THE PERILS OF DARWINIAN THOUGHT:

Widening class distances produce class prejudice, classism. This is a prejudice based on visceral attitudes about competence. People in the "respectable" class have meritocratic virtues: executive function, grit, a capacity for delayed gratification. The view about those in the untouchable world is that they are short on these things. They are disorganized. They are violent and scary. This belief has some grains of truth because of childhood trauma, the stress of poverty and other things. But this view metastasizes into a vicious, intellectually lazy stereotype. Before long, animalistic imagery is used to describe these human beings.

This class prejudice is applied to both the white and black poor, whose demographic traits are converging. But classism combines with latent and historic racism to create a particularly malicious brew. People are now assigned a whole range of supposedly underclass traits based on a single glimpse at skin color.

During the civil-rights era there was always a debate about what was a civil-rights issue and what was an economic or social issue. Now that distinction has been obliterated. Every civil-rights issue is also an economic and social issue. Classism intertwines with racism.

It's often said after events like Ferguson that we need a national conversation on race. That's a bit true. We all need to improve our capacity for sympathetic understanding, our capacity to imaginatively place ourselves in the minds of other people with experiences different from our own. Conversation can help, though I suspect novels, works of art and books like Claude Brown's "Manchild in the Promised Land" work better.

But, ultimately, we don't need a common conversation; we need a common project. If the nation works together to improve social mobility for the poor of all races, through projects like President Obama's My Brother's Keeper initiative, then social distance will decline, classism will decline and racial prejudice will obliquely decline as well.

In a friendship, people don't sit around talking about their friendship. They do things together. Through common endeavor people overcome difference to become friends.

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