In his Philosophical Investigations , Ludwig Wittgenstein wrote that "the importance of the true confession does not reside in its being a correct and certain report of a process. It resides rather in the special consequences which can be drawn from a confession whose truth is guaranteed by the special criteria of truthfulness " (1953, p. 222). In two earlier papers I argued that when the contrast between "reporting" and "confessing" thoughts is properly understood, Wittgenstein was right to hold that sincerity ("truthfulness") guarantees the truth of the confession. 1 I assumed without argument that the resulting "expressivist" explanation of this guarantee is also an explanation of the philosophically puzzling phenomenon of fi rst-person authority. A. Minh Nguyen takes me to task for this further assumption, and so compels me to address matters that were evaded in those earlier papers. 2 On his view my argument might successfully forge a connection between the truth of (at least some) self-ascriptions of mental states and their sincerity but, even so, what it explains is not fi rstperson authority.