By JESSE SINGALJAN. 11, 2018

My note: the genesis of #FakeNews, #tribalism

The idea that Mr. Pinker, a liberal, Jewish psychology professor, is a fan of a racist, anti-Semitic online movement is absurd on its face, so it might be tempting to roll your eyes and dismiss this blowup as just another instance of social media doing what it does best: generating outrage.

But it’s actually a worthwhile episode to unpack, because it highlights a disturbing, worsening tendency in social media in which tribal allegiances are replacing shared empirical understandings of the world.

What social media is doing is slicing the salami thinner and thinner, as it were, making it harder even for people who are otherwise in general ideological agreement to agree on basic facts about news events.