Teletransportation paradox

The teletransportation paradox or teletransport paradox (also known in alternative forms as the duplicates paradox) is a thought experiment on the philosophy of identity that challenges common intuitions on the nature of self and consciousness, formulated by Derek Parfit in his 1984 book Reasons and Persons.

The Polish science-fiction writer Stanisław Lem described the same problem in the mid-twentieth century. He put it in writing in his philosophical text Dialogs in 1957. Similarly, in Lem's Star Diaries ("Fourteenth Voyage") of 1957, the hero visits a planet and finds himself recreated from a backup record, after his death from a meteorite strike, which on this planet is a very commonplace procedure. In chapter 6 of his later discursive book "Summa Technologiae", first published in 1964, he discussed in detail the identity paradoxes associated with teleportation and hibernation of human beings.

Similar questions of identity have been raised as early as 1775. "I would be glad to know your Lordship's opinion whether when my brain has lost its original structure, and when some hundred years after the same materials are fabricated so curiously as to become an intelligent being, whether, I say that being will be me; or, if, two or three such beings should be formed out of my brain; whether they will all be me, and consequently one and the same intelligent being."

Derek Parfit's version
Derek Parfit and others consider a hypothetical "teletransporter", a machine that puts you to sleep, records your molecular composition, breaking you down into atoms, and relaying its recording to Mars at the speed of light. On Mars, another machine re-creates you (from local stores of carbon, hydrogen, and so on), each atom in exactly the same relative position. Parfit poses the question of whether or not the teletransporter is actually a method of travel, or if it simply kills and makes an exact replica of the user.

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 some forms of 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.