Full Idea
If I am largely paralysed, and my twin brother is dying of brain disease, then if the operation to graft my head onto his body is offered, I should accept the operation, and it is irrelevant whether this person would be me.
Gist of Idea
It is fine to save two dying twins by merging parts of their bodies into one, and identity is irrelevant
Source
Derek Parfit (The Unimportance of Identity [1995], p.308)
Book Reference
'Personal Identity', ed/tr. Martin,R /Barresi,J [Blackwells 2003], p.308
A Reaction
Parfit notes that the brain is a particularly significant part of the process. The fact that I might cheerfully accept this offer without philosophical worries doesn't get rid of the question 'who is this person?' Who should they remain married to?