Brain transplants:the implications [3 of 3]

Are we our brains? Or, put another way, if your brain was transplanted into another body, would ‘You’ go with the brain? Answering the troubling question “Who survives a brain transplant?” becomes doubly complicated if the transplanted human brain were to be divided into two parts – in so-called ‘Fission’ thought-experiments. Scholarly speculations on the subject go back many years, with many crediting Sydney Shoemaker (Susan Linn Sage Professor of Philosophy Emeritus at Cornell University (retired)) for planting the seeds of the idea back in 1963 with his book “Self-Knowledge and Self-Identity”. In the Fission scenario, philosophers traditionally consider a setting where a person’s brain is bisected (back to front) and each half is transplanted into the empty skulls of two other bodies which are healthy (aside from their lack of a brain). The two ‘new’ people are called, by convention, ‘Lefty’ and ‘Righty’ – and the question arises, from the point of view of the owner of the brain – ‘Am I still me, or am I Lefty, or Righty, or both?’ Philosophical opinions – like the brains in question – are divided. For a clarification of current thinking, see the Stanford Encyclopaedia of Philosophy :

“It follows that you are Lefty and also that you are Righty. But that cannot be: Lefty and Righty are two, and one thing cannot be numerically identical with two things. Suppose Lefty is hungry at a time when Righty isn’t. If you are Lefty, you are hungry at that time. If you are Righty, you aren’t. If you are Lefty and Righty, you are both hungry and not hungry at once: a contradiction.”

Perhaps, oneday, a brain transplant will be considered a simple procedure, and questions such as these will be straightforwardly answered by the brain-recipients themselves, but until then, as the encyclopaedia puts it :

“What I really want is for there to be someone in the future who is psychologically continuous with me, whether or not he is me. The usual way to achieve this is to continue existing …”

Further resources :

‘Identity, Personal Identity and the Self’ : John Perry (2002)

‘Personal identity and self-consciousness’ : Brian Garrett (1998)

Can The Self Divide?‘, John Perry Journal of Philosophy 69: 463-88 (1972)