Basic Information
Quantum Immortality is a concept stemming from the Quantum Suicide Thought Experiment.
The Many-Worlds Interpretation of Quantum Mechanics says that every event creates multiple universes - one where the event happened just like we experienced, one where it didn't happen at all, and possibly a few variants on other ways it could happen.
So, anytime a person dies, there's also another parallel world where they didn't die. Which means, from a certain point of view, there's no such thing as death. Your consciousness will extend forever.
The big questions are whether your consciousness extends automatically to the other realities where you survived, and to what extent the other realities exist independently of this one. Is there an infinite number of you, are they all the same, or does just one matter? One possible answer to those questions is that each of us exists in our own reality where just that individual person is immortal and cannot die. It's a pretty crazy idea, but definitely fun and useful for a variety of gaming scenarios.
Note that even if Quantum Immortality exists, there's no reason to believe it renders you immune to crippling injuries. Don't try this at home, kids.
See Also:
Another Dimension
Coincidence
Immortality
Quantum Suicide
Sources
According to the Wikipedia page on Quantum Immortality in Fiction, several novels and short stories have made use of this concept.
Game and Story Use
- May be used as scientific justification for Script Immunity. We're playing the game of the universe of a specific character, so bizarre coincidence always prevents them from dying. Heck, that alone could be a superpower or a whole superhero character concept - Mr. Coincidence, the man who survives everything.
- Two Mad Scientist types are both working in the field of Quantum Mechanics. They meet, fall in love, and marry. Years later, they're in a car crash, and the wife dies. He can't go on without her, and he feels horrible that he crashed the car. So he tries to commit suicide. After several failed suicide attempts, he realizes that MWI and Quantum Immortality must be true, and he can't die. Which means somewhere out there is his wife. Meanwhile, in a parallel universe where she was driving, her husband died. She can't live without him, and tries several unsuccessful suicide attempts. She comes to the same conclusion he did. They each know the other exists in another universe. Working at it from multiple ends, they are able to create a pair of machines that open up doorways to each other's universes, and are reunited.
- Or, for maximum Angst, they spend long lifetimes trying to reach each-other and never manage to do so.
- In a solo campaign, the PC is a famous historical figure, still alive in the modern day. They've never died, living life like Julius Beethoven Da Vinci. They can't die, probability works out to always save them at the last moment. They can still experience pain, be handicapped or disfigured, etc. Maybe the campaign is set in the Far Future, then, with the sort of tech that can heal those crippling injuries?
- The plotline may eventually involve discovering another person who's similarly immortal. There's at least two ways this could happen.
- You could create a device that allows transit or communication between realities. Aside from the normal complexities of Parallel Worlds, this also adds the concern of immortality only being valid when within your own original universe. It's possible that interacting with an immortal of another universe deprives you both of your immortality - I mean, whose reality are you in, after all.
- The other route involves the notion that over extremely long sample durations, the probability of rare events happening is greatly heightened. So, in recorded history, you're the first person to live more than 200 years. However, after 5 million years or so of your existence, there may be born another person who will live an arbitrarily long amount of time. Or, maybe you're the second one, and they're some proto-human big foot or hominid Pan Prior that's been hiding from society for millenia. Are you in their reality, or they in yours?
- The plotline may eventually involve discovering another person who's similarly immortal. There's at least two ways this could happen.
- Let's say the idea of Quantum Immortality is proven. What impact would that have on civilization?
- Would people start taking more risks? Would the number of stupidly avoidable crippling injuries sustained increase?
- Would murder become less criminal, and wounding more criminal?
- Could ecological catastrophe be averted by a lottery of Euthanasia that creates an infinite number of parallel worlds each with 75% fewer humans to strain the resources?
- What is the true nature of the soul and the afterlife? Is Quantum Immortality true "I can never die" immortality, or is it more akin to reincarnation?