On Tue, 5 May 1998, David Bradley wrote:
> *If the consciousness is both contained in, and produced by the cells of the brain*
> (and is the reason you die if you do not get enough oxygen to the brain) one sould
> be able to *logically* assume that:
>
> 1) If the cells are all taken away and the new system is implanted, that the
> original consciousness *is* lost. There should be no more reason for the original
> consciousness to exist than there would be for a person 'a' to still be living
> in an apartment after 'a' has been replaced by person 'b'. The apartment may
> still be a home (or the body may still have a consciousness,) but there is a new
> 'tenant.'
Actually, I find this dubious. If I am playing Bach's "Goldberg Variations" on my CD player, and then remove the CD and replace it with another identical one, is the same music being played? Yes. The CDs are different, but the music is the same.
Similarly, if I replace all of your cells with cells which act just like your cells, then perhaps I am doing the same thing as switching the CDs. There is no externally observable difference between the music on the two CDs; there would be no externally observable differences between your consciousness before the experiment and whatever was left.
We cannot determine whether your consciousness would remain intact by experiment, or even thought experiment; if we are not feeling it, we can only presume that consciousness exists when we observe intelligent behavior. Since the behavior would be the same, however, by that same presumption we must conclude that the consciousness would remain and would be the same. If this presumption is not true, then we cannot presume that anyone else is conscious either, because we aren't them.
Since we can and do presume the existence of consciousness which we don't feel based on observed behavior, and since the observed behavior would be identical, we must conclude that the consciousness would be identical.