The teletransportation paradox or teletransport paradox is a thought experiment on the philosophy of identity that challenges common intuitions on the nature of self and consciousness. It first appeared in full published form presumably in Derek Parfit's 1984 bookReasons and Persons, but similar questions have been raised as early as 1775. The Polish science-fiction writer Stanisław Lem discovered the same problem independently in the middle of the twentieth century. He put it in writing in his philosophical text "Dialogi", 1957. Similarly, in Lem's Star Diaries of 1957 the hero visits a planet and he finds himself recreated from a backup record, after his death from a meteorite strike, which on this planet is a very commonplace procedure.
Derek Parfit's version
In Divided Minds and the Nature of Persons, Parfit asks the reader to imagine entering a "teletransporter", a machine that puts you to sleep, records your molecular composition, breaking you down into atoms, and relaying it to Mars at the speed of light. On Mars, another machine re-creates you, each atom in exactly the same relative position. Parfit poses the question of whether or not the teletransporter is a method of travel—is the person on Mars the same person as the person who entered the teletransporter on Earth? Certainly, when waking up on Mars, you would feel like being you, you would remember entering the teletransporter in order to travel to Mars, you would even feel the cut on your upper lip from shaving this morning. Then the teleporter is upgraded. The teletransporter on Earth is modified to not destroy the person who enters it, but instead it can simply make infinite replicas, all of whom would claim to remember entering the teletransporter on Earth in the first place. Using thought experiments such as these, Parfit argues that any criteria we attempt to use to determine sameness of person will be lacking, because there is no further fact. What matters, to Parfit, is simply "Relation R", psychological connectedness, including memory, personality, and so on. Parfit continues this logic to establish a new context for morality and social control. He cites that it is morally wrong for one person to harm or interfere with another person and it is incumbent on society to protect individuals from such transgressions. That accepted, it is a short extrapolation to conclude that it is also incumbent on society to protect an individual's "Future Self" from such transgressions; tobacco use could be classified as an abuse of a Future Self's right to a healthy existence. Parfit resolves the logic to reach this conclusion, which appears to justify incursion into personal freedoms, but he does not explicitly endorse such invasive control. Parfit's conclusion is similar to David Hume's view and also to the view of the self in Buddhism, though it does not restrict itself to a mere reformulation of them. For besides being reductive, Parfit's view is also deflationary: in the end, "what matters" is not personal identity, but rather mental continuity and connectedness.
