26 November 1997
Thank you for your letter of 19 November with your essay on Body Duplication and Identity (The Possible World Machine units 4-6).
The philosopher to read in conjunction with Dawkins is Daniel Dennett, an enthusiastic supporter of Dawkins' orthodox, mechanistic Darwinism. (See Dennett's book Darwin's Dangerous Idea.) Dennett sees evolution as the key to explaining how a material entity such as a human brain can embody 'content' or possess 'consciousness'. The human brain is designed to 'evolve' during infancy, building up the structures that perform essentially the same function as a computer program, though in a far more complex and subtle way than human programmers have succeeded in mimicing — to date. Dennett's Consciousness Explained (Penguin) would be the thing to look at, though it builds upon his earlier books Content and Consciousness (Routledge 1969) and Brainstorms (Harvester 1981). Dennett's latest stocking filler is Kinds of Minds (Phoenix 1997).
Would it have been easier to have repaired Michael Harding's leg? I wonder. It is a lot easier to photocopy a five pound note than fill in by hand details that have been erased. Even if there could one day be a mechanical process of scanning and copying people, it does not follow that the skills of the surgeon could ever be mechanically duplicated. All people are basically alike, so a copying process that worked on one would work on others. Every repair job, on the other hand, is, in the nature of things, unique.
Now to your essay:
'Selbe' would translate in English as 'one and the same', a phrase that rarely crops up outside philosophy text books! Now the main thrust of your argument, as I understand it, is that were two 'copies' to be produced from one 'original' (say, I step into the transporter booth on the Starship Enterprise and two Geoffrey Klempners appear moments later on the surface of the planet) then the two GK's could not be 'one and the same'. (I am ignoring, as you have, the asymmetry introduced by a more conventional copying process, where we can track the original and so distinguish it from a 'mere' copy, however perfect. This distinction is in fact irrelevant to the problem we are dealing with.) I would indeed make a stronger claim than you make. Even at the moment when the two GK's materialise they cannot be 'one and the same' for the simple reason that one and the same entity cannot be in two different places at the same time.
But before we go any further, let's ask, Why do we care about personal identity in the sense of 'being one and the same'? Though we change through time, it is our very own selves that we identify when we think about the future. It will be me undergoing that operation; it will be me receiving that award. If I heard that someone just like me — perhaps by some fluke of nature a perfect doppelganger living in Australia — was going to undergo an operation or recieve an award, I might be interested but not moved. What moves me is that these things are going to happen to this individual, myself.
Only now this intuition comes into head-on conflict with the duplication thought experiment. The two GK's who materialise cannot be identical with one another, that much is accepted. But it seems each GK has a much right as the other to be considered identical, or one and the same, as the 'I' that exists now. You can say that both are 'I', declaring that we shall henceforth talk as if there had been two GK's there all along, two GK's writing this letter etc. Or you can say that neither is 'I', i.e. that at the moment of duplication I cease to exist and am replaced by two 'mere' copies.
One thing you can't say (unless you're a Cartesian dualist) is that the 'I' mysteriously 'goes' into one of the two individuals that materialise but not the other. — But I would argue that even embracing dualism does not get you off the hook: souls can be 'copied' too!
Whichever way you turn, there are tough choices to face.
I totally agree with your last point, that a cloned individual will lack the memories of the original. In the fourth 'Alien' film that has just been released, the character played by Sigourney Weaver is 'resurrected' by cloning her from a piece of preserved genetic material. (At the end of 'Alien 3' she was burned to a cinder.) Well, is it her? I haven't seen the film, but I guess the premise is that the clone shares her exceptional abilities, and perhaps has learned about the exploits of the original. — It reminds me of the tale about the writer of a successful radio adventure series who, wanting more money, put the protagonist into a predicament from which it was absolutely impossible to extracate oneself, then refused to write the next episode. He got his raise. The next episode began, 'With one bound he was free.'