There is no evidence for this thing you call a soul and it completely contradicts even abstract logic. Where is this soul? I can cut off a person's arms and legs yet their soul is not gone. I can replace organs with new ones yet the person never takes on the personality of the donor. Obviously it must be in their head. If I preform a lobotomy on them they still have feelings, thoughts, and memories. If I cut off their cerebellum they simply have severe problems with motor skills but again they have complex thoughts and feelings.
I can do this for many parts of the brain yet they still exhibit thoughts and feelings. When I get into the limbic system suddenly I am having an effect on this thing they call a soul. But wait... What's this... When I cut out different parts the individual only loses aspects of their soul... It's almost as if this is some type of biological system?! But I thought souls ran on magic and pixie dust?!
Like the other poster who mentioned a "soul", I did not mean it in a religious sense, I meant it as the center of self and consciousness. I did not imply anything about magic and pixie dust, I merely said that consciousness is not very well understood. Ignoring the fact that many scientists consider the definition of a limbic system to be obsolete and unuseful, the organs used under that term control emotion and memory, this still has nothing to do with a sense of self (you could argue its an emotional sense and it is in a way, but does taking away all emotion and feeling remove your self-identity? Can you still look at someone and think "thats John Smith"? If yes, then can you see yourself and say "thats me"? Then seeing a copy of yourself, would you still say "thats me"? A copy is still a separate entity). Do you have any references to medical or scientific studies where damaging these organs lead to the subject losing a sense of self?
Anyway, I am sure its a biological system, I just don't think we're very close to understanding its function. If you reread my post I said that there is a higher function which controls our consciousness and sense of self (which religion calls a "soul" and attributes to supernatural forces - I do no such attribution, I'm just reusing their term because it has a similar observable end result), that we do not currently understand it and that if we do some day understand it scientifically, it will most likely be after our lifetimes (going by our current level of understanding and by what I've been told by researchers in neuroscience and BCI). I did not ever claim that the "soul" was not a biological system.
You also did not address the fact that if you do a copy-and-paste that there are two "you"'s and that the original "you" will still not feel like the second person is them. Do identical twins think they are one person? Would a cloned human think they are the original? They have the same genetic make-up. If they also have the same memories, does that make them the same person? If that is so, in the future when we can implant memories and reprogram our DNA, can I become you? What if I now kill the original (making it a cut-and-paste)? If you transplant part of the person (ie, keep the organs that create a sense of self) and rebuild the rest of the body, then it is really just an extreme repair job and the concept of a "soul" (as a biological system or otherwise) still remains.
As I see it, if you can duplicate a body and they are identical in every way, identical DNA, identical cell structure, identical memories, at the point of duplication, they are both the exact same. Both have a sense of identity. If they feel that the they and the copy are the same bing or not is irrelevant. What if one now goes one way and the other another, now their experiences and their memories will diverge. Maybe one falls and breaks a bone or catches a cold or something. Now they aren't even physically identical any more. Are they one person regardless? I think if something has the potential to be different than something else, then it is not really the same entity. If it were, then changing one would also change the other (kinda like quantum entanglement). A Brain in a Vat makes some good points here though. What if we can duplicate our bodies and our identity with it? What if both bodies think that both are one and the same? What if memories were somehow synchronized between both bodies? If they were in a state of quantum entanglement and changing one also changed the other. I guess it would be a kind of hive-mind, but would each still have its own individuality and sense of identity, except with a shared cognition and shared memories, or would they both be the one in every way? It would be very strange then to have two sets of senses (possibly in different locations) and still identify as one. I suppose its not impossible if you then think of a body like a cell within a larger organism, contributing to a single consciousness.
If we could ever reach that point, technologically, though is, in my humble opinion, doubtful. The questions that arise from this are difficult, if not impossible, to answer. In any case, *we* will not live to see it.
EDIT: One thing I have to credit SteveDeFacto with is getting everyone to argue about this It would make an awesome concept for a game and you could explore some pretty interesting questions!