The notion of “centrism” aims to stake out ideological ground between the extremes of contemporary left and right. But the centrism-extremism distinction fails to get at essential differences. Finding those means going deeper into Western intellectual history. Ideologies are like organisms, and tracing their origins back to common ancestors starts with a system of classification based on careful observation and comparison. Our goal is ultimately to unravel the DNA of ideological movements. However before DNA, you need Darwin and Linnaeus. So let’s start with some actual specimens of “centrism.” Here I mean ‘neo-Enlightenment’ thinkers like Sam Harris, Steven Pinker, George Will, Maajid Nawaz, Scott Alexander, Christina Hoff Sommers, Christopher Hitchens, Bret Stephens. And their ideas have a clear line of descent from core Enlightenment values, which are under attack from factions on the left and right today. Anti-Enlightenment ideas are springing up from the left in: attempts to shut down speech in the academy, increasing toleration of violence in “anti-fascist” and “anti-racist” protests, and rhetorical strategies aimed at opponents’ racial or sexual attributes rather than …