Originally Posted by CSflim

This thought experiment left open a rather interesting idea, which many people picked up on. The fact that the Mark II machine could be set so as not to destroy the original. Instead you would end up with a "photocopier" rather than a teleporter. So if I stepped into the duplicator, two of me would walk out. But which one would be me...you know; the original me..me as in actually...me?

They both would be of course. But they would instantly start being different 'me's, due to the fact that they would recieve different sensory inputs*, and hence the patterns which I mentioned would evolve in a different manner. They would end up being two entirely independant people, just with a shared history.