Quantum suicide and immortality
Quantum suicide, closely related to quantum immortality, is a highly speculative thought experiment positing that if the Everett interpretation of quantum mechanics is correct—i.e. if every possibility is realized through a different branch of the quantum wavefunction of the universe—one would be effectively immortal, as (a) the contents of experience in the branches in which one is dead are zero and (b) there is always at least one branch in which the subject survives. The thought experiment was independently published by Hans Moravec in 1987 and Bruno Marchel in 1988.
Proof-of-principle can be realised, for example, by an experiment in which the radioactive decay of an isotope with probability fifty percent triggers the release of a gun aimed directly at the subject's head. From the perspective of any third-party observer, the subject is killed an inordinate number of times, but from the perspective of the subject, the gun keeps misfiring, or is otherwise presented from executing its task, thus proving the many-worlds hypothesis.
MIT physicist Max Tegmark, an advocate of the Everett interpretation of quantum mechanics, jokingly states that he plans to conduct the experiment when he is much older. Tegmark remarks that life-and-death situations are rarely contingent upon the sorts of binary yes-or-no quantum decision trees such as those called for in the thought experiment, thus calling into question the probability of quantum immortality under the natural evolution of the wavefunction absent the experiment.
Note that the same thought experiment also indicates one would find oneself awake 100% of the time—as there is always a branch of the wavefunction in which one is in a waking state—with the caveat that one can be minimally awake while in sleep state. Note also that there are a number of branches in which the subject could be shot and maimed, rather than killed instantly—hence the effectiveness of the suicide method must be 100% for the experiment to achieve the desired results, even if the hypothesis were to be proven correct.
- "The Many Minds Approach".
- Marchal, Bruno (1991). De Glas, M.; Gabbay, D., eds. "Mechanism and personal identity" (PDF). Proceedings of WOCFAI 91. Paris. Angkor.: 335–345.
- Eugene Shikhovtsev's Biography of Everett: Keith Lynch remembers 1979–1980. MIT servers, Max Tegmark faculty pages.