Swinburne On Personal Identity

The problem, according to Richard Swinburne, with the body theory is that one part of the body, the brain, seems to be of crucial importance for determining the characteristic behavior of the rest, which isn’t true of other body parts. You could have a heart or liver transplant and be the same person, but the same cannot be said of the brain. So the brain would have to be “the core” of the body and not the body simpliciter. This makes it susceptible to duplication problems. If you were to split the brain of some Person P1 into its two hemispheres and put each hemisphere into an empty skull, both hemispheres would seem to have a claim of being P1. So if the brain is the core of the person, and the brain can be split into two, then it seems you can have two of the same persons, which would fail the criterion of identity. The problem with memory theory is that it also has duplication problems. Suppose someone claiming to be Guy Fawkes claims to have done all the things Fawkes has done and those which can be verified are verified and those that cannot seem plausible. But then suppose that another man claiming to be Fawkes makes the same claims, and thus fits the criteria of being Fawkes as well, then we would have two Fawkes’. But we can't say they’re identical to Fawkes because then they would be identical to each other, which clearly they are not. So, memory theory cannot constitute personal identity, though it may be fallible evidence of it. You could amend these theories to say that a person meets the criteria of identity so long as no one else does, but this seems ad hoc. To admit of degrees of person as an alternative would make the answer arbitrary and it would be absurd to say at some degree I am no longer me when identity is thought of as being all or nothing.