> how do you know your experience of the world cannot be superposed?
For your experience of the world to be superposed it would mean that you carry out a quantum experiment with two mutually exclusive outcomes |x> and |y> and you actually experience the superposed result |x>+|y>. This would be like opening the box in the Schroedinger's cat experiment and actually observing the cat to be |alive>+|dead>, instead of either alive or dead. Maybe it's possible, but such an experience has never been reported.
It's "possible", but not really possible. The larger the object is, the harder it is to maintain superposition. Even the slightest nudge will tend to push it all into one state or other. Seeing the superposition directly would be like standing twenty octillion strands of spaghetti on end.
So it's "possible" but would never happen in a trillion lifetimes of the universe. You can tell the difference between that and "impossible" by watching the quantum mechanics work for a few isolated particles, and observing what it means for them to fall out of superposition equilibrium. But in practical terms, it's equivalent to impossible.
For your experience of the world to be superposed it would mean that you carry out a quantum experiment with two mutually exclusive outcomes |x> and |y> and you actually experience the superposed result |x>+|y>. This would be like opening the box in the Schroedinger's cat experiment and actually observing the cat to be |alive>+|dead>, instead of either alive or dead. Maybe it's possible, but such an experience has never been reported.