  Nevertheless, this option has some uncomfortable implications. For  one thing, we think “I” uniquely refers, but  “I” in X's mouth would, in this case, actually  be referring to two people, Y and Z. Or  perhaps that is not quite right; perhaps instead “I” in  X's mouth refers to only one person, either  Y or Z. But in that case, no one, not even “the” speaker, could possibly know to which one it  referred. And there are other worries. For instance, whether or not  the pre-fission X consists in two overlapping persons  depends entirely on what happens in the future, i.e., on whether or  not X goes through with the fission. So if X is  driving from the bank to the fission doctor and then gets cold feet,  there will be no fission and thus no Y or Z. But  then whether or not Y or Z exist at the time of X's cold feet depends on whether or not X even gets cold feet, which seems, at the very least, quite odd. Whether or not “I” now consist in one or two people should not, we  want to say, depend on what happens to “me” in the  future.