In a short story published last October, “Sort by Controversial,” Scott Alexander imagines a Silicon Valley company that accidentally comes up with an algorithm to generate what it calls a “Scissor.” The scissor is a statement, an idea or a scenario that’s somehow perfectly calibrated to tear people apart — not just by generating disagreement, but by generating total incredulity that somebody could possibly disagree with your interpretation of the controversy, followed by escalating fury and paranoia and polarization, until the debate seems like a completely existential, win-or-perish fight.

When you start arguing with someone over a Scissor statement, Alexander’s narrator explains, “at first you just think they’re an imbecile. Then they call you an imbecile, and you want to defend yourself. … You notice all the little ways they’re lying to you and themselves and their audience every time they open their mouth to defend their imbecilic opinion. Then you notice how all the lies are connected, that in order to keep getting the little things like the Scissor statement wrong, they have to drag in everything else. Eventually even that doesn’t work; they’ve just got to make everybody hate you so that nobody will even listen to your argument no matter how obviously true it is.”

The twist in the short story comes with the narrator’s realization that several Scissors on the algorithm-generated list have happened already — the “ground zero mosque,” the N.F.L. and the national anthem, the Brett Kavanaugh confirmation hearings.