Massimo Pigliucci has recently referred to the classic puzzle I alluded to in my previous post on this site about whether the destruction of one's body entails annihilation if a reconstructed version of one's body survives.
He was trying out a new online tool for addressing questions to the philosophical community, and one of his questions concerned 'what happens when Captain Kirk steps into a transporter device'.
The answers he got were all over the place. The most common one amongst philosophical academics interested in metaphysics was: 'Kirk dies, a Trekkie cries.'
But, as a commenter put it: 'Presuming 1) that the Kirk who emerges at the end of the transportation process is physically identical to the Kirk that went in, and 2) there's no untransportable and intangible soul-stuff that makes Kirk Kirk, I don't understand how you can meaningfully say that Kirk has died after being transported.'
The response to Pigliucci's query (coupled with the comment thread attached to his post) illustrates a problem with much philosophical discourse.
The topics being addressed may or may not be interesting or important this one is both, I think but there is no standard or rigorous method for dealing with them, and so no real evidence of a coherent academic discipline (or profession) in operation. (Bear in mind that Derek Parfit set the ball rolling on this particular discussion three decades ago.)
Often philosophical questions seem to be without satisfactory answers (which suggests that the questions are confused, in the sense of carrying too much implicit metaphysical baggage). If an answer comes, it is, more often than not, a mere trigger for counterarguments, and more questions... The process just doesn't move forward most of the time.
Scientific knowledge is relevant to making sense of thought experiments like this, however. For example, if the processes involved violate known science then the whole discussion is just a fantasy and a waste of time. (Bad science fiction, if you like.)
One important scientific issue raised in the discussion relates to whether atoms can be distinguished from one another as macro-objects can. It seems not. Apparently, it just doesn't make sense to ask whether the atoms constituting the reconstructed body are the same ones which constituted the original body or different ones. The very notion of a 'copy' is called into doubt.
Inanimate objects (specifically the Mona Lisa) are discussed in the light of this fact. I think Ian Pollock goes too far in suggesting that if there was a perfect (atom for atom) copy of the Mona Lisa, then the notion of the real, original Mona Lisa would no longer have a clear, objective meaning. It would, surely. It is the one Leonardo actually painted. As Massimo Pigliucci points out, Pollock is not taking history seriously.
And, if the real Mona Lisa is the one actually painted by Leonardo (defined by its history as well as physics), so my real body (on which my subjective consciousness depends) is also defined in part by its history.
The heart of the question of personal identity relates to first-person experience, to my consciousness of being me and being alive. Would Kirk be right to have misgivings about entering the transporter?
Clearly, subjective experience is entirely dependent on a particular physical body. It is the body that is conscious. So, in the end, 'I' am my body in the sense that 'my' fate is inextricably bound up with the fate of this body. If it goes, 'I' go.
I put the pronouns in quotes to indicate that I personally doubt that there is any substantial thing, any entity, which is me. 'I' am a kind of composite of experiences: very basic sentience in the here and now (the sort of thing any living creature even the most basic might have) plus memory. When a certain level of neuronal complexity is reached, you have a sense of a continuing self.
The real mystery lies, in my view, with basic sentience rather than with identity. Sentience is a real, robust phenomenon whereas personal identity is arguably an illusion as there is no 'self', just a (sentient, etc.) body with a complex brain.
At my death nothing of substance will die, apart from the body.
Regarding the transporter, I would have to agree with Massimo Pigliucci that it kills Kirk. The copy may have Kirk's memories, but subjectively Kirk goes into the transporter, is scanned and never wakes up.
To finish, here is a little thought experiment of my own, a little meditation on the nature of death.
We willingly go to sleep at night. We willingly get anaesthetized for an operation. We might also be happy to go into 'cold storage' for a long space journey or to survive a devastating catastrophe on earth (a 'nuclear winter', for example).
But, what if, though we could be certain the hibernation device would not fail to keep our body alive and in a resusitatable state, we just did not know whether or not it would ever get around to waking us up?
Going into such a device becomes exactly equivalent to a game of Russian roulette. Death (as in the death of the body) is functionally equivalent to not waking up, ever. All the death of the body does is make it impossible ever to wake up. It takes away hope.
But, from the point of view of the unconscious person, hope or any kind of expectation is irrelevant. So the experience of death is equivalent to the experience of going into a state of unconsciousness nothing more.
[Update, July 11, 2014: I have realized that there is a flaw in this argument. As soon as I have time I will write a new post explaining what I see the flaw to be.]