Reviewed by: How to Talk to a Science Denier: Conversations with Flat Earthers, Climate Deniers, and Others Who Defy Reason by Lee McIntyre Michael Filas (bio) Lee McIntyre, How to Talk to a Science Denier: Conversations with Flat Earthers, Climate Deniers, and Others Who Defy Reason. MIT Press, 2021, 264 pages, $24.95 cloth. This book is Lee McIntyre’s fourth monograph from MIT Press, and it continues his examination of how we understand truth and post-truth. While he examines science deniers of many stripes—from flat-earthers to anti-vaxxers to climate deniers—he juggles his own deference to the principles of science with an earnest investment in swinging science deniers, one at a time, face-to-face, into the fold of science believers. Readers get a thorough review of the history and key moments in several pockets of science denial, but this review comes in the context, as advertised, of a reformer’s guide to converting the nonbelievers. McIntyre discovers that you do not convert science deniers by throwing volumes of data at them, or by belittling their perspective. Science deniers hold on to their beliefs less as rational facts than as a dimension of their identity. Only a respectful, recursive, face-to-face conversation will initiate a person’s belief transformation, and commensurate identity shift. The book begins as McIntyre recounts his investigatory trip to the 2018 Flat Earth International Conference in Denver, engaging with “six-hundred shouting, clapping true believers” (xvi), and documenting, through personal accounts, how he engaged with the convention attendees. He sustained listening, respect, and a measured approach throughout his interactions with the flat-earthers, but his mind was not changed (“don’t worry, I’m not one of them” he writes [p. 29]). However, through respectful dialogue, McIntyre learns how to recognize the telltale attributes, a nomenclature of five tropes he calls a “secret decoder ring” for fighting science denial (xiii). This methodological centerpiece argues that all science deniers make “the same [End Page 497] few mistakes in human reasoning: (1) Cherry picking evidence; (2) Belief in conspiracy theories; (3) Reliance on fake experts (and denigration of real experts); (4) Committing logical errors; and (5) Setting impossible expectations for what science can achieve” (p. 33). And McIntyre uses this five-trope critique throughout subsequent chapters, which include discussions of anti-vaxxers, climate denial, coronavirus denial, and opposition to genetically modified organisms (GMOs). The book is structured in part as a travelogue through various brands of science denial, exemplifying as it goes McIntyre’s method for engaging in dialogue. Through the introduction and first chapter, we learn the nuances of how and why flat-earthers at the 2018 Denver conference have come to believe that “globalists” have bought into a hoax, sustained by faked photos from NASA; this exemplifies the conspiracy theory element of the five-trope critique. In chapter 2, we get a more in-depth explanation of each of the five telltale tropes, enumerated above, that reveal the errant thinking in science denial, plus a look at the motivational and psychological roots of science denial. This section importantly shifts the focus from how science denial is created to why people believe it, such as “motivated reasoning . . . whereby we are more prone to look for information that backs up things we want to believe” (p. 47, emphasis in original). And it also broaches one of the main insights of this book: “The content of the belief may not be as important as the social identity it affords” (p. 54). Chapter 3 goes deeper into the psychology of how and why science deniers hold their beliefs, and why they are difficult to convince with facts alone. He writes about concepts like the “backfire effect,” wherein a person becomes more convinced of their original mistaken belief when they are presented with correcting information (p. 63). “Belief formation and change are not just a matter of having correct factual information, but of the emotional, social, and psychological context within which beliefs are formed” (p. 66). The second part of the chapter illustrates the importance of face-to-face conversations in convincing hard-core science deniers to reconsider their beliefs. And here, McIntyre provides an...