and no one is around to hear it does it make a sound?... my real question is, does the tree even exist if no one is around? and what qualifies an "observer". do wave functions collapse only in the presence of humans? why can't schroedinger's cat tell if it is dead? I guess I'm asking for a general overview so that I can contribute CORRECT information the next time conversation of this type starts. Nothing worse than asserting incorrect facts about physics, or anything for that matter.