But in the Copenhagen interpretation, “collapse of the wavefunction” has exactly the same sort of reality as “collapse of the probability distribution” does. It is not supposed to be a physical process like “apple falls to the ground”.
I don’t understand the distinction. If the probability distribution collapses, why is that not a physical process? Is it an immaterial, spiritual probability distribution?
Anyway, Schroedinger is the person who came up with the cat thought-experiment; which shows that he thought at the time that the collapse of the wavefunction had tangible, physical reality.
You may wish to read Schrödinger’s original article. It is about whether quantum mechanics could possibly be a complete description of reality. He considers two options: either that the wavefunction is a statistical description of an ensemble of possible states, or that the properties of microphysical systems are objectively undefined prior to observation. The cat shows up (in part 5) as a demonstration that the second option is absurd. This is the part where it may sound (to a modern reader, versed in MWI-think) that he is talking about a physical process of wavefunction collapse, but he’s not. He’s discussing a situation where the cat goes from “neither alive nor dead” to one or the other, at the moment of observation. At this stage, the wavefunction is not being proposed as a description of the cat’s physical state.
Parts 7 through 9 are where he addresses the Copenhagen interpretation, and contrasts it with wavefunction realism: “psi-function as expectation catalog”, versus “psi-function as description of state”.
If the probability distribution collapses, why is that not a physical process? Is it an immaterial, spiritual probability distribution?
Flip a coin but don’t look at it. Then look at it. The probability distribution of the coin just “collapsed”. The collapse of the wavefunction in the Copenhagen interpretation is the same thing. A wavefunction is like a prior; you adjust it on the basis of information acquired.
I don’t understand the distinction. If the probability distribution collapses, why is that not a physical process? Is it an immaterial, spiritual probability distribution?
Anyway, Schroedinger is the person who came up with the cat thought-experiment; which shows that he thought at the time that the collapse of the wavefunction had tangible, physical reality.
You may wish to read Schrödinger’s original article. It is about whether quantum mechanics could possibly be a complete description of reality. He considers two options: either that the wavefunction is a statistical description of an ensemble of possible states, or that the properties of microphysical systems are objectively undefined prior to observation. The cat shows up (in part 5) as a demonstration that the second option is absurd. This is the part where it may sound (to a modern reader, versed in MWI-think) that he is talking about a physical process of wavefunction collapse, but he’s not. He’s discussing a situation where the cat goes from “neither alive nor dead” to one or the other, at the moment of observation. At this stage, the wavefunction is not being proposed as a description of the cat’s physical state.
Parts 7 through 9 are where he addresses the Copenhagen interpretation, and contrasts it with wavefunction realism: “psi-function as expectation catalog”, versus “psi-function as description of state”.
Flip a coin but don’t look at it. Then look at it. The probability distribution of the coin just “collapsed”. The collapse of the wavefunction in the Copenhagen interpretation is the same thing. A wavefunction is like a prior; you adjust it on the basis of information acquired.