Erwin Schrödinger was a physicist who wanted to illustrate the absurdity of applying quantum properties to the macroscopic world.  It was (and still is) popular to look at the state of a quantum object, such as an electron or photon, to be “in flux” until its state is observed.

The basic thought experiment is that a healthy, well-fed cat is placed into a box with a vial of toxic gas, a very sensitive particle detector, a quantum particle with a half-life of one day, and various mechanisms to connect them.  The particle detector is set up so that, if the quantum particle decays, it will trigger a mechanism to open the vial of toxic gas, killing the cat.

So, using the common quantum paradigm, the particle is in flux between decayed and not decayed the second we place it into the box.  Because the box is closed and we’re forbidden by the rules of the experiment to look inside until a day is passed, the vial of toxin is in flux between contained and released.  The cat, therefore, is in flux between being alive and dead.

Schrödinger intended this, as I said before, as an illustration of the absurdity of taking this idea to the macroscopic dimension – but many people chose instead to take it seriously.  They spoke with a grave sense of wonder about the poor cat, neither alive nor dead, in this state of flux, until someone opened the box.

Many of these people would also argue that, if a tree fell in the forest and nobody was there to hear, there might not be a sound.  But my view is that there is no reason to believe there would not be a sound, unless longitudinal shock waves traveling through the air do not qualify as sound until there is an ear to hear them.  If you want to tell me there won’t be any sound waves, then you might as well tell me that the tree might fall up instead of down, or that any number of other physical rules don’t apply when there are no observers.

I understand that all this is philosophically possible.  There is no proof that the physical laws of the universe apply in the absence of any observer, but we have very good evidence that the universe acts very much as if they do.  Perhaps, when we come upon a fallen tree for the first time, all of the universe’s laws get instantly applied to it, retroactive to the last time it was observed.  But that seems pretty silly to me.  It’s much simpler, in my opinion, to believe that the unobserved tree fell in exactly the same way as if it had an audience of thousands watching it, that it disturbed the air, and that it made sound waves.

And so, back to Schrödinger’s cat, I believe that the simplest view is best.  The cat, at any one moment, is either alive or dead, the same as if the nation were watching it on video.  The gas vial is either released or unreleased, and the particle is not in flux, either.  It’s possible that the last statement goes further than Schrödinger might have wanted to go.

Erwin Schrödinger might have believed that the particle was in flux, and that the silliness was in the act of taking the concept to the macroscopic world.  I’ll say more on the subject in another posting, but I believe that far too much weight is given to human observation in dealing with the quantum world.

It’s true that observation changes the quantum world, but it’s the mechanical act of observation, not the entrance of data into a human brain, that causes the changes.  So I don’t believe that the unobserved particle is “in flux” between being decayed and not being decayed.  I believe, instead, that the particle is in a state unchanged by observation, a state that we don’t understand.

But, you see, the vial is not in a state we don’t understand.  It’s a macroscopic object, and its potential transition between closed and open is well understood.  Similarly, the cat is a macroscopic animal, and the workings of the toxin (should the cat find itself in the unfortunate 50% of possible scenarios) is also well understood.  There are no quantum states required, and the fact that a quantum state decides the cat’s fate does not, in any way, translate to the cat having a quantum state of its own.

I’m open to people disagreeing with me on this point.  It’s certainly possible that I have oversimplified the concepts behind quantum flux.  But I’ve yet to find anyone who could convince me that a tree of any size falling in a forest ever fails to make a sound, or that a cat in a box is ever in flux between life and death for any appreciable period of time.

If you feel you can change my mind, by all means, please have a go at it.

This entry was posted on Sunday, December 30th, 2007 at 5:15 PM and is filed under Steve Thinks. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.