“Without Evidence, There Is No Answer”: Uncertainty and Scientific Ethos in theSilent Spring[s] of Rachel Carson

Abstract The 50th year anniversary of Rachel Carson's monumental Silent Spring invites reflection on how the controversy over chemical pesticides shaped environmental discourse in the modern era. This essay focuses on uncertainty as a boundary device that shapes scientific ethos in crucial ways and negotiates a relationship between technical science and public deliberation. Situated in rhetorical analysis, the author takes a comparative approach towards the use of uncertainty and scientific ethos in the Silent Spring controversy. Drawing from Carson's published book, and from the famous CBS Reports investigative television program seven months after the book's publication, this essay demonstrates how CBS Reports directly received, and amplified, Carson's uncertainty frameworks, and used them to drive the public evaluation of scientific ethos. This analysis reveals three ways uncertainty shapes scientific ethos: uncertainty as a probability (ethos of expertise), as a moral certainty (ethos of civic participant), and as an unknown or unconcern (ethos of ignorance). Finally, the author suggests that the circulation of these uncertainty frameworks of scientific ethos helped drive the momentum from the books' publication, to public evaluation, to policy-making, and suggests these uncertainty frameworks are enduring forces in debates about the role of experts in scientific controversies.