As he prepares to tell the story of his birth, Trevor Noah explains why being mixed-race in apartheid South Africa was so difficult—it was literally against the law, and he could be taken away from his mother because of his different skin tone—and then, more theoretically, why the apartheid regime had to outlaw race-mixing in order to keep its “divide and conquer” strategy working. In short, he shows that racism only works if racists can convince people that there are essential and unbridgeable differences among races, and that people want to be apart and do better when they don’t interact…