Quantum Immortality: From Two Outcomes to a Story of Survival

Picture an electron going through a measurement with two possible readings. The screen may show an arrow pointing up or down, while the person beside the machine sees only one result. In 1957, physicist Hugh Everett III asked whether the result missing from the screen truly disappears or continues in another branch of reality. Decades later, some writers used that question to argue that an observer would always find themselves alive in at least one branch. They called this claim quantum immortality.

Everett did not publish a paper about immortality. His “Relative State” Formulation of Quantum Mechanics proposed a way to describe quantum mechanics. The phrase many-worlds interpretation came later. Several separate inferences stand between that interpretation and the claim that no one ever experiences death, so they need to be kept apart.