Suppose that transporters (like in Startrek) existed. You would be scanned somehow so that every atomic detail
of yourself could be be recorded. Then that information is transmitted to the destination, and a duplicate of you
is reconstructed. If the reconstuction is succesful, the original is destroyed.
What would you experience?
If the reconstucted duplicate is completely accurate, it seems that it should be no different than travelling some
great distance while you were unconscious, and then waking up at the destination. There should be continuity
of the conscious self between your departure (and destruction) and your arrival (and reconstruction).
Now, what if there was a malfunction; the duplicate 'you' was reconstructed at the destination, but the original 'you'
wasn't destroyed, The original 'you' awakens, and should obviously still have a continuity of the conscious self.
But the reconstructed 'you' also has this, just as it did in the previous example.
Now what do you experience?
Are you in two places at once? Which one is 'you'?