Does the individual consciousness depend on the actual atoms or only on the configuration of the atoms?
Suppose we have mastered cryo-freezing and atom-manipulation technology. We can freeze and unfreeze people at will.
We freeze Sarah. We replace Sarah's atoms one by one. With all atoms replaced, we wake her up. Is it the "same" Sarah? (the same to herself, not just to us).
Let's call the being that results from all this replacement Sarah2 . We can ask a pair of questions that seem different. One is whether Sarah2's conscious states will be like Sarah's. I agree with Mark that the answer to that question is yes; at least, it's hard to see why it would be no. But we can ask another question that seems to a different one: is Sarah2 the same person as Sarah? That's a lot more controversial. A comparison, based on an example by Peter van Inwagen: Suppose little Johnny builds a house from a small number of blocks and leaves it in the middle of the floor. And suppose that I come in and clumsily kick the house over. If I re-arrange the blocks in exactly the same way, then the house I assemble will be indistinguishable from the one Johnny built, but it's not so clear that it's literally the same house. And if I actually replace the blocks with new ones that are just like the old ones, then it's even less clear. So if we cryo-freeze Sarah, interrupting her normal...