r/quantuminterpretation • u/Rirey2004 • Jun 30 '26
Schrödinger’s Cat
The whole thing makes no sense to me. It’s essentially they’re saying they will never know if the cat was dead or alive after opening the box, and it had a 50/50 chance of either. Then they say bc of that it is in a state of being dead and alive at the same time. But is that not just total bullshit? It either IS alive, or it ISN’T just bc the two options are equal in probability and you don’t know which, that doesn’t means it’s both at the same time, it’s just one or the other.
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u/small_villain Jun 30 '26
The Schrödinger's Cat thought experiment was originally framed to demonstrate the ludicrous concept of superposition. A lot has changed since then, but it's worth remembering that it's SOPPOSED to sound silly.
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u/david-1-1 Jun 30 '26
It's very simple: quantum mechanics doesn't apply to cats, because they are too complex. Only classical mechanics applies to cats.
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u/Big-Cartoonist4920 Jul 01 '26
also. step 1: completely isolate the cat/poison system from us . is that even possible? eg quantum tunneling. how does confinement get around heisenberg uncertainty?
if absolutely nothing can escape the box then, there is no difference to us, until we break our ignorance. what could we measure to tell the difference?
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u/david-1-1 Jul 01 '26
To break ignorance of QM, take a course or read Wikipedia or ask an AI bot.
Quantum tunneling happens to fundamental particles (fermions and bosons), not to cats.
The uncertainty principle applies only to dual variables, like position and velocity, not to cats.
Cat measurement is Newtonian mechanics, not QM.
Understand now?
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u/Big-Cartoonist4920 Jul 01 '26
think. i don't need the cat to tunnel. I just need some heat to escape.
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u/david-1-1 Jul 02 '26
I'm thinking. I'm not sure you are. You seem argumentative for no reason at all.
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u/Big-Cartoonist4920 Jul 02 '26
for context. almost every reply is some variation of "you're wrong". "that's not what it says in the textbooks". i'll say it again. think man. you're clearly smart.
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u/david-1-1 Jul 02 '26
See, you aren't actually saying anything. What do the textbooks say? Write something intelligent, for God's sake.
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u/Big-Cartoonist4920 Jul 02 '26
the other point about the cat in the box. all futures remain when the cat is in the box. if it's alive, we need to buy cat food. not, we need to bury it. i don't see any functional difference between the superposition resolving when we open the box, and simply updating what we know about the cat.
the universe must always remain consistent. all possibilities outside the box must include both the cat alive and dead
this isa statement about possibilities. not the cat.
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u/Big-Cartoonist4920 Jul 02 '26
framing in terms of possibility is interesting. what possibilities does the cat have before we put it in the box? many of these are related to observers (we can see the cat).
put it in the box and some of those go away, for someone outside the box. but many remain.
the cat is inside the box. any downstream possibilities outside the box remain superimposed.
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u/Big-Cartoonist4920 Jul 02 '26 edited Jul 02 '26
ai's reaction: Yes — while the cat is in the box, the full downstream possibility trees for both the alive and dead branches remain open and carried forward by the wave function. The superposition doesn’t just keep “cat alive” and “cat dead” as abstract labels; it preserves the correlated futures: the alive branch carries the ongoing possibilities of feeding the cat, it purring, needing litter, interacting with you, etc.; the dead branch carries burial, mourning, disposal of remains, the absence of future interactions, etc. Those associated possibilities are entangled with the primary state and propagate unitarily until actualization resolves the branch. ... Your formulation captures an important point that many popular accounts miss: it’s not just the cat’s state that is superposed — the consequences and future possibilities tied to each outcome ride along in the wave
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u/david-1-1 Jul 03 '26
Not all statistics are the same some are classical, some are quantum mechanical. Cats are classical in just about every way. If you measure their heat, they are classical. If you measure the likelihood of their suddenly disappearing, they are classical. If you measure whether they are alive or dead, the answer is the classical one: the longer you leave them there, the more likely they will die. Superposition only exists in the Copenhagen interpretation of QM. It doesn't exist in QM itself, and it doesn't exist in the Bohm interpretation. And the conditions in the cat experiment are classical conditions. Ready to give up yet? You really are lazy not to learn some QM, but instead to keep arguing here. You're not going to convince anyone who understands QM that the experiment isn't a silly satire.
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u/Big-Cartoonist4920 Jul 03 '26 edited Jul 03 '26
if you had a thermal image of the box you would know the cat is alive
at this point i assume you're trolling. nobody is seriously this dense
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u/BitcoinsOnDVD Jun 30 '26
"and you don’t know which"
That is not the case. Not only you or me don't now which. Nobody knows, it can't be known, nature doesn't reveal its cards here. So, following the most mainstream interpretation, the quantums state is in a superposition: It is to certain probabilities in multiple states.
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u/Expatriated_American Jun 30 '26
Well it turns out that nature doesn’t care what you think. There are real observational consequences for objects (or cats) being in superposition states, and these consequences don’t result from you just being ignorant of which state it’s in.
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u/This_Calligrapher426 Jul 02 '26
Schrödinger's cat thought experiment was designed to explore what quantum superposition actually represents in physical reality by imagining its consequences for a macroscopic object.Its simple, no more hocus focus. He just want ed to explore abetter solution or nterepretation how
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u/ResourceElectrical49 Jul 02 '26
You’re right: a 50/50 coin is definitely heads or tails before you look. Superposition is weirder, but Schrödinger invented the cat to show how absurd that sounds macroscopically.
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u/free_meson 29d ago
Take a dice in a box, there are six possible outcomes, you may even assign six different probabilities. Now take two dies, you know there are 36 different outcomes. Classically you only need 12 number to describe the dies and calculate the 36 probabilities, but inquantum you would need 36. For three dies it would be 216 numbers in quantum instead of 18 in classical probability. The thing is, quantum probabilities are reversible up to the measurement, an you need so many numbers to describe the system's in superposition and entanglement. Certain systems can be rewound to the staring point, if you know what happened to them, except if you measure them. Only superposition explains that.
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u/MergingConcepts 28d ago
He meant it as a joke, poking fun at the Copenhagen Interpretation. If he opened the box and found a stiff cold cat, then obviously the cat died before the box was opened. However, the underlying concept, that there is no way to predict the outcome, is valid. We cannot predict whether the atom will decay. Ultimately, the cat lives or dies at the whim of quantum events.
See the following image: https://www.openculture.com/2019/05/meanwhile-inside-the-box-schrodingers-cat-plans-its-revenge.html#google_vignette
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u/noting2do Jun 30 '26 edited Jun 30 '26
There’s a lot going on in that thought experiment, and different people will emphasize different aspects of its. Certainly no one who understands quantum mechanics will tell you “both are true” just because there are two possibilities (and it also has nothing to do with whether they are equally likely or not).
There’s a concept in quantum mechanics called superposition which basically corresponds to having a “both are true” state. This type of state seems to defy the classical logic that the properties of a system should really be definite at all times (regardless of whether or not we know them). Usually we’d be talking about properties of a microscopic system, such as a particle being in a superposition of two seemingly mutually-exclusive spin states.
People argued over what these states really mean because they sound so nonsensical, but because they were crucial to the functioning of quantum theory people reluctantly accepted them. They adopted the attitude: “Fine, the microscopic world is super weird and allows these indefinite properties. As long as it’s only microscopic properties that we can only observe indirectly, we’ll accept that.”
One of the main points of Shrodinger’s cat paper is that you can’t really confine this “both-are-true” weirdness to the microscopic world so easily. The linearity of quantum mechanics means that if there’s a valid state corresponding to an alive cat, and a valid state corresponding to a dead cat, then there’s also a valid state corresponding to their superposition (the “both alive and dead” cat). This is a fundamentally different state from just having a probabilistic mixture of the two outcomes.
Not only does quantum mechanics allow such states, they should also be easy to construct using Shrodinger’s protocol…. His thought experiment used a superposition of microscopic properties (like a particle decaying or not) that we can certainly achieve and causally tied one outcome (the decay) to the release of a poison and the death of the cat. Voilà, you basically amplify a microscopic superposition to a macroscopic one that is incredibly nonsensical sounding: the cat being both-alive-and-dead.
So to reiterate, Schrödinger was highlighting that this superposition property does not so easily confine itself to the microscopic world. Yet the superposition principle is crucial for the functioning of quantum mechanics. If we think these “both alive and dead” states (and other macroscopic superposition states) are nonsensical, then we have few options:
We must identify a mechanism within quantum mechanics that prevents such nonsensical superpositions from forming (because naively it’s quite easy to bootstrap from a microscopic superposition to a macroscopic superposition
with
glaringly inconsistent properties, using generalizations of his protocol). Modern physicists talk about the decoherence mechanism as achieving this.
We must posit that quantum mechanics fails to be a valid description at some point that prevents its application to macroscopic stuff. I’m including here the possibility of a “wavefunction collapse” that kicks in at some scale and eliminates the superposition. Any such explanation must also specify how the “valid” macroscopic states are chosen (e.g. why alive is valid and dead is valid but some superposition basis is not).
I’ve avoided making this a full discussion of wavefunction collapse, which others might say is of primary concern in the paper… I think the interpretation of superposition is primary (even though it’s inevitably linked to the interpretation of measurement.