Quantum Mechanics and Immortality
The idea of “quantum immortality” arises from the combination of the many-worlds interpretation (MWI) of quantum mechanics and taking the point of view of the cat in Schrödinger’s famous thought experiment. The MWI says that the reason we observe randomness in elementary particles’ behavior is not that they’re random, but that every possible outcome does happen, in different worlds. So, for every physically possible outcome of any event, there is a universe where this outcome happens. In a sense, it says that whatever is physically possible, will happen in one universe.
Now consider a physicist who sets up a gun to shoot him. It seems possible that by some miraculous, highly improbable circumstances, the gun fails to fire, and the physicist survives. It seems there’s nothing physically impossible about this happening time after time after time, it’s just very improbable. But it could happen, and according to the MWI, if it physically could happen, it does happen in one universe.
So there is at least one universe in which the physicist doesn’t die. And think about it: wouldn’t this be true not just of guns, but of any cause of death? It’s physically possible that all causes of death will fail, and you will live, if not forever, at least for an extremely long time. So, according to MWI, there’s one universe where this happens. And since the branches where you die will mean the end of your consciousness, this would mean that eventually, only the immortal (or very-very-very-long-lived) version of you is conscious. So, you will not die, you will live as long as it’s physically possible to live. You will see everyone you know die, you will be the lone immortal, from your point of view. And any other sentient being will feel the same, from their POV.
That’s the argument, anyway. Both the MWI and Quantum Immortality are hotly disputed. It’s not like these ideas are uncontroversial. I don’t believe it, but the argument isn’t without its appeal. It’s interesting.
