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Op/ed: A Breakdown of the ‘Denialist Playbook’

From Vaccines to Evolution, UMD Biologist Finds Pattern of Dismissing Science

By Sean B. Carroll

Children receive polio vaccine

Photo by AP Photo, file

First and second graders are inoculated against polio with the Salk vaccine in Los Angeles in 1955. Opponents lobbed numerous objections at the vaccine that eventually led to the eradication of the disease—arguments that remain in use by those seeking to deny established medicine or science that conflicts with their beliefs.

As medical researchers and drug companies rush to deliver a COVID-19 vaccine, and up to one-third of Americans say they won’t take it, University of Maryland biology Professor Sean B. Carroll examines an earlier tussle over vaccines in a new essay in Scientific American.

Carroll, the Balo-Simon Professor of Biology at UMD and vice president of science education at the Howard Hughes Medical Institute, finds the ‘50s-era arguments that chiropractors made against the vaccine that eventually led to the eradication of polio were similar to those used by creationists arguing against evolution. He argues that those seeking to overturn established medicine or science that conflicts with their beliefs use nonfactual, rhetorical arguments—a “denialist playbook.” Here are its six main plays, edited for length:

Doubt the Science
“The first tactic of denialism is to raise objections to scientific evidence or interpretations. This may take the form of seemingly legitimate specific arguments against a scientific claim. For example, chiropractors sought other explanations besides vaccine efficacy to account for the decline of infectious diseases.”

Question Scientists’ Motives and Integrity
“(O)ne fallback is to impugn the source. In the vaccination arena, this often takes the form of alleging financial conflicts of interest on the part of scientists, greed on the part of manufacturers, and complicity of government officials … In the evolution arena, scientists are often accused of being part of a conspiracy to undermine religion through educational systems.”

Magnify Disagreements Among Scientists and Cite Gadflies as Authorities
“In all scientific arenas, there is honest disagreement about the interpretation of evidence. However, these differences are deliberately inflated by denialists to imply a lack of consensus on more fundamental points, while often propounding the contradictory views of a few unqualified outliers.”

Exaggerate Potential Harm
“When the evidence contradicts a position, another recourse is to try to incite fear. No vaccine or medicine is 100 percent safe, without any risk of side effects. Chiropractors have long emphasized the potential side effects of vaccines, for example in a statement in Dynamic Chiropractic offering a litany of possible effects: ‘death, encephalopathy, demyelinating diseases, brachial neuritis, Guillain-Barré syndrome, infections generated by vaccine agents, anaphylaxis, subacute sclerosing panencephalitis, seizure disorder, optic neuritis, arthritis,’ and so on. However, they generally fail to acknowledge the serious consequences of infections that would be prevented by vaccination.”

Appeal to Personal Freedom
If fear is not persuasive, there is another fallback position that resonates strongly with Americans: the freedom of choice. The American Chiropractic Association leaned on this cherished notion when it established its official vaccination policy … Similarly, the teaching of evolution in public schools is viewed as an assault upon the religious freedom of those who oppose it.”

Reject Whatever Would Repudiate a Key Philosophy
“Once the courts have spoken, and the scientific evidence grows to be overwhelming, one might think that denialists would be out of plays. But there is one last line of defense that reveals the nucleus of denial: It is not that some scientific claim is untrue; it is that it is unacceptable in light of some philosophical commitment. The science must be summarily rejected.”

Read the rest in Scientific American.

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