Faversham Stoa is a philosophy discussion group meeting on the 3rd Tuesday of every month from 7.30 to 9.30pm in the The Bull in Tanners Street. We cover a large range of topics. If you have an idea for a topic that you would like us to cover why not drop us a line? There's no charge for membership and everyone is welcome to drop in. Just bring your brain and some beer money!


The press had given him the nickname 'worm man; but his friends knew him as Derek. Scientists had manipulated his DNA to mimic one of the most amazing features of the common or garden worm: the ability to regenerate lost tissue. And it had worked. When they chopped off his hand to test him out, a new one had regrown within a month.

Then it all went wrong. His body was slowly deteriorating. To save his life they had to transplant his brain into a new body. However, a major mistake during the operation severed his brain in two.

Fortunately, both halves fully regenerated and both were successfully transplanted into new bodies. The only problem was that both the men who now had one of the brains believed they were Derek. What is more, both had Derek's memories, mental skills and personality. This created problems for Derek's boyfriend, who couldn't tell them apart. It also led to the Dereks getting entangled in a legal battle to claim Derek's assets. But which was the real Derek? They couldn't both be him, could they?

Like a good detective, before we start trying to account for what has happened, we should get the facts clear. Where once we had one Derek, now we have two. Call them right-Derek and left- Derek, after the hemispheres of the original brain they grew from. Which, if either, is Derek?

They can't both be Derek, because since the split they have been two people, not one. If right-Derek died, for example, and left-Derek lived on, would Derek be dead or alive? Since one person cannot be both dead and alive, Derek couldn't be both right- and left-Derek.

Perhaps neither right- nor left-Derek is Derek. But this seems a strange solution. If, for example, the left hemisphere had been destroyed in the operation and only the right had fully regener- ated, we would surely say that right-Derek was Derek. If the left hemisphere had also regenerated, however, suddenly right-Derek isn't Derek at all, even though he is exactly the same in both cir- cumstances. How can a difference in something external to right-Derek stop him being Derek?

The only remaining possibility is that one or other of right- and left-Derek, and one only, is Derek. But since they have an equal claim to his identity, why should we pick one rather than the other? An ascription of identity cannot be arbitrary. So all three possibilities – both, either or neither – seem wrong. But one must be right: there are no other options.

If none of the possible answers to a question is adequate, per- haps we're just asking the wrong question. It's like demanding an answer to 'When did you stop beating your wife?' when the beatings never started.

In the case of the worm man, the problem is that we are asking a question about identity over time – a one-to-one relation - when the thing in question has a one-to-many relation over time. The logic of identity just doesn't fit. We should talk instead about succession or continuation. So, both right- and left-Derek are continuers of Derek, but we should not ask which, if either, is Derek.

So perhaps the question we should ask is if Derek survived his ordeal. It looks as though he did. If that is true, it seems that Derek achieved personal survival without personal identity.

Of course, ordinary selves do not divide as Derek did. Nonetheless, his tale may still be instructive. For what it suggests is that what matters for our survival is not that identity over time is preserved, but that there is the right kind of continuity between us and our future selves. Then it becomes a question of what we want to see continue. Is it our bodies? Our brains? Our inner lives? Our souls?

from The Pig Who Wants to be Eaten by Juian Baggini (page 136)

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