As the national argument about the killing of Trayvon Martin continues, the people who sympathize with Martin’s killer keep bringing up this point: Yes, it’s racist to be suspicious of young black men for no reason beyond their youth, blackness, and manhood – but given the crime statistics, isn’t that reasonable?

Before I start addressing that question, I need to tell you that I spent nearly six years as a graduate student at the University of Chicago, which at the time (the Eighties) was an oasis of middle-to-upper class, integrated-but-mostly-white America, surrounded by a predominantly black ghetto. (Since then, the siege has been lifted by an army of gentrifiers marching south down Michigan Avenue from the Magnificent Mile.) Just about everybody I knew had been a crime victim at some time or other. Personally, I was never threatened with bodily harm, but I had a car stolen once, and my bike was stolen out of my girlfriend’s car.

Like just about all my classmates, I developed a special awareness of young black men (despite the fact that one of them was a fellow grad student whose office was just down the hall from mine). I spotted them at a great distance, and might cross the street if I couldn’t figure out what they were up to.

Sometimes, my wariness turned out to be so ridiculous I had to laugh at myself. Once, I remember, closer inspection showed that the “young men” were more like 12, and the mysterious objects they were carrying were musical instruments. What they had done to raise my suspicion was mill around on the sidewalk waiting for someone to unlock the door to their recital.

Clearly I had been just minutes from death.

Prejudice. During those years I came to understand that there is a difference between prejudice and bigotry. Prejudice is exactly what it sounds like: a pre-judgment, an opinion that you have before you learn any specific facts about the situation. Your prejudices may be justified or unjustified, they may save your life or create dangerous confrontations out of nothing. But you can’t help having some, because the human mind constantly creates expectations of the near future. A well-trained mind will base those expectations on facts if it has some, but if it doesn’t it will expect something anyway.

So anybody who tells you that they’re not prejudiced is blowing smoke. Everybody is prejudiced. Your prejudices may or may not be racial (though if you grew up in America they probably are), but if you’re dropped into a situation you know nothing about, you’ll react to it somehow, based on some pre-judgment.

Bigotry. Prejudice is universal, but bigotry is more sinister; it’s an attachment to your prejudices. Sometimes people fall in love with their prejudices to the point that they don’t want to know the facts. If confronted with facts that conflict with their prejudices, they will ignore them and make up new facts.

So imagine that you’re a white admissions officer at an Ivy League college. Your mail today includes two applications, one from a white student at an upscale suburban high school, the other from a black student at a ghetto school. If your snap expectation is that the white kid will have higher SAT scores than the black kid, that’s prejudice.

But what you do next determines whether or not you’re a bigot. When the test scores become available, do you look? If it turns out that the ghetto kid’s scores are higher, do you accept them or do you assume something funny must have happened? Do you scour the application looking for evidence that he’s not really that smart?

If you’re not a bigot, you look at the scores and change your opinion accordingly. And the next time you get an applicant from the same ghetto high school, your prejudice will be a little less sure of itself.

Everybody has prejudices. But reasonable people hold those prejudices lightly, re-judge a situation when facts become available, and continually re-train their prejudices to be more accurate.

Zimmerman and Martin. OK, now imagine you’re George Zimmerman doing your Neighborhood Watch thing. You spot a black teen you’ve never seen before, and it sets your alarm bells ringing. That’s prejudice, but so what? Maybe it’s got some reasonable basis.

When I listen to Zimmerman’s 911 call, though, I hear bigotry. He can’t point to a single suspicious thing Martin is doing, but he’s trying hard to interpret anything he sees so that it will confirm his prejudice. Mostly, he reports judgments rather than facts. Martin is “up to no good”, he “looks like he’s on drugs” and so on. (Actually, we know, Martin is staying with someone in the neighborhood, has been to the store and is on his way back. He’s talking to his girlfriend on the phone, which might be why he’s in no hurry.) “They” always get away with it. And so on, right up to the much-debated “fucking coons” comment.

So anyway, I’m willing to cut Zimmerman some slack for his original suspicions. Who knows, maybe I’d have been suspicious too. But what should he have done then?

How about this: No gun, no 911 call. You just walk up to Martin with a smile and say, “Hi, I’m with the Neighborhood Watch. I didn’t recognize you so I thought I’d introduce myself. I’m George Zimmerman and I live over on XYZ Street. Do you live around here or are you visiting someone?” Maybe you get an answer and go on your way. Maybe Martin tells you to go fuck yourself. Maybe he runs. Maybe (for all you know before you ask) he really is the thug you’re afraid of, and he pulls a handgun out of his hoody and starts blasting.

I think that’s the chance you have to take. If you’re not brave enough to take it, you’ve got no business being out there in the first place. Stay home, lock your door, and let somebody else watch the neighborhood.

When is racism reasonable? Finally, we come to the question of whether suspicion of blacks is a reasonable prejudice in the first place. After my Trayvon Martin post last week, a reader emailed me a link to FBI crime statistics broken down by race. If that’s where your analysis ends, being suspicious of black men looks reasonable.

But chaunceydevega on Daily Kos went a little further and challenged the basis of those statistics. How much black crime do police find simply because they are looking for it?

As compared to white neighborhoods, black and brown communities are also subject to more severe surveillance and aggressive police tactics.

And how often is a white let off with a warning where a black might be charged? (It seems particularly ironic to quote crime statistics when discussing Martin and Zimmerman. So far, Zimmerman killing Martin doesn’t register as a crime. How many similar cases don’t draw national attention and so never show up in crime statistics?)

Sometimes when illegal drug use is measured in ways unrelated to the criminal justice system, whites turn out to be at least as guilty as blacks and Hispanics. Yet, they are arrested, charged, convicted, and jailed far less often. Maybe that’s true of other crimes as well.

So where does that leave us? In my Chicago days, I doubt chaunceydevega’s arguments would have convinced me. (Even though I never actually saw the people who stole my car. For all I know, Saul Bellow and Bruno Bettelheim took it for a midnight joy ride. Their alibis were never checked.) I thought I knew what I thought I knew, so young black men scared me.

As any white-knuckle flier can testify, telling scared people not to be scared usually doesn’t work very well, even if you have statistics. Or reason to challenge the prevailing statistics.

Here’s my hope: Maybe encouraging scared people to be brave works a little better. Whether you think your prejudices are justified or not, keep your eyes open and try not to give in to fear too quickly. Hold your prejudices lightly. Watch carefully for evidence that contradicts them.

Otherwise you might end up running from 12-year-old musicians. Or shooting Trayvon Martin.