Is Facebook the enemy of truth and civic unity?

The defining political achievements of the past decade have favored tolerance and empathy - and online discussion has fuelled them all, argues Steven Johnson

Every new technology threatens to kill off some revered institution. But in the waning months of 2015, more than a few smart and tech-savvy commentators began suggesting a radical hypothesis: that the rise of social media threatened to deliver a death blow to civic consensus and even to truth itself.

"The news brims with instantly produced 'hot takes' and a raft of fact-free assertions," Farhad Manjoo observed in the New York Times. "The extremists of all stripes are ascendant, and just about everywhere you look, much of the internet is terrible."