What is "you", then?

Let's say that in addition to the technology described in the story, we can create a completely simulated world, with all the people in it simulated as well. You get your brain scanned an instant before you die (from a non-neurological disease), and then "boot up" the copy in the simulated world. Are "you" alive or dead? Your body is certainly dead, but your mind goes on, presumably with the ability to have the same (albeit simulated) experiences, thoughts, and emotions your old body could. Get enough people to do this, and over time your simulated world could be populated entirely by people whose bodies have died, with no "computer AIs" in there at all. Eventually this simulated world maybe even has more people in it than the physical world. Is this simulated world less of a world than the physical one? Are the people in it any less alive than those in the physical world?

Let's dispense with the simulated world, and say we also have the technology to clone (and arbitrarily age) human bodies, and the ability to "write" a brain copy into a clone (obliterating anything that might originally have been there, though with clones we expect them to be blank slates). You go to sleep, they make a copy, copy it into your clone, and then wake you both up simultaneously. Which is "you"?

How about at the instant they wake up the clone, they destroy your "original" body. Did "you" die? Is the clone you, or not-you? Should the you that remains have the same rights and responsibilities as the old you? I would hope so; I would think that this might become a common way to extend your life if we somehow find that cloning and brain-copying is easier than curing all terminal disease or reversing the aging process.

Think about Star-Trek-style transporters, which -- if you dig into the science of the sci-fi -- must destroy your body (after recording the quantum state of every particle in it), and then recreate it at the destination. Is the transported person "you"? Star Trek seems to think so. How is that materially different from scanning your brain and constructing an identical brain from that scan, and putting it in an identical (cloned) body?

While I'm thinking about Star Trek, the last few episodes of season one of Star Trek Picard deal with the idea of transferring your "consciousness" to an android body before/as you die. They clearly seem to still believe that the "you"-ness of themselves will survive after the transfer. At the same time, there is also the question of death being possibly an essential part of the human condition; that is, can you really consider yourself human if you are immortal in an android body? (A TNG episode also dealt with consciousness transfer, and also the added issue of commandeering Data's body for the purpose, without his consent.)

One more Star Trek: in a TNG episode we find that, some years prior, a transporter accident had created a duplicate of Riker and left him on a planet that became inaccessible for years afterward, until a transport window re-opened. Riker went on with his life off the planet, earning promotions, later becoming first officer of the Enterprise, while another Riker managed to survive as the sole occupant of a deteriorating outpost on the planet. After the Riker on the planet is found, obviously we're going to think of the Riker that we've known and followed for several years of TV-show-time as the "real" Riker, and the one on the planet as the "copy". But in (TV) reality there is no way to distinguish them (as they explain in the episode); neither Riker is any more "original" than the other. One of them just got unluckily stuck on a planet, alone, for many years, while the other didn't.

Going back to simulated worlds for a second, if we get to the point where we can prove that it's possible to create simulated worlds with the ability to fool a human into believing the simulation is real, then it becomes vastly more probable that our reality actually is a simulated world than a physical one. If we somehow were to learn that is true, would we suddenly believe that we aren't truly alive or that our lives are pointless?

These are some (IMO) pretty deep philosophical questions about the nature of consciousness and reality, and people will certainly differ in their feelings and conclusions about this. For my part, every instance above where there's a "copy" involved, I see that "copy" as no less "you" than the original.