The race-and-IQ debate is back. The latest round started a few weeks ago when Harvard geneticist David Reich wrote a New York Times op-ed in defense of race as a biological fact. The piece resurfaced Sam Harris’ year-old Waking Up podcast interview with Charles Murray, co-author of The Bell Curve, and launched a Twitter debate between Harris and Vox’s Ezra Klein. Klein then responded to Harris and Reich in Vox, Harris fired back, and Andrew Sullivan went after Klein.