John Tierney has a fascinating article about opinion "cascades" among hard scientists. He writes about a small group of eminent scientists who dared to buck a powerful consensus on a scientific subject that is deeply entwined with U.S. government public policy:
But the report’s authors were promptly excoriated on Capitol Hill and in the news media for denying a danger that had already been proclaimed ....The scientific issue that Tierney writes about is the effects of dietary fat on mortality (apparently there's no scientific correlation between the two), but the parallels with current debates about global warming are striking.
The scientists, despite their impressive credentials, were accused of bias because some of them had done research financed by ... industry. And so the informational cascade morphed into what the economist Timur Kuran calls a reputational cascade, in which it becomes a career risk for dissidents to question the popular wisdom ....
[A prominent senator] subsequently asked [one of the scientists] at a hearing to reconcile his skepticism with a survey showing that the ... recommendations were endorsed by 92 percent of [leading experts].
“Senator ... I recognize the disadvantage of being in the minority,” Dr. Ahrens replied. Then he pointed out that most of the [experts] in the survey were relying on secondhand knowledge because they didn’t work in this field themselves.
“This is a matter,” he continued, “of such enormous social [and] economic ... importance that it must be evaluated with our eyes completely open. Thus I would hate to see this issue settled by anything that smacks of a Gallup poll.” Or a cascade.
Not that I'm exactly a global-warming skeptic. Having no knowledge whatsoever about climate science, I'm pretty much stuck with relying on the scientists to be good scientists. And Tierney's article shows very clearly that scientists are as liable to form opinion "cascades" as anyone else.
So I get a little twitchy when I hear people say stuff like "the debate is over" about climate science. In real science, the debate is never over. There's always something new to be learned, and every great scientific paradigm should have its opportunity to be tested and overturned.
Good scientists should welcome that kind of criticism and scrutiny, or else they may someday find themselves playing the Inquisition to some other scientist's Galileo.