Wave function collapse is not observed physical phenomenon. Some interpretations of QM require it to exist, but there is no empirical evidence of that happening.<p>Apparent wave function collapse happens when a wave function in a superposition of several eigenstates appears to reduce to a single eigenstate. The apparent wave function collapse collapse is mathematically equivalent of quantum decoherence where the wave function never really collapses but the states gets entangled with the observer.<p>If somebody were able to formulate and experience that would show the difference between decoherence and collapse, that would be new physics and we would be able to rule out some interpretations of quantum mechanics. Until that happens, 'shut up and caluclate' seems to be valid course of action.<p>As far I understand, the philosophical difference between apparent and actual wave function collapse is that in the apparent collapse probabilities of other states get so close to zero that they don't matter, in actual collapse they are exactly zero.<p>The assumption that human consciousness has something to do with setting all other states to zero is weird one and can't completely understand the assumptions behind it. I guess the idea is that we would not experience the world as we experience it now if there is just continuing decoherenće.
Ok, I'm going to hijack this thread to get an answer to something I've always struggled with: how does 'observation' cause the wave function to collapse.<p>It won't happen in a closed box, but what about an open box in a closed room? What about a closed box with a live video camera? What about a live video camera whose display no one is watching?<p>I'm sure this is a basic question but for the life of me, I've never really understood it. Thanks.
It's worth mentioning that "quantum theory" has no implications for consciousness, especially given the headline proclaiming the opposite. There are plenty of interpretations that don't involve consciousness at all - and hopefully my use of the word interpretation clues you in to the fact that this is isn't really a physics question.<p>Weird philosophy aside, this does look like a good explanation of the Bell inequality.
I'm deeply sick of the absurdly drawn-out living death of the Copenhagen interpretation, and its even more absurd "consciousness is made out of magic" descendants. This is bordering on straight-up irresponsible misinformation.