Motivational interviewing (MI) is an American behavioral health intervention that has spread dramatically across professional fields, including counseling psychology, corrections, dentistry, nursing, nutrition, primary-care medicine, safe-water interventions, and social work. This article explores how the central methodological principles of American pragmatism-if understood and learned as MI-take root among a group of contemporary American helping professionals. More specifically, the article shows how professional training in MI inculcates: (1) a steadfast focus on the immediate consequences of one's acts rather than floating or abstract conceptions of the true, the good, or the right; and (2) an investment in a highly reflexive mode of knowledge acquisition, which relinquishes the certainty of positivist explanations and embraces doubt. Indeed, learning how not to know is part and parcel of becoming an American pragmatist, and this article details the labor, costs, and rewards of adopting a pragmatic, or (in)expert, sensibility.