Message from the underworld

Originally posted by jman566
you can join the philosophy club if you like.

There's a philosophy club?

Originally posted by DeepThought
Your chances of survival would be 0.01%.

No, but you´d feel less alive because of all the anti-psychotics the psychiatrists would make you take.

Either you are alive or you are dead. There isn´t a superposition of states at this scale.

Why do you believe schrodinger's theory doesn't apply to humans?

Originally posted by Thequ1ck
Why do you believe schrodinger's theory doesn't apply to humans?

Planck´s constant is small. This means that at large distance scales Schrödinger´s equation reduces to something called the Hamilton-Jacobi equation. The Hamilton-Jacobi equation is a way of writing down classical physics. Humans live in this regime, Mapping states like alive and dead to microscopic quantum states of individual molecules in an organism is made trickier by cells dieing at different rates during the death of the organism as a whole. One of the properties of death is irreversibility. Quantum phenomena are reversible, the irrevsersibility of death means that properties like alive and dead refer to thermodynamic properties which puts them in the macroscopic regime. Yay - how´s that for an argument.

Originally posted by DeepThought
Planck´s constant is small. This means that at large distance scales Schrödinger´s equation reduces to something called the Hamilton-Jacobi equation. The Hamilton-Jacobi equation is a way of writing down classical physics. Humans live in this regime, Mapping states like alive and dead to microscopic quantum states of individual molecules in an organi ...[text shortened]... dynamic properties which puts them in the macroscopic regime. Yay - how´s that for an argument.

Your argument is fine with me, but I would like to know if we can also suppose the following:

If it is dead, the cat is settled into that specific state before you collapse the wavefunction; the cat didn’t die just because you collapsed the wavefunction, but because its condition was determined from previous states, which they all led up to its death.

In case the cat is alive, the thought remains the same;

Therefore you just happen to observe a dead or an alive cat (after you collapse the wavefunction, that is).

Is the above correct or am I stranded?
😵

Originally posted by black beetle
Your argument is fine with me, but I would like to know if we can also suppose the following:

If it is dead, the cat is settled into that specific state before you collapse the wavefunction; the cat didn’t die just because you collapsed the wavefunction, but because its condition was determined from previous states, which they all led up to its death ...[text shortened]... at (after you collapse the wavefunction, that is).

Is the above correct or am I stranded?
😵

Which wavefunction are you collapsing, the cat´s or the quantum state of the radio-active atom. The problem with the Schrödinger´s cat scenario is that the wave-function collapse (or entanglement or whatever) happens in the detection stage of the apparatus. By the time the cat is gassed, or you look in the box, the event is classical. Which means that the wavefunction collapse has happened before the cat dies, not after.

The cat itself is a measurer, any interaction with the cat as a whole will collapse the wavefunction.

Originally posted by KazetNagorra
The cat itself is a measurer, any interaction with the cat as a whole will collapse the wavefunction.

I agree that that is what the Copenhagen interpretation says. I´m skeptical about interpretations of quantum mechanics that give some kind of mystical centrality to observers though, I prefer interpretations involving some kind of ¨irreversible amplification¨ to macroscopic scales. The stuff in relativity is not problematic as the observers are passive. Penrose introduced the possibility of using a porcelain cat and a hammer so that you could avoid the cat observing its own wavefunction.

Originally posted by DeepThought
Which wavefunction are you collapsing, the cat´s or the quantum state of the radio-active atom. The problem with the Schrödinger´s cat scenario is that the wave-function collapse (or entanglement or whatever) happens in the detection stage of the apparatus. By the time the cat is gassed, or you look in the box, the event is classical. Which means that the wavefunction collapse has happened before the cat dies, not after.

The cat's -I was following Thequ1k's thought regarding his question "...If I survived, would I be less alive than I was before?".

Therefore, according to my argument too, Schroedinger's theory does not apply to humans😵

Originally posted by KazetNagorra
The cat itself is a measurer, any interaction with the cat as a whole will collapse the wavefunction.

Any interaction with "whom" and by what "means"?!

This is exactly the quality of "mind" that was mentioned the other day by clearlight I reckon😵

Originally posted by DeepThought
I agree that that is what the Copenhagen interpretation says. I´m skeptical about interpretations of quantum mechanics that give some kind of mystical centrality to observers though, I prefer interpretations involving some kind of ¨irreversible amplification¨ to macroscopic scales. The stuff in relativity is not problematic as the observers are passive ...[text shortened]... ing a porcelain cat and a hammer so that you could avoid the cat observing its own wavefunction.

Sure, but the porcelain cat is equally as much an "observer" as the live cat. Perhaps this "irreversibility" criterion is a pretty good one.

Originally posted by KazetNagorra
Sure, but the porcelain cat is equally as much an "observer" as the live cat. Perhaps this "irreversibility" criterion is a pretty good one.

I think statements in terms of irreversible amplification are due to Wheeler initially. It avoids philosophical problems with observers having too much of a role, but the problem of the EPR paradox remains, as the irreversible amplification at the second observer´s apparatus has to be consistent with the eigenstate the first observers apparatus detected.

I´ve been thinking about it, it´s as if you need one space for wave-functions to live in. where information travel is restricted to the speed of light, and another space for occupancy of quantum states where information is not restricted by a speed of propagation. You need consistency rules to make everything (more or less) sensible. Wave-functions evolve in the slower than light space as per the Schrödinger equation, but any change involving an increase in entropy happens in the space of state occupancy. The randomness of the selection of states prevents any kind of faster than light signalling of usable information. The problem with this is I think it´s just a restatement of wave-particle duality.

EPR paradox? That's already been resolved.

Originally posted by KazetNagorra
EPR paradox? That's already been resolved.

No, it still stands, this is the point of the Aspect experiment. The EPR paradox was invented by Einstein et al. as an attempt to falsify quantum theory. It´s been tested and apparently you are allowed ¨spooky action at a distance¨ therefore the paradox still stands. Anyone claiming it´s been resolved really means that their pet interpretation of quantum mechanics has some method of explaining it. In a many universes interpretation you deal with the problem by having a separate reality for each possible set of combined outcomes. As far as I know Everett´s theory isn´t cannon yet.

Originally posted by DeepThought
No, it still stands, this is the point of the Aspect experiment. The EPR paradox was invented by Einstein et al. as an attempt to falsify quantum theory. It´s been tested and apparently you are allowed ¨spooky action at a distance¨ therefore the paradox still stands. Anyone claiming it´s been resolved really means that their pet interpretation of quan ...[text shortened]... for each possible set of combined outcomes. As far as I know Everett´s theory isn´t cannon yet.

"Spooky action at a distance" is not allowed, relativity is still intact. However, the EPR paradox is resolved by realizing that the instantaneous collapse of the wavefunction does not allow any information to travel faster than light. Even if some particle has assumed a certain state 10 million light years away because you've measured its entangled particle, you can't make anything special happen faster than the speed of light because of it.

Originally posted by KazetNagorra
"Spooky action at a distance" is [b]not allowed, relativity is still intact. However, the EPR paradox is resolved by realizing that the instantaneous collapse of the wavefunction does not allow any information to travel faster than light. Even if some particle has assumed a certain state 10 million light years away because you've measured its entang ...[text shortened]... rticle, you can't make anything special happen faster than the speed of light because of it.[/b]

The collapse of the wavefunction of the one particle causing the collapse of the other is what Einstein meant by ¨spooky action at a distance¨. The resolution you are appealing to just sort of sweeps the problem under the carpet by stating that no physical information can be transmitted this way. If the wavefunction has physical meaning then information (regarding the state of it´s entangled partner) has traveled instantaneously, you just can´t use it.

I was an undergraduate about 20 years ago (getting old 🙁) and there wasn´t reference to stuff like entanglement in the course. When I was a graduate student I was more concerned with the technical problem at hand rather than issues of quantum philosophy. Is this just some new language to describe the problem or is there some real physical content?