Is global warming caused by humans? Is Barack Obama a Christian? Is evolution a well-supported theory?

You might think these questions have been incontrovertibly answered in the affirmative, proven by settled facts. But for a lot of Americans, they haven't. Among Republicans, belief in anthropogenic global warming declined from 52 percent to 42 percent between 2003 and 2008. Just days before the election, nearly a quarter of respondents in one Texas poll were convinced that Obama is a Muslim. And the proportion of Americans who believe God did not guide evolution? It's 14 percent today, a two-point decline since the '90s, according to Gallup.

What's going on? Normally, we expect society to progress, amassing deeper scientific understanding and basic facts every year. Knowledge only increases, right?

Robert Proctor doesn't think so. A historian of science at Stanford, Proctor points out that when it comes to many contentious subjects, our usual relationship to information is reversed: Ignorance increases.

He has developed a word inspired by this trend: agnotology. Derived from the Greek root agnosis, it is "the study of culturally constructed ignorance."

As Proctor argues, when society doesn't know something, it's often because special interests work hard to create confusion. Anti-Obama groups likely spent millions insisting he's a Muslim; church groups have shelled out even more pushing creationism. The oil and auto industries carefully seed doubt about the causes of global warming. And when the dust settles, society knows less than it did before.

"People always assume that if someone doesn't know something, it's because they haven't paid attention or haven't yet figured it out," Proctor says. "But ignorance also comes from people literally suppressing truth—or drowning it out—or trying to make it so confusing that people stop caring about what's true and what's not."

After years of celebrating the information revolution, we need to focus on the countervailing force: The disinformation revolution. The ur-example of what Proctor calls an agnotological campaign is the funding of bogus studies by cigarette companies trying to link lung cancer to baldness, viruses—anything but their product.

Think of the world of software today: Tech firms regularly sue geeks who reverse-engineer their code to look for flaws. They want their customers to be ignorant of how their apps work.

Even the financial meltdown was driven by ignorance. Credit-default swaps were designed not merely to dilute risk but to dilute knowledge; after they'd changed hands and been serially securitized, no one knew what they were worth.

Maybe the Internet itself has inherently agnotological side effects. People graze all day on information tailored to their existing worldview. And when bloggers or talking heads actually engage in debate, it often consists of pelting one another with mutually contradictory studies they've Googled: "Greenland's ice shield is melting 10 years ahead of schedule!" vs. "The sun is cooling down and Earth is getting colder!"

As Farhad Manjoo notes in True Enough: Learning to Live in a Post-Fact Society, if we argue about what a fact means, we're having a debate. If we argue about what the facts are, it's agnotological Armageddon, where reality dies screaming.

Can we fight off these attempts to foster ignorance? Despite his fears about the Internet's combative culture, Proctor is optimistic. During last year's election, campaign-trail lies were quickly exposed via YouTube and transcripts. The Web makes secrets harder to keep.

We need to fashion information tools that are designed to combat agnotological rot. Like Wikipedia: It encourages users to build real knowledge through consensus, and the result manages to (mostly) satisfy even people who hate each other's guts. Because the most important thing these days might just be knowing what we know.

Email clive@clivethompson.net.

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