Derek Parfit
All Souls College, University of Oxford. 1942 to 2017
Functionalist What matters is the organisation of the processing, not the material
Derek Parfit gave contemporary philosophy its sharpest account of what survives a copy. In Reasons and Persons (Oxford University Press, Clarendon Press, 1984) he argued that personal identity is not what matters. What matters is Relation R, psychological connectedness and psychological continuity, and that relation can hold to more than one later person at once.
His two cases do the work. The teletransporter case scans a body on Earth, destroys it, and reconstructs the person on Mars from the transmitted information. The branch-line case has a scanner that fails to destroy the original, so two people wake with the same past. Parfit’s conclusion is that in the first case survival occurs without identity, and in the second identity fails without the loss of what matters. He holds that a rational person should not fear the first and should not prefer the second.
Parfit did not write a theory of artificial consciousness and he did not claim that a copy is the same person. His claim is narrower and stronger. He says the question “is it the same person” is not the question that should drive the decision. This is the sharpest available answer to the branching objection, and it cuts against both the view that a copy is a murderer’s victim and the view that a copy is a continuation.
Known for. Reasons and Persons (1984), the branch-line case, and the claim that personal identity is not what matters
Coverage on this site
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Derek Parfit is listed with the other functionalists and computationalists, who hold that what matters is the organisation of the processing, not the material. The theory family behind that position is set out in the index of consciousness theories. Every researcher covered on this site is indexed in the directory of consciousness researchers.