“Some might question whether it makes sense to talk about setting up the experiment and running it again with exactly the same conditions--that it is, in fact, impossible. Locally, you might get the conditions exactly the same, but you have to embed the experiment in the universe, and that has moved on. You can't rewind the wave function of the universe and rerun it. The universe is a one-time-only experiment that includes us as part of its wave function, and there's no going back.”