Purposeful Agnosticism

Allan Bradt's book The Cigarette Century: The Rise, Fall, and Deadly Persisitence of the Product that Defined America describes how the industry successfully defended itself when the causal relationship between smoking and lung cancer became clear in the early 1950s.

From a review by Jonathan Miles in The New York Times Book Review:

"Faced with damning evidence, the industry devised a cagey defense: rather than denying the harms of smoking, it insisted there were "two sides" to the story, and corralled skeptical scientists-- perennially available on any subject-- to rebut or at to least cast doubt on the medical consensus. Journalists were urged to consider "fairness" and "balance" in covering the invented "controversy." The industry's pubic relations arm, Brandt writes, was "adept at taking a single dissenter and assuring widespread media coverage of his views." This purposeful agnosticism, which served the tobacco industry well, will sound eerily familiar to anyone following th global warming "debate"-- another case in which a few pedigreed skeptics, whose views align with those of a powerful ndustry, are framing consensus as controversy."

The same strategy in which doubt is fact has been used in other so-called debates, such as creationism, gun control, and holocaust revisionism. It also helps to leverage American first principles to defend the indefensible, for example, freedom of religion for creationism, the second amendment for mass gun ownership, and freedom of the press for holocaust revisionism.