Is the collapse of the wave function exclusively caused by perception?

[gib65]

I just finished watching What the Bleep Do We Know. There was that one scene in which the kid playing basket ball said of the ball that, before we observe it, it was in a state of superposition - that is, it was in a whole array of different positions (or, more accurately, its exact position was undefined). It was only upon observing the ball that it "collapses" into the position we see it in.

 

Now, they made this out to seem like it was exclusively our perception of the ball that causes this collapse. But it leads me to wonder if there are other kinds of interactions that can lead to collapse, interactions that can go on outside the scope of our perception. For instance, would it be unreasonable to say that two particles somewhere in space where no observer perceives them, can be in states of superposition, and somehow their probability waves interact in such a way that they both collapse (or at least one of them does) into more precisely defined positions? Would it not be reasonable to say that a book sitting on your desk, or a coke sitting in your fridge is still, more or less, in a precise position (precise enough on a macroscopic scale) because all the molecules making it up are constantly interacting with each, being so closely interconnected, thereby bringing about their collapse so often that their probability waves have nearly no chance of expanding to a macroscopic range. In other words, the molecules themselves keep the whole object in a (more or less) precise position by constantly collapsing each other. If so, human perception is obviously not the only thing to bring about these wave function collapses.

 

I think I can predict the answer to this question. I have a feeling someone will reply with "Well, if particles do collapse each other's wave functions beyond our observation, we could never know about it. We must observe in order to know." Fair enough. Then let me restate my question: Are there some (professionals, that is) who believe that perception is the only thing that brings about the collapse of the wave function, while others believe that the collapse can come about without observation? What are the reasons for and against either claim?

[swansont]

You collapse the wave function by any interaction that requires it to be in a particular state. Observation is just one type of interaction that does it.

[gib65]

Ah! So it would NOT be unreasonable to assume everyday rigid object remain in the same positions and states as we saw them in before we turn away. Of course, weather or not they DO remain in these states cannot be verified empirically. Does this sound right.

[Severian]

The problem is, it doesn't matter what mechanism you come up with it will be untestable becasue all observations by you require you to interact with the system. So you can never show what it is which is collapsing the wavefunction. You can make some statements though, since we see interference effects for electrons in slit experiments we know that the electron travelled a macroscopic distance without its wavefunction being collaped.

 

One viewpoint is that it is not us who is collapsing the wavefunction, but any very complicated system. The interaction of the electron with a large ensemble of particles (eg. a measuring device such as a lens, an eye or a colorimeter) collapses the wavefunction. This is impossible to test though (until we have an observer who is a couple of particles only...)

[Kygron]

Would it be possible to "rig" the formulas in a way that the wave function does not collapse, but that our observation is of only one state?

 

I guesss I'm asking how important the phenomenon is for our current understanding.

[swansont]

Would it be possible to "rig" the formulas in a way that the wave function does not collapse' date=' but that our observation is of only one state?

 

I guesss I'm asking how important the phenomenon is for our current understanding.[/quote']

 

No. When you measure, you can only measure it being in one state.

[YT2095]

if it can`t be tested, how do we know it`s true?

[Severian]

if it can`t be tested, how do we know it`s true?

 

We don't. That is why we call it the Copenhagen interpretation.

 

But it really isn't a scientific question - it is a question of philosophy, since it can't be tested. The evolution of the wavefunction in QM can be tested of course. It is just the mechanism of collapse which cannot.

[YT2095]

aha! thnx