Martine Nida-Rümelin has argued recently for subject-body dualism on the basis of reflections on the possibility of survival in fission cases from the literature on personal identity. The argument focuses on the claim that there is a factual difference between the claims that one or the other of two equally good continuers of a person in a fission case is identical with her. I consider three interpretations of the notion of a factual difference that the argument employs, and I argue (...) that on each of them the argument either begs the question or is unsound. (shrink)