The teletransporter
On the axis: Nature of the self · a person
If you are scanned here, your body destroyed, and an exact copy with all your memories rebuilt on Mars, is it you who arrives, or did you die, replaced by a double who believes he is you?
This problem is brought out by the thought experiment The teletransporter:
You step into a teletransporter. The machine records the exact state of each of your cells, destroys your body, then transmits the information to Mars, where an identical body is rebuilt from fresh matter. The person who walks out has all your memories, your character, and the feeling of having just stepped into the booth. Convinced she is you, she takes up your life where you left it. Usually the trip goes without a hitch; but today, a question holds you back on the threshold.
Derek Parfit, Reasons and Persons (1984)
Is the person who wakes on Mars you, or did you die in the booth, replaced by a copy who believes she is you?
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Justification
Locke detaches personal identity from substance, whether material or spiritual: what makes me the same person over time is the continuity of consciousness, and notably the memory linking my past actions to my present. Person is thus a forensic term, bound to imputation: before the name existed.
As far as this consciousness can be extended backwards to any past action or thought, so far reaches the identity of that person.Essay Concerning Human Understanding, II, ch. 27, §9
Essay Concerning Human Understanding, II, ch. 27 ("Of Identity and Diversity")
Anchors: Parfit · Locke