The thesis of this article is that Nietzsche's use of irony in On the Genealogy of Morals is so pervasive that it cannot be relied upon to report Nietzsche's views, even at the moment of writing, on a historical sequence of events or the causal sources of the phenomena that Nietzsche identifies. I argue, primarily on the basis of textual evidence, that Nietzsche's procedure is neither to reliably report his own views nor to assert the reality of what might be (...) called the theoretical terms of the account. I offer as an explanatory hypothesis that Nietzsche adopted this procedure as a response to a problem of epistemic authority that he confronted in assessing morality. I also provide some historical context for Nietzsche's method and discuss some implications of my view for the interpretation of Nietzsche's project. (shrink)