.5 degree angles, the number that get blocked at C seems much too high. So look back at our Venn diagram, what does
it mean if a photon has some hidden variable determining that it passes A but is blocked
at C? It means it’s somewhere in this crescent
moon region inside circle A and outside circle C. Grant: Now, experiments show that a full 50
of these 100 photons that pass through A should get blocked at C, but if we take into account
how these photons would behave with B there, that seems impossible. Either those photons would have passed through
B, meaning they’re somewhere in this region we talked about of passing both A and B but
getting blocked at C, which includes fewer than 15 photons. Or they would have been blocked by B, which
puts them in a subset of this other crescent moon region representing those passing A and
getting blocked at B, which has 15 photons. So the number passing A and getting blocked
at C should be strictly smaller than 15 + 15…but at the same time it’s supposed
to be 50? How does that work? Grant: Remember, that number 50 is coming
from the case where the photon is never measured at B, and all we’re doing is asking what
would have happened if it was measured at B, assuming that it has some definite state
even when we don’t make the measurement, and that gives this numerical contradiction. Grant: For comparison, think of any other,
non-quantum questions you might ask. Like, take a hundred people, and ask them
if they like minutephysics, if they have a beard, and if they wear glasses. Well, obviously everyone likes minutephysics. Then among those, take the number that don’t
have beards, plus the number who do have a beard but not glasses. That should greater than or equal to the
number who don’t have glasses. I mean, one is a superset of the other. But as absurdly reasonable as that is, some
questions about quantum states seem to violate this inequality, which contradicts the premise
that these questions could have definite answers, right? Henry:  Well…Unfortunately, there’s a
hole in that argument. Drawing those Venn diagrams assumes that
the answer to each question is static and unchanging. But what if the act of passing through one
filter changes how the photon will later interact with other filters? Then you could easily explain the results
of the experiment, so we haven’t proved hidden variable theories are impossible; just
that any hidden variable theory would have to have the interaction of the particle with
one filter affect the interaction of the particle with other filters. Henry:  We can, however, rig up an experiment
where the interactions cannot affect each other without faster than light communication,
but where the same impossible numerical weirdness persists. The key is to make photons pass not through
filters at different points in time, but at different points in space at the same time. And for this, you need entanglement. Henry: For this video, what we’ll mean when
we say two photons are “entangled” is that if you were to pass each one of them through
filters oriented the same way, either both pass through, or both get blocked. That is, they behave the same way when measured
along the same axis. And this correlated behavior persists no matter
how far away the photons and filters are from each other, even if there’s no way for one
photon to influence the other. Unless, somehow, it did so faster than the
speed of light. But that would be crazy. Grant:  So now here’s what you do for the
entangled version of our photon-filter experiment. Instead of sending one photon through multiple
polarizing filters, you’ll send entangled pairs of photons to two far away locations,
and simultaneously at each location, randomly choose one filter to put in the path of that
photon. Doing this many times, you’ll collect a
lot of data about how often both photons in an entangled pair pass through the different
combinations of filters. Henry:  But the thing is, you still see all
the same numbers as before. When you use filter A at one site and filter
B at the other, among all those that pass through filter A, about 15% have an entangled
partner that gets blocked at B.  Likewise, if they’re set to B and C, about 15% of
those that do pass through B have an entangled partner that gets blocked by C.  And with
settings A and C, half of those that through A get blocked at C. Grant: Again, if you think carefully about
these numbers, they seem to contradict the idea that there can be some hidden variable
determining the photon’s states. Here, draw the same Venn Diagram as before,
which assumes that each photon actually does have some definite answers to the questions
“Would it pass through A”, “Would it pass through B” and “Would it pass through
C”. Grant: If, as Henry said, 15% of those that
pass through A get blocked at B, we should nudge these circles a bit so that only 15%
of the area of circle A is outside circle B.  Likewise, based on the data from entangled
pairs measured at B and C, only 15% of the photons which pass through B would get blocked
at C, so this region here inside B and outside C needs to be sufficiently small. Grant: But that really limits the number of
photons that would pass through A and get blocked by C.  Why? Well the region representing photons passing
A and blocked at C is entirely contained inside the previous two. And yet, what quantum mechanics predicts,
and what these entanglement experiments verify, is that a full 50% of those measured to pass
through A should have an entangled partner getting blocked at C. Grant: If you assume that all these circles
have the same size, which means any previously unmeasured photon has no preference for one
of these filters over the others, there is literally no way to accurately represent all
three of these proportions in a diagram like this, so it’s not looking good for hidden
variable theories. Henry:  Again, for a hidden variable theory
to survive, this can only be explained if the photons are able to influence each other
based on which filters they passed through. But now we have a much stronger result,
because in the case of entangled photons, this influence would have to be faster than
light. Henry: The assumption that there is some deeper
underlying state to a particle even if it’s not being probed is called “realism”. And the assumption that faster than light
influence is not possible is called “locality”. What this experiment shows is that either
realism is not how the universe works, or locality is not how the universe works, or
some combination (whatever that means). Henry: Specifically, it’s not that quantum
entanglement appears to violate realism or the speed of light while actually being locally
real at some underlying level – it the contradictions in this experiment show it CANNOT be locally
real, period. Grant: What we’ve described here is one
example of what’s called a Bell inequality. It’s a simple counting relationship that
must be obeyed by a set of questions with definite answers, but which quantum states
seem to disobey. Grant: In fact, the mathematics of quantum
theory predicts that entangled quantum states should violate Bell inequalities in exactly
this way. John Bell originally put out the inequalities
and the observation that quantum mechanics would violate them in 1964. Henry: Since then, numerous experiments have
put it into practice, but it turns out it’s quite difficult to get all your entangled
particles and detectors to behave just right, which can mean observed violations of this
inequality might end with certain “loopholes” that might leave room for locality and realism
to both be true. The first loophole-free test happened only
in 2015. Grant: There have also been numerous theoretical
developments in the intervening years, strengthening Bell’s and other similar results (that is,
strengthening the case against local realism). Henry: In the end, here’s what I find crazy:
Bell’s Theorem is an incredibly deep result upending what we know about how our universe
works that humanity has only just recently come to know, and yet the math at its heart
is a simple counting argument, and the underlying physical principles can be seen in action
with a cheap home demo! It’s frankly surprising more people don’t know about it

## 100 thoughts to “Bell’s Theorem: The Quantum Venn Diagram Paradox”

1. Draw Slash Play says:

My brian herts for know raisin.

so light when not directly observed is a wave not a particle. i think the reason why the light seems to be 50% when 15 and 15 are involved is because light is not to be quantified. light is not just little balls of particles going through a filter. its something metaphysical.

3. Hearts Hope says:

The hidden variable could be field Dynamics

4. Dan Solomon says:

I'm not an educated man but I am smart enough to know this is not right. I have my own ideas but I'm also smart enough to keep that myself.

5. Sherry Krivosheev says:

call me a sceptic, but there is a much simpler explanation that can be found here: http://www.alienryderflex.com/polarizer/ Basically each filter modifies all orientations to just one if they are <45deg apart and blocks others. So the middle filter just rotates the light 45%

6. Charles Bolanos says:

This dude say's that these filter readings are pretty much impossible to produce more light the way they do, YET he thinks the Immovable object and unstoppable force is easily explained.. Ok I'm checking out

7. Jeremy Mettler says:

Black or ying isn't opposite of good it's the beginning of all light .yang has to ying for there to be a yang. Only a idiot would believe evil has anything to do with good . Just like me the strong survive this Fucking dumbass as that . The wormy one percent not close to beyond guilt or strong or shit . rich are worms . How few lead manyis may works that to fake ass to be worms . They just pretend that there not wormy and want worny to robbed tbemlie to them piss the worm idiots of so manycango worm because there leader wormsat get them. Pathtic or scared or dumbass or you lie to self you one are .sure as hell not Americans or you wouldn't be killing America . without unbaised unopionated facted checked news you pukes all do exactly that the constition says

8. Charles Ringling says:

What if some of the photons are passing through but also the lens itself it reacting to the photons hitting it and generating new polarized photons but at a different wavelength like UV then by hitting the 3rd lens its slowed slightly to visible light. Has anyone measured non visible light between each lens or measured angular deflection with a laser?

9. joe cool says:

so like sound phase ? you get a silence in audio when the frequencys match using digital audio programs … you can press a 'phase' button to counteract the silence which just flips the wave frequency so they are not but are the same …… is this the same ?

10. maurice richards says:

It knows its path faster than light. We see light but not gravity

11. enes akar says:

Rip high school students

12. Jahkra says:

QUANTUM IS SO WEIRD

13. Gerardo Moscatelli says:

This is already the 10th time I watch this video. Tks

14. Pikeandslippers says:

Is this the same as a Bell End experiment?

15. Marce says:

I guess sometimes the hardest questions have the simplest solutions in some way. I mean maybe it is possible that the filter doesnt filter the light by blocking it but transforming its energy to somesort of non visual light until third filter kinda turns in back. I guess measuring heat absorption could maybe explain us something about it.

16. mmlgamer says:

Isn't it possible that you're just seeing the reflection of light that is going in the opposite direction?

17. Uwe B says:

Sorry, you probably are right, but you are speaking too quickly.

18. Orsel Louis says:

What if each particles has two properties? Such that affects visibility and presence? What if each filter removes some visibility but not the actual presence of the particles? Therefore as you introduce a third filter this changes or rather reverts the visibility of said particle allowing it to be reshaped? What do you guys think?

19. Tony Lovering says:

What happens when you put the 3rd filter behind the 2nd?

20. halneufmille says:

This is definitely proof we don't live inside a simulation. What alien in their right mind would invent a world with such counter intuitive laws of physics?

21. Дима Авениччи says:

Universe: can we have math please?
Quantum physics: we have math at home
Math at home: 15+15=50

22. Sanoseph says:

so how does this affect what we know now with quantum entanglement being able to transfer things instantly faster than light, does it affect this theory at all i believe it was discovered after this video was posted

23. N. Eckert says:

It's not a grand question, you are polarizing the light in one direction then setting a polarizer with a transmission axis of 45° to the polarized light. This results in a transmission intensity of I=(I"initial" •cos(theta)^2) which in this case makes an intensity of about half, adding another polarizer at 45° the the second would half the second intensity making the new intensity I"initial" divided by 4

24. English Guy says:

25. rashed a564 says:

Am I on the right channel, wasn't this supposed to be one minute or is it just the relativistic effect

26. Gary McLaughlin says:

The actual demo part of the video was great. The additional 40 minutes of self-congratulation, not so much.

27. SEO-Greg Johnson says:

the problem is they are measuring it as a partical Humar me and try the same experiment but measurement application should be waves or freaquency :?}good luck

28. Roy Lavecchia says:

There is no mystery here and this has nothing at all to do with quantum physics or quantum entanglement. First, take 2 lenses and measure the amounts that the light dims or brightens as you rotate the second lens from 0 to 360 degrees (0 degrees = 100% brightness, 22.5 degrees = 92.39% brightness, 30 degrees = 86.60%, 45 degrees = 70.71% and so on and you will see that it follows a simple sine curve. Now, when we use 3 lenses and place a second lens on top of the first at 45 degrees it reduces the light to 70.71%, then a 3rd lens on top of the first 2 at a 45 degree turn from the second (90 degrees from the first) will take the light (currently at 70.71% brightness) and reduce it again by 70.71%, resulting in a final light intensity of 50% (as seen filtered through the 3 lenses). However, what is important here is the order you place the lenses. Had we taken the middle lens (lens B) out and placed it on top of lenses A and C the final light intensity would be 0%. The reason is because if we start with lens A, then place lens C on top of it at 90 degrees, it will result on 0% brightness, so adding lens B on top of that at 45 degrees would be 70.71% of 0%, which would be 0%. You can try this experiment yourselves quite easily at home using simple polarized lenses

29. Aslan Guseinov says:

Think of it like balls in billiard. They go back and forth between filters!

30. Dario Rigon Channel says:

Mhh so theories about variables are totally wrong…, maybe it is not blocked but “absorbed”

31. benno291980 says:

"Hidden variable theory"? We're real quick to jump to mentioning that without any knowledge of the behavioral mechanics of photons, aren't we?

There's no such thing as random.

32. Ivan Lopez says:

When they came up with the theory of perfect filters, that made me think that, sure entanglement, but the filters in quantum theory, it would make more sense without doing the math.

33. imperfekt says:

It seems clear to me that putting a filter at 45 degrees between the 0 and 90 perpendicular ones, you're "nudging" or, rotating the photons more gradually, instead of expecting them to just go from 0 to 90…

34. Momma Llama says:

35. Mel Clifford says:

Man you have to back off on the amount of charlie you're putting up your nose!

36. SteelBlueVision says:

What if each polarizer either adds or changes "information" in the photon and this change is only visible when three or more filters are in its path?

37. Wes Small says:

The lenses don't just block light, they effect light. Like how the legs of a dock don't just block waves, they effect waves.

38. Pankaj Thorat says:

Its simple…
What i think is that electro magnetic spectrum isn't the complete thing we humans know about.. Just because we dont have detectors, we haven't completely explored the matter spectrum.
Filter B isnt actually blocking every particle, as we see it. There are particles which still travel through B but are invisible to our eyes or cameras, or detectors we have with us today. These particles show up at filter C

39. laen programmation says:

maybe some get reflected and finish by changing a bit of polarity?

40. Michał B. says:

OK, but in what direction are the photons polarised in the end?

41. Jason Okoro says:

So basically since one setup lets more than another setup’s 50% of photons through, the photons must either change their mind or communicate faster than light after each filter to let more of themselves through and themselves through more . Interesting theory. Just a long vid 😂. Loved it tho.

42. Boris Tiutrin says:

if you say exactly photons are waves or particles then it will not be paradox any more. 🙂

43. ImThe 11Dimensions says:

Unlike the voice of 3B1B, the voice of this 1minphysics is so bothering! Why are you fucking yourself to speak fast? You think you sound smarter in this way?

44. Gerardo Moscatelli says:

15% + 15% blocked is simply wrong : you don't know how much is filtered by each polarizer independently when they are together and you can't measure it independently, you can only measure the intensity at the end of the three filters

45. Gerardo Moscatelli says:

The analogy with the circles is confusing. One person can't be in the group of not wearing a hat and wearing a hat at the same time but quantum particles can be in a superposition. Trying to explain Quantum Mechanics with people or balls always leads to more confusion : a photon is not a little ball

46. Gerardo Moscatelli says:

So we can conclude that photons behave like photons and not like people wearing glasses or not wearing glasses? Is this the essence of Bell's inequality? Comparing things that aren't comparable?

47. Brandon Brown says:

Could this be the reason the human eye perceives light different person to person? Eye to eye even?

48. Eden Lumbroso says:

My bet is that quantum physics is bs because this can be explained easily with just waves

49. Andre Dias says:

I bought some filters and it did not work. Where can I buy 3 that will work?

50. Eric Fleet says:

If I want to do this experiment myself, is there any special type of lens to buy? Is it simply a polarized circular lens?

51. Mystically Toned says:

im gonna start watching these videos high

52. Kyle Groat says:

All you have to do is change the distance to also change the effect thus proving refraction, not magic this is like a flat earth discussion as far as variables explored

53. Rick Kephart says:

I don't have enough neurons still firing to truly understand that but still enjoyed trying to understand.

54. Yulia S says:

Damn it, Minute Physics, stopping using + signs.

55. PresidentialWatch says:

This phenomenon isn’t so mystifying when you understand how polarizing filters are made and work. Adding a middle filter, thus allowing more light through is well understood and very logical.

However the seemingly probabilistic nature of particles ie “Which will pass and which will not”, which I think is all the video is ultimately getting at, is left to many interpretations of the nature of reality.

56. Social Experiment says:

Please someone tell me, how does light even go through ANY other angle of the second polatrizer than the first one? I dont get it, if a polarizer only lets one angle through, shouldnt light be blocked by any other angle after being polarized?

57. Gerald Duke says:

What if any light that gets blocked transfers it’s energy to either a wave beside, behind, or a combination of both to alter if a wave will pass through a filter 🤔 meaning if 2 waves get blocked, they instead combine and attempt to pass through again before losing enough energy and becoming the shadow which determines the % of light that passes through a filter

58. Zeus Thor says:

5:36 There are actually 101 photons.

59. Arcticnerd says:

Entanglement passing information faster then light doesn't seem that crazy if you consider that the entangled pair are connected through higher dimensions. They wouldn't be independent particles but rather two parts of a while.

60. John m Gannon says:

All the light passes through ,but we cant see it ,because it is polarised the next filter unpolarises the light ,then we see it again .Quantum is tooth fairy nonsense, stop trying to trick people into thinking you are smarter than them ,you are just paid to lie.

61. Jack Warden says:

Serious question. Is it possible that the 22.5 degree lens alters the photons in such a way that it makes itself seem like the new "0 degree point", thus another 22.5 degree turn (making a total of 45 degrees) is still only 22.5 from the previous "0 degree point", thus only filtering out the expected 15% from such a variance. Also if you tilt the 3rd filter 45 degrees from the SECOND filter (a total of 67.6 degrees) does it reduce the light by 15% at the second and then 50% at the third? (Also might be fun to try more than 3 filters all tilted 22.5 degrees from each other and see if it reduces the light by 15% each time.)

62. tim baldwin says:

Scientists need to create new laws that photons can adhere to. Lawlessness and chaos in our universe cannot tolerated.

63. DABGOD says:

Mah poor brain…

64. wayne Last says:

Maybe slow down a little and think how sentences may run together. Otherwise excellent content . But I had to slow it down and replay several times.

65. wayne Last says:

Are you saying the evidence is mounting that realism is not possible either locally or not locally? I personally am a local realist.

66. Meer Selengera says:

this is the trick. he put the third lense BETWEEN two lenses, that not allow the light propagation. if he put the third one AFTER the two ones, he will get the penis, but the light.

67. HairlessWookie OfHoth says:

What if its like interference… When playing guitar no matter what the 2 notes resonate and make louder sound.. With precision speakers they can cancel sound… If 2 sounds really cancel how can they re amplify in interferometry? Same with light? There must be an ether like tesla said.. Incompressable medium for action at distance.. And all electrical connections go as far as the nearest charged particle

68. Glenn Racette says:

So if 85% pass thru at 22.5 and it always "forgets" the previous one then filter 3 is now 2 again at 22.5 which blocks 85% again. That's not hard.

69. Anh Nguyen says:

I like your videos. But please, topics are complicated enough yet you make the video too fast to follow. Man, you talk like somebody is chasing you.

70. neo24483 says:

Excellent job guys! Keep it up!

71. Benjamin Cushwa says:

As a physicist and a photographer, this video was supremely satisfying and interesting.

Thank you both Henry and Grant.

72. Leslie Munday says:

Great video explanation, but where did the word ex-spear-mint come from? I've heard this pronunciation of experiment just once before and was interested if this is going to become a new trend.
I agree with a previous comment that because this is such a complicated concept, it would help the reader if the speaker went a little slower. I found myself pausing the video and reversing quite often.
Still not going to claim to fully understand.

73. PP says:

Ok, ok, maybe i missed the answer or i dont get it…
But how can it be, that more light passes through those filters when a third filter is put in between? For me, to say they have no hidden variables does not explain why more light gets through three filters, then through two…

74. Trendy says:

Please correct me on my understanding. But as i understood this the point of reference from the 0 to 45 degrees was 0. Thus, due to the equation Cos^2(theta), you get only 50% of particles moving through but with 22.5 you get 85% pass through. Well, if you have 22.5 degrees in the middle, then the reference from 22.5 to 45 becomes 22.5 and the change in degrees is only 22.5. So if the equation is manipulated to cos^(theta) where theta is the change from the previous angle to the current one, then you would get cos^2(45-22.5) resulting in the 85% once again. Why is this wrong if it is?

75. Little Monk says:

This is a fundamental universal law. For example, if you give money to a needy person, 100% goes to that person. But if you include a middleman ie. give it to a charity to give it to the needy person, only 15% goes to the needy person, so what happened to the 85%.

76. BrettVsAll says:

So the polarized glasses that let's call it warping light a different angle would just bounce back when bounced through b to realign for c kinda like the negative light isn't visable to the naked eye similar to infrared. Hidden variables are how polarized glasses polarized light by not blocking light but warping it.

77. Brian Martin says:

lmao why not try putting this on a phone no one would see it on except you

78. Seán O'Nilbud says:

Burn the witch.

79. Victor Eduardo says:

Guys this could be it. The answer to the question of how women think.

80. jacob enthoven says:

hehe, wiggiling

81. Java McPhearson says:

Have we established that polarizing filters do not modify the polarity of pass through photons?

82. yttrium says:

Could they use that thing with the two lenses to make prescription glasses that can turn into sunglasses?

83. judgeomega says:

"all these filters do is remove light"
obviously that is a false assumption. nature is the ultimate judge of the truth. and the experiment clearly demonstrates that polarizers do NOT 'just remove light'.

84. timwins31 says:

I'm all for people asking questions in the comments. . .but man are there some arrogant douche bags commenting on this video. Its amazing to watch people claim to know how something works, when really they KNOW they don't, like rejecting the explanation makes it wrong somehow. I'm always reminded of a quote from NDT – "the universe is under no obligation to make sense to you. . .". So if something doesn't make sense to you, sure, ask questions, be curious, try to understand. . .but don't just assume its wrong because you don't grasp it. That's the sign of a real dickhead.

85. Pierre Jouve says:

The main difference between Classical electromagnetism and the quantum model is that in one case you measure the energy passing through and the other one the number of photons passing through using the probability. But both relation depend on the cosine^2 (angle between two polarizers). So the theory of electromagnetism can actually explain that the filter is brighter if you add one at 22.5 degree, due to the nonlinearity of the energy passing through. The classical model breakdowns when there is only one photon, WHICH is a particle and not a wave, so you have to work out the probability because one photon can only pass or not pass. The fact that the illegality is broken is that the successive measurement do change the state of the photon, but you can explain that with a classical theory too. And sure the bell's experiment shows that one measurement affects the other but the 3 filters don't show nothing about this, at least not more than the classical theory. Any thoughts about this ?

86. Troy Gardner says:

In playing with this it's far from the only fun thing with light and shadow.

Try playing with any specular (e.g. RA/sun SOURCE vs MID) your shadow and ball or comb (e.g. a taco bell hot sauce wrapper) to see SHADOW bending

87. envagyok gyuri says:

old polarizing filters? Have you heard about B&W, Hoya, Kenko, etc companies?

88. Basil Baccouche says:

This was an amazing video

89. Greivin Altamirano says:

Don't think of it as a whole, take it one by one. Once light passed through the first one, that first one won't be part of the equation anymore. Does it make any sense?

90. Michael Price says:

Look it's simple, the guy who coded this simulation was too lazy to do a coherent atomic level physics. Probably thought as long as it gets aproximately the right results at macroscopic levels nobody would notice. But buggy as it is, Outside is the best game ever. Wish they hadn't nerfed dinos.

91. Paul says:

You don't need to look into the box to know if the cat is alive or dead. You simply wait an amount of time and the cat will have to be dead.

92. northhamptonshire says:

"This feels inexplicably weird!" No it doesn't… Polarized light is oscillating along a given axis. Just work out the problem with vectors and you'll see how easy it is to explain the behavior of light when you add in-between filters lol Clearly a bad pitch… The rest is great tho

93. Alexander Mo says:

What if, hypothetically, polarized photons are spinning clockwise explaining the angles and probabilities. I'm curious what would happen if you swap the positions of angled filters B (22.5l and C (45)

94. Andrey Lebedenko says:

Light carries information about each step in the experiment (entanglement included). That's what light usually does. That's why we trust our eyes (usually). =) On top of that Bohm's interpretation looks like a winner here.

95. Sheikh Ovais says:

Brilliant.org has made an amazing quiz on this: https://brilliant.org/practice/quantum-light

96. Donald Amaele says:

So, imagine if you closed your eyes between for longer periods of time in the day for 3 hours peak and off-peak between 9 and 3. What will the experimenter experience????

97. noneed toknow says:

I'm no PHD, but it seems perfectly sound to me using the sine value as the determinant for %of pass between filters, and as for the paradox, could it be a waveguide? keeping in mind the superpositioning nature of the multiverse, could it be persuading the photons/wavefunction to twist toward the next polarization? I think all particles are just waves of different types (some full integral, some half integral lol) and I think coulombic force may have something to do with polarization. after all, the electrons that emit microwaves aren't half a centimeter in diameter, but you can polarize and lense microwaves with parralel tinfoil sheets spaced half a centimeter apart. just some thoughts

98. jubuttib says:

Ah cool that this video popped up in my recommended feed, I had recently noticed this while playing around with a TV and two polarized clip-ons (flat TVs have a polarizing filter in them as well, so total number of filters was 3).

99. ballz deep69 says:

Witch craft I say

100. Jamie Wilson says:

Trash