Quantum suicide and immortality

Quantum suicide is a thought experiment in quantum mechanics and the philosophy of physics. Purportedly, it can falsify any interpretation of quantum mechanics other than the many-worlds interpretation by means of a variation of the Schrödinger's cat thought experiment from the cat's point of view. Quantum immortality refers to the subjective experience of surviving quantum suicide. It is sometimes conjectured to be applicable to real-world causes of death as well.

As a thought experiment, quantum suicide is an intellectual exercise in which an abstract setup is followed through to its logical consequences merely to prove a theoretical point. Virtually all physicists and philosophers of science who have described it, especially in popularized treatments, underscore that it relies on contrived, idealized circumstances that may be impossible or exceedingly difficult to realize, and that its theoretical premises are controversial even among supporters of the many-worlds interpretation. Thus, as cosmologist Anthony Aguirre warns, "it would be foolish (and selfish) in the extreme to let this possibility guide one's actions in any life-and-death question."

History

Hugh Everett III did not mention quantum suicide or quantum immortality in writing; his work was intended as a solution to the paradoxes of quantum mechanics. According to Eugene Shikhovtsev's biography of Everett, "Everett firmly believed that his many-worlds theory guaranteed him immortality: his consciousness, he argued, is bound at each branching to follow whatever path does not lead to death". Peter Byrne, another biographer of Everett, reports that Everett also privately discussed quantum suicide (such as playing high-stakes Russian roulette and surviving in the winning branch), but adds, "It is unlikely, however, that Everett subscribed to this [quantum immortality] view, as the only sure thing it guarantees is that the majority of your copies will die, hardly a rational goal."

Among scientists, the thought experiment was introduced by Euan Squires in 1986. It was published independently by Hans Moravec in 1987 and Bruno Marchal in 1988; it was also described by Huw Price in 1997, who credited it to Dieter Zeh, and independently presented formally by Max Tegmark in 1998.