Common wisdom holds that half of everything you read on the internet is a lie. Whether that’s true or not, President Barack Obama has had enough.

Speaking from the White House Frontiers Conference in Pittsburg on Thursday, President Barack Obama told the crowd at Carnegie Melon University that the amount of false content on the internet is its ironic Achilles heel. While the internet has given us vast troves of knowledge, it’s hard to tell when that information is false. What we need, he said, is a way to measure ‘truthiness.’

(Yes, he used the word created by Stephen Colbert in 2010. “I wanted a silly word that would feel wrong in your mouth,” Colbert said at the time.)

Obama, though, was using the word sincerely. He wants the Web to be truthier. “We’re going to have to build within this Wild Wild West some kind of curating function that people can agree to,” Obama said.

His particular concern was the vast web of misinformation on the web about climate change.

“Everything on the internet looks like it might be true,” he said. “Everything suddenly becomes contested.”

Obama didn’t spell out how exactly he’d like to defeat the internet rumor mill. It would be easy for “fact-checking” the web to start looking an awful lot like government censorship. Take China, where authorities have taken to deleting speculation, unverified commentary and false information posted online, a practice that is widely viewed as just another method of the government’s dictatorial censorship.

While light on details, Obama said that censorship was not what he had in mind.

“The answer is obviously not censorship, but in creating places where we can say that the information is reliable,” he said. “There has to be some sort of way we can sort through information that passes some sort of truthiness test.”

Others before Obama have, of course, taken a stance against misinformation, but the web of internet lies has proven hard to untangle. Last year, Facebook announced that it would label suspected fake news with a warning and reduce the appearance of posts with misinformation in the News Feed. But instead of stamping out all the misinformation circulating on Facebook, Facebook is now instead dealing with an uptick in its spread. As the Washington Post recently reported, “Facebook has repeatedly trended fake news since firing [the] human editors” who used to curate its Trending Topics.

Google also announced Friday that it will point out fact-checking articles in Google News to users who search for a news topic:

But despite all the fact checking in the world, lies from presidential candidate Donald Trump still circulate enthusiastically online. Fake news, it turns out, can be awfully hard to discredit.