Social Media Is Making Us Dumber. Here’s Exhibit A.

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.

.. 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.

.. the pernicious social dynamics of these online spaces hammer home the idea that anyone who disagrees with you on any controversial subject, even a little bit, is incorrigibly dumb or evil or suspect. On a wide and expanding range of issues, there’s no such thing as good-faith disagreement.

.. The clip was deeply misleading. If you watch the whole eight-minute video from which it was culled, it’s clear that Mr. Pinker’s entire point is that the alt-right’s beliefs are false and illogical — but that the left needs to do a better job fighting against them.

.. Mr. Pinker saying he agrees with the other panelists (two journalists and a lawyer) that “political correctness has done an enormous amount of harm in the sliver of the population that might be — I wouldn’t want to say ‘persuadable,’ but certainly whose affiliation might be up for grabs.”

.. when members of this group encounter, for the first time, ideas that he believes to be frowned upon or suppressed in liberal circles — that most suicide bombers are Muslim or that members of different racial groups commit crimes at different rates — they are “immediately infected with both the feeling of outrage that these truths are unsayable” and are provided with “no defense against taking them to what we might consider to be rather repellent conclusions.”

.. while at the moment it’s true that, according to the Bureau of Justice Statistics, the homicide rate is higher for blacks than for whites, that doesn’t really tell us anything about a group of people since at different times in history, different groups have had elevated crime rates — at one point Irish-Americans did. By that same token, he says, “the majority of domestic terrorism is committed by right-wing extremist groups,” not Muslims.

.. Steven Pinker will be O.K. A fleeting Twitter blowup isn’t going to bruise his long and successful career as a public intellectual. But this is happening more and more — and in many cases to people who don’t have the standing and reputation he does.

.. It’s getting harder and harder to talk about anything controversial online without every single utterance of an opinion immediately being caricatured by opportunistic outrage-mongers, at which point everyone, afraid to be caught exposed in the skirmish that’s about to break out, rushes for the safety of their ideological battlements, where they can safely scream out their righteousness in unison. In this case: “Steven Pinker said the alt-right is good! But the alt-right is bad! We must defend this principle!”

This is making us dumber.