This is an old revision of this page, as edited by Schaefer (talk | contribs) at 07:53, 22 December 2005 (Removing unattributed criticisms. See talk.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 07:53, 22 December 2005 by Schaefer (talk | contribs) (Removing unattributed criticisms. See talk.)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)Quantum immortality is the controversial speculation that the Everett many-worlds interpretation of quantum mechanics implies that a conscious being cannot cease to be.
Overview
The idea derives from a variant of the quantum suicide thought experiment. Imagine that a physicist detonates a nuclear bomb located beside him. In almost all parallel universes, the nuclear explosion will vaporize the physicist. However, there should be a small set of alternative universes in which the physicist somehow survives (ie. the set of universes which support a "miraculous" survival scenario). The idea behind quantum immortality is that the physicist will remain alive in, and thus able to experience, at least one of the universes in this set, even though these universes form a tiny subset of all possible universes. Over time the physicist would therefore consider himself to be living forever. There are some parallels with this concept in the anthropic principle.
Another example is that provided by quantum suicide where a physicist sits in front of a gun which is triggered, or not triggered, by radioactive decay. With each run of the experiment there is a 50-50 chance that the gun will be triggered and the physicist will die. If the Copenhagen interpretation is correct, then the gun will eventually be triggered and the physicist will die. If the many-worlds interpretation is correct, then at each run of the experiment the physicist will be split into a world in which he lives and one in which he dies. In the worlds where the physicist dies, he will cease to exist. However, from the point of view of the physicist, the experiment will continue running without his ceasing to exist, because at each branch, he will only be able to observe the result in the world in which he survives, and if many-worlds is correct, the physicist will notice that he never seems to die therefore proving himself to be immortal, or at least according to quantum immortality.
Proponents point out that while it is highly speculative, quantum immortality violates no known laws of physics.
Although quantum immortality is motivated by the quantum suicide thought experiment, Max Tegmark, one of the inventors of this experiment, has stated that he does not believe that quantum immortality is a consequence of his work. He argues that under any sort of normal conditions, before someone dies they undergo a period of diminishment of consciousness, a non-quantum decline (which can be anywhere from seconds to minutes to years), and hence there is no way of establishing a continuous existence from this world to an alternate one in which the person continues to exist.
Fictional depictions
The Greg Egan novel Permutation City relies heavily on the theory of quantum immortality. In it, a main character miraculously survives several would-be deaths, and eventually organizes and participates in a mass-suicide with dozens of eccentric millionaires in the belief they would find themselves in a self-contained universe of their own design. Egan's first novel, Quarantine, also explores topics related to quantum immortality.
Other science fiction stories exploring these and related ideas include "All the Myriad Ways" by Larry Niven, and "Divided by Infinity" by Robert Charles Wilson.
See also
- Immortality
- Many-Worlds Interpretation
- Copenhagen interpretation
- Doomsday argument
- Final anthropic principle