Let's talk about trolls: The rise of digital media over the last 20 years has given birth to a new phenomenon, online reader comments. Usually found at the end of newspaper or magazine stories online -- perhaps on this very column you're reading -- comments often drive journalists and their readers crazy with misinformation, ugly vitriol and out-of-left-field accusations. This week, Popular Science magazine said it would no long allow comments, calling them a "grotesque reflection" of the media culture.

Do reader comments damage democracy? Even if they do, is it possible to put them aside? Joel Mathis and Ben Boychuk, the RedBlueAmerica columnists, debate the issue.

MATHIS: Here's how the 21st century differs from its predecessors: The audience gets to talk back.

That can be enormously frustrating for writers, reporters and editors who still aspire to be gatekeepers to public discourse. Many of those professionals still long for a time when the public's voice was largely limited to a few well-selected letters each day on a newspaper's op-ed page. It was a less anarchic time, certainly, and the contents of those letters were much less mean than one will normally find under your average newspaper opinion column.

In truth, the best comments sections -- like society itself -- offer both a large degree of freedom, as well as a guiding hand to sort out the racists, trolls, jerks, and other riff-raff who desire less to debate issues and exchange ideas and more to cause as big a mess as possible. They are vandals and bomb throwers (metaphorically speaking, of course). In real life, such folks are usually removed from polite company with great haste.

Such a strategy has helped The New York Times cultivate ever-better online comments, while blogger Ta-Nehisi Coates has found his writing and thinking sharpened by the daily conversation with his readers. The very worst -- like Philly.com, in Philadelphia where I live -- appear to be untouched by any editor most days, except when editors there turn off comments on a story rather than have the vitriol go public.

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"Guiding hands" are also known as editors, though, and in this day of tight-tighter-tightest belt-tightening among media companies, paying a person to help create a great comments section is an expense most publishers and editors won't shoulder.

Which is why so many comments sections appear to be rude, lawless places.

Popular Science is shutting off comments because, at heart, it doesn't want to see its reporting challenged. Even in a science setting, that's not wise.

There are ways to cultivate the best conversations with the best participants. It's not a free-for-all or nothing. But you do have to let the audience talk back.

BOYCHUK: Popular Science made the right decision to end comments, but for the strangest of reasons.

If the editors said anonymous commenters debased the quality of discourse at the site with their silly snark, many readers would have grumbled but they likely would have understood. Besides, people have no shortage of online outlets where they may snark freely.

Instead, Suzanne LaBarre, PopSci's online content editor, explained that readers were trying to change public opinion with malicious aforethought. And that sort of behavior simply could not be tolerated.

"A politically motivated, decades-long war on expertise has eroded the popular consensus on a wide variety of scientifically validated topics," Labarre wrote. "Everything, from evolution to the origins of climate change, is mistakenly up for grabs again." It should go without saying that experts don't know everything, and that "popular consensus" has no place in science. Alas, so much of the obvious needs repeating these days.

Our discourse is a mess and most online comments are probably a waste of time. But the consensus on both of those propositions -- and much else -- is far from clear.

A century ago, the consensus among reputable scientists held that the theory of continental drift was "utter damned rot" and anyone who "valued his reputation for scientific sanity" would reject the idea. Today, continental drift is taught as basic geography.

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Today, we're also told that 97.1 percent of scientists agree on the causes of global climate change. Well, the latest report from the United Nations' Intergovernmental Panel on Climate Change is out, and the forces of "consensus" have a problem.

Turns out, the global warming that so many computer models predicted hasn't occurred in the past 15 years. Scientists disagree why, though many still insist man-made carbon emissions are likely to cause catastrophic problems.

If the evidence doesn't bear out the models, then the models are wrong. Maybe the hypothesis is wrong, too. And if the hypothesis is wrong, maybe we should think twice before letting experts reshape the way we live. Maybe the consensus is "utter damned rot" -- and more people should say so.

Ben Boychuk is associate editor of the Manhattan Institute's City Journal. Joel Mathis is a contributing editor to Philadelphia Magazine.