h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Schrodinger was not proposing the experiment as a super-anything. He was trying to show the fallacy of the Quantum-waveform-probability-collapsing thingy.

His thought experiment was meant to show how ridiculous it was, by bringing to the macroscopic level, the consideration of a waveform's probability states as equally "true" until its collapse.

His assertion was that considering the cat neither alive nor dead until the box is opened and the probability waveform collapses makes absolutely no difference to the cat, which may be beyond caring. Its state is either alive or dead, not a pair of super-imposed probability waveforms.

He meant to explain that a true state was already true, whether or not it is measurable or known, and the other probabilities can just take a flying leap.

So the only thing that collapses is my ignorance of the cat's current state!
ps. Thanks for the context, FT! Elsewhere I've read explanations of the thought experiment, but not why Shroedinger came up with it.

One could also argue that the cat observes the hammer falling or not falling, so it isn't really a non-observed event...

Of course, to most folks talking about the experiment, the cat doesn't count

But what if you blindfolded the cat, eh...?
THAT would do it

Alright.... getting a bit beside the point, but I felt like it...

It'd hear/not hear the hammer strike the capsule

Yes, Yes, I suppose a blind and deaf cat would fulfill the necessary ignorance quotient. Or, perhaps I just did by agreeing to the suggestion.

The whiskers'd feel the air vibration

(Oh, I'm ornery)

Well that's exactly what I think--We can't explain our ignorance by saying that until we know, we aren't wrong. We're wrong or right at all times, but we may not know it. It's an educated guess as to whether or not the cat is dead--not knowing is simply not knowing, not a matter of physics.

Wasn't this experiment talked about in Dirk Gently's Holistic Detective Agency? I do remember it...because he had to find half a cat oh how I loved those books

Darth Zaphod

So true... we should really try and realize just how ignorant we are... It is quite likely that science is still making huge blunders... Only we wouldn't know about them, until some revolutionary and shocking theory is put forth.

But still, let's say that you wrap the bloody blind and deaf feline up in duct tape... that would stop it from feeling the vibration. Or you could obviously rig the experiment in a way that wouldn't involve such a brutal release of the cyanide.

Oh, and yes, it was discussed in Dirk Gently's, but I think the half cat was from "Salmon of Doubt"... Wasn't it?

mmm, I don't know... I could have sworn that one of his missions was to find half a cat...but I read his stuff so much over and over, I keep mixing up all of my stories

Perhaps we should just not kill a cat at all--how inhumane is THAT?! I'd rather read a , go , or eat some . (sorry, have to try out some smileys I haven't done it in a while!)

Darth Zaphod

Well, it was, it ws the one he refused in salmon of oubt, bcause the client asking him to do it was a beautiful female (and you know how he hates attractive women, because of their utter loveliness, and their complete refusals to date him), and because he had indigestion.
Or so I think, I'm not in any position to check it out now.

Oh, and yeah, I've also read those books way too many times...

Allright, how a bout we drug it, then, it is really quite irrelevant what you actually do to the bloody cat, just as long as it achieves superposition.

Anywaym I just read somewhere that they were going to test the whole experiment (in an alternate way, not by killng the cat)... So maybe we'll get the paradox answered soon.

To get a bit more serious surely the state of the cat is a philosophical issue. We have no way of telling what is inside the box until we open it so from out perspective there could be anything. We can say that in all probability there will be a cat and that, within that probability the cat has a 50% chance of being alive or dead

Since we have no way of knowing for sure what is in the box and also given the knowledge that all of the theories do not point more one way than another we are not open to supporting either ideas. All we can say beyond almost any doubt is that there is either an uncolapsed waveform (the cat currently existing in both an alive and dead state in a kind of mini duo dimension within out own) or just that the consequence has happened and the cat is already dead or has remaind alive and the waveform collapsed instantly.

Please correct me if I am wrong, I havn't studied it for ages!

Quantum theory mathematically represents the state of any paricle as a wavefunction. This wavefunction can be expressed as a LINEAR COMBINATION of the ENERGY EIGENSTATES (states with a definite energy) of the system, which form a COMPLETE BASIS. Upon measurement, the wavefunction 'collapses' and the particle is forced into one of these energy eigenstates. However, between measurements the wavefunction evolves according to the TIME-DEPENDENT SCHRODINGER EQUATION:

E |psi> = (ih/2pi)x(d|psi>/dt)

where E is the energy, |psi> is the wavefunction of the state, i is the square root of -1, h is Planck's constant, pi is 3.14159... and (d|psi>/dt) is how quickly the wavefunction changes with time.

Basically this means that, between measurements the wavefunction evolves away from the measured state and contains a mixture of other states. When the next measurement is taken, the proportions of these eigenstates in the wavefunction give the probability of getting each different energy (or whatever property you measure).

This is all accepted physics. What follows is my take on the situation.

Imagine a machine set up to measure the state of the isotope in the box every 10 minutes and display the results on a screen for the user to see. Every 10 minutes then, the wavefuntion collapses into an energy eigenstate and we know whether the isotope has decayed. Now the user leaves the room and does not look at the screen for an hour.

However, every 10 minutes, the machine still takes readings, so the wavefunction must collapse. In this supposed paradox the machine is the hammer-vial system, which is regularly measuring the state of the particle, or at least does so as soon as it decays, depending on the proposed mechanism.

It is ludicrous to suggest that only a human observation, or even an observation by a living thing, collapses the wavefunction. The device in the box is the observer, as must necessarily be anything that depends on the particle's state, and the paradox appears to me to be no paradox at all.

Hope that's helpful rather than just confusing.

It doesnt have to be observation by a living thing just observation. This is not so hard to believe. Heisenbergs uncertainty principle shows that measuring something indirectly effects the object being read. This comparison has no scientific relation to the problem being discussed here but it does prove that an indirect observation can have aa direct effect upon the object being observed.