I think there's a problem with the Copenhagen Interpretation in the way some people consider that the quantum world is "observer dependant" in some special way thats different from the way we interperet everything else thats not quantum. Everything in normal space-time has any number of positions depending on where you view it from - which is exactly the same in the quantum world. The bit thats missing is the point at which the different observational perspectives become so real they actualy exist together at the same time, and even interfere with each other, something I can't quite relate to non quantum things. Say you have a path, and a balls about to come rolling down the path. You can either stand on the "top" side of the path, or you can stand at the "bottom". Now until you decide that, you cannot relate to me whether the ball is moving left to right or right to left. I feel there is a way in which this is exactly the same as the Youngs Slit experiment. The possibilities that have to remain an implicate part of this scenario are that you decide to stand at the top, in which case the ball goes left to right, or you stand at the bottom and the ball goes right to left, or possibly you stand one side and a friend stands the other side, in which case your combined observations on the direction of the ball say that there was no ball.
