If it's a "different me", it's not me at all.

Mmmm, I'm not so certain. If you were to install a synthetic memory bank in the back of your head, you would be a "different you," but there would be sufficient continuity of identity, of what cyberpunk author Shirō Masamune called "ghost," that most people would still argue - rightly, in my view - that you would still be "you."

Given appropriate technology, you could progressively replace every part of your brain with enhanced, synthetic substitutes, and still retain sufficient continuity to qualify as "you," even though there would be nothing left of the original wetware. On the other hand, simply copying your brain architecture into an advanced neural net computer and then shooting you would kill "you," at least in most people's view.

What this suggests is that the relevant distinction is in terms of the degree of continuity, or the rate of change and the fraction of the body replaced in each step.

Under that convention, the children's argument in this case is wrong, because you have a 100 % discontinuity when you flush the embryo and plug in a new one. But it is not a completely silly argument that you could in principle replace the zygote with a different one, if only you could do it one cell at a time.

- Jake

Friends come and go. Enemies accumulate.