
The “dead and alive” cat myth - c3d
https://gutoe.wordpress.com/2016/12/11/the-dead-and-alive-cat-myth/
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pranjalv123
No, this is wrong. If the box is made of glass and you can see what's
happening inside, the photons that reflect off the cat collapse the
wavefunction so the cat really is alive or dead. In the case of the metal box
and the completely isolated system, the cat is really in a fundamental way in
a superposition of alive and dead - you can construct an experiment [1] that
shows that entanglement can't be explained by local hidden variable theories.

[1]:
[https://en.wikipedia.org/wiki/CHSH_inequality](https://en.wikipedia.org/wiki/CHSH_inequality)

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QuantumRoar
Nothing about this makes any sense. The cat is an analogy, the box is an
analogy. Everything about that thought experiment is an analogy.

The moon is still there, even if noone looks up into the night sky. The cat is
either alive or dead because it is constantly "observed." That's why there's
no differnce between a glass box and a metal box. Observation in the quantum
mechanical sense doesn't mean that the author has to eyeball an object. It
means that the object interacts with its environment (e.g. the particles of
the cat interact with each other and the particles in the air).

The analogy with statistics, that quantum mechanics is simply the evolution of
"what we know" is not correct either. A superposition is much more than that.
When a particle is in superposition of two states, it can interact with itself
as if it was in one state and as if there was another particle in the other
one (but there has never been a second particle).

If you simply assume that you "don't know" in which state it was and that it
would still behave classically, you would not be able to explain the double-
slit experiment. You also wouldn't be able to explain why light is slower in a
dielectric. Also, physics would be way easier.

P.S.: What the hell are those little snow flakes on that website. At first I
thought I was seeing stars and that I was about to pass out...

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joncrocks
I'll just leave these here:

[https://en.wikiquote.org/wiki/Talk:Richard_Feynman#.22If_you...](https://en.wikiquote.org/wiki/Talk:Richard_Feynman#.22If_you_think_you_understand_quantum_mechanics.2C_you_don.27t_understand_quantum_mechanics..22)

[http://www.smbc-comics.com/comic/law-of-social-media](http://www.smbc-
comics.com/comic/law-of-social-media)

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geon
While I agree that the box cat is not a valid thought experiment, just
dismissing quantum superposition is not a solution.

The double slit experiment (while tangential) shows that discrete events can
somehow be connected.

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daine
I am a particle physicist, and this article is confused. The substitution of a
glass box _fundamentally_ changes the experiment by allowing phenomena inside
the box to correlate with phenomena outside (including your senses). This
isn't magic, it's the natural result of light exchanging between stuff inside
and out. In the biz, we call this smearing of correlations 'decoherence.'

As for whether the cat 'is' both "dead and alive" in the true black-box
Schrodinger scenario, that's very much up for debate. Theorists and
philosophers have yet to reach a consensus on how to interpret quantum
mechanics, though progress is being made--our quantitative understanding of
'decoherence' being one example.

Don't be fooled: this is an open question.

For more on interpretations:
[https://en.m.wikipedia.org/wiki/Interpretations_of_quantum_m...](https://en.m.wikipedia.org/wiki/Interpretations_of_quantum_mechanics)

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cyborgx7
>But if we instead use a glass box, we can then observe the cat along the way.

The use of the word observe is what makes me think this is a troll. Collapsing
the waveform through observation is such a common phrasing, it seems silly to
assume the author wouldn't have come across it.

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digi_owl
We effectively have the whole cat thing going on because the alternative is
pilot wave. but that means that a quantum even on the other side of the
universe can have repercussions here on earth "instantly", and that was not
something physicists were happy to contemplate.

Crazy thing though is that the "holy" double slit experiment can be replicated
using water and drops of oil. Set a wave going on the water, and then add
drops of oil (particles). What you get out the other end is an interference
pattern even though each drop only travel down one slit.

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msimpson
This seems to be just an argument for the Ensemble interpretation of this
experiment in opposition to the more commonly held Copenhagen interpretation.

In the Copenhagen interpretation, a system stops being a superposition of
states and becomes either one or the other when an observation takes place.
Where as the ensemble interpretation states that superpositions are nothing
but subensembles of a larger statistical ensemble. Where the state vector
would not apply to individual cat experiments, but only to the statistics of
many similarly prepared cat experiments.

So it's not that the author is incorrect; they're a proponent of an
alternative interpretation.

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al2o3cr
"I can’t possibly be the first person to notice that Schrödinger’s cat
experiment does not change a bit if the box in which the cat resides is made
of glass."

Nor are you the first one to have missed the role of the observer in a
quantum-mechanical thought experiment: you change the experiment UTTERLY by
observing the cat.

There's a very detailed writeup of some similar thoughts in the Fenyman
Lectures, focused on the particular case of the electron double-slit
experiment and the observational consequences of trying to "see" the electrons
passing through one slit vs the other using different wavelengths of photons.

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WhitneyLand
Of course. Not to mention the "reality" of QM still has parts open to
interpretation.

Just a few years ago people were debating if QM meant the future could change
events in the past. In one interpretation that could be true, but further
learning has mostly ruled it out.

[https://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser](https://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser)

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WhitneyLand
>The words crackpot probably flashed through your mind

In fact that's what makes this post interesting, it's a great example of a
crackpot.

Another nice thing about this post is it makes fake news easier to understand.
Lots of laypeople could find this plausible.

What in the human brain creates the state of crackpotism? These people are
intelligent, usually have some technical understanding, etc. Yet it wouldn't
occur to this guy to write up a scientific paper?

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DiThi
A bit unrelated, but there's a possibility that quantum mechanics are not
exactly probabilistic and that they're actually deterministic, while still
being compatible with observed quantum phenomena. This video explains it well
[https://www.youtube.com/watch?v=WIyTZDHuarQ](https://www.youtube.com/watch?v=WIyTZDHuarQ)

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dTal
Is there any reason to think the wavefunction "collapses" rather than simply
spreading to the observer? Any explanatory power gained? Or is "collapsing" an
illusion caused by the basic fact that no version of you gets to see more than
one universe?

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sauronlord
What a ignorant jackass. The quality of posts here has taken a sharp dive
downward.

The observer collapses the wave function of the system. It's like he doesn't
understand the original thought experiment, or quantum mechanics at all.

~~~
WhitneyLand
No, please see mo other post, it's good to study crackpots sometimes.

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thebooktocome
This is what happens when statistics educators teach frequentism.

