Sure. But either term is usually passive in classical contexts and always destructive in QM contexts. You can't uncollapse a wave function! Consider a twist o

Sure. But either term is usually passive in classical contexts and always destructive in QM contexts. You can't uncollapse a wave function! Consider a twist on Schrödinger's cat experiment: there are two scientists, A and B. The box can only be opened by one scientist at a time... the other scientist must wait outside the room. Scientist A looks in the box and collapses the wave function and sees that the cat is dead. What is the probability that scientist B will see a dead cat when she opens the box afterwards? 50%? 100%?