Years ago I was blathering to a science-writing class at Columbia Journalism School about the complexities of covering psychiatric drugs when a student, who as I recall had a medical degree, raised his hand. He said he didn't understand what the big deal was; I should just report "the facts" that drug researchers reported in peer-reviewed journals.

Journalist Chris Mooney argues that the views of anti-vaccine activist Jenny McCarthy can be dismissed because she is not a "scientific expert," but by this logic the views of journalists like Mooney should also be discounted.

I was so flabbergasted by his naivete that I just stared at him, trying to figure out how to respond politely. I had a similar reaction when I spotted the headline of a recent essay by journalist Chris Mooney: "This Is Why You Have No Business Challenging Scientific Experts."

Mooney is distressed, rightly so, that many people reject the scientific consensus on human-induced global-warming, the safety of vaccines, the viral cause of AIDS, the evolution of species. But Mooney's proposed solution, which calls for non-scientists to yield to the opinion of "experts," is far too drastic.

In support of his position, Mooney cites Are We All Scientific Experts Now?, a book by sociologist of science Harry Collins. Rejecting the hard-core postmodern view of science as just one of many modes of knowledge, Collins argues that scientific expertise is uniquely authoritative. Here's how Mooney puts it:

"Collins carefully delineates between different types of claims to knowledge. And in the process, he rescues the idea that there's something very special about being a member of an expert, scientific community, which cannot be duplicated by people like vaccine critic Jenny McCarthy… Read all the online stuff you want, Collins argues—or even read the professional scientific literature from the perspective of an outsider or amateur. You'll absorb a lot of information, but you'll still never have what he terms 'interactional expertise,' which is the sort of expertise developed by getting to know a community of scientists intimately, and getting a feeling for what they think. 'If you get your information only from the journals, you can't tell whether a paper is being taken seriously by the scientific community or not,' says Collins. 'You cannot get a good picture of what is going on in science from the literature,' he continues. And of course, biased and ideological Internet commentaries on that literature are more dangerous still. That's why we can't listen to climate change skeptics or creationists. It's why vaccine deniers don't have a leg to stand on."

Mooney is hardly the only person insisting "You Have No Business Challenging Scientific Experts." Versions of this assertion constantly pop up in debates over hot-button scientific issues. Defenders of supposedly canonical views of global-warming, genetically modified foods and vaccines dismiss non-expert dissidents. Just last week, a friend and fellow journalist mocked meteorologists who doubt climate change--because they're meteorologists, not climate scientists.

The irony is that the "No Business Challenging Scientific Experts" argument applies not only to activists like Jenny McCarthy but also to journalists like Mooney and me. After all, we journalists are "outsiders" and "amateurs," especially compared to the scientists whose work we cover, so how dare we second-guess them?

I agree with Mooney and Collins on some fundamental issues. I'm not a Kuhn-style postmodernist, the kind who puts scare quotes around "truth" and "knowledge." Science is a uniquely potent method for discovering how nature works, and it gets some things right, once and for all: the atomic theory of matter, the (basic) big bang theory, evolution by natural selection, DNA-based genetics.

Also, I give great weight to consensus and credentials, which provide a fast and dirty way to decide whether a claim should be taken seriously. One of the reasons I doubted that "cold fusion" had been achieved in the late 1980s was that scientists claiming to have observed room-temperature fusion tended to be at second-rate institutions; scientists at top-tier institutions could not replicate the results.

But the history of science suggests—and my own 32 years of experience reporting confirms—that even the most accomplished scientists at the most prestigious institutions often make claims that turn out to be erroneous or exaggerated.

Scientists succumb to groupthink, political pressures and other pitfalls. More than a half century ago, Freudian psychoanalysis was a dominant theory of and therapy for mental disorders. The new consensus is that mental illnesses are chemical disorders that need to be chemically treated.

This paradigm shift says more about the financial clout of the pharmaceutical industry--and its control over the conduct and publishing of clinical trials--than it does about the actual merits of antidepressants and other drugs. That's why I was so stunned when that Columbia student said peer-reviewed "facts" could speak for themselves.

Here's another example related to the work of Harry Collins, who inspired Mooney's column. Collins's respect for scientific expertise stems in part from his decade-long immersion in the field of gravitational-wave studies. Gravitational waves made headlines a year ago, when astrophysicists overseeing an experiment called Background Imaging of Cosmic Extragalactic Polarization 2 announced they had discovered the "first direct evidence" of inflation, a 35-year-old theory of cosmic creation. According to the group, gravitational waves triggered by inflation had distorted the big bang's microwave afterglow in measurable ways.

No less an authority than Stephen Hawking declared that the BICEP2 results represented a "confirmation of inflation." I nonetheless second-guessed Hawking and the BICEP2 experts, reiterating my long-standing doubts about inflation. Guess what? Hawking and the BICEP2 team turned out to be wrong.

I'm not bragging. Okay, maybe I am, a little. But my point is that I was doing what journalists are supposed to do: question claims even if--especially if—they come from authoritative sources. A journalist who doesn't do that isn't a journalist. He's a public-relations flak, helping scientists peddle their products.

And it's precisely because we journalists are "outsiders" that we can sometimes judge a field more objectively than insiders. Mooney surely agrees with me on this. There is an enormous contradiction buried within his "No Business Challenging Scientific Experts” argument. He obviously doesn't want us to yield to every scientific consensus, only to those that he, Mooney, deems credible.

Google is reportedly working on algorithms for evaluating the credibility of websites based on their factual content. But there will never be a foolproof way to determine a priori whether a given scientific consensus is correct or not. You have to do the hard work of digging into it and weighing its pros and cons. And anybody can do that, including me, Mooney and even Jenny McCarthy.

By the way, I think McCarthy grossly overstates the dangers of vaccines--I'm glad my kids got vaccinated--but I, too, have concerns about some vaccines.

Update: I hoped this column would jumpstart a conversation about authority in science, and it has. Some science-y folks have emailed me comments that I thought worth posting here. John Horgan

From Corey Powell, old friend, distinguished science writer, former editor-in-chief of Discover, whom I quote dissing meteorologists above:

Just to be clear--my argument wasn't that meteorologists lack the ability (or worse, the right) to challenge climate studies. My argument is that they suffer from a false sense of expertise that makes them think they can speak with authority without bothering to really understand the other field. It's a lazy kind of arrogance. This often happens when scientists get taken with their own brilliance and think, hey, I know about genes, I'll bet I really understand consciousness or solar energy or alien life or whatever. Of course almost everybody with a healthy ego does this to some extent, fantasizing that they are experts at something they know nothing about. But with the meteorologists (as a case study) there is a more specific type of confusion, and a more specific type of unearned claim to authority. I liked our quick Twitter exchange about the role of curiosity vs. gall. Both of them are about questioning everything, including expert testimony & peer-reviewed truths. I take a bit longer to reach full boil when I come across BS, but I get there eventually. Corey Powell

From Matthew C. Nisbet, Associate Professor of Communication Studies, Northeastern University:

In American political culture, liberal commentators and advocacy journalists tend to put scientists on a sacred pedestal and are often funded to do so and attract audiences by doing so.

Climate scientists especially are not only portrayed as innocent priests and powerful seers but also as vulnerable martyrs that must be protected and defended against any criticism, even when such criticism comes from social scientists or specialist journalists who are speaking from the perspective of their own expertise.

On complex, wicked problems like climate change, the only way we identify paths forward and opportunities for political cooperation is through healthy disagreement. Criticism helps widen the menu of options that might be pursued and calls attention to faulty assumptions.

Another example of the need for informed criticism of experts, as I discussed in a recent co-authored paper, is the work of the journalist Gary Taubes who helped spur scientists to reconsider their assumptions about the linkages between diet, obesity, and other negative health outcomes.

From David Gorski, physician and blogger at "Science-Based Medicine":

Gorski critiques my column in a post titled "On the 'right' to challenge a medical or scientific consensus." Like Mooney--and like me!--Gorski has concerns about the propagation of pseudoscience, but his piece is one long exercise in begging the question. That is, he implicitly assumes what he is attempting to argue. He writes: "It’s… important to remember that there are scientific consensuses and then there are scientific consensuses. What I mean is that some consensuses are stronger than others, something Horgan seems to ignore or downplay." The primary point of my piece is that there is often no way to know whether a consensus is legitimate or not; scientists often claim more certainty than is merited, and hence outsiders are justified in questioning scientists' proclamations. Gorski's own field, oncology, offers an excellent example of this problem. For decades, the consensus was that cancer should be combatted with frequent testing and aggressive treatment, but now that consensus is unraveling. "In the end," Gorski concludes, what Horgan seems to be arguing is that we should take pseudo-expertise seriously." Actually, I am arguing that the public should be wary not only of pseudoscientific charlatans peddling homeopathy and "energy healing" (Gorski's examples) but also of genuine experts like Gorski.

Further Reading, Viewing, Listening:

"Sociologist Steve Fuller: Scientists Aren’t More Rational Than the Rest of Us."

"Journalist Chris Mooney Is Wrong, Again, About Experts."

My Bloggingheads.tv chat with anonymous blogger "Neuroskeptic," an expert who displays admirable skepticism toward his own field.

My chat about this column on New Hampshire Public Radio.

"Advice to Young Science Writers: Think Like Chomsky."

A Dig through Old Files Reminds Me Why I’m So Critical of Science.”

What Should We Teach When We Teach Science Communication?

Should the Humanities Embrace Scientism? My Postmodern Response to Pinker’s Patronizing Plea.”

Photo: Wikimedia Commons, https://www.flickr.com/photos/gamerscore/144446661/.