In my argument for subject body dualism criticized by Ludwig I use the locution of a genuine and factual difference between two possibilities. Ludwig distinguishes three interpretations of this locution. According to his analysis the argument does not go through on any of these interpretations. In my response I agree that the argument is unsuccessful if ‘factual difference’ is understood in the first way. The second reading—according to a plausible understanding—cannot be used for the argument either. The discussion of this reading raises fundamental issues about different notions of propositional content. I disagree with Ludwig's diagnosis with respect to the third reading. Contrary to Ludwig's claim, there is no modal error involved if ‘factual difference’ is understood in the third way. Ludwig's objection to the argument according to its third reading can be answered by pointing out that every individual has its identity conditions necessarily. At this point fundamental and general metaphysical issues (concerning the link between identity conditions and the nature of ontological categories and between transworld and transtemporal identity) prove relevant. Finally, I make more explicit how ‘factual difference’ should be understood in the context of the argument (this is a fourth reading not considered by Ludwig) and explain how this reading strengthens the argument (compared to the third reading) by weakening its central premise. I conclude that Ludwig's attempt at undermining the argument from transtemporal identity for subject body dualism is unsuccessful.