unwise wrote:The Copenhagen view is simply a cop out. A very very old one. It does not try to say or understand anything. It is simply saying, if we can't measure something, let's forget it.....and let's forget trying to form some philosophical understanding. We can't locate a particle or even wonder what is going on here, so let's forget it. Not very philosophically satisfying.
I'm not too fond of it either - but the Copenhagen works for practical purposes in physics, and does not attempt to be philosophically satisfying. It draws a line and says this part is physics, and we can study it, and this other stuff is too metaphysical - in the sense that we can't come up with an experiment to verify it. The interpretation of QM is generally speculative,
Bell's Theorem being a nice exception.
Schrödinger's cat demonstrates nicely the collapse of the wave function and its consequences. It does, in fact, work very well in the Many Worlds theory. Schrodinger's cat is a simplified version of my original post.
Dude.
In the Copenhagen-style interpretation, when you look in the box, the wave function collapses and your indeterminate cat "collapses" into either a dead cat or an alive cat. In this view, the wave function represents your state of knowledge about the cat. This is problematic, because what does "collapse" mean exactly? Why is it that a scientist can collapse a wave function, but the cat can't?
In Many Worlds,
the wave function does not collapse. The superposition of states is taken to mean that the universe has split into a universe where the cat is alive and another where it is dead. When you open the box, you discover which universe you are in, not what happened to the cat - you
already know that the cat both lived and died.
The cat thought-experiment underlines that you must
interpret what you take the wave function to be. The wave function really specifies a probability of what you will observe. If you take that in a statistical sense, then you are sampling from a population - and Many Worlds takes that literally, that there must then be such a population from which to sample.
There are other interpretations that take the wave function to actually specify
a wave. For reasons that are unclear to me, these interpretations are less popular. You'd think it would be the logical interpretation among physicists.
All interpretations of QM have something weird about them. You can move the weirdness around to different spots, depending on which weirdness bothers you the most, and come up with different interpretations. Most interpretations reject local realism (Many Worlds being an exception, instead rejecting
Counterfactual definteness).