there was an amy, then there was another amy. there may have been two amy's at once, i dont remember. but there was definitely the first amy, then another amy.
they dont look alike, but they are both amy's. first amy is somewhere else, other amy is still amy. other amy is not a replacement for first amy, simply another amy. one amy is more than anyone deserves, really. but there is still an amy, when there quite possibly have been no amy's since first amy left.
i know why now-amy is amy-0, and not amy-O. i don't know why first amy is gone, or if she was amy-1 or amy-N.