This essay examines the function of argumentation in making and defending critical judgments. When claims cannot be verified empirically, and yet we wish for them to be justified rather than arbitrary or whimsical, argumentation is the method employed. The goal is to convince critical listeners that what are offered as reasons for a claim do count as reasons, making the claim more acceptable. Although the specific focus is on rhetorical criticism, the essay applies to critical claims more generally. This essay originally was published in the Journal of Communication, 58 (December, 2008), 629–640, as part of a symposium about how different methods of inquiry can enrich and benefit from one another.