Fission, First Person Thought, and Subject-body Dualism

Abstract

In “The Argument for Subject Body Dualism from Transtemporal Identity Defended” (2013), Martine Nida-Rümelin (NR) responded to my (Ludwig 2013) criticism of her (2010) argument for subject- body dualism. The crucial premise of her (2010) argument was that there is a factual difference between the claims that in a fission case the original person is identical with one of the successors. I argued that, on the three most plausible interpretations of ‘factual difference’, the argument fails. NR responds that I missed the intended, fourth interpretation, and that the argument on the third interpretation goes through with an additional assumption. I argue that the fourth interpretation, while insufficient as stated, reveals an assumption that provides an argument independently of considerations involving fission cases: in first person thought about future properties we have a positive conception of the self that rules out having empirical criteria of transtemporal identity. However, I argue that the considerations offered for this thesis fail to establish it, and that we do not, in fact, bring ourselves under any positive conception in first person thought, but rather think about ourselves directly and without conceptual mediation. This explains why it appears open in fission cases that the original person is identical with one of the successors, while what is possible is constrained by the actual nature of the self as referred to in first person thought. I argue also, incidentally, that on the third interpretation, the first premise of the argument is inconsistent with the necessity of identity.